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HIS
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BRIDGE ENGINE
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••• -•-
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• • • ••
• • • •
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• •••••• *•*
HISTORY
OF
BRIDGE ENGINEERING
BY
HENRY GRATTAN TYRRELL, C. E.
Graduate of Toronto University
Bridge and Structural Engineer
Author of
"Mill Building Construction" (1900)
"Concrete Bridges and Culverts*'
"Mill Buildings" (1910), etc., etc.
PUBLISHED BY THE AUTHOR
CHICAGO, 1911
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• • • • ••••_%••
••• • •• • ••• • . • • • •••
Copyright 1911
By
Henry Grattan Tyrrell
CHICAGO, ILL.
THE G. B. WILLIAMS CO., PRINTERS
1911
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PREFACE
PROFICIENCY in any art or science is not attained until its
history is known. Many a student and a designer finds, after
weary hours of thought, that the problems over which he
studied were considered and mastered by others, years or
centuries before, perhaps with better results than his own.
History is very fully taught in Schools of Architecture, but
up to the present, very little time or thought has been given in the
Engineering Schools to the History of Engineering, which is cer-
tainly quite as worthy of attention. The absence of such courses
is generally ascribed to insufficient time and the dearth of litera-
ture. A need for this book is therefore evident, especially as there
is at present no other on the subject in the English language.
A noted writer has said that "the most remarkable trend of
modern thought notwithstanding the effervescent boastfulness of
the present century, is an appreciation of the work done by those
who have gone before. During this busy age of specialists in every
profession, the active thinking men that can spare the time from
bread winning, are engaged more or less in looking backward. Ret-
rospection is as surely the watchword of the modern philosopher
as was introspection of his mediaeval brother. In the world of
applied science no less than in the domain of ideas, we must reverse
cur mental telescopes if we would measure at its full the glory of
human achievement. To aid in our investigations, the excavator,
tie archaeologist, the ethnologist and the philosopher are constantly
at work. In our longings to complete the history of the develop-
ment of any art we must look to them to supply the missing link
in the chain of human activities that connect us with the past."
An effort has been made to condense the subject, which might
easily fill a thousand pages, into a small volume coniparing in size
with other text books, and for this reason, general references were
prohibitive. As many quotations have been made from the writer's
work, often without credit, footnotes refer to a few of the original
articles. A hundred or more views of ancient and mediaeval bridges
were crowded out because of insufficient space, and only a few il-
lustrations are included from a collection of about two thousand,
[31
222580
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PREFACE.
preference being given to recent types which are the most useful
for present needs. While the book is essentially historical, it
should be useful also for reference, especially in the selection of
economic types, and the preparation of comparative designs and
estimates. To assist in finding names and subjects, the more im-
portant ones are printed in black type.
Movable bridges are not included, as they are so different
from others. They may be better considered as machines,* and
should be designed as such, with parts proportioned for service as
found desirable from long observation and experience.
Much difficulty was experienced in the preparation of the
earlier chapters because of the conflicting accounts of ancient
writers and the difficulty in securing accurate dates. A large part
of the volume is necessarily devoted to comparatively recent his-
tory, as the majority of bridges have appeared since 1760 when
bridge building was revived in France under the direction of Perro-
net. Nearly all the great metal bridges of the world are the product
of little more than half a century, since Mr. Whipple's investiga-
tions in 1847.
Most of the illustrations are from original diagrams, sketches
and photographs, though a number are from the Engineering News,
Engineering Record, and other technical papers and reports. I
have been assisted in publishing this history by my wife, Maude K.
Tyrrell, and especially so in making illustrations, and translations
from foreign languages.
H. G. TYRRELL.
Evanston, Illinois, February, 1911.
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TABLE OF CONTENTS
Pave
Chapter I Egyptian, Babylonian and Persian Bridges .. . 15
Chapter II Roman Bridges 23
Chapter III Mediaeval Bridges 39
Chapter IV Renaissance Bridges / 59
Chapter V Modern Stone Bridges 72
Chapter VI Pontoon Bridges 104
Chapter VII Aqueduct Bridges 112
Chapter VIII Wooden Bridges 121
Chapter IX Cast Iron Bridges 151
Chapter X Simple Truss Bridges 164
Chapter XI Tubular and Plate Girder Bridges 195
Chapter XII Suspension Bridges 202
Chapter XIII Cantilever Bridges 257
Chapter XIV Wrought Iron and Steel Arches 309
Chapter XV Trestles and Viaducts 365
Chapter XVI Solid Concrete Bridges 396
Chapter XVII Reinforced Concrete Bridges 407
[5]
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- • • • •
•• • : •: • : ••• • •
6 CONTENTS.
LIST OF ILLUSTRATIONS
No.
Alexander III Bridge, Paris, Frontispiece.
1. Bridge at Assos, Greece.
2. Bridge in Fayal, Azores.
3. Dizful Bridge, Persia.
4. Pons Sublicius, Rome.
5. Ponte Rotto, Rome.
6. Pons Aemilius, Rome.
7. Pons Fabricius, Rome.
8. Caesar's Bridge over the Rhine.
9. Bridge at Rimini, Italy.
10. Bridge at Alcantara, Spain.
11. Trajan's Bridge over the Danube.
12. Vicenza Bridge, Italy.
13. Drin River Bridge, Turkey.
14. St. Chamas Bridge.
15. Saintes Bridge over the Charente,
16. Valentre Bridge over the Lot at Cahors.
17. Devil's Bridge at Lucca.
18. Spoleto Aqueduct Bridge.
19. Ponte Vecchio, Florence. •
20. Arch at Trezzo Italy.
21. Alcantara at Toledo.
22. St. Martin's Bridge at Toledo.
23. Karlsbrucke, Prague.
24. Croyland Bridge, England.
25. Old lojndon Bridge.
26. Auld Brig o' Ayr.
27. Ronda Viaduct.
28. Rialto, Venice
29. Kintai River Bridge at Ikakuni, Japan.
30. Srinagar Bridge, India.
31. Auteil Viaduct, Paris.
32. Luxemburg Stone Arch, Austria.
33. Plauen Bridge, Prussia.
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CONTENTS.
UST OF ILLUSTRATIONS— Contiiiaed
No.
34. London Bridge.
35. Grosvenor Bridge.
36; High Bridge, New York City.
37. Cabin John, Washington.
38. Echo Bridge, Newton, Mass.
39. Hartford Memorial.
40. Stoney Brook Bridge, Boston.
41. Entrance to Forest Hills Cemetery.
42. Weed Street, Chicago.
43. Cologne Bridge of Boats.
44. Pont du Gard, France.
45. Aqueduct of Bourgas near Constantinople.
46. Palladio Truss.
47. Palladio Truss.
48. Palladio Truss.
49. Bassano Bridge at Brenta.
50. Wood Bridge over the Kandel.
51. Schauflfhausen Bridge.
52. Waterford Bridge.
53. Mellingen Bridge.
54. Bridge over the Delaware at Trenton.
55. Permanent Bridge, Philadelphia.
56. Woodsville Bridge.
57. Mohawk River Bridge.
58. Columbia Bridge over the Susquehanna.
59. Colossus over the Schuylkill at Fairmont.
60. The Town Truss.
61. Wood Bridge over the Clyde at Glasgow.
62. Patapsco River Bridge at Elysville, Md.
63. The Howe Truss.
64. The Pratt Truss.
65. Willington Dean Bridge.
66. Bridge over the Connecticut at Windsor Locks.
67. Utica and Syracuse Railroad Bridges.
68. Bamboo Bridge in Java.
69. William TyrrelKs Truss Model.
70. Ladykirk and Norham Bridge over the Tweed.
71. Spreuerbrucke.
72. Grand Rapids Lattice Bridge.
73. Tredgold^s 400 foot Timber Arch.
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8 CONTENTS.
UST OF ILLUSTRATIONS— Coathiaed
No.
74. Coalbrookdale Cast Iron Arch.
75. Sunderland Bridge over the Wear.
76. Thirsk Bridge over the Swale.
n. Chepstow Bridge.
78. Whipple's Bridge at Troy.
79. Newcastle High Level Bridge.
80. The Bolbnan Truss.
81. The Fink Truss.
82. Cologne Railroad Bridge.
83. Saltash Bridge over the Tamar.
84. Kuilenburg Bridge.
85. Post Truss.
86. LouisviUe Bridge (1870).
87. Hamburg Bridge over the Elbe.
88. Bismark Bridge over the Missouri.
89. Henderson Bridge over the Ohio.
90. Ohio River Bridge, Louisville and Jeffersonville.
91. Wear River Bridge at Sunderland.
92. Bellefontaine Bridge over the Missouri.
93. Middletown Bridge over the Connecticut.
94. Sixth Street Bridge, Pittsburg.
95. St. Francis River Bridge at Richmond, Quebec.
96. Columbia River Bridge at Hamilton, Ohio.
97. New Baltimore Bridge, Ohio.
98. The Clarion Bridge.
99. Great Miami River Bridge at Elizabethtown.
100. Grand Rapids Steel Bridge.
101. Britannia Bridge in Wales.
102. Suspension at Chuka Castle.
103. Anderson's Design for Bridge over the Firth of Forth.
104. Newburyport Suspension.
105. Menai Suspension.
106. Old Hammersmith's Bridge, London.
107. Bridge over the Danube Canal, Vienna.
108. Fribourg Suspension.
109. Dredge's Suspension over the Spey.
110. Dordogne Bridge over the Cubzac.
111. Roche-Bernard Suspension.
112. Ordish Suspension.
113. Roebling's proposed bridge at St. Louis.
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CONTENTS.
UST OF ILLUSTRATIONS— Contiaaed
No.
114. Frankfort Bridge over the Main.
lis. Point Bridge, Pittsburg.
116. St. Ilpize Suspension,
117. Mr. Bouch's Design for the Forth Bridge.
118. Brooklyn Bridge.
119. Washington Bridge, New York. Proposed Design.
120. Washington Bridge, New York. Proposed Design.
121. Grand Avenue Suspension, St, Louis, Mo.
122. Loschwich Stiff Suspension.
123. East Liverpool Bridge, Ohio.
124. Tower Bridge, London.
125. Suspension over the Niagara at Lewiston.
126. Bridge over the Lehigh River at Easton, Pa.
127. Qsclard Type of Suspension.
128. Williamsburg Bridge, New York City.
129. Manhattan Bridge, New York City.
130. Manhattan Bridge, Mr. Lindenthal's Design.
131. Proposed North River Bridge.
132. Wandipore Bridge at Thibet.
133. Bulkley River Indian Bridge.
134. Armeria River Bridge in Colima.
135. Hassfurt Cantilever over the Main.
136. Smedley's Bridge at Calcutta.
137. American Proposed Cantilever of 1869.
138. Early Design for Blackwell's Island Bridge.
139. Bridge at Posen, Poland.
140. Kentucky River Bridge at DixviUe.
141. Mississippi River Bridge at St. Paul.
142. Niagara Cantilever.
143. Fraser River Bridge, British Columbia.
144. St. John Cantilever, New Brunswick.
145. Kentucky and Indiana Bridge, at Louisville.
146. Poughkeepsie Bridge.
147. Design for Washington Bridge, New York City.
148. Design for Washington Bridge.
149. Design for Washington Bridge.
150. Mr. Schneider's Blackwells Island Cantilever.
151. Mr. Harding's Design for the Washington Bridge.
152. Hoogly River Cantilever.
153. Sukkur Bridge over the Indus, India.
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10 CONTENTS.
UST OF ILLUSTRATIONS-Continued
No.
154. Muscatine Cantilever over the Mississippi.
155. Clinton Cantilever over the Mississippi.
156. Point Pleasant Bridge.
157. Tyrone Cantilever over the Kentucky River.
158. Red Rock Cantilever over the Colorado.
159. Verrugas Viaduct.
160. Pecos Viaduct and Cantilever.
161. The Forth Bridge. As Proposed.
162. The Forth Bridge. As Built.
163. Cemavoda Bridge over the Danube.
164. The Cincinnati Cantilever.
165. Memphis Bridge over the Mississippi.
166. Lincoln Park Cantilever Arch, Chicago.
167. Winona Bridge over the Mississippi.
168. Davis Avenue Bridge, Pittsburg.
169. Tolbiac Street Bridge, Paris.
170. Francis Joseph Bridge at Buda Pest.
171. Proposed English Channel Bridge.
172. Northfield Cantilever.
173. The Schell Memorial.
174. Ottawa River Cantilever.
175. Highland Park Cantilever, Pittsburg.
176. Tygart's River Bridge near Fairmoifnt.
177. Long Lake Bridge.
178. Connel Ferry Bridge, Scotland.
179. Marietta Cantilever over the Ohio.
180. Wabash Cantilever over the Ohio.
181. Villefranche Cantilever.
182. Thebes Bridge over the Mississippi.
183. Moline Bridge over Rock River.
184. Ruhrort-Homberg Bridge.
185. Weser Bridge at Hameln.
186. Tunxdorf over the Ems.
187. Mr. Fidler's Design for the Quebec Bridge.
188. Quebec Bridge. Proposed Design.
189. Quebec Bridge. Phoenix Bridge Company's Design.
190. Quebec Bridge. Proposed Design.
191. Quebec Bridge. Design by the Board of Engineers.
192. Proposed Charleston Cantilever.
193. Proposed Cantilever. Mr. Tyrrell's Design.
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CONTENTS. 11
UST OF ILLUSTRATIONS ConHnued
No.
194. Proposed Cantilever.
195. Proposed Cantilever.
196. Blackwell's Island or Queensboro Bridge.
197. Khushalgart's Bridge over the Indus.
198. Westerburg Bridge, Prussia.
199. Daumer Bridge, Red River, China.
200. Beaver Cantilever over the Ohio.
201. Sydney Harbor Bridge. Desig» by A. Rieppel.
202. Sydney Harbor Bridge. Design by Wm. Arrol.
203. Proposed North River Bridge.
204. Arch Bridge over the Ruhr at Dussern.
205. Coblenz Arch (1864).
206. Foot Bridge over the Bollatfall.
207. Eads Bridge, St. Louis.
208. Proposed Design for the Eads Bridge.
209. Retiro River Bridge, Brazil.
210. Pia Maria over the Douro at Oporto.
211. Schwarzwasser at Berne.
212. Kirchenfeld at Berne.
213. Foot Bridge at Bedford.
214. Blaauw Krautz Viaduct, Cape Colony.
215. Garabit Arch over Truyere.
216. Luiz I Arch over Douro, Oporto.
217. Grant Memorial Bridge. Design by Paul Pelz.
218. Grant Memorial Bridge. " " " "
219. Grant Memorial Bridge. " '' " "
220. Main Street Bridge, Minneapolis.
221. Lake Street Bridge, Minneapolis.
222. Washington Bridge, New York City. Mr. Schneider's De-
sign.
223. Washington Bridge, New York City. Mr. Hildenbrand's
Design.
224. Washington Bridge, New York City. As Built.
225. Rochester N. Y. Bridge over Genessee River.
226. Hawk Street, Albany.
227. Pont du Midi over the Rhone, Lyons.
228. Paderno Arch over the Adda River.
229. St. Guistina Arch over Noce Schlucht.
230. Bridge over the Wear at Sherburn House.
231. Stoney Creek Bridge, British Columbia.
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12 CONTENTS.
LIST OF ILLUSTRATIONS-CoBliaaed
No.
232. Salmon River Bridge, British Columbia.
233. Surprise Creek Bridge, British Columbia.
234. Grunenthal Arch.
235. Riverside Cemetery Bridge, Cleveland.
236. Street Bridge at Lansing, Mich.
237. Panther Hollow Arch.
238. South Twenty-Second Street Bridge, Pittsburg.
239. St. Lawrence River Bridge at Montreal.
240. St. Lawrence River Bridge at Montreal.
24L Great Arch over the Garonne at Bordeaux, France. (Pro-
posed.)
242. Kaiser Wilhelm Bridge, Mungsten.
243. Viaur Viaduct, France.
244. Komhouse over the Aare at Berne.
245. Carlsburg Viaduct, Denmark.
246. Niagara Railroad Arch.
247. Niagara Railroad Arch. A Proposed Design.
248. Niagara-Clifton Highway Arch Bridge.
249. Fairmount Park Bridge. Mr. Schneider's Design.
250. Proposed Arch Cantilever Bridge at Massachusetts Avenue,
25 L Alaska Cantilever^
252. Alexander III Bridge at Paris.
253. Paris Exposition Foot Bridge.
254. Austerlitz Bridge, Paris.
255. Elbe-Trave Canal, MoUn.
256. Bonn Bridge over the Rhine.
257. Dusseldorf Bridge over the Rhine.
258. Bridge over the Elbe at Harburg.
259. Worms Railroad Bridge.
260. Bridge over the Rio Grande in Costa Rica.
26L Bellows Falls Arch.
262. Oakland Bridge, Pittsburg.
263. Zambesi Falls Arch.
264. Assopos Viaduct, Greece.
265. Yunnan Railway Bridge over Nami Gorge, China.
266. Salmon River Arch. Mr. Tyrrell's Design, No. L
267. Salmon River Arch. " " No. 2.
268. Proposed Design for Quebec Bridge. By Mr. Worthington.
269. Portage Viaduct. First Wooden Structure.
270. Deamess Viaduct.
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CONTENTS. 13
UST OF ILLUSTRATIONS-ConHnued
No.
271. First Iron Bridge, West Auckland, over the Gaunless River.
272. Carey Street Trestle, Baltimore.
273. Tray Run and Buckeye Trestles.
274. Crumlin Viaduct.
275. Jordan Creek Trestle.
276. Belah Viaduct.
217. "Big Bridge" over the Humber at Weston, Ontario.
278. Lyon Brook Viaduct.
279. Bender's Patent.
280. La Bouble Viaduct.
281. Verrugas Viaduct.
282. Castelleneta, Italy.
283. Cumberland Trestle.
284. Nidda Viaduct.
285. New Portage Bridge.
286. Marent Gulch Trestle.
287. Gokteik Viaduct in Burmah.
288. Boone Viaduct over the Des Moines River.
289. Montreal River Viaduct, Algoma.
290. Salmon River Viaduct.
291. Viaduct at Ogden, Utah.
292. Leithbridge Viaduct.
293. Greenville Maine, Trestle.
294. Key West Viaduct.
295. Kempton Bridge over the Iller River.
296. Danville Bridge.
297. Avon Bridge.
298. Walnut Lane Bridge.
299. Concrete Bridge at Portland, Pa.
300. Bridge at Eden Park, Cincinnati.
301. Mr. Thacher's Design for Schenley Park Bridge.
302. Topeka Bridge Kansas.
303. Concrete Bridge at Auckland, New Zealand.
304. Zanesville, Ohio, Y Bridge.
305. Zanesville, Ohio, Y Bridge.
306. Chatellerault Bridge, France.
307. Niagara Falls Concrete Bridge.
308. Topeka Bridge.
309. Wayne Street Bridge, Peru, Ind.
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14 CONTENTS.
UST OF ILLUSTRATIONS-Contiiiued
No.
310. South Bend Bridge, Jefferson Street.
311. Dayton, Ohio, Concrete Bridge, Main Street.
31^. Dayton, Ohio, Concrete Bridge, Washington Street.
313. Madison, N. J., Park Bridge.
314. Bridge at Hyde Park-on-Hudson.
315. Yellowstone Park Bridge over Yellowstone River.
316. Concrete Arch Bridge in Lake Park, Milwaukee.
317. Bridge over the Hudson at Sandy Hill, N. Y.
318. Howard Street Bridge, Spokane.
319. Stein-Teufen Bridge, Switzerland.
320. Proposed New York State Barge Canal Viaduct
321. Galvestoq Causeway.
322. Meadow Street Bridge, Pittsburg.
323. Bridge at Derby Conn.
324. Bridge at Reno, Nevada.
325. Two Span Bridge.
326. Maumee River Bridge, Waterville, Ohio.
327. Monterey, Mexico, Market Bridge.
328. Pasadena Concrete Bridge.
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HISTORY
OF
BRIDGE ENGINEERING
CHAPTER I.
EGYPTIAN, BABYLONIAN AND PERSIAN BRIDGES.
(Prior to 600 B. C.)
1. Bridges have existed since the dawn of human history.
Primitive races were content with rude structures made of
logs or trees thrown across the streams, or with slabs resting
on stepping stones in the water, but the development of
civilization and the beginning of commerce created a need
for more secure and better crossings. Assyria and Egypt,*
which witnessed the origin of the human race, are the countries
where the first traces of bridge construction have been found.
The art of bridge building and the profession of civil engineer-
ing, whether known by its present name or a different one,
are therefore as old as the races, and have been coexistent
with the building of cities and the progress of civilization in
all ages. The materials used then were much the same as now,
the difference being chiefly in the forms employed.
2. Bridges are not mentioned in the Bible, and secular
history contains little reference to the early ones of Babylonia,
Assyria and Egypt, but existing ruins and the known state of
civilization indicate that they were used. War bet\veen ancient
nations, and the constant liability to hostilities were serious
checks to progress, for in those days bridges were as much an
invitation to the invader as they are now to commerce.
Permanent ones were often undesirable, for cities and castles
were surrounded by walls, outside of which were deep motes
or ditches crossed only by movable platforms. Many of the
best known bridges of ancient times were built during military
fl5l
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16 BRIDGE ENGINEERING.
campaigns for the transportation of armies, and they are
described among the achievements of their originators.
Assyrian Bridges.
3. The country adjoining the valleys of the Euphrates and
Tigris rivers and their tributaries in Assyria was a very fertile
region, capable of yielding large agricultural products and
supporting a great population. Historians have variously
estimated the population of Babylon from two to twenty mil-
lions. Nineveh and other cities were also large, and the urban
residents must have depended upon the products of the
surrounding country for subsistence. Elaborate systems of
canals were used for bringing food supplies to the metro-
j>olitan centers, and existing remains show that the canals
were often in double lines, 6 to 15 feet in depth, and 20 to 30
feet in width. These canals must have been crossed at fre-
quent intervals by bridges corresponding in size and dignity
with other buildings of the time. History mentions dams on
the Tigris and the Euphrates, and the builders of dams would
doubtless be familiar also with bridge building. The Tigris
river dams for diverting water into irrigation canals, were
encountered by the boats of Alexander 350 B. C.
4. The date when arches were first introduced is unknown,
but they were used to some extent by ancient races, for in
recent excavations at the supposed sites of the cities of
Nineveh, Nippur and Babylon which were destroyed between
700 and 600 B. C, remains of pointed brick arched sewers were
found, dating back to about 4,000 B. C. Similar sewer arches
were also found (1,300 B. C.) under the ruins of the ancient
palace of Nimrod in the city of Calah on the Tigris. Calah
was 19 miles below Nineveh and was founded thirteen cen-
turies before the Christian era. In the ruins of Khorsabad,
16 miled from Nineveh, semicircular voussoir arches of 18-foot
span were found over gateways in the city wall, dating back to
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EGYPTIAN AND PERSIAN BRIDGES. \7
at least 720 B. C. These are some of the earliest known traces
of the true arch, though false arches over doors and gateways
have also been discovered in ancient ruins. True arches were
made of wedge shaped bricks in spans up to 15 feet, but their
theory appears to have been unknown until a later period.
Most of the early forms were really corbels, bracketed from the
adjoining piers and meeting at the span center, exerting only
vertical reactions. The constant horizontal thrusts from true
arches tending to overturn their abutments caused builders in
early times to use other and more permanent forms.
5. History states that Babylon was 15 miles square and
was surrounded by a brick wall 350 feet high and 87 feet thick,
on which were three hundred and fifty towers for defense. A
great ditch surrounded the city outside the wall, and the earth
excavated from it was used^ in making brick. The River
Euphrates, which flowed through the center of Babylon, had
quay walls at either side, of the same thickness as the city
wall, and outside of the city was a great lake or reservoir 52
miles square and 75 feet deep, containing the overflow from
the river for use in times of drought. It is further stated that
100 years after the flood (2,200 B. C.) in the time of Nimrod,
third ruler after Noah, the river was spanned in the center of
the city by a single brick arch, one furlong (660 feet) long and
30 feet wide, the great quay walls at the side serving as abut-
ments for the arch. At the ends of the bridge were two palaces,
which were connected also by a brick tunnel beneath the
river. The bridge probably endured as long as the city, for
if it had fallen, the historian describing it would also have
described it fall. It must have been made of brick, as that
was the only building material of Babylon. A prototype for
this bridge may have been found in some natural arch like the
great Augusta Bridge in Southern Utah, which is 265 feet
high and 30 feet wide, with a clear span of 320 feet.
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18 BRIDGE ENGINEERING.
6. The earliest record of a wooden bridge is given by
Herodotus, "the father of history" (484 B. C), describing one
built 783 B. C. over the Euphrates River in Babylon during the
reign of Nitocris who succeeded Semiramus as Queen of
Assyria. The bridge had stone piers connected with wooden
platforms which were removed at night to prevent thieves
from entering the city. Its width was 35 feet and length 660
feet (one furlong). Another writer says that the piers were
built "with great skill on the sandy river bottom with arches
of hewn stone fastened together with iron chains and melted
lead." While building the piers, the river was diverted from
its course into an artificial lake or basin 13 miles square, with
high artificial banks to prevent the adjacent country from
being inundated, and two outlet canals discharged the over-
flow. One historian relates that the bridge was roofed over
and was equal in beauty and magnificence to any other struc-
ture in Babylon, but no trace or remains of it have ever been
discovered. Diodorus Siculus says that it was built under the
direction of Queen Semiramus.
7. The Caravan Bridge over the River Meles at Smyrna
in Asia Minor, is believed by archeologists to be one of the
very oldest in existence. The river does not exceed 40 feet
in width, and it is crossed with a single span. On the banks of
this river, Homer lived and played when a boy twenty-nine
centuries ago, and Saint Paul on his journey into Smyrna
probably entered the town over Caravan bridge. The parapets
and pavement have been renewed within the last two cen-
turies, but the remainder of the bridge is in its original condi-
tion.
Egyptian Bridges.
8. Stone arches were found over the entrance of the Great
Pyramid of Ghizeh near Memphis in Egypt, dating back from
3,100 to 4,200 B. C, but these were not true arches, being made
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EGYPTIAN AND PERSIAN BRIDGES. 19
of single sloping stones meeting over the center of the open-
ing. A tomb was also found at Ghizeh, 26 by 30 feet in plan
and 53 feet deep, which is supposed to have been covered about
600 B. C. with a masonry arch. Brick arches of very primitive
form were found in the ruins of Thebes on the river Nile,
which were probably built about 2,900 B. C. The seventy or
more other pyramids in the vicinity of Memphis are made of
limestone and granite brought from quarries 500 miles up the
Nile. The largest pyramid is 764 feet square at the base and
480 feet high, and the building of it is said to have required
the services of one hundred thousand men for twenty years.
The builders of the pyramids were expert in handling mate-
rials, and must have been able to erect bridges or other struc-
tures to suit their time and needs. They used heavy timbers
for moving and transporting the stone, and were as well able
to use stone for bridges as for pyramids. The early Egyptians
were great engineers and builders, as is shown by the annual
diversion of water from the Nile into great storage reservoirs
for use in dry seasons. They had "Joseph's Canal" for irrigat-
ing lower Egypt, and as early as 1,450 B. C, had a canal join-
ing the Nile and the Red S^a. Some authorities say that the
Egyptians crossed the rivers on floats drawn by swimming
horses, and in Genesis it is stated that the water of the Red
Sea was parted and Pharaoh's army marched over on dry
ground without need for either floats or bridges. Notwith-
standing the lack of positive records, it is probable that so
great a people and race of builders must have had bridges
over their canals and rivers.
Grecian Bridges.
9. Bridges of ancient Greece built by the Cretians in pre-
historic times, like that of a later date on the island of Euboea
over the Euripus river, erected during the Peloponnesian war,
425 B. C., had heavy piers and abutments connected with
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BRIDGE ENGINEERING.
wooden planks, or like the bridge at Assos (Fig. 1), had stone
lintels doweled together on stone piers. The Assos bridge
had seventeen elongated diamond shaped piers, 10 feet apart
Fig. 1.
on centers, with stone lintels 20 inches thick and 24 inches
wide, doweled together. A similar bridge (Fig. 2) is over the
Valley of Flamingos^ Fayal, Azores. In later years piers were
built with the upper stone courses overhanging, to meet in the
center of the span in the form of a false triangular arch.
Figr. 2.
Bridges at Metaxidi, Sparta, and in Messenia over the river
Pamisus are built in this way. Other stone bridges of un-
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EGYPTIAN AND PERSIAN BRIDGES.
21
known date remain in the vicinity -of Phlius and Mycenae. The
semicircular arch afterwards used by the Romans, is a develop-
ment of the earlier false arch of the Greeks.
Persian Bridges.
10. One of the oldest, if not the very oldest, existing
bridge in Persia is at Dizful in the Province of Khuzistan
over the river Diz. It is 1,250 feet long and is still in a fair
state of preservation (Fig. 3). It has twenty pointed
arches 23 feet long, between piers 29 feet thick. The large
pointed arches and the minor ones through the piers above
the level of the main springs, are characteristic of Mohamme-
dan architecture, and are believed to date from 350 B. C. in the
Fig. 3.
reign of the later Archaeminid Kings over Iran, though a
French historian attributes it to the fourth century A. D. A
similar bridge 1,700 feet long exists at Shuster (Chouster) in
Persia over the Karun river, which suggests that the Gothic
or pointed arch may have originated in Persia. The Shuster
bridge is made of brick and it follows a zig-zag course across
the river with about a dozen bends or angles.
11. Pontoon bridges were used by the ancient Persian
Kings Cyrus, Darius and Xerxes 536 to 480 B. C, and earlier
ones of unknown date or origin are referred to by Homer, who
lived about 880 B. C. (See Pontoon Bridges.)
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BRIDGE ENGINEERING.
Chinese Bridges.
12. Records of ancient bridges in China have not been
preserved, but masonry arches are known to have existed 2,000
B. C. The Chinese used both slab and arch construction, and
were either the earliest bridge builders or contemporary with
the Babylonians. Bridge construction in that country is there-
fore as old as any other art. The Chinese were great builders,
for the wall of China, completed 214 B. C, is 1,500 miles long
and 50 feet high in many places, and is the largest artificial
structure on earth. Arches were used for carrying the wall
over streams and rivers, and smaller arches over doors and
gateways through the wall.
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ROMAN BRIDGES. 23
CHAPTER II.
ROMAN BRIDGES, 700 B. C— 600 A. D.
i;^. The bridges of the Romans have shown the greatest
permanence, since at least twenty of them remain. Not less
than eight bridges crossed the Tiber river at Rome and many
others were scattered throughout the empire. For two thou-
sand years or more they have withstood floods, earthquakes
and the violence of war, and many of them are still in a good
state of preservation as models for succeeding ages. The
Tiber has experienced at least thirty disastrous floods, and the
wonder is that any bridges remain. They were designed with-
out much theoretical knowledge of their stresses and were
proportioned by judgment or empirical rules, but they show
great merit both in design and construction, and have hardly
been excelled. The arch stones were often so carefully fitted
that they appear to have been ground together, and in these
joints mortar was not generally used, but the stones were
united with iron clamps. It is said that Roman builders were
required to make repairs on their bridges and keep them in
good condition for a period of forty years, and the final
payments were withheld till after that time, all of which
clearly shows their purpose of constructing works of perma-
nence. Slave labor was probably employed in bridge building
as in other public works of the ancients.
14. The great era of Roman bridge building began with
the construction of the Roman highways. This people foresaw
that the development of their domain depended largely on the
condition of their roads, and in warfare against other nations,
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24 BRIDGE ENGINEERING.
the bridge builders were in the lead*of the Roman army Not
including the footways at the side, their roads had a width of
14 to 18 feet. The Flaminian Way commencing at the Milvian
bridge at Rome, terminated at the bridge in Rimini, and the
Appian Way, which was 350 miles long, was built in the years
312 B. C. to 30 B. C, and was in good condition until 500 A. D.
Other Roman roads were the Aurelia, Aemilia, Cassia, Latina,
Salario and Valeria.
15. During the seventh and sixth centuries B. C. the piers
of stone bridges in Italy were frequently corbeled out till they
met at the span center, forming a pointed false arch, and
those at Cora, Vulci and Bieda were of that type. Between
600 and 500 B. C. the semicircular true arch began to appear,
after which, all Roman arches were of that form. The true
arch is known to have existed in Greece in tombs and domes
as far back as the days of Pericles, 450 B. C, but it was not
used for bridges in that country until a later period. The city
of Athens was adorned with splendid buildings, but there is
no trace or evidence of bridges in the city, and the river
Cephisus must have been crossed by wading. At a later pe-
riod, a bridge was thrown across this stream by Emperor
Hadrian, between the territories of Attica and Eleusis, on the
most frequented road in Greece. The Roman bridges were
noted more for their durability and permanence, than for their
length of span, which rarely exceeded 70 to 80 feet. Piers
were usually very thick, often one-third of the adjoining open-
ings, and the failure of one arch in a series did not cause the
others to fall. The excessive pier thickness was, however,
a serious obstruction to the water, and often caused the founda-
tions to be undermined. Above the springs the piers were
usually pierced with smaller openings, and stones were some-
times left projecting from the piers for the support of tempo-
rary centering, as on Pont du Gard Their bridges generally
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ROMAN BRIDGES. 25
had an uneven number of openings, with span lengths decreas-
ing from the center to the ends, and the springs of adjoining
arches were usually at the same level. They frequently had
triumphal arches over the roadway, as is shown by those at
Antioch, Magnesia, Martorell, Alcantara and Fabricus, and
many were further adorned with statues.
16. The materials in Roman arches were usually tufa,
peperino and travertine, with a filling of Pozzuolana cement.
Tufa stone is a mixture of volcanic ash and sand, and peperino,
a conglomerate of ash, gravel, limestone and broken lava.
Travertine is a creamy white limestone, and it has great dur-
ability when laid pn its natural bed. Concrete was made with
Pozzuolana cernent, which is a reddish earth found at Pozzuoli
near Naples, and also at Rome. The earth was pulverized and
mixed with lime to form hydraulic cement. Bridges were fre-
quently faced with blocks of travertine, and ring stones laid
dry without cement.
17. One of the. earliest examples of arch construction is
the Cloaca Maxima^ a large arch canal or stone sewer built
by one of the Tarquins B. C. 615, to drain a tract of marshy
ground between Palatine and Capitoline hills in Rome. It ran
from the valley of the Circus Maximus, emptying into the
Tiber below the island, and the reclaimed land afterwards
became the Forum. The arch is formed of three concentric
rings of volcanic stone put together without mortar. It is
1,740 feet long, and at the river end is 15 feet wide and 11 feet
high, while at the upper end it is only 7 feet wide and 9 feet
high. The walls contain large stones, some of them 8 feet
long, 3 feet wide and 2J4 feet thick. A new section 365 feet
long, back of the Forum, was discovered in the latter part of
the nineteenth century. The sides were probably walled up
as early as 800 B. C, but the arch covering was added at a
later period.
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BRIDGE ENGINEERING.
The Bridges of Rome.
18. The eight known bridges of Rome are Sublicius (621
B. C), Aemilius (178 B. C), Milvius (100 B. C), Fabricius
(62 B. C), Cestius (46 B. C.) Aelius (136 A. D), Jani'culanus
(260 A. D.), and Triumphalis or Vaticanus.
(1.) The first wooden bridge of the Roman period of
which any record exists, is the Pons Sublicius (Fig. 4), built
according to Plutarch, by Ancus Martins, and so arranged that
the floor could be removed. It is generally believed to be the
first bridge over the Tiber at Rome, though some historians
endeavor to show that a bridge existed on the site, long before
II r 1 M II 11 II II II II II TT-n 11 irri it ii rririi
Mill, ,11 M, ,1111,
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621 B. C, explaining that the work of Ancus Martins was
merely a restoration. Pons Sublicius is noted for the legend
of its defense by Horatius Codes, a Roman knight who saved
the city against the Etruscans under the leadership of Lars
Porsenna B. C. 598. It is referred to by Lord Macaulay, **How
well Horatius kept the bridge in the brave days of old." The
bridge was destroyed about 500 B. C, but was twice restored
by the Chief Priests. One historian states that it was rebuilt
of stone in the seventh century B. C. In the year 23 B. C.
it was washed out by a flood and again in the time of Anton-
inus Pius, 140 A. D., but each time was rebuilt, and the ruins
of the last structure remained till 1877, when they were re-
moved to clear the river channel As the word "Sublicius"
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ROMAN BRIDGES.
27
means piles, it is generally believed to have been of hewn tim-
ber, supported on piles, and neither nails or iron of any kind
to offend the river gods, were used in its construction. Some
authorities, however, think that the piers were stone, with
a superstructure of timber arches. It was probably not over
600 feet in length, for on its site now stands the iron bridge
Ponte Sublicio. Another writer says that this bridge was re-
constructed of stone by Aemilius Lepidus, the last censor
under Augustus, but was again carried away by a flood in
780 A. D. It was the custom in early times to cast human
beings from Pons Sublicius as sacrifices into the Tiber, but in
later years during the Ides of May twenty-four rush images
were used instead.
(2.) A period of 400 years elapsed with no records of
bridge construction, until B. C. 192, when two wooden ones
were thrown across the Tiber at the site of Fabricius and
Fig. 5.
Cestius. These were followed in 178 B. C. by a stone arch
bridge on the site of Ponte Rotto. As it stands today, this old
bridge (Fig. 5) has three arches and a suspension span over the
gap where other arches originally stood. The present bridge
is on the site of Pons Aemilius (Fig. 6), built B. C. 178-142,
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BRIDGE EXGIXEERING.
above Pons Sublicius and just below the island. The three
remaining arches date from the time of Julius III., and are
richly ornamented. Two arches were carried away by a flood
in 1598 A. D., and have never been replaced. The bridg^e was
unfortunately located for it has been swept out at leasr four
times, the first time in the year 280 A. D. It was erected by
Caius Flavius and is claimed by some authorities on ancient
history, to be one of the first, if not the very first ap-
pearance of the arch in bridge construction. It has semicircular
arches and a level roadway over the central portion, with end
Fig. 6.
arches shorter than the intermediate ones. It was called Pons
Palatinus, Senators* Bridge and Pons Lapideus. In construc-
tion it is similar to the other old stone bridges of Rome, being
built of peperino and tufa, faced with blocks of travertine an-
chored into the masonry. The parapets and spandrels are
highly ornamented with carved panels, and each of the piers
above the arches and foundations are penetrated with smaller
arch openings. The panel work has disappeared from the
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ROMAN BRIDGES. 29
shore spans and the method of construction is plainly revealed.
The arch ring is made of different material and is differently
laid to the filling above it, and numerous openings appear in
the backing, showing the method of anchoring the facing
blocks to the body of the structure. A large amount of con-
crete was used in the construction of the Roman bridges and
aqueducts. It is possible that when first built, the piers only
were of stone with wooden floor.
Pons Probi (381-387 A. D. ?), which was the furthest
bridge down stream, is thought by some to be the same as
Pons Aemilius. It was partly burned in the eleventh cen-
tury and completely in 1484, though the base of piles still
remains.
(3) Pons Milvius, known also as Ponte MoUey carries the
Flaminian Way over the Tiber about a mile and a half from
Rome, and was probably built in the time of Sulla by censor
Aelius Scaurus about 100 B. C. As the Flaminian Way was ^
completed B. C. 220, it is possible that the bridge is of earlier
origin. It has seven spans varying in length from 51 to
79 feet, and the total length of bridge was 413 feet. Its width
is 28 feet 9 inches. Over the roadway were arches, placed
there by Augustus in honor of himself, and notwithstand-
ing numerous changes and restorations, including one in
1808, some parts of the original bridge still remain. The
piers, as in other ancient Roman bridges, are pierced with
minor arches. Over this bridge the conspirators associated
with Catiline, fled in confusion.
(4.) Pons FabriciuSy over the Tiber at Rome, later knowp
as Ponte Quattro-Capi, was built 62 B. C. at the time of the
Catiline conspiracy, by Lucius Fabricius, engineer of roads
and bridges. As mention is made of wooden bridges to the
island in 291 B. C, the stone structure may have been a re-
construction. It is 250 feet long and has two semicircular
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BRIDGE ENGINEERING.
80-foot arches with rings 6 feet thick. A 13-foot arch pierces
each abutment and it has a similar 16-foot arch through the
center pier, which is 33 feet thick. Like other bridges of
Rome, it is said to have additional arches at the ends buried
in the embankments. The bridge spans one channel of the
Tiber to the island of Aesculapius and is a continuation of
Pons Cestius over the other channel. It was originally of
wood, but was reconstructed just before the Christian era
(21 B. C.) of peperino and tufa faced with travertine. It
Fig. 7.
once had triumphal arches over the roadway, and is the
only one of all the ancient bridges of Rome remaining com-
plete and in use up to the present day. On a tablet beneath
the parapet and on all the arch rings are historical inscrip-
tions. (Fig. 7.)
(5.) Pons CestiuSy or Gratianus, sometimes called Ponte-
di-San Bartolomeo, originated 46 B. C, was several times re-
built, the first time in A. D. 365, the third time in the eleventh
century, and again in the years 1886-1889. Originally there
were on the bridge two marble tablets with inscriptions, but
in 1849 one of these was lost in the river when a portion
of the bridge was removed by order of Garibaldi, to prevent
soldiers from entering the city. It crossed the Tiber to the
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ROMAN BRIDGES. 31
island with one span of 76 feet, and a small opening at each
side, being a continuation of Pons Fabricius.
(6.) The bridge of St. Angelo at Rome was built by Em-
peror Hadrian in the year A. D. 135 to connect Campus Mar-
tins with the Mausoleum which he erected for himself. The
tomb is now generally known as the Castle of St. Angelo. The
bridge crosses the Tiber and was originally known as Pons
Aelius. It is said to have had a roof of bronze supported on
forty columns, which was afterwards destroyed by the bar-
barians. Pope Nicholas III. made some restorations and
others were added by Clement IX. in 1668, who embellished
it with ten colossal statues of angels carved in white marble.
The statues of Saint Peter and Saint Paul at the ends were
erected in 1530 by Clement VII., taking the place of two
chapels. The idea in placing figures of angels at either side
was evidently to show that heavenly messengers welcomed pil-
grims to the sacred shrine. Originally it had three main arches
with two smaller ones on the right and three on the left, but
two of the latter were buried in the bank and not discovered
until the restoration of 1892. Only six arches are now visible,
though three are enough for the river in dry seasons. The
span of the largest is 62 feet and the smallest 26 feet, the
width over parapets being 50 feet. Piers are 21j4 feet thick
and the roadway is 50 feet above low water. Excepting the
parapets, the bridge is almost entirely ancient. The pedestal
of one statue bears the impression of a cannon ball, made
during the siege of Rome in 1849.
The remains of another old bridge (A. D. 60-64), which
once carried Via Triumphalis, can be seen when the river is
low, about 100 yards below the Bridge of St. Angelo. It has
been called Pons Neronianus, and connected Campus Mar-
tins with the Gardens of Agrippa, the Circus of Nero and the
Vatican meadows.
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32 BRIDGE ENGINEERING.
(7.) Ponte Sisto at Rome was constructed under Sixtus
IV. in 1474 on the ruins of the old Pons Janiculensis crossing
from Trastevere. The old Roman bridge Pons Valentinianus,
or bridge of Valentinian I., is said to have occupied the same
site, and been rebuilt A. D. 366. Other reports seem to show
that Pons Aurelius stood on the site and was restored in the
time of Hadrian. Still other records indicate that the site
was once occupied by Pons Antonius. After a flood had de-
stroyed part of the bridge in 772, it was renamed Pons
Fractus. It crosses the Tiber with four semicircular arches
and at either end are steps leading down from the street to
the river. The deck has side extensions supported on pairs
of heavy brackets at the piers, and the road is guarded with
railings. An inscription on the bridge begs the prayers of
travelers for its founders, and a fountain at one end was
added by Paul V. Ruins of three or four rows of piers, found
in 1889, 340 feet up stream from Ponte Sisto, indicate the
probable site of some old bridge of which nothing is known,
but which may be Pons Agrippae, A. D. 34.
(8.) Pons Triumphalis, or the Triumphal Bridge of the
Caesars, sometimes called Pons Vaticanus, from its proximity
to the Vatican, and Ponte Ferrato or Cestius Gallus Bridge,
both over the Tiber at Rome, have disappeared, and only
encumber the Tiber with their remains. When building the
new Garibaldi bridge at Rome, remains of an old one having
two 10-foot arches and a middle pier 7^ feet thick and 20
feet wide, were found in the Tiber and removed. It was
probably built in the early years of the Roman republic.
Other Roman Bridges.
19. Ponte di Nona, near Gabii, Italy, built in the years
124-121 B. C, has seven stone arches of tufa and travertine,
with a total length of 225 feet, and is still in use.
20. Julius Caesar's bridge over the Rhine (Fig. 8), 65
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ROMAN BRIDGES.
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B. C, is said to have been built in ten days in the face
of the enemy. It was a wooden trestle with sloping piles
driven into the river bottom, supporting cross timbers which
carried the floor joist. It was 1,800 feet long, 40 feet wide,
^nfrmr
Fig. 8.
and contained about fifty spans, and the piers were protected
with fender piles at the up-stream end. One historian states
that it was located near Bonn, and others, between Coblenz
and Andernach. It is fully described in Caesar's Commen-
taries.
21. The bridge at Narni, Italy, was considered the finest
of all the Roman bridges. It was built by Caesar Augustus,
over the Nera, between the years B. C. 27 and A. D. 14, and
had four spans of 75, 135, 114 and 142 feet, respectively. Its
total length was 367 feet, height 112 feet, width 75 feet. The
stones were put together without cement, and history states
that in 1676 only one span remained. Nothing is now left
but the barest ruins.
Other bridges of Augustus, of which only vestiges remain,
were at Borghetto, Aosti and Calzi, while others by the same
ruler at Verona and Vincenza, which were once destroyed,
?.r
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34 BRIDGE ENGINEERING.
have since been rebuilt. Ponte Felice, over the Tiber near
Borghetto, had four spans, the end ones 51 feet long, and
the middle ones 59 feet, between very heavy piers. It is said
that the boast of Augustus was that **he found Rome a city of
brick and left it a city of marble."
22. The old Roman bridge (Fig. 9) crossing the Marachia
at Rimini (Ariminium), Italy, is supposed to have been built
during the reign of Augustus. It has five arch spans with
very heavy piers, and the details still remaining show that
originally the bridge was very ornamental. Above the piers
are panels formed by columns supporting entablatures, and
Fig. 9.
the heavy stone cornice is carried on numerous brackets. The
arches are all semicircular, the end ones having spans of 23
feet, while the three intermediate ones are 28 feet. The stones
in the arch ring are so finely jointed that they appear to have
been ground together. At one time marble porticos stood
above the roadway.
23. The remains of a very ancient structure known as
Caligula's Bridge" has stood for centuries on the bay of Poz-
zuoli near Naples. It is thought to have extended across the
bay to Baie with a length of about three miles, but there is
much doubt as to its origin and date of construction, though
generally believed to be the work of Caligula. (See Pontoon
Bridges.)
24. A bridge over the Tagus river at Alcantara (Arabic
word for bridge), near the border of Spain and Portugal, was
built during the years A. D. 98 to 105, by Lacer, in honor
of Emperor Trajan (Fig. 10). It contains six semicircular
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ROMAN BRIDGES.
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granite arches of various spans, the largest being 115 feet,
and has a total length of 670 Spanish feet. It was 26 feet
wide and the roadway was 205 feet above the water, and it
remained in use until A. D. 1809, when the second arch from
the right bank was destroyed by the English army. Tem-
porary repairs were made, but it was again destroyed by the
Carlists in 1836 and has not since been restored. The stones
Fig. 10.
were put together without mortar, and it is said that originally
triumphal arches stood above the roadway at the ends, but if
so, they have long since disappeared. Only one of the river
arches now remains, and this one compares favorably with
briclges of the present day.
25. Trajan's bridge, over the Danube near Warkel in Hun-
gary (Fig. 11), below the rapids of Iron Gate, was built A. D.
104 under the direction of Apollodorus of Damascus, who was
the greatest engineer and architect of his time. The bridge
was 150 feet high, 60 feet wide, and the length is variously
reported at 3,900 to 4,500 feet. It was built to form a road-
way over the Danube river for Trajan's soldiers during his
warfare into Dacia, and was one of the earliest permanent
war bridges, previous ones being constructed chiefly of boats
or rough timber. It had twenty wooden arches of 170-foot
span, supported on piers of squared stone, but was destroyed
by Hadrian, A. D. 120, because of his jealousy of Apollodorus,
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BRIDGE ENGINEERING.
its builder. Remains of some piers are still visible, and foun-
dation piles have occasionally been drawn from the river bed.
Trajan's Column at Rome shows the bridge in bas relief, with-
out dimensions, and there is doubt as to the actual form of
Fig. 11.
arch and length of span, as those on the Column may be
merely suggestive and not to scale. The river at the site
has a depth of 18 feet and the piers were built by sinking
caissons.
26. Ponte Salaro, carrying the Salarian Way over the
Anio or Teverone river, was built by Narses in the sixth cen-
utry A. D. It had a central arch of 87 feet 9 inches, and two
small arches 14 feet wide in each abutment. The bridge was
27 feet 9 inches wide, and the height of the deck at the center
was 50 feet above the springs. At one time a fortification
tower stood at one end. The bridge was blown up by the in-
habitants in 1867, to prevent the approach of Garibaldi to
Rome. In its earliest state it has been attributed to Tar-
quinius Priscus about 600 B. C. The Roman bridge at Mos-
tar, Bosnia, with slightly pointed arch and sloping roadway,
is of unknown origin.
27. Pontoon bridges used by Alexander the Great, 330-
327 B. C, Caligula's bridge, 40 A. D., and others of the Ro-
man period, are described under Pontoon Bridges.
28. A timber arch with a platform suspended from it,
which is probably the old bridge at Mayence, is clearly shown
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ROMAN BRIDGES.
37
on an old Roman medal. Wooden piles have been removed
from river beds in Germany, where they have been for two
thousand years or more.
29. A bridge over the Guadiana river at Merida, Spam,
with 64 arches, and 3,900 feet long, is believed to be the work
of Trajan. It bears Arabic inscriptions, and piers are made
in Roman style suggesting its probable origin. Other Roman
Fig. 12.
bridges in Spain attributed to Trajan, which have been well
preserved by the Moors, are those at Alconeter, Almazar,
Cuence, Chaves, Evora, Martorell, Orense, Olloniego, Sala-
manca and Ona. Pont de Martorell, over the Noya, with a
center 124rfoot span, and smaller arches at each side,* is sur-
mounted at the center with an enclosure, but the Salamanca
Figr. 13.
bridge is the finest one of all. The three-span arch bridge
at Vicenza, with center and side openings of 69 and 55 feet,
is also said to be of Roman origin (Fig. 12). A bridge over
the river Drin in western Turkey (Fig. 13), on the road from
Monaster to Sculari, still remains, after the lapse of cen-
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BRIDGE ENGINEERING.
turies. It has at least three main arches with long arched
openings in the piers, and other minor arches through the
spandrels. Its origin is uncertain, and while tradition attrib-
utes it to the Roman period, tb.e treatment of piers and the
spandrel arches are more oriental than Roman.
30. Many of the finest Roman bridges were those sup-
porting aqueducts, some of which are still in an excellent
state of preservation. These include no less than fourteen
for the city of Rome, Pont du Gard at Nimes, France; Se-
govia and Tarragona in Spain; Alcantara in Portugal, and
others at Antioch, Metz, and Bourgas near Constantinople.
(See Aqueduct Bridges.)
KIMINI BRIDGE
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MEDIAEVAL BRIDGES. 39
CH4IPTER III.
MEDIAEVAL BRIDGES. 500^1500 A. D.
31. Bridge building, like architecture and many arts, suf-
fered a severe decline during the Dark Ages (500-ilOO A. D.),
following the fall of the Roman Empire, and was not revived
again until the eleventh and twelfth centuries. Very few im-
portant bridges were built during these ages excepting those
in Spain by the Moors, who were a careful and cultured race.
The semicircular arch continued almost exclusively in use
from its introduction before the Christian era, until the thir-
teenth century, when pointed arches reappeared, and elliptical
and segmental forms were usual in the fourteenth century.
In the 400 years (1100-1500 A. D.)' following the Dark Ages,
bridges were poorly and cheaply made, frequently not more
than 6 or 8 feet in width, and seldom more than 20 feet.
They often had steep grades at the ends, were inferior to those
of the Romans, and frequently had unequal spans. The hos-
tile condition of adjoining countries often made it necessary to
provide means of protection, and fortification towers at the
ends were a common feature.
32. A religious order under which much bridge building
was done, was known as "The Brothers of the Bridge" found-
ed in the twelfth century by Benedictine monks. The Order
established houses at the river crossings for the comfort and
safety of travelers and for protection against thieves and ban-
dits, and the building and preservation of bridges became a
sacred duty. The Brothers also raised money for building
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BRIDGE ENGINEERING.
bridges and sometimes superintended their construction. The
director of this religious order was called the Pontifex Maxi-
mus, a title in the church of Rome to the present day.
French Mediaeval Bridges.
33. Among the bridges in France built during the Dark
Ages (500-1000) were those at Vaison, Chateau Neuf and
Saint Chamas, the last having triumphal Corinthian arches at
the ends, mounted with figures of reclining lions. Saint
Chamas bridge (Fig. 14) spans the Tolubre river with a clear
span of 41 feet and a total length of 83 feet, the funds for
Fig. 14.
its construction being a private donation. Some writers con-
sider the bridge to be of much earlier origin, dating back to
the Roman period in the reign of Caesar Augustus (14 A. D.).
During the latter part of the eleventh century, bridges were
built at Vienna, Tours, Orleans and Lyons. One of the ear-
liest by the Brothers was that at Maupas or Botipas over the
river Danube, with towers at each end, but it was washed out
soon after its completion.
34. The bridge at Avignon over the Rhone, in Southern
France, was built 1178 to 1186 under the direction of Saint
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MEDIAEVAL BRIDGES. 41
Benezet, who was once a shepherd boy. Four pointed arches
still remain, having a smaller radius of curvature at the crown
than at the haunches. Money for building it was raised by a
pretended miracle. It originally contained 22 spans, the long-
est 110 feet, and it had a clear width between parapets of
13 feet, a height of 46 feet, and a length of 2,000 feet. A chapel
to Saint Nicholas, protector of those who travel on the river,
originally stood on the third pier. The bridge was bowed up
stream to better resist the force of the current. Some of the
arches were destroyed in 1385 by Pope Boniface IX., and in
1410 a tower was blown up by the inhabitants, carrying down
three spans with it. Several more spans were washed out in
1670. Other bridges built by the Brothers are those at Ceret,
Nions, Saint Esprit and Villeneuve.
35. The bridge over the Charente at Saintes (Fig. 15) was
probably built in the middle of the fourteenth century, though
one historian attributes it to Isembert, the engineer who com-
Flfif. 15.
pleted old London bridge in 1209 after the death of Colechurch.
Ornamental towers of different design rose high above the
roadway on each side of the river at the low water line, while
other smaller towers with gateways were erected at the ends.
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42 BRIDGE EXGINEERIXG.
The design of the towers at one end was made to conform in
architectural treatment with the adjoining castle, while the
main tower at the other end was a monumental Roman arch
with two roadways. The part between the main river towers
was divided into seven spans, while the end sections between
the main towers and the entrance gates, was divided into three
arch spans. The platforms of the three spans at each end were
of wood, and were so arranged that they could easily be re-
moved to obstruct travel in case of hostilities. The towers
and gateways and their relative positions, make the bridge
one of the finest early examples on record.
36. Thirty miles from Nimes in Southern France, a bridge
was built over the Rhone at Saint Esprit, with 26 stone arches
of various lengths from 81 to 114 feet. It is 18 feet wide, and
.2,700 feet long, and the piers are 28 feet thick at the springs.
The piers are pierced with smaller arches conforming with
Roman practice, and the rapid current of the river at the site
was doubtless due to some extent to the obstruction of the
heavy piers. It was built from 1265 to 1309 A. D. by the
Brothers of the Bridge, and for many years was the longest
stone bridge in existence. Money for its construction was
raised by voluntary offering.
37. Another bridge over the Rhone known a§ the Guillo-
tiers, was built at Lyons in 1265 A. D. It had 18 spans of
various lengths from 26 to 102 feet with piers 34 feet thick at
the springs, and like the one at Saint Esprit, was under the
direction of the Brothers. It was blown up in time of war,
and for a long time remained in ruins.
38. Pont Valentre (Fig. 16), over the Lot at Cahors (1280)
in Southern France, has six pointed arches and three towers
for defense, one at each end and the other in the middle.
Montauban also has a stone arch bridge of many spans, built
1303 to 1316, with slightly pointed arches, and Pont du Ceret,
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over the Tech river near Perpignau, is a semicircular arch
order are at Castellane over the Verdun river, with 90-foot"^
span (1494) and one over the Allier river at Brioude (1454),^
with a semicircular span of 150 feet, a width of 16 feet andj
a height of 60 feet, by Estone and Greiner, engineers. The
bridge of 147-foot span and 13 feet wide, built by the Broth-
ers (1336). Other bridges built under the direction of this
ii
Fig. 16.
arch ring was very thin and was the only cut stone used, the
rest of the masonry being fubble. The piers above high water
were faced with cut stone but were filled inside with sand and
gravel. It collapsed in 1822 and was soon afterwards rebuilt.
Another bridge at the same place is attributed to the Romans.
39. The bridge at Sisteron over the Durance, with a single
span of 65 feet, and the Notre Dame bridge at Paris, were both
started in 1500. The Notre Dame bridge, still remaining, re-
placed one which fell in 1498, and was rebuilt with six spans
of 56 feet and a width of 77 feet, but was not completed until
1507.
Other French bridges of the Middle Ages are the Roman
Pont Sommieres, over the Virdoule, with a long series of 32-
foot openings; Pont Albi (1035), with seven pointed arches
and five houses balanced over the piers; Pont Carcassonne,
over the Aude, with a series of 46-foot openings (1180) ; Or-
thez, over the Gave, with three or more spans and a central
tower (thirteenth century) ; and a bridge over the Isere (fif-
teenth century), with a house over the first pier.
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44 BRIDGE ENGINEERING.
Italian Mediaeval Bridges.
40. From the decline of the Roman empire (500 A. D.)
until the thirteenth century the Italians built many bridges
of wood which have not endured like the stone ones of their
predecessors, and records of which are not extant. With the
general revival of art, marble began to appear as a structural
material, and two of the most noted ones remaining are of
this beautiful variety of limestone. A bridge by Narses in the
sixth century, over the Teverone river, is a single semicircular
span of 87 feet with a smaller arch in each abutment. The
earliest structure at the site is attributed by some authorities
to Tarquinius, about 600 B. C, and a fuller description is in-
cluded under Roman Bridges.
41. The Serchio river bridge near the baths of Lucca»
Italy known as one of the "Devil's Bridges," built prior to
A. D. 1000, has one span of 120 feet and four smaller ones of 17
to 46 feet, and a roadway 68 feet above the water (Fig. 17). It
is very narrow, being only 9 feet wide in the clear and 12 feet
Fig; 17.
outside, resembling a great wall more than a bridge. It has re-
sisted several heavy floods, in one of which the water rose 30
feet above the springs. The grade of the roadway is very steep
and difficult to ascend, and it is impassable for modern vehicles.
42. The Spoleto viaduct, according to Gauthey (Fig. 18),
was built by Theodelapius 741 A. D. to carry an aqueduct
across the valley. It has ten Gothic brick arches of 70-foot
span on piers 11 feet thick, and the deck was 426 feet above
the valley, being the highest stone bridge in the world. There
is, however, some doubt about the account, as the viaduct
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which now exists is quite different to this description. It is
only 250 feet in height, and is believed to have been built in
the thirteenth century, not by an emperor but by the munici-
/^»^^w^>y^yvg^f^fww-v^g>^^^
Q
pHMUUlMfHUUUUl^^
Fig. 18.
pality. The present piers are wider than the arches, and in
several of the spans are intermediate braces at half the height
above the valley, added at a later period.
Fig. 19.
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46 BRIDGE ENGINEERING.
43. Pontc Vecchio, over the Arno at Florence (Fig. 19), is
the most important and interesting of the four old ones at that
city. It w:as originally built in the year 1177, though some
authorities state that it has existed since the Roman period,
but was rebuilt by Neri di Fiorvante in 1345 A. D. The three
segmental arch spans with lengths of 85 to 96 feet and a rise of
19 feet, carry rows of jewelers' shops on both sides, with an
upper footwalk between them, the covered gallery forming a
continuation of the passage between the Pitti and old Ducal
Palaces. Its total width is 105 feet and the piers are 20
feet in thickness, the design having been executed by the archi-
tect Gaddi. There is another very plain single span arch
bridge known as Ponte Vecchio at Calci near Pisa.
44. The Verona bridge, over the Adige river near Vieux-
Chateau, was built in 1354 under Scala, and consists of three
segmental arch spans of 146, 87 and 33 feet, respectively, with
piers from 22 to 36 feet thick, and round battlemented towers
at each end. The first permanent wooden bridge on the
present site of the Rial to was erected in 1180 by Nicolo Barat-
tiere, and in 1260 was replaced by another of wood, contain-
ing a small draw span. The bridge was intended both as a
passage across the canal and a lounging place for citizens.
Ponte della Paglia, Venice, near the southwest corner of the
Ducal Palace, was completed in 1360, and is still a favorite
assembling place for the inhabitants. The floor rises with
steps like the Rialto, but has no shops or other enclosures.
Ponte di Pietra, at Verona, was rebuilt in the fifteenth cen-
tury by Fra Giocondo, the architect of the Notre Dame bridge
at Paris. It replaced an old Roman bridge on the same site,
the two arches at the left bank being the original Roman ones.
45. For centuries the arch at Trezzo, over the Adda river,
was the longest masonry span ever attempted (Fig. 20). Its
erection belongs to the latter half of the fourteenth, century,
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MEDIAEVAL BRIDGES.
47
ing 87 feet above the springs. Two separate ring courses, the
inner one being 3 feet 3 inches, and the outer one only 9
probably in the year 1380, and was ordered by Barnabo Vis-
counti, Duke of Milan. It was a single granite arch in two
courses, with a span of 251 feet and a radius of 133 feet, ris-
Flg. 20.
inches thick, made a total arch ring thickness of 4 feet. The
bridge carried a highway, and, although fortified, was de-
stroyed by Carmognola about 1410. In 1838 about 20 feet of
each abutment arch still remained.
46. A bridge over the Ticino at Pavia, of very unusual
design, was built in the fourteenth century under the direction
of Galeas Viscounti, Duke of Milan. The seven pointed arches
were of 70-foot span and 64-foot rise, with crown thickness
of 5J4 feet and pier thickness of 16 feet. The bridge proper
was of brick and was covered by a roof supported on one
hundred granite or marble columns. The original construc-
tion no longer exists, though the present one, with six arch
spans, the largest 100 feet, is several centuries old.
47. Other bridges of the period are the Admiral bridge
(1113) over the Oreto near Palermo, designed by George of
Antioch, a bridge at Pavia over the Tess (thirteenth century)
with several spans of 41 to 77 feet, and central deck towers.
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BRIDGE ENGINEERING.
and Alexandria bridge over the Tanaro (fourteenth century)
with covered passageway on a series of arches from 54 to 68
feet. The bridge at Torccllo is also interesting because of the
stepped parapet following the grade of the roadway. In the
year 1474 Ponte Sisto, over the Tiber at Rome, was rebuilt
under Sixtus IV., on the ruins of the old Pons Janiculensis.
The site is a historic one, for its was previously occupied by
Pons Valentinianus. Bridges at Signa and Mossa probably
belong to the fifteenth century.
Mediaeval Spanish Bridges.
48. Roman bridges were better preserved in Spain during
the Dark Ages (500-1100 A. D.) than in any other country.
The Moors, who were a cultured and educated people for their
Fig. 21.
time, were careful of their public works and built some new
bridges patterned after Roman ones, among which were those
at Cordova and the Alcantara bridge at Toledo. The Cordova
bridge, over the Guadalquiver river, has sixteen spans and
was built in 916 by Saraceus, in the reign of Hesham or Is-
Flg. 22.
sem, the second Moorish king in Spain. The bridge of Alcan-
tara at Toledo, Spain (Fig. 21), also by the Moors, has two
semicircular arches of 50 and 93 feet, and was completed in
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MEDIAEVAL BRIDGES. 49
997. It has triumphal arches and is still in good condition. St.
Martin's bridge, over the Tagus at Toledo (1203) (Fig. 22),
has a central span of 132 feet with 38-foot span at each side,
and a shorter one at each end. The central arch is very slightly
pointed.
Other bridges of this period in Asia Minor are at Adana,
Aspendon, Antioch, and Aleppo, the two latter having four
and thirteen arches, respectively. A bridge at Beirut has seven
arch spans, and another at Hamarth eleven spans. Some au-
thorities have, however, attributed these six bridges to Trajan,
A. D. 98-117.
Mediaeval Austrian and German Bridges.
49. Few records are available concerning any new bridges
in Austria and Germany during the Dark Ages (600-1100).
The first one of the period was over the Danube at Ratisbon or
Regensburg, Bavaria, built by the Germans in 1135. The
semicircular arches were fifteen in number, and 33 to 53 feet
in span, and total length was 994 feet. Following this was the
stone arch bridge at Dresden over the Elbe. It belongs to the
period of Augustus II., between 1179 and 1260, and during
1727 to 1731 was widened by adding brackets to support side-
walks. It is believed to be the first stone arch bridge over
the Elbe* at Dresden. It is nearly one-quarter of a mile in
length, 37 feet in width, and contains sixteen or eighteen semi-
circular arches of 34 to 65-foot span, supported on piers about
80 feet thick. Engineer Fotius directed the construction. Dur-
ing the war of 1813 it was partly destroyed by Marshal Davout.
Fine fortification towers at the ends are notable features of
both the Ratisbon and Dresden bridges.
50. The old Holy Cross bridge at Feldkirch, Austria, over
the 111 river, of 1250, contained one semicircular arch of 60
feet and 11 feet wide, and was replaced in 1898. The old bridge
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50 BRIDGE ENGINEERING.
at Frankfort on the Main (1342), of red stone, supports a
statue of Charlemagne, and near it an iron cross with a figure
of Christ, surmounted by a cock. Charlemagne enacted laws
for the preservation and protection of bridges and placed the
care of them upon the local bishops, authorizing them to col-
lect tolls and make necessary repairs. The bridge of Kosen
over the Saale, erected in the thirteenth century, has pointed
arches, eight in number, of 20 to 27 feet, with roadway inclin-
ing to the center.
At Berne, Switzerland, the first bridge over the Aar river,
adjoining Nydeck castle, was built in 1204, with a span of
150J4 feet.
51. The stone arch bridge over the Moselle river near its
junction with the Rhine at Coblenz, was erected in 1344 by
Elector Baldwin, and contains fourteen spans. It was repaired
in 1440 ; in 1832 a tower was added ; and in 1884 it was further
rebuilt. In 1864, when the water in the river was very low,
remains of an old Roman wooden pile bridge was discovered
just below the site of the stone bridge, which remains are
believed to date back to the fifth century.
52. A greater length of time was occupied in building
the Karlsbrucke, over the Moldau at Prague (Fig. 23), than any
other bridge in history. It was commenced by Emperor
Charles IV. of Germany in 1348, but not completed until 1507,
after a period of one hundred and forty-nine years. It has
sixteen arch spans, the largest 69J^ feet, and over the piers
' on either side are thirty statues and groups of saints. The
total length is 1,855 feet, and at either end are gate towers
with unsymmetrical roofs. Notwithstanding the unusually
heavy piers and icebreakers, it was seriously damaged by flood
in 1890 and since has been repaired. The large bronze statue
was erected in memory of St. John Nepomuc, the patron saint
of Bohemia, to visit which thousands of pilgrims come an-
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MEDIAEVAL BRIDGES.
51
nually. It is said that St. John had received confidential in-
formation from the Empress, and on refusing to betray the
secrets, the Emperor caused him to be thrown from the bridge
and drowned. It is further related that Emperor Ferdinand
II., after defeating the Protestant Bohemian king, in the bat-
Flgr. 23.
tie of White Mountain, near Prague, in 1620, caused twenty-
seven Bohemian noblemen to be beheaded, and their heads
-hung in iron cages on the Karlsbrucke tower.
53. A bridge at Kreuznach, Germany, has at least three
arch spans with large buildings balanced on the piers, present-
ing an unstable appearance; which one at Tournai, Belgium,
has three pointed arches and heavy round towers with battle-
mented parapets at each end.
Mediaeval British Bridges.
54 The oldest stone bridge in Britain was one over the
East Dart at Dartmoor, England, supported on three piers
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52 BRIDGE ENGINEERING.
made of large granite blocks. It is believed to date back two
thousand years or more. The floor consists of granite slabs,
some of which are 15 feet long and 6 feet wide.
55. The Croyland bridge (Fig. 24) is probably the most
ancient arch bridge in the British Isles. This strange triangu-
lar structure which seems to be quite useless, crosses the
Welland river at a point where it divides in two channels,
known as the Nyne and Catwater rivers. The three pointed
arches have their abutments at the angles of an equilateral
triangle in three different counties, spanning the three streams,
and forming separate roadways meeting at the center. Each
of the semi arches has three stone ribs beneath it, and the
grade of the. floor is so steep that it is suitable for pedestrains
only. It is believed to have been first built about 860, as a
charter referring to it is dated 943. The present structure has,
however, indications of more recent origin and was probably
rebuilt from the original design in 1380. At one end is an
image, supposed to be that of King Ethelbald with a globe in
the left hand and a crown on his head. The Abbot of Croyland,
Lincolnshore, at the head of a religious order, probably
directed the work. In 1854 the stream passing under it
was arched over, and the surface is now dry.
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56. A stone bridge at Bow near Stratford, England, was
erected (1110 to 1118) over the river Lea, by order of Queen
Matilda, wife of Henry L, but was replaced in 1835 to 1839 by
a stone arch of 66-foot span. It is the earliest stone bridge
in England of which definite records remain. For better re-
sisting the force of the current it was bowed up stream, and
was the first curved bridge on the island. Lives are said to
have been lost in crossing the ford, and as the Queen had her-
self been in peril there, she ordered this bridge and another at
Channelsea, to be erected.
67. An old Thames bridge at London is believed to have
existed A. D. 978, though the first authentic records refer to
Fig. 25.
one of 1014, which was partly destroyed by fire in 1136. The
old London bridge with shops on either side (Fig. 26), was
started in 1176 by Peter of Colechurch, the same year that St.
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54 BRIDGE ENGINEERING.
Benezet began the Avignon bridge in France, but it was not
completed until 1209. Peter is supposed have belonged to
the religious order known as The Brothers of The Bridge, who
built and raised funds for building bridges throughout Europe.
He died in 1205 before the work was completed, and his re-
mains were buried in a cr3rpt of the chapel on the center pier
according to the rules and customs of the society. After
his death King John appointed as his successor, one Isembert,
a French engineer who formerly directed the building of the
Saintes and La Rochelle bridges. This bridge contained
nineteen or twenty pointed arches with spans of 9 to 20 feet
and a single draw span. Like other bridges of the time, it had
defense towers, and on them were often hung the heads of
decapitated traitors. The piers were 25 to 34 feet thick,
founded on elm piles overlaid with plank, and occupied two-
thirds of the whole waterway, with an enormous surplus of
material, forming a serious and dangerous obstruction in the
river . The total length of the bridge was 940 feet, but the
clear space between the piers was only 310 feet. In 1212,
three years after its completion, fire broke out at the south end
and great crowds of spectators gathered on the bridge. An-
othej fire then started among the houses at the north end, and
people on the bridge were locked in between two fires and
three thousand or more were drowned or burned. It was re-
built in 1300, but was again burned in 1471, and again in 1632.
The outside width did not exceed 40 feet and buildings often
projected far over the water. In 1481 a whole block of these
overhanging houses became loosened and fell over into the
river. Up to this time the passageway between the shops or
houses had been only 12 to 14 feet, and was hardly sufficient
for vehicles to pass. Therefore in 1666, when the houses were
again burned, they were rebuilt with a passageway of 20
feet. Another fire occurred in 1725, and in 1756 all houses
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MEDIAEVAL BRIDGES. 55
were removed and the middle pier and two arches replaced
with a 72-foot span. Toll charges were discontinued in 1782,
but it remained the only bridge across the Thames at London
until the completion of the Westminster bridge in 1760, not-
withstanding its excessive repair and maintenance cost of
about $20,000 per year.
The tolls and offerings made at this and other bridges,
were for their maintenance and repair, and had these offerings
been honestly collected and carefully disbursed, decay in
many cases would have been avoided. But as the manage-
ment of bridges was frequently given to court favorites, the
receipts were too often appropriated for private use.
68. A bridge, probably of the twelfth century, located
at Burton in Staffordshire over the river Trent, has thirty-
six arches of squared freestone, and a total length of 1,646
feet, being the longest in England. Originally it was erected
by a religious order under Abbot Bernard, but was replaced
in 1864. A bridge was also built at Norwich in 1295.
Two very interesting bridges in Scotland are "The
Bridge o' Balgownie" and the "Auld Brig o* Ayr." The first is
a single Gothic arch of 67 feet crossing the river Don near
Aberdeen, and its erection is attributed to Bishop Cheyne, in
-A A ^
' y V S7 ^
Fig. 26.
the year 1281. A stone bridge at Newcastle-on-Tyne is also
recorded in the same year. The Auld Brig o' Ayr (Fig. 26)
was of an earlier date, and is at least 700 years old, for it is re-
ferred to in a charter of 1236. The four segmental arches of 63-
foot span and 18-foot rise, are borne on piers 16 feet thick with
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56 BRIDGE ENGINEERING.
lotig pointed cutwaters, the whole being founded on a grillage
of oak logs a few feet below the surface. It has recently been
restored by underpinning the piers and adding new concrete
spandrel walls. The 12-foot roadway was so narrow that a
new and more commodious bridge was erected close to it. It
is one of the best known of the old bridges of Britain, having
been immortalized by the poet Robert Burns.
59. Another old bridge of ten spans was built at Rochester,
England, over the Medway about 1200, with piers 43 feet apart
on centers, the openings between them being spanned with
three lines of beams covered with plank. At the east end
was a wooden tower for defense, but both tower and bridge
were burned in 1264 by Simon Montford, Earl of Leicester.
It was afterwards rebuilt in stone (1394) chiefly at the ex-
pense of Robert Knolles and Baron de Cobham, and is referred
to during the reign of King Richard II. In order to raise
money for repairing it, John Morton, Archbishop of Canter-
bury (1489), gave remissions to persons contributing for this
purpose. Other bridges of the thirteenth century in Scotland
crossed the Tay at Perth; the Esk at Brechin; the Dee at
Kincarden and the Clyde at Glasgow (1345). The old Forth
bridge at Stirling (1400) has at least four arch spans of about
53 feet and small towers at one end. Near it was foUght
the battle of Stirling in 1297. The Bishop Auckland bridge
(1388) carrying a highway over the river Wear, has one 100-
foot span with 22-foot rise, and one 91-foot span with 20-foot
rise, and was the first segmental arch in England.
Mediaeval Oriental Bridges.
60. Records of engineering and architecture in China,
Japan and other countries of the Orient, have not been well
preserved and dates are not generally available. Recent travel
in those lands show that bridges of fifty arch spans exist, and
smaller ones with five to seven spans or less are very numer-
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MEDIAEVAL BRIDGES. 57
•
ous. The early engineers generally made their bridges with an
uneven number of openings. Some single spans are, however,
carried to heights out of good proportion, but made necessary
for the passage of boats with sails. The city of Soochow, in
China, has thirty miles of canals, crossed two hundred times
or more with stone bridges. Bronze and marble bridges were
common in China in the eighth century of our era. History
reports the existence of a bridge over the Laffransri river be-
tween two mountains, with a single 600-foot semicircular arch
of white marble, 750 feet above the water. It was called the
"Flying Bridge" and was built of blocks 7 to 12 feet in length.
In the province of Fo-Kien, was another bridge 11,880 feet
long (180 chains) and 25 feet wide with three hundred and
one arches on three hundred rows of pillars. There were
parapets at each side, and at intervals were figures of lions
and other sculptures. Another similar structure is reported
at Fechew, the capital of Fo-Kien, which is 4,950 feet long
with one hundred lofty arches. It, too, has parapets orna-
mented with figures of lions, and is believed to be many ages
old. The material in both these is fine hard white stone. Loy-
ong bridge, five miles long over an arm of the China Sea, has
three hundred stone arches, 70 feet high and 70 feet broad, and
each 'pillar supports a marble lion 21 feet in length. Other
bridges of remarkable proportions are reported at Focheu with
a length of 22,000 feet and width of 60 to 70 feet.
61 A curious cantilever at the sacred city of Nikko, Japan,
which is known as "Shogun's Bridge" was erected 600 or 600
A. D. It is described as follows: "The abutments are of
hewn stone, the shore piers of hewn granite, octagonal and
monolithic, mortised for stone girders. Monolithic plate beams
receive the wooden structure. The stringers which fasten
into the abutments balance over the stone beams, but do not
reach by a considerable distance, the gap being fitted by mid-
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BRIDGE ENGINEERING.
die stringers let into the stone stringers. It is not used by
the laity." At Osaka, Japan, there are* said to be 7,000 bridges
over rivers and canals.
62. Three bridges at Adabazar, Adana and Mopsuestia in
Asia Minor are believed to be the work of Justinian (A. D.
527-565). The one at Adabazar has eight arches of 75 feet
each and a total length of 1,400 feet, while the Adana bridge
in Cilicia has eighteen arches on very heavy piers, and the
Mopsuestia has nine arches.
There are several bridges in Persia belonging to this period.
Krast-Nemoust of the eleventh century is very plain with
four arches of unequal span, the largest being 98 feet between
piers with stone ice breakers. In Northern Persia is a very
simple bridge in the village of Erivan (12th century) with two
spans of 46 feet, and a smaller span at each end, the roadway
being 20 feet wide. It was restored in 1830. The Doktare-Pol
crosses the Kisilousou river near Tauris with three equal
spans, and also belongs to the twelfth century.
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RENAISSANCE BRIDGES. 59
CHAPTER IV.
THE RENAISSANCE PERIOD (A. D. 1600-1760).
French Bridges.
63. During the 250 years following A. D. 1500, bridge
building was more active in France than in any other coun-
try and was chiefly under the direction of the Brothers of the
Bridges or Pontifeces until the seventeenth century. The
tendency was to make piers much thinner than formerly, and
during the sixteenth and seventeeth centuries they were gen-
erally one-quarter of the. clear opening, or one-fifth of the
distance between pier centers. The use of elliptical and other
flat arch forms commenced in France towards the close of the
seventeenth century, the form resulting from the need of wider
spans without excessive rise or too steep a roadway grade.
A brick arch bridge at Toulouse over the Garonne river (1543-
1632) containing seven spans from 45 to 113 feet and 64 feet
wide, was very ornamental and a fine bridge for the time, A
stone bridge at Toumon over the Doux river (1545) had one
span of 157 feet, while the bridge of Chenonceaux (1556) sup-
ported the chateau with its three stories and many towers on
a series of seven arches over the river. But the most important
new bridge of the whole period was Pont Neuf over the river
Seine at Paris. It crosses the end of an island, which divides
the bridge in two sections. One of these sections has seven
spans from 46 to 62 feet and the other has five spans in
lengths of 31 to 48 feet. The construction was started in 1575,
but was delayed by war until 1602, and was not completed till
1606. The width over parapets is 72 feet and the piers have
heavy triangular cutwaters extending up to high water or a
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60 BRIDGE ENGINEERING.
little above the springs. From the cutwaters to the cornice
are semicircular stone columns of the same width as the piers,
supporting at the deck, lookouts or sidewalk retreats which
are provided with stone seats. The bridge has a solid balus-
trade with two lamp posts at each side over the piers and a
heavy cornice supported on stone brackets. On the island
between the two sections is an equestrain statue of Henry IV.
enclosed by an iron railing. The bridge was designed by
Androuet du Cerceau, but was remodeled in 1863 by placing
elliptical arches under the circular ones. Its total length is
now 1,080 feet.
64. The Claix bridge over the Drac river near Grenoble in
France, with a single span of 150 feet and width of 20 feet, was
completed in 1611, but as it was narrow and the grade steep,
a new stone bridge with a flat arch of 170 was placed beside it
in 1874. Pont St Michael in Paris, originally completed in
1617 was rebuilt in 1859, the number of spans being reduced
and the width increased. Four other bridges over the Seine
at Paris are Pont au Change (1639-47), Pont Tournelle (1656),
Pont Marie (1635-58), and Pont Royal (1685). Pont au Change
had seven short semi-circular spans of 35 to 51 feet, but was
rebuilt in 1858 with fewer spans and greater width. Pont
Tournelle, designed by Marie, has six spans of 45 to 59 feet,
and was 53 feet wide. It was widened in 1845 by the addition
of cast iron arches. The next bridge, known as Pont Marie
from its designer, had five seitiicircular spans of the same
length as the one previously designed by him, but was 77 feet
wide. Pont Royal was designed by Mansard with five longer
elliptical arches from 68 to 76 feet and piers 15 feet thick at
the springs. St. Michael, Marie and au Change bridges stifl
exist. The Cognet bridge over the Drac river at Hautes Alpes,
France, with two semi-circular arch spans of 85 feet was only
11 feet wide. An ancient bridge of uncertain date over the
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RENAISSANCE BRIDGES. 61
river Vienne at Limoges has seven or more pointed arches
of uncouth design with heavy projecting round ended piers
extending up to the parapet.
65. The dredging machine was used for the first time in
building the foundations of a bridge at Maastricht over the
Maas river in Holland, begun in 1635 under the, direction oi
the Dominican monk, Romano. The use of fiat vaulted arches
in France began about the close of the seventeenth century.
66. At the beginning of the eighteenth century, it became
evident in France that the public bridges, after centuries of
neglect were in a dangerous condition and many of them must
be rebuilt. The French Government therefore, in 1715, created
a department of Bridges and Roads with M. Gabriel as chief
engineer. This was the real beginning of the modern revival
of bridge building in Europe. The movement was afterward*
promoted by the establishment of an Engineering School in
1747, which was reorganized and enlarged in 1760 under the
direction of Perronet. Under the new department of Bridges
and Roads, development in bridge building was rapid. Ellip-
tical and segmental arches of longer spans with slender piers
were used and greater attention given to their architectural
treatment. Piers were thinner than before, the usual thick-
ness being one-fifth of the clear opening. But progress was
sometimes accompanied with failure, for a three-span bridge at
MouHns over the AUier river by Mansard (1705) with center
and side spans of 147 and 115 feet, and piers 36 feet thick at the
springs, collapsed in 1710. The Blois bridge over the Loire was
built by Pitron in 1733 under the direction of Gabriel, having
eleven elliptical arch spans of 64 to 68 feet, with a spire like
finial on the balustrade to mark the center. Piers were 22}4
feet thick at the springs, temporary centers being supported
at the ends only, without intermediate blocking. Other bridges
were built in 1732 at Tetes over the Durance, at Villeneuve
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over the Lot and in 1740, one at Charmes over the Moselle.
Spanish Bridges.
67. The Ronda viaduct (Fig. 27) of the seventeenth cen-
tury, is the principal one of the period in Spain. It is 460 feet
high and 280 feet long on top, with a central opening 46 feet
wide extending from the water nearly to the deck, the opening
Flgr. 27.
•being crossed by an intermediate arch 230 feet above the bot-
tom. At each side of the center opening is a_35-foot arch, and
the piers between them are highly ornamented. The aqueduct
of Alcantara at Lisbon (1774) is described in the chapter on
Aqueducts.
Italian Bridges.
68. Italy made less progress in bridge building during this
period than France, but it produced at least three of historic
interest. Trinity bridge at Florence and the Rialto and Bridge
of Sighs in Venice. A development of greater importance than
the mere construction of a bridge was the discovery in 1560
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RENAISSANCE BRIDGES. 63
by Palladio, an Italian architect, of the principle of the truss.
It was first used in roofs and smaller edifices, but at a later
period revolutionized the art of bridge building by making it
possible to design trusses in iron and steel. Palladio was pro-
ficient in design, but unfortunately much of his finest work
was never executed. A bridge at Munster on the Navante
formerly in one span, was much superior to the Rialto. An-
other which was one of his grandest conceptions is described
as containing several streets, "not for vehicles, but of lodges
and porticos with statues of marble and bronze." Ponte Curve
over the Metza (1505) is a fine production with seven spans
74 to 94 feet in length, with a rising grade towards the center,
and the bridge of Capodarso over the Imera, Sicily (1553),
has a single span of 95' feet. Trinity bridge over the Arno
at Florence, ma^le of white marble, has three arches, the
intrados of each being approximately a semi-ellipse, but really
two parabolic curves meeting at the center, the Gothic center
being covered with an ornamental shield. It was built in 1669
from a design by B. Ammanati, and has spans of 95 feet with
a rise of 15 feet, or one-sixth the opening. The piers are 26
feet thick, and the width of deck is 33.7 feet, while the arch
ring has a crown thickness of 2.75 feet. The clear water way
between the piers is 270 feet and the total length 322 feet.
At the corners are four allegorical statues representing the
seasons. It is known in Italy as Pont della Santissima Trinita,
and is believed to be the earliest bridge with flat elliptical in-
trados. Ponte Nuovo at Pisa is very ornamental and similar
to Trinity.
69. The Bridge of Sighs between the Ducal Palace and
prison in Venice was designed by Antonio da Ponte and com-
pleted in 1597. It crosses the Rio della Paglia, 32 feet above
the water. It is enclosed on the sides, arched overhead, and
provided with a partition down the center, forming two sepa-
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BRIDGE ENGINEERING.
rate passages. The bridge is small and contains little of in-
terest apart from its historic association. A more important
one is the Rialto over the Grand Canal, designed by the same
architect as the last one. The Rialto (Fig. 28) is probably the
best known bridge in Europe, and was built during the years
1588 to 1591. There is little doubt but that Michael Angelo
prepared plans for it, and it is therefore often accredited to
him. The Encyclopaedia Britannica in commenting on the
subject says, "Erroneous statements have often been made that
FifiT. 28.
this bridge was built from a design by Michael Angelo.
The mistake has arisen from the misinterpretation of a passage
in the works of Vasari." Michael Angelo believed that a
bridge should be built as though it were intended for a cathe-
dral, with the same care and of the same materials. Along
with other Italian architects, he had a preference for marble
over other building stones. The bridge has an extreme length
of 158 feet, and a width of 72 feet. On the roadway are two
rows of shops with a passage way between them, six shops in
each row on either side of the center, or twenty-four in all.
In the center of the bridge is an open passage connecting the
roadway with the walks, the whole arrangement forming an
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RENAISSANCE BRIDGES. 65
arcade. The footwalks on the outside are carried on project-
ing brackets, and as the floor grade is steep, the walks are
provided with marble steps and enclosed with ornamental
balustrades of beautiful design. The intrados is segmental,
about one-third of a circle, and the arch ring and spandrels are
ornamented on the face with figures of angels, and tablets
with inscriptions. The material is white marble. Steps at
either end lead up from walks along the canal, and the ar-
rangement of arcades on the rising grade, together with the
central passageway and the arch above, all present a general
effect both pleasing and harmonious. At this time Venice
is said to have had no less than three hundred and fifty-seven
bridges. Wheeled vehicles were not generally used in Venice,
and the bridges were almost exclusively for pedestrain travel,
and yet none were neglected or allowed to fall into decay.
The Pleischbrucke over the Regnitz at Nuremburg, somtimes
called Pont des Boucheries, or Executioners* Bridge, was built
in 1599 by Peter Carl and was plainly modeled after the Rialto
in Venice. It is 63 feet wide, has a single arch of 97 feet, re-
markable at that time for its flat curve, the rise being only 13
feet. It is founded on obliquely driven piles. Ponte di Mezzo
(1660) with three spans, the center and side ones being 78 and
68 feet respectively, has flat segmental arches and heavy piers.
Some other Italian bridges were remodeled during this period,
among them the bridge of St. Angelo at Rome.
German Bridges.
70. A few new stone bridges appeared in Germany and
Holland during this period, including one at Prague over the
Moldau (1660), the bridge of Livettan near Torgan with a
series of opening 46 to 49 feet long, and cut waters on alter-
nate piers, the Meuse bridge at Maestrich (1683) and the Kur-
fursten bridge at Berlin (1696). The Prague bridge was 820
feet long with a series of 77-foot openings. The Kurfursten
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66 BRIDGE ENGINEERING.
bridge like others in Berlin is very ornate, but its principal
feature is the central arch which is wider than the rest of the
bridge. This extra width is carried down to the foundations
with an offset at the two central piers, and the greater width
on the deck is partly occupied by statuary.
British Bridges
71. Spanning the river Ross at Ross, England, is the Wil-
ton bridge with five arches supported on wide piers with tri-
angular cutwaters. It was built in 1590, but in 1644 the arch
nearest the town was broken down by Colonel Rudhall to
impede the advance of Colonel Massie's forces. On the north
wall of the parapet is a quadrangular stone with a sun dial on
each side. A stone bridge over the Ouse at York, England,
erected during the reign of Queen Elizabeth (1658-1603), has
five pointed arches, the largest being 81 feet. At one end
was a house and clock tower, but the whole bridge has since
been removed. The Dorchester bridge, with five or more
pointed arches of unequal length and triangular cut-waters
extending up to the deck, is interesting and very old. The
bridge at Llanrwst, Wales, over the Conway river, was de-
signed by Inigo Jones in 1634. Of its three spans, the center
one was 58 feet, and as it vibrated easily, was known as the
"shaking bridge."
72. Previous to opening the Westminster bridge in 1760,
the Thames was crossed at only one other place in London.
The word "bridge" as found in descriptions of London and the
Thames, often refers to landing piers on the river, and this im-
proper use of the word has given rise to some misunder-
standing. An effort was made in 1671 to erect another over
the Thames at Putney, but like similar projects, met with very
serious opposition. One member of the London Council de-
clared that another bridge would turn traffic away from the
city and bring ruin to London, though the old one was not
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RENAISSANCE BRIDGES. 67
wide enough for two carts to pass. Westminster bridge was
begun by Labelye in 1738 and completed in 1760. It was 44
feet wide and contained fifteen semicircular stone arches, the
longest or center one having a span of 76 feet, while the suc-
ceeding ones on each side decreased continuously by 4 feet,
excepting the two end arches which were 25 feet each. Its
total length was 1,164 feet, the arches having an aggregate
opening of 820 feet, but they have since been replaced by cast
iron. It marked the beginning of a new era in bridge founda-
tions, for the piers were built with caissons instead of coffer-
dams, this being the first application of the new method. The
caissons were sunk on a pile foundation, covered with timber.
The cost of Westminster bridge was $1,120,000. A wooden
arch bridge with stone piers, designed by John King, was be-
ing erected at the site and the stone piers were approaching
completion, when Labelye in 1739, published a pamphlet stat-
ing the merits of his stone arch design and showing that Mr.
King's plan could still be changed to give the city a permanent
stone bridge instead of a wooden one, which latter he de-
clared would be a disgrace to London. Labelye's efforts pre-
vailed and after the city had paid the contractor a liberal sum
to relinquish his wooden bridge contract, the plans were
changed and the bridge completed in stone.
73. The Tay bridge at Aberfeldy, Scotland, was built in
1733 with one central arch and four smaller ones, two at each
side. Four obelisks rise from the parapet at the ends of the
main span, and over the center span is a tablet engraved with
cross, crown, swords and the initials of King George. A
mounment was erected at one end in 1887 to commemorate the
raising of the Black Watch Regiment which was first mustered
there in 1740. The bridge Bettws-y-Coed in Wales, is said by
some historians to be of Roman origin. Pont-y-Pridd, near the
town of Newbridge, Wales, crosses the river Taff with a
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68 BRIDGE ENGINEERING.
single 160-foot stone arch with a rise of 35 feet. The grade
was one in four and was so steep that wagons had difficulty in
ascending. It was 14 feet 6 inches wide at the soffit, increasing
by six offsets to 16 feet 10 inches at the springs, and the road-
way was 11 feet clear width at the center. The arch ring on
the face was of cut stone 2 feet 6 inches thick at the crown,
but the remainder of the ring, rubble masonry. The first bridge
on the site was a three span arch built by William Edwards
in 1746, and soon afterwards washed out, but as Mr. Edwards
had given security for a seven year's guarantee he was ob-
liged to rebuild it. The second bridge failed by rising at the
crown, due to excessive weight in the haunches, and at the sug-
gestion of the English engineer, Smeaton, when rebuilding it
in 1760, it was lightened by coring out large circular holes in
the masonry and using charcoal for spandrel filling. The de-
signer and builder, William Edwards, was a village stone
mason who had formerly been a clergyman for forty years. The
first Essex bridge at Dublin was founded 1676 by Sir Hum-
phrey Jarvis, but was taken down and rebuilt in 1753. Arran
bridge in the same city, erected in 1684, was replaced in 1763
by Queen's bridge.
American Bridges.
74. The most notable bridge of the period in North
America was the Tempoalo aqueduct-viaduct, built 1663 to
1570, seven miles south of Huauchinango, Mexico. It was
erected by Tembleque under the direction of Franciscan friars
and had sixty-eight semicircular stone arches, the largest be-
ing 58 feet. It lies on two connecting tangents containing an
angle of 170 degrees, the maximum height being 124 feet and
the water duct very small, only Syi by 12 inches. Other similar
aqueduct viaducts in Mexico are at Cuernavaca and Orizaba,
while ruins of an ancient one are found at Acambarro, Mexico.
An interesting old bridge at Santiago, Chili, croses the Mapocho
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RENAISSANCE BRIDGES.
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river on eight or more arches, the piers having round ends ex-
tending above the roadway at each side in the form of towers.
At Callao, Peru, a stone bridge of four arch spans or more has
heavy piers with round ends extending up to the parapet, and
one at Arequipa, Peru, has similar piers extending to the road-
way on each side of the center span, while the semicircular
cutwaters of the other piers terminate below the arch springs.
Other old stone bridges of uncertain date are found at Quito,
Ecuador. Interesting ones in Colombia are Comun bridge with
five stone arches; the Colon bridge, Bogota, with two stone
arches, and the San Francisco, Bogota, with a single pointed
arch.
75. In 1668, the Great Bridge at Boston, Mass., was built
on the present site of North Harvard street bridge. This
wooden pile structure was considered an important one at the
time, for the population of Boston did not exceed three thou-
sand, and the surrounding district was required to pay a por-
tion of its cost.
Oriental Bridges.
76. A five-span wooden arch bridge designed by the
Daimio, was placed over the Kintai river at iwakuni, on tlic
Isle of Honda, Japan, in the year 1673 (Fig. 29). Each of
Fig. 29.
the three central arches is 149 feet, the total length being
746 feet and the roadway 18 feet wide. The piers are 37
feet high and their clear height beneath the center span is
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70 BRIDGE ENGINEERING.
71 feet. The arch ribs are made of keaki wood, which has.
high working strength, while the covering and balustrade is
hinoki wood, a species of cypress. In ancient times, one of
the spans was replaced every five years, to the whole bridge
was rebuilt four times every century. As the floor follows
the curve of the arches, it is evidently suitable for pede-
strians only, and is built with treads and risers, the width
of treads being uniform. Some of the stones in the piers
were fastened with metal dowels and others cemented to-
gether with lead.
77. Persian bridges are very interesting, and picturesque
and some of the later ones, elegant with rich ornamentation,
characteristic of both East Indian and Moorish architecture.
The arches are pointed (or ogival), the piers very thick, and
brick is chiefly used in the construction. Of the earlier ones
in this period may be mentioned Mianeh (1580) with twenty-
three arches, and Tauris, constructed in 1610, with eighteen
arches in a sinuous course across the river similar to Shuster
bridge, and over 500 feet long. The ancient capital of Persia
is Ispahan and in it are several beautiful bridges over the
Senerud river, built during the reign of Shah Abbas the Great
(1585-16^8). One of these is described as being "2,250 feet
long, 120 feet high and 156 feet broad with the center roadway
of 60 feet. It has twenty-nine Moorish arches of 50-foot span
with piers 25 feet thick. The sidewalks, which are paved with
marble, are through elevated covered arcades which are
reached by stairways in the four towers and supported by
arches, three of which stand over each of the main fifty arches
beneath. It is sometimes known as the bridge of Barbaruh."
The bridge of Allah- Verdi-Kahn is named for the general
who bore the expense of its construction. Its thirty-six free-
stone arches of 18-foot span carry the deck, the entire length
of which is nearly 1,000 feet and 46 feet in width, and the
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RENAISSANCE BRIDGES.
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whole is elaborately decorated. It has a level roadway with gal-
leries 10 feet wide on either side over the whole length of
the bridge, raised several steps above the roadway. The gal-
lery walks are supplied with frequent openings to admit light
and air and give a river view, and there are open passageways
above the galleries. The bridge of Hassan-Bey, which is
about 415 feet in length and about 40 feet wide, is similar to
that of Allah-Verdi-Kahn, but has a prominent central feature
of added height and octagonal plan. The galleries with promi-
nades supply a place of recreation for the inhabitants away
from the heat of the city. The balustrades, spandrels and other
parts of these bridges are treated in the highly decorative
manner, with mosaics of stone and tiles in color, characteristx
of oriental work.
78. The single stone arch bridge of El Ghajar crosses a
stream which is one of the chief sources of the Jordan. The
covered bridge of shops at Srinagar, India (Fig. 30), is sup-
ported on a series of large wooden cribs which occupy about
Fl«. 30.
half the river width. The piers are protected with cutwaters up
to high water, and the timbers are corbeled out at the top until
they nearly meet at the center. The deck of the bridge is cov-
ered with a number of separate rustic buildings of various
form and sides, and altogether, it is a unique production.
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72 BRIDGE ENGINEERING.
CHAPTER V.
MODERN STONE BRIDGES (1760^1900).
79. The revival of stone bridge building began in France
about the middle of the eighteenth century, and many of the
finest ones of the period are found in that country. In Eng-
land, only one bridge spanned the Thames at London previous
to the new Westminster bridge in 1760, and excepting the
Blackfriars, most modern ones were not commenced until after
the beginning of the nineteenth century. Prior to 1830, bridges
were chiefly for highways and aqueducts, but with the build-
ing of railroads, came the use of many stone and brick via-
ducts in France, England and Germany, this form being the
accepted type for thirty years, until quite generally supplanted
by those of iron and steel. In America stone bridges were
not extensively used prior to 1880, excepting for a few aque-
ducts, but since that date both stone and concrete bridges have
been adopted by many American railroads. The commercial
activity and prosperous conditions of the nineteenth century
have brought masonry bridges more into use as permanent
structures for American cities, and not only large city bridges
but also smaller ornamental ones in city parks are made of
the more durable material. The number of stone bridges
built in all countries during the last one hundred and fifty
years is therefore so great, that it is impracticable to tabulate
or describe more than a few of the more important ones, the
majority of those referred to having spans exceeding 60 feet.
Long spans are not, however numerous, and in 1886 there
were less than sixty brick or stone arch bridges with spans
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MODERN STONE BRIDGES. 73
exceeding 120 feet. Of these, twenty-seven were in France,
thirteen in Italy, ten in England, two in Spain, two in Austria
and one each in Switzerland, Germany and the United States ;
thirty carrying highways and twenty-two railroads. One had*
a span exceeding 214 feet ; three, spans of 214 to 187 ; ten had
spans of 187 to 152, and forty, spans of 162 to 120.
French Bridges.
80. France and England have been the leading nations u
building masonry bridges since 1750. This was due in France
chiefly to the government supervision of bridges by the dt
partment of Bridges and Roads created in 1715, and to the
establishment and reorganization of an engineering school
in 1760 under the direction of Jean Rodolph Perronet, who
lived from 1708 to 1794. At the beginning of this period
in France, the department of Bridges and Roads was under
the direction of Hupeau, by whom the bridge over the Loire at
Orleans was built. This bridge has nine elliptical arches of
98 to 107 English feet in length, and replaced an ancient one
with nineteen smaller openings. It cost complete, over half a
million dollars. The intrados curves are semi-ellipses, pre-
senting a very satisfying outline and the piers have round ends
extending above the springs and terminating in stepped semi-
cones. The solid balustrade and the heavy stone work give the
appearance of strength and permanence. M. Hupeau was suc-
ceeded by M. Perronet under whose direction many other fine
bridges were built, including those at Trilport over the Marne,
Nogent and Neuilly over the Seine, St. Maxence, and Pont de
la Concorde or Louis XVI. bridge over the Seine at Paris.
The Trilport bridge was the first oblique elliptical one and
the first entirely under Perronet's direction, but the later one
at Neuilly is considered his finest production. The bridge at
Neuilly, 1768-1774, with five elliptical arch spans of 128 feet
each and rise of 32 feet, is 766 feet long and the soffits are
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74 BRIDGE EN-GINEERING.
conoidal, being the first appearance of this form ("cow horns")
Each of the two center piers of St. Maxence bridge (1785)
which is on the road from Paris into Flanders, is made of four
cylinder pillars 9 feet in diameter with an open space between
the middle ones, and on the deck at each end of the balustrade
are shafts or obelisks. The Gignac bridge is distinctive in hav-
ing a central 161-foot elliptical arch with a semi-circular one
of 72 feet at each side.
81. Pont de la Concorde, or bridge of Louis XVI., with
five segmental aches of 83 to 102-foot span, was begun in 1787
and completed in 1791. The piers are very slender, being only
10 feet thick, and the round ends extend to the balustrade in
the form of columns with capitals supporting pedestals. A
heavy coping with dentils and the open railing with turned
balusters are interesting details.
82. During the nine years from 1804 to 1813, when M.
Lamande was chief engineer of the department of Bridges
and Highways, France spent more than 40,000,000 francs for
bridges, many of which were erected to commemorate the vic-
tories of Napoleon. Two memorial bridges of this period over
the Seine at Paris, were Pont de Jena, 1807, and Pont de
Austerlitz, completed in 1813. Pont de Jena commemorates the
battle of Jena in which Napoleon was victorious over the Prus-
sians in 1806, and its location over the river to the Trocadero
is very prominent and appropriate. It has five elliptical arches
of 92-foot span and a clear roadway of 42 feet. Pont de Aus-
terlitz commemorates Napoleon's victory at the battle of Aus-
terlitz, and above each pier is a wreath surrounding the
initial "N." It has five flat arch spans and the complete
bridge cost over 3,000,000 francs.
83. The bridge over the Garonne river at Bordeaux was
commenced in 1813 and continued to completion in 1822. It
is chiefly notable for its large number of spans, which are
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MODERN STONE BRIDGES. 75
elliptical, and the combination of brick and stone, both of
which give it a distinctive appearance.
84. The building of aqueducts to supply water to metro-
politan districts frequently involved the construction of large
masonry viaducts, such as the near Aix, which crosses the
Arc river on the canal from Durance to Marseilles. This
viaduct, known as the Roquefavour, is described under "Aque-
ducts."
85. Pont au Change at Paris was built in 1859, with three
stone arches of 104-foot spans, carrying the Boulevarde de Se-
bastopol over the Seine, the bridge being the full width of the
street.
86. The Auteil viaduct, or Pont du Jour (Fig. 31), over the
Seine, has double decks, the upper story being supported on a
series of thirty-one small arches with other arches crosswise
Piar. 31.
through the supporting piers. The lower deck has five arches,
and over each pier is the imperial letter "N." Altogether there
are not less than thirty-two bridges over the Seine within the
city limits.
87. Soon after the beginning of railroad building French
engineers, following the example of others in England, con-
structed many large railroad viaducts of stone and brick, some
at a great elevation above the ground. Among these are the
viaducts at Montlouis with twelve spans (1844), which was
damaged during the war of 1870, but rebuilt, and Cinq-Mars,
with nineteen spans (1845), both across the Loire river and
valley. The Barentin viaduct (1844) with twenty-seven arch
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76 BRIDGE ENGINEERING.
spans of 50 feet, 112 feet high, fell after a great storm when
nearly completed, causing a loss of $150,000. The contractor,
Thomas Brassey, was advised by French lawyers that he was'
neither morally or legally responsible for its failure, but it is
said that he considered himself morally so, and therefore, re-
built it at his own expense. The Moret railroad viaduct
over the Loing river has thirty spans of 32 feet and two larger
ones of 132 feet, while the Din ^ lailroad viaduct over the
Ranee has ten spans with a maximum of 62 feet and is 130 feet
above the water. Other similar structures are at Chalonnes
with seventeen spans, and the Crueize river viaduct at Marve-
jois with a height of 207. Ihe Morlaix viaduct, which carries
the Paris and Brest railway, is a stone structure with fourteen
arch spans, an aggregate length of 934 feet, a height of 207
feet above the water and breadth at the top of 28 feet. It
carries a line of railroad and a paved roadway and is built in
two stories, the lower arches having a clear span of 44 feet,
while the upper ones have spans of 50 feet 10 inches. The
Piers are 14 feet thick at th esprings with a batter of one in
twenty-two below the first deck and one in forty above it,
while sideways, the batter is one in one hundred. After two
years in construction, it was completed in 1863 under the
direction of M. Planchet at a cost of $500,000.
88. The Chaumont viaduct (1858) is in three stoneb,
while later ones at Altier (1860), Selle (1874), and Busetti are
in double stories. Others at Aulne (1867), Vezouillac (1875),
Pompadour (1S75), and Rancidite (1880) are in single stories,
those at Rancidite and Bussetti having every third or fourtn
pier heavier than the regular ones. Another stone briagt: of
great height is the single span 140-foot arch of St. Sauveury
1860, in the Maritime Alps, springing between rock side walls
with the floor 215 feet above the stream, one of the most pic-
turesque in Europe.
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MODERN STONE BRIDGES. 77
89. A recent bridge of much merit, built in 1897, is located
at Verdun, France, over the Doubs, which cost $41,000. Three
spans with the center one of 134 feet, cross the stream, and the
intrados curves are semi-ellipses, with circular arcs for the
extrados. The whole length is 478 feet and width 20 feet. The
abutments, piers and main arches are gray stone, and the
spandrel arches, reddish brown brick, a pleasing color combina-
tion. The Tarn river brru^isiat Alby is also light and very
artistic in outline. A large masonry arch on the Bellegrade-
Chizery Railroad in France, front designs by Chief Engineer
Picard (1909) has a span of 262 feet 9 inches, and a height of
215 feet above the valley, the decWbeing supported by eleven
smaller spandrel arches. Centers were supported on three
timber towers, and the whole work cost $90,000.
90. The earliest extensive use of monolithic concrete for
modern masonry bridges is believed to be in connection with
the aqueducts for the city of Paris. Concrete filling was used
in the ancient Roman bridges, but on the Grand Maitre aque-
duct a long series of spans carrying the water across the Foun-
tainebleau valley, arches of solid concrete were employed to a
great extent without stone facing.
. 91. Statistic compiled in 1873 show that 1982 important
bridges existed at that time in France; 861 were built before
the nineteenth century, 64 during the First Empire, 180 dur-
ing the Restoration, 580 during the reign of Louis Philippe,
and 297 since 1848. The aggregate length of bridges is esti-
mated at 106 kilometers, and cost of their construction at 286,-
607,761 francs.
Spanish Bridges.
92. The Madrid bridge over the Mancanares, has a series
of semicircular 34-foot stone arches between heavy piers with
curved ends, and the Valence bridge over the Guadalaviar,
many flat segmental arches, both dating from the eighteenth
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78 BRIDGE ENGINEERING.
century. The Fuentecen bridge, over the Riaza, has four flat
spans of 52 feet, built in the nineteenth century.
Stone Bridges in Germany, Austria, Switzerland and Belgium.
93. Germany and Austria have produced some of the most
remarkable stone bridges of the last 150 years, comparing
favorably with those in France and England, though perhaps
not so numerous as in the latter countries. One of the earliest
of the period is the long stone bridge over the Neckar river at
Heidelberg, constructed in 1788 by the Elector Charles Theo-
dore, whose statue now stands on the pier at one end. The
chief interest in connection with this bridge is its association
and history. Located close to the famous old castle and to the
Heidelberg University, the place is deserving of a better struc-
ture, for the bridge shows but little merit either constructively
or artistically. The roadway has a broken grade and the
parapet and railings are a varied forms. On a pier near the
middle of the river is a statue of Minerva while over the other
piers are balcony retreats.
94. The Schloss or Palace bridge at Berlin was completed
in 1824 from designs by Schinkel. There are two stone arches
and between them a draw span, which is no longer used. It is
106 feet wide and the roadway is adorned at either side with
eight groups in marble, more than life size, illustrating the
life of a warrior. Other fine bridges at Berlin are the new
Oberbaum and the Frederick bridges, both of which are beauti-
ful architectural productions. The Oberbaumbrucke has
double towers over the middle piers marking the position ol
the channel, and over the sidewalk at one side is an overhead
structure supported on a series of brick arches carrying the
elevated railroad. The Freiderichsbrucke is a substantial mas-
onry arch with an open balustrade and crosses the river in the
vicinity of some fine monumental buildings. Over the piers
at the balustrade are pedestals mounted with statues holding
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MODERN STONE BRIDGES. 79
aloft ornamental lamp globes, the whole forming a beautiful
bridge and one in harmony with its surroundings. The Munich
bridge over the Isar river adjoining the Maximilianeum is also
worthy of its fine location.
96. Many of the largest stone bridges in Germany and
Austria have been built since 1833 to carry lines of railroad,
some of them at great height. Among these are the viaducts
at Spreethal, Goeltzschthal, Elsterthal, Gorlitz, Boberthal,
Konigstein, Waldi-Tobel, Jaremcze, Coppel and Wiesen. The
Goeltzschthal viaduct on the Saxon-Bavarian railway has four
tiers of brick masonry arches at the sides but only two tiers
at the center. The lower central arch has a span of 94 feet and
a height of 136 feet, while the upper center arch has a span
of 102 feet and a height of 105 feet. It has twelve sets of
arches on one side of the center and sixteen sets on the other
side, making altogether eighty arch openings. It is 1900 feet
long, 263 feet high and was completed in 1846 under the direc-
tion of R. Wilke. The Elsterthal viaduct, also on the Saxon-
Bavarian railroad, is a two story stone arch viaduct with a
length of 650 feet on the lower tier of arches and 918 feet on
the upper tier, and a total height of 224 feet. It was built in
1861 under the direction of R. Wilke and H. Krell, civil en-
gineers.
96. The Spreethal, Loban and Gorlitz railroad viaducts
have semi-circular arches and are very imposing. The Dolhain
viaduct, Belgium, with a length of 880 feet and height of 57
feet, has semi-circular spans of only 31J4 feet. The bridge of
Baden, near Vienna (1842), 1,430 feet long, the Neckar bridge
at Lademburg (1852), 870 feet long, and the Amsterdam
bridge (1874), 1,940 feet long, are all large and important. The
two single span railroad bridges over the Gutach and
Schwaenderholz, with spans of 210 and 187 feet, cost about $12
per cubic yard in place.
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BRIDGE ENGINEERING.
97. Another large railroad arch is the one at Jaremcze, in
Galacia, over the Pruth river, with a span of 213 feet, and is the
longest railroad masonry arch. The ring is 8 feet 8 inches
thick at the crown and 10 feet thick at the springs. It has six
approach arches at one side and one at the other, with spandrel
arches at either side and was built in 1892 at a cost of $33,900.
The Waldi-Tobel railroad bridge in Austria is somewhat
similar to the Jaremcze, but is faced with rough stone, giving
a decided rustic effect. It was built in 1884 under the direc-
tion of Ludwig Huss, chief engineer of the Austrian state rail-
ways, with a span of 134 feet, and the road is 160 feet above
the water. The Konigstein and Boberthal railroad viaducts
have thirty-four and thirty-five arches respectively, the road-
way of the latter being 75 feet above water. The Wiesen via-
duct in Switzerland is 300 feet above the bottom of the gorge
and has a central arch span of 180 feet with six approach spans.
The Albula river masonry arch at Soles in the Swiss Canton
of Grisons, 500 feet long, carries a railroad at a height of 292
feet above the valley, and has a central arch of 140 feet with
smaller ones at the ends, there being twelve arches altogether.
98. Two highway bridges of very unusual proportions have
lately been built at Luxemburg, Germany, and Plauen, Saxony.
Fig. 82.
The Luxemburg arch (Fig. 32) over the valley of the Petrusse
river, has a central span of 277 feet and its clear height is
137 feet with a rise of 102 feet and road 144 feet above the
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MODERN STONE BRIDGES. 81
water. The spandrel arches of the main span have an open-
ing of 17.7 feet and the two approach spans are 71 feet long
each. It consists of two parallel arches about 19 feet apart,
with an outside width of 50 feet and a total length of 1,148
feet. Much saving resulted by omitting the central part, the
actual cost being $270,000. The arch bridge at Plauen, which
is the longest stone arch in the world (Fig. 33), was built in
1903 under the direction of C. H. Leibold. It crosses the
valley of the Syra river, 58 feet above the ground. As the
valley was used for travel and other purposes, a single arch of
295 feet and one-fifth rise was selected, * 'ith minor arches in
Tig. 33.
the spandrels and a very ornamental facade. The material in
the arch is slate from a quarry near by, while Bavarian granite
is used for moldings, balustrade, stairs, corbeled sidewalks
and other trimmings. It has a total width of 56 feet and cost
$125,000. The masonry viaduct over the Isonzo river near
Triest and Gorz, Austria, completed in 1908, contains a river
span of 279 feet, with three semicircular approach arches at
one side, and six on the other. The material is limestone, and
the principal arch ring which rises at each side from low skew
backs, is 18.4 feet wide and 6.9 feet thick at the crown, in-
creasing to 23.6 feet wide and 11.5 feet thick at the springs,
the deck being supported on ten transverse arches.
99. A barbarous custom of the Dark Ages required that a
human body be built into one of the piers, and conforming to
this ancient practice, an infant was entombed in a pier of the
Kerventhal bridge in Saxony in the early part of the nine-
teenth century. When building the Halle bridge in Germany
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82 BRIDGE ENGINEERING.
in 1843, a child was to have been built into it, but a chicken
was used instead.
1.00. Other fine stone bridges are the Lombards, Roesen-
damms and Wandrahms bridges in Hamburg, the Albert
bridge at Dresden, the Lahn near Friedelhausen, Germany,
with fine stone portals and double entrance ways, the Nidda**
bridge near Vibel, Germany, the Zoel Elbe in Magdeburg
adorned on either side with statues, the Neckar bridge near
Ladenburg and the new bridge at Coepenick, Germany.
Italian Bridges.
101. The viaduct of Civita Castellane (1712-1864) crosses
a rugged gorge 285 feet wide and 162 feet deep with a cen-
tral arch of 68 feet and side openings of 33 feet each. The
Arricia viaduct near Albano (1852) is 1052 feet long in three
stories, w^th 26-foot openings in the lower story and 29 and
31-foot openings in the upper ones, and a height of 192 feet
above ground. The bridge of Hannibal over the Volturno
near Capua (1869) contains some remarkable features. The
water is crossed with a central fiat arch of 115 feet and through
each masonry abutment are circular openings 30 feet in
diameter instead of the usual archways. At each side of these
openings are round pilasters with ornamental tops. The
''Devil's Bridge" over the Sele near Poestum (1872) has a
single fiat conoidal arch with round pilasters extending up to
the railing with battlemented tops. The bridge of Solferino
over the Arno at Pisa (1872) has three fiat elliptical spans, the
side ones. 85 feet and the center, 92 feet. A bridge over the
Fegana near Lucca (1877) has a central fiat segmental arch
of 156 feet between heavily paneled abutments, giving the
appearance of great strength. The two story viaduct of
Pozillo (1880) is 89 feet high with 33-foot semicircular arch
openings and a total length of 530 feet. Other long bridges
over the Po at Turin of 1881 with several spans are Ponte di
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MOD.ERN STONE BRIDGES. 83
Valentino, 550 feet long, and Ponte di Vanchiglia, 410 feet
long, the latter with conoidal intrados. This form seems to be
a favorite with modern Italian engineers, for the bridges at
Capua and Poestum have similar outlines.
102. Several modern Italian bridges cross the Tiber river
at Rome, including the Margherita bridge with three arches of
99 feet each, built in 1891 under the direction of Vescovali and
carrying the Porta del Popolo over the river above the new
Palace of Justice. The Victor Emmanuel bridge crosses the
Tiber near the bend of the river adjacent to the Castle of St.
Angelo and was erected in the years 1905 and 1906.
103. A long span stone arch bridge, built in 1903, car-
ries the railroad between Colico and Soudrio, over the Adda
river. It is a three centered arch with a clear span of 230 feet,
an outside width at copings of 16 feet and a width at abut-
ments of 20.5 feet. There are steel hinges at the springs
and crown and the crown thickness is 4.7 feet. The main arch
and all faces are granite, but the spandrel arches are concrete.
It is the largest masonry railroad arch erected up to the
present time. The water below the bridge has a maximum
rise of 21 feet.
104. On the Damascus and Mecca line, was completed
about 1892, a stone arch viaduct with ten semicircular arches
of 20-foot span each, and two decks. The upper deck carries
a railroad 80 feet above the valley, while the lower one is a
highway passing through openings in the piers.
British Bridges.
105. This period in England is notable for the large num-
ber of fine stone bridges, many of which have not since been
excelled. They were chiefly the work of a few engineers,
who, profiting by the completion of the new Westminster
bridge and those recently built in France, developed the art
of stone bridge building to its highest state. The leading
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84 BRIDGE ENGINEERING.
engineers of the period were Robert Milne, John Smeaton
(1724-1792), John Rennie (1761-1821), and his two sons,
George Rennie (1791-1866) and Sir John Rennie (1794-1874),
Thomas Telford (1757-1834), George Stephenson (1791-1848),
and his son, Robert Stephenson (1803-1859), Sir Marc Isam-
bard Brunei (1769-1849), and his son, Isambard Kingdon
Brunei (1806-1859), and Thomas Harrison. Mr. Rennie's first
bridge was a three-span arch in Midlothian over the Water of
Leith, built in 1784, but his best and largest ones were the
Southwick, Waterloo and London bridges. The London
bridge was completed by his sons, the younger one being
knighted in 1831 when the work was finished. Sir John Ren-
nie was also engineer on the Kelso, Leeds, Musselburg, New-
ton-Stewart, Boston and New Galloway bridges.
106. The forward movement in bridge building in Great
Britain was due chiefly to the establishment by the Govern-
ment of a board or commission with power to construct roads
and bridges throughout the islands, conditional on the local
municipalities or towns desiring such roads, bearing a part of
the expense. The chief engineer for this commission was
Thomas Telford, a man of strong character and leadership,
who had once been a practical stone mason. Under this Board
more than 1,000 miles of roads were built in England and Scot-
land, including over twelve hundred bridges. Telford's first
stone bridge was a three-span elliptical arch across the Severn
at Montfort, built in 1792. In addition to stone bridges, he
built many other kinds, including the Menai and Conway sus-
pensions, as well as canals, harbors and other public works.
Another prominent engineer of the period was George Ste-
phenson, chief engineer of the Stockton and Darlington rail-
way. He and his son, Robert Stephenson, built many stone
bridges and railroad viaducts, and some notable cast iron and
wrought iron bridges, including the Britiannia in Wales and
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MODERN STONE BRIDGES. 85
the Victoria tubular bridge at Montreal. Sir Marc I. Brunei,
the French engineer who was knighted in 1841 for building
the Thames river tunnel, being forced to leave France, came
to America and undertook the engineering of many public
works here and in England. He prepared competitive plans,
which were not accepted, for the national capital building at
Washington, and was later appointed chief engineer of the
city of New York. In 1833 his son, I. K. Brunei, was made
chief engineer of the Great Western railway of England, and
he designed and built many notable bridges and viaducts.
107. Soon after the completion of the Westminster bridge
at London, a movement was started for building a third one
over the Thames, now known as the Blackfriars bridge. It
was designed by Robert Milne and built in the years 1760
to 1768, with nine multi-centered arches and a total length
of 995 feet. It was 43 feet wide and the piers, which had
double ornamented columns above the springs, were built
in caissons, the whole bridge costing, when finished, 152,800
pounds. It wa3 repaired in 1833 at a cost of 105,100 pounds
and replaced in 1865, with a cast iron bridge of only five spans.
Both the Westminster and the Blackfriars failed by scouring
the foundations.
108. The Kelso bridge at Glasgow over the river Tweed
near its junction with the Teviot, was designed by Mr. Ren-
nie and built 1799-1803. It has five elliptical arches of 72-
foot span, 21-foot rise, and is 26 feet in width. The piers are
12 feet thick and have rounded ends surmounted by semi-
columns extending up to the cornice, which is supported be-
tween the piers by numerous brackets. The roadway is level,
29 feet above the water, and its total length is 410 feet.
The parapets are solid with ornamental lamp posts over the
piers. This was -Mr. Rennie's first important work.
109. The Waterloo bridge at London, designed by John
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BRIDGE ENGINEERING.
Rennie, Sr., and George Dodd, was built in the six years prior
to 1817, and had nine elliptical arches of 12()-foot span and 34-
foot rise, supported on piers with semi-circular ends. The
design was planned to conform with the architecture of
Somerset House, which is in the near vicinity. Piers 30 feet
thick at the base and 20 feet at the springs, are ornamented
above the springs with twin Doric columns similar to those
on the Kelso bridge. The level roadway is 28 feet wide with
two seven-foot walks and has lamp posts over the span-cen-
ters — an unusual arrangement. It is faced with granite and
cost $4,687,000.
110. London Bridge (Fig. 34) is perhaps better known
than any other. The present structure of 1821 to 1830, re-
placed the old bridge that was lined with shops and houses.
FiK. 34.
(Fig. 25.) The new one is a very fine illustration of high-
class stone construction. There are fivt elliptical arches, the
center one being 152 feet long, the two adjoining, 140 feet,
and the end ones 130 feet. Its entire length is 926 feet. The
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MODERN STONE BRIDGES. 87
original width was 54 feet, and it is estimated that 120,000
foot passengers and 25,000 vehicles cross the bridge daily. It
was designed by the elder John Rennie and constructed under
the direction of his two sons, George and Sir John Rennie,
Jr. The total cost with approaches was 1,458,000 pounds,
while the bridge alone cost 426,000 pounds. In the years 1902
to 1905, Sir Benjamin Baker increased the width 11 feet at
an additional cost of $500,000 by adding brackets and chang-
ing the solid parapet to an open one. The two center piers
are 24 feet thick and are founded on cofferdams, and the road-
way is 60 feet above the water. Stone voussoirs vary in thick-
ness from 4 feet 9 inches at the crown to 9 feet at the springs
and the face work throughout is granite. The engineers on
the reconstruction were E. Cruttwell and Sir Benjamin Baker.
An excellent example of more recent construction in masonry
is the Putney public bridge designed by Sir J. Bazalgette
and built at a cost of 240,000 pounds.
111. Essex and Queen's bridges over the Liffy river at
Dublin were built in 1753 and 1768 respectively. The original
Essex bridge was the work of Sir Humphrey Jarvis (1676) but
it was rebuilt in 1753 from plans by George Semple- The
Airon bridge at Dublin (1684) was destroyed 1763, and re-
built as Queen's bridge by Colonel Vallency (1768). Many
others were also erected throughout the island, including
those at Killarney and one over the Lea at Cork. But the
finest one in Ireland is the Wellcsley bridge at Limerick, de-
signed in 1827 by Alexander Nimmo. The five arches are
segmental on the face with conoidal (cow horn) soffits. It
is 41 feet wide, 410 feet long and has a tower at one end.
112. The Tongueland bridge with a single large span of
118 feet, has three pointed 9-foot arches in each abutment.
It has three lines of inside spandrel walls and a battlemented
railing, giving it a distinctive appearance. The Cartlane Crags
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BRIDGE ENGINEER! XG.
bridge over the Mousewater (1821), 122 feet long in three
spans, is imposing and very artistic. The Pathhead bridge
over the Tyne (18»-i(i) and the Dean bridge at Edinburg (1831)
have much smaller rise for the arches under the sidewalks than
those under the roadway, with corresponding offsets in the
piers.
113. The largest stone arch bridge in England is the Gros-
venor at Chester over the Dee (Fig. 35.) It was designed by
Thomas Harrison and built in 1833 by Tames Trubshaw —
contractor— at a cost $250,000. It has a single arch of 200
feet, 42-foot rise and 140-foot radius, supporting a roadway
Fig. 35.
33 feet in width. The ring stones vary from 4.5 feet in thick-
ness at the crown to 7 feet at the springs, and its total length
is 345 feet. The springs are unfortunately too low to escape
high water, a difficulty which might have been avoided by
using an elliptical intrados similar to that on the Trinity bridge
at Florence.
114. The old Forth bridge at Stirling in Scotland, designed
in 1832 by Mr. Stephenson, has five segmental arches, the
center one being 60 feet. Another notable one in Scotland is
the new bridge at Ayr, the third one on the same site. It is
one of "The Twa Brigs o' Ayr" made famous by the poet,
Robert Burns. The old one, which was 12 feet wide between
parapets, with four spans of 52 to 53 feet, has recently under-
gone extensive repairs for the purpose of preserving it. Of
plain design, used for pedestrians only, it stands out in striking
contrast to the new one with its ornamental balustrades and
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MODERN STONE BRIDGES. 89
Other features. Other fine stone bridges of this period are
those on the private estates of England and Scotland, among
which are the Chatsworth and Wilton bridges. The original
Broomielaw bridge at Glasgow, Scotland, was planned by-
Thomas Telford and built during 1833-1836. It crosses the
river Clyde and connects the northern with the southern
divisions of the city. The old bridge has seven segmental
arches varying in length from 52 to 58 feet with piers 8 to 9
teet in thickness at the springs. The walks were paved
with stone slabs and the road with brick. There are two
lines of railway and a smooth stone track for heavy trucks.
It was 58 feet wide in the clear between parapets, with arch
and spandrel face of granite, and piers of free stone. The
pier ends were octagon up to the springs, and continued to
the cornice in the form of ornamental octagon pedestals in
the balustrade for the lamp standards. With increased travel,
the bridge was too narrow for the demand upon it, and
in 1895-99 was taken down and rebuilt, the width being in-
creased to 80 feet. The present bridge contains 80,000 cubic
feet of granite, and each of the six piers rest on four cylinders
15 feet in diameter, filled with concrete. The piers are new
and are more massive than the old ones, and the whole bridge
is faced with granite, the parapets being polished. The engi-
neers on the construction were Blyth and Westland.
115. Railroad building began in England about 1830 and
in the following twenty years many large brick railroad via-
ducts, mostly with semicircular arches, were built chiefly under
the direction of Brunei, Stephenson and Harrison. Such via-
ducts are those at Maidenhead (1837) the earliest one, and at
Dalton, Victoria at Washington, Congleton, Ouse Valley,
Warfield, Lockwood, Berwick, Dee, Stockport, Llangallen and
Anker. Though of very plain "construction without ornament,
these viaducts have often, because of fhe great size, a more
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90 ^ BRIDGE ENGINEERING.
imposing appearance than lower highway bridges, some being-
over 150 feet in height with thirty to forty spans. The
arch bridge at Ballochmyle over the Ayr, has a. center semi-
circular arch of 180 feet with three smaller 50-foot arches at
each end, the center span being the longest railroad arch in
England. There was, however, little or no uniformity in refer-
ence to the proportion of span length to height, for the Ouse
Valley viaduct, 94 feet high (1841) and the Lockwood, 122
feet high (1849), were made with 30-foot spans, while the
Warfield, 90 feet high (1846), the Berwick, 124 feet high
(1850), the Dalton, 73 feet high and the Llangallen viaducts
all have 60-foot spans, and the Congleton 101 feet high (1<S39)
has 61-foot spans. The viaduct over the river Dee has nine-
teen spans of 90 feet, and the Rugby (1839) on the Midland
railway, over the Avon, eleven arches of 50 feet each. A more
recent one (1880) called the Harrington viaduct, carries the
Midland railway on eighty-two arches of 40-foot span.
116. The bridge at Carlisle over the river Eden with five
semi-elliptical arches, designed by Sir Robert Smirke, is de-
serving of special mention, because of its pleasing outline and
fine detail. The proportion of rise to span with full cen-
tered intrados have been carefully chosen to produce the best
eflfect.
American Bridges.
117. One of the earliest stone bridges in America is the
Witmer bridge near Lancaster, Pa., built by A. Witmer and
^lary Witmer, his wife, and completed in the year 1800. There
were, however, few important stone bridi^cs" in America prior
to 1820, when the construction of the Rochester stone aqueduct
was commenced under the direction of David Stanhope Rates.
Another stone aqueduct at Washington over the Potomac
river was commenced in 1837, with seven arch spans, and the
♦The stone bridgre at Ipswich. Mass.. with two spans of 28 feet, built by Col. John
Choate (1764) is probably the first of Its kind in the United States.
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MODERN STONE BRIDGES.
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same year witnessed the beginning of the Croton aqueduct
over the Harlem river at New York City, carrying the Man-
hattan water supply into the city on a series of stone arches
known as High Bridge (Fig. 36). The water supply for
Washington is brought into the city over a single masonry
arch, the Cabin John bridge (Fig. 37) which for many years
held the record as the longest masonry arch, but has since
been exceeded by the Luxemburg, Plauen and Salcano, as
Fig. 36.
well as by several concrete bridges now under construction.
Cabin John bridge carries a road and the aqueduct over Rock
creek, and was built under the direction of General M. C.
Meigs during the years l(S57-64. A third notable stone aque-
duct, generally known as Echo Bridge, is that at Newton
Lower Falls, Mass. (Fig. 38), built by the lk)ston Water Com-
mission under the direction of Chief Engineer Fitzgerald, to
carry a conduit across the Charles river. It is often viewed by
Boston residents, especially in the summer season. The
smaller spans are all at one end, making the bridge unsym-
metrical, but the shrubs and foliage are so arranged that the
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MODERN STONE BRIDGES.
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large span only is conspicuous from the roadway. These
bridges are more fully described under "Aqueducts."
118. The introduction of railroad building in America
about 1830, made a demand in some places for more permanent
bridges than those of timber, though the necessity for rapid
construction usually prevented the building of permanent
Fig. 37.
structures until after the road was in operation. The opening
and settlement of new countries ever since the founding of
the Roman empire, has always been dependent on the con-
struction of roads and highways, and in America wnth so
large a territory to develop, the completion of roads and their
operation could not be delayed for permanent structures. The
custom, therefore, has been to erect temporary ones at first,
and renew or replace them with better ones after the road
is opened to travel. In 1835 the Carrollton stone railroad via-
duct was built over Patapsco Creek under the direction of
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94 BRIDGE EXGIXEERIXG.
Benjamin Latrobe, and in 1847 was commenced the largest
one of the kind — Starucca viaduct — carrying the Erie railroad
over Starucca Creek. It has seventeen flat arch spans 51 feet
long each, a height of 110 feet and a total length of 1200 feet.
It was built for only a single track, but a second one has since
been added without alterations. The material is sandstone,
piers 7 feet thick at the springs, and deck 25 feet wide. It
was built under the direction of Engineer Adams and is similar
to many in England of the same time. Few other important
stone railroad bridges appeared in America until 1881, when
a stone arch viaduct was begun at Philadelphia to carry the
Philadelphia and Reading railroad over Wissahickon Creek
near its mouth at Manayunk. It is prominently situated and
can be seen for quite a distance up and down the Schuylkill
river and from both banks. It was built from designs by
C. W. Buckholz, chief engineer for the railroad company, and
has five spans of 70 feet each, with a rise of 23 feet. The
thickness of the arch ring is 3 feet, the outside width of
bridge 28 feet and the thickness of piers at springs 9J/^ feet.
Including the four small arches, 10 feet wide, two in each
abutment, the extreme length of bridge is 510 feet. The
height above the drive beneath 80 feet, and above the foun-
dations, 103 feet. It contains 15,400 cubic yards of Talcose
slate masonry and cost complete $375,000. Two tracks are
carried by it across Wissahickon creek and valley, which is
part of the Fairmount Park system. A stone railroad viaduct
quite similar to that at Wissahickon was at Painsville, Ohio,
over the Grand river. It had four semicircular arches of 80-
foot span and a height of 90 feet above the water, and was
owned by the Lake Shore and Michigan Southern railroad,
E. A. Handy, chief engineer. Piers were 10 feet thick at the
springs and arch rings 3 feet thick, but it was replaced with
a single concrete arch in 1909.
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MODERN STONE BRIDGES. 95
119. Another notable railroad bridge constructed during
the years 1881 to 1893, is one over the Mississippi river at
Minneapolis^ Minn., carrying two tracks of the union rail-
roads into that city. Col. Charles C. Smith directed the work.
There are four spans of 100 feet, one each of 71 feet, 43 feet
and 40 feet, and fifteen of 80 feet. The piers are made of St.
Cloud gray granite, the regular ones being 7 feet thick, while
the abutment piers have twice that dimension. Above the
piers, the material is Kasota limestone- A portion of the
structure, 800 feet in length, is on a 6 degree curve, and as
it is situated just below St. Anthony Falls, the view from the
bridg^e shows this most interesting part of the river and is
quite picturesque. It contains 30,550 cubic yards of masonry,
18,000 cubic yards of stone filling and has a total height of
82 feet, 65 feet being above high water. It is 36 feet across
the top, and the masonry part alone cost $650,000.
120. The greatest forward movement in the building of
stone railroad bridges in America began in 1888, when the
Pennsylvania Railroad company under the direction of Wil-
liam Brown, chief ?^ngineer, commenced replacing its wood
and iron bridges with permanent ones of stone and concrete.
Several of these safely resisted the Johnstown flood of 1889,
though one over the Little Conemaugh river was destroyed.
The test was, however, so successful that for twenty years,
that railroad has continued rebuilding bridges in masonry, and
many of great magnitude have been erected, including those
over the Susquehanna river at Rockville, Trenton, Brunswick,
Coatsville and Shocks Mills, as well as many other smaller
ones. The bridge at Trenton has eighteen spans, while those
at Brunswick, Coatsville and Shocks Mills have twenty-one,
ten, and twenty-eight spans, respectively. The Rockville
bridge with forty-eight spans of 70 feet, and 20-foot rise, is
3,820 feet long, contains 100,600 cubic yards of masonry and
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% BRIDGE ENGINEERING.
cost $800,000. It is 52 feet wide, supported on piers 8 feet
thick at the springs and had a concrete body with stone
facing. Previous to building the stone bridge in 1901, three
different iron and steel bridges had occupied the site, each one
being succeeded by a stronger one.
121. Following the example of the Pennsylvania Rail-
road company, other roads began replacing their old bridges
with permanent masonry ones, and in the last ten years many
of this kind have been constructed on the railroads of the
United States, including the Lake Shore and Michigan South-
ern, the Big Four and other branches of the New York Central
system, the Fitchburg, and several other roads. The two span
bridge at Bellows Falls, carrying the Fitchburg railroad over
the Connecticut river, replaced an old wood Burr truss, with
track 80 feet above the water. The spans are 140 feet each
with 20-foot rise and has a 27-foot width for double track
railroad. The location with rock side walls and a rock sup-
port in the middle of the river was inviting and economical
for a masonry arch. It was built in 1899, under the direcfion
of A. S. Cheever, chief engineer.
122. The building of ornamental park bridges in American
cities began in 1850, tvhen George Kellar, architect, of Hart-
ford, Conn-, designed the memorial bridge at Bushnell Park
(Fig. 39). It is one of the most beautiful park bridges in Amer-
ica, and was built of Portland brown stone, with five arch
spans, at a cost of $15,000, being widened in 1885 at additional
cost of $11,300. The three center spans are semicircular while
the two end ones are three-centered, all having a clear span
of 25 feet. The width was originally 35 feet, but was increased
to 41 feet by removing th6 spandrel masonry down to the
arch rings and rebuilding the deck, the extra width being car-
ried on stone brackets. Located close to the State Capitol
the beautiful memorial arch forms a more prominent feature
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MODERN STONE BRIDCHiS.
97
than the bridge itself. The roadway passes beneath the arch,
while sidewalks are curved outside the memorial piers. In
summer the whole is surrounded with ivy and other climbin-g
vines, and forms one of the most beautiful features of the
landscape. The memorial arch cost $60,000 in addition to the
cost of the bridge itself.
FiR. 39.
123. In 1891, the city of Boston began on quite an ex-
tensive scale, the building of ornamental stone bridges on the
Fenway and other portions of its park system. Fifteen or
more bridges were completed, including those at the Bridle
Path, Audubon Road, Leverett Pond, Forest Hills, Scarboro
Pond, Boylston Street, Charlesgate, Aga^siz, Stony Brook,
Railroad Brook, Fen Bridge, Tremont Street, Brookline, Belle-
vue and Neptune bridges. Stony Brook bridge (Fig. 40) con-
tains five arches of 10 feet each, three of which are over the
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BRIDGE ENGINEERING.
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MODERN STONE BRIDGES.
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water and two over the foot paths. It is 80 feet wide between
parapets, and the arches are supported on piers with trans-
verse arches underneath the deck. At each end is a flight of
steps from the sidewalk on the bridge to the walks beneath
it. The face work masonry is spreckled brick with trimmings
of Milford granite, and at each stairway is a drinking fountain.
The barrel vaults beneath the floor are lined with glazed brick
of different colors laid in patterns. It was designed by F. L.
Figr. 41.
Olmstead & Co. and Walker & Kimball, architects, and cost
$40,000. Another bridge in the Boston park system is that
which carries the parkway over the traffic road leading from
Forest Hills street to the entrance of Forest Hills cemetery.
(Fig. 41.) This bridge is 125 feet in length and the main span
has a segmental arch of 45 feet. A stairway connects the side-
walk over the bridge, with the foot path along the traffic road
beneath. The slopes of the bank are supported by retaining
walls on the lines of the traffic road. Crossing the bridge at
the end the masonry piers for a gateway have been built, the
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100 BRIDGE ENGINEERING.
piers of the side gates being connected with the parapets.
This gateway has three openings, one each for the drive, the
road and the walk. At one side of the gateway is a recess
with seats, and a drinking fountain. The total cost was $51,000.
All face work is of seam faced granite, except the coping and
cap stones which are of red granite. The soffit is light colored
brick, while the remainder of the arch is of common brick.
124. Following the lead of Hartford and Boston, the cities
of Milwaukee, Detroit, Pittsburg, New York, Philadelphia
and Chicago, built many ornamental stone bridges in their
parks, many of which were described by the author in the
American Architect of 1901. Detroit has a greater number of
ornamental park bridges than any other American city, twenty
or more being located in Belleview, Clark and Belle Isle Parks.
They are of various outlines and built of different ma-
terials, most of them being constructed in 1893. A stone
arch over Cresheim creek in Wissahickon valley, at Phila-
delphia, Pennsylvania, was built in 1892 to carry a sewer over
Devil's Pool, and in the following year some ornamental stone
and brick bridges were erected in Lake Park, Milwaukee, from
designs by Oscar Sanne. A brick arch in this park was built
in the same year with the body of the arch made of five rings
of hard burned sewer brick, spandrel faces and wings of brown
brick and the arch blocks on the face, and also trimmings and
railings, of terra cotta. It has a length of 100 feet and cost
$10,500.
125. The competitive designs submitted in 1885 for the
proposed Washington bridge at New York City, contained
three designs of much merit, for stone arch bridges. One by
W. J. McAlpine has six elliptical arches with a maximum of
210 feet, while another submitted by the Union Bridge Co.
proposed three segmental arches of 2.80-foot clear span. A
design by J- W. Adams shows three principal arches of 196
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MODERN STONE BRIDGES.
101
feet with many smaller ones at each end. The bridge in Gar-
field Park, Chicago, with others in the same city, were part
of the preparation for the World's Fair of 1893.
126. A park bridge of much larger proportion than those
previously described, was built in Schenley Park, Pittsburg, in
1896, over a ravine 70 feet deep, known as Pierre Hollow.
It has a clear span of 150 feet and a total length of 341 feet,
with an extreme width of 85^ feet. It is a segmental arch
with 36-foot rise, carrying a roadway and two footwalks, and
was built under the direction of the Department of Public
DD
C
Works, with H. B. Rust as engineer. It has heavy paneled
pilasters at each side of the arch, the spandrels are relieved
with panels, and contains 12,360 cubic yards of masonry. The
cost was $112,000, and it is one of the finest heavy stone arches
in America. In the same year (1896) was built the Ritten-
house Lane bridge, . Philadelphia, carrying the Wissa-
hickon drive over Wissahickon Creek, replacing the old
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102 BRIDGE ENGINEERING.
wooden Red Bridge. The material is rock faced ashlar from
a near-by quarry, and it has a clear span of 105 feet, a rise
of 11 feet, and a 25-foot road and two walks, paved with
asphalt. It is. on a slight skew and the depth of key is 3
feet, the arch springing from lines above normal water. The
right abutment is unusual but attractive. It was designed
under the direction of Russell Thayer, chief engineer of Fair-
mount Park Commission and cost, including removal of the
old bridge, $27,700-
127. The competitive designs received by the United
States Government in 1900 for the proposed bridge across the
Potomac river at Washington, called forth some of the finest
bridge designs which have ever been made in America, varying
in estimated cost from 2^2 to 15 millions of dollars. The
Government asked for plans showing one and two decks,
widths of 60 and 80 feet, with a length of about 4,000 feet. A
design by George Morrison showed five limestone and granite
arches of 172 to 183 feet, with bascule draw spans at each end,
William R. Hutton submitted plans with two central steel
arches of 550 feet with a draw span between them, and six
elliptical masonry arches of 100-foot span at each end, while
others of great merit were submitted by William Burr and
L. L. Buck.
128. The four span arch bridge (1903) at Watertown,
Wis., over Rock river, is plain and substantial with arch ring
and cornice of different stone from that used in the spandrels.
The spans are 64 feet with 16-foot rise, width 30 feet, and
length of 360 feet. It replaced an iron bridge, and cost $40,700.
For several years there had been a movement by interested
parties to build a bridge across the Connecticut river at Hart-
ford, to replace the old covered wooden bridge which had been
in use since 1818. The matter was suddenly forced on public
attention by the burning of the old wooden bridge in May,
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MODERN STONE BRIDGES.
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1895, and a commission was then appointed, with Senator
Bulkley as chairman, to proceed with the building of a per-
manent one, which resulted in the present stone arch bridge
being opened to travel in 1908. It has nine spans varying in
length from 68 to 119 feet. The regular piers vary from 13
to 19 feet in thickness, and the two abutment piers are 40
feet thick. It is 82 feet wide and 1,100 feet long and was built
of Maine granite at a cost of $1,600,000. A. P. Boiler was
consulting engineer and E. M. Wheelwright, architect.
TRINITY BRIDGE
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104 BRIDGE ENGINEERING.
CHAPTER VI.
PONTOON BRIDGES.
Assyrian and Persian Bridges.
129. The earliest pontoon bridges were probably those
used by ancient armies, since they were mentioned by Homer
as common in his time about 800 B. C. The writings of Lu-
carus, Herodotus and Xenophon state that pontoon bridges
with casks as floats were used for military purposes. The ear-
liest bridge of this kind of which records are extant is one
made by Cyrus, King of the Persians, for transporting his army
in the year 536 B. C, stuffed skins being used as floats. Baby-
lon was taken, 538 B. C, by the Persian army under Cyrus,
diverting the course of the Euphrates and entering the city
at night under the water gates of the river. They knew, there-
for, both how to bridge the river and to dam it.
130. Darius Hystaspes, fourth King of the Persians, who
began to reign 521 B. C, built a bridge of boats across the
Danube river (510 B. C.) when engaged in his Scythian war-
fare. In 493 B. C, the same King, on a Scythian expedition
when about to invade Thrace, constructed a bridge of boats
over the Bosphorus at a place where it -was 3,000 feet in
width, over which he marched his army of 600,000 soldiers.
His head bridge builder was Mandrocles of Samos.
131. In 480 B. C, Xerxes, King of the Persians, who suc-
ceeded his father, Darius, built a double bridge of boats at
Abydos, or between Sestos and Madytus, over the Hellespont
(or Dardenelles), which separates Europe from Asia- The
strait varies from one to four miles in width and the bridge is
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PONTOON BRIDGES. 105
believed to have been at least 5,000 feet long. Herodotus says
that the first bridge was destroyed by a violent storm, and
in great anger, Xerxes ordered the engineers or builders to be
executed and the v^rater of the Hellespont to be scourged with
rods and blasphemous words. Xerxes then built two other
pontoon bridges, one of which on the side adjoining the Euxine
Sea, was supported on three hundred and sixty, and the other
on three hundred and forty anchored boats of the largest size
used by the ancient navies. The first were placed trans-
versely, and the others parallel with the current to diminish
the strain on the cables. The boats were connected with six
large cables of white flax, extending the whole length of the
bridge and fastened to piles on either shore, the cables being
drawn tight with wooden capstans. The platform, which was
protected by a railing at each side, consisted of trunks of trees
laid across the cables and covered with flooring and a layer
of earth. The work was done by Egyptian and Phoenician
artisans. Over these bridges Xerxes marched his army of
2,000,000 men across into Europe when on his way from
Sardis to conquer Greece and seven days and nights were oc-
cupied in making the passage.
Roman, Grecian and Chinese Bridges.
132. At a later period the young Emperor — Alexander the
Great — who died when only thirty-three years of age, built a
pontoon bridge over the river Ganges, about 330 B. C, for
the purpose of transporting his soldiers, and in crossing the
OxuSy 327 B. C, he used rafts made of hides stuffed with straw,
as all the available boats had been burned. He was accus-
tomed to carry with his army a kind of boat in sections, which
could be joined together when required for use- Pyrrhus,
King of Epirus (318-272 B. C), also had a bridge of boats
on the Adriatic Gulf. Caligula's bridge, referred to under Ro-
man Arches, is thought by some historians to have been con-
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106 BRIDGE ENGINEERING.
structed chiefly on boats. It was three miles long and was
in the form of a crescent across the bays of the Puteoli and
Baiae, or Tyrrhene Sea, and was supported over the water
on a double row of boats or pontoons. The roadway was
made of plank covered with earth and gravel, and the deck
was lined on either side with shops and houses, and was*
illuminated at night with torches. Caligula's boast was that
he would turn sea into land, and night into day, and when it
was completed, the Emperor had great festivities, lasting for
several days, which terminated by his ordering a large num-
ber of the citizens to be thrown into the sea. The date of
completion was in the latter part of his reign, about 40 A. D.
133. Movable boat bridges were common in China, and
one in the province of Chausi, at the junction of two rivers, was
made with one hundred and thirty barges, chained together
and arranged to open for the passage of vessels. In the fourth
century A. D., the Greeks, under Emperor Julian, used boat
bridges for crossing the Tigris and Euphrates rivers in their
retreat from Persia.
The Pontoons.
134. Floating military bridges which had been used since
the days of Cyrus, had boats or pontoons five to fifteen feet
apart in the clear, supporting a platform ten to twelve feet
wide, made of plank on stringers, but pontoons for many old
Roman bridges were of wicker work covered with hides.
In succeeding centuries the armies of other countries have
made their pontoons with wooden frames covered with plank,
sheet copper, sheet iron, india rubber, or canvas water-proofed
with tar or paint. The Germans, in the seventeenth century,
used timber pontoons covered with leather, and the Dutch,
similar ones covered with tin, while the army of Napoleon
preferred copper. For ease in transporting, they are sometimes
made in two or more pieces, which were fastened together be-
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PONTOON BRIDGES. 107
fore being launched. Recent ones have water-tight compart-
ments, so a single leak will not cause them to sink, and the
platforms usually lie on trestles standing in the bottom of the
floats. Floating piers have also been made of an assemblage
of casks or logs lashed together, with sufficient buoyancy to
sustain their loads, closed casks being floated on their side and
open ones on end.
135. Floating bridges have frequently been assembled
either up or down stream from their final position, in .a place
sheltered from the enemy or from a rapid current, and after-
wards towed or swung around into position in either one
piece or several sections. This plan was adopted by Na-
poleon for a bridge over the Danube the day before the battle
of Wagran. The quiet water around an elbow of the river
on the inner side has been found convenient for this purpose.
Mediaeval and Modern Pontoon Bridges.
136. The Servians used a pontoon bridge in the fourteenth
century for crossing the Danube to assist in the defense of
Nicopolis, and a bridge of boats over the Rhine between
Cologne and Deutz, Germany, was constructed in 1674 and was
replaced by a new one in 1832. (Fig. 43.) It is 1,400
feet long and carries a highway and pedestrian travel and has
a wooden floor which is renewed occasionally as required.
The Rouen bridge of boats was 900 feet long, and paved with
stone, and was very firm under heavy travel, the boats being
anchored with chains.
137- A floating bridge, 511 feet long, which was probably
the only one of its kind, was built in 1802 near Lynn, Mass.,
over a pond which was believed to have no solid bottom.
It was made in three sections, by Moses Brown, and was
floated into position. The platform was of timber, 53/2 feet
thick, but it had so often been re-floored that its thickness in
1904 was 17 feet. It was then so watersoaked that light loads
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108
BRIDGE ENGINEERING.
passing over it caused it to sink below the surface of the water,
and it was replaced by a modern bridge, though the old one
still remains. The only similar one known was made by
George Stewart of Port Hope, Ontario, who many years ago
built a floating bridge like a corduroy road, three quarters of
a mile long between Sturgeon, and Scugog lakes. Rafts 30
feet square of flattened timber were connected by six or seven
longitudinal beams on which a platform was laid. A floating
Fig. 43.
bridge at Hertford, North Carolina, was supported on empty
barrels, and was used for fifty years. A bridge over Chemonc;
Lake near Peterborough, Ontario, with a length of 36.'yS
feet, was built about VM)0. The fixed approach is 013 feet
long, and the pontoon 2620 feet, which contains a draw of
105 feet. At i\\i: plac^^s, the road is 21 feet wide to permit
teams to. pass, but the rest of the deck is only IS feet wide.
It cost $26,000.
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PONTOON BRIDGES. 109
138. Pontoon bridges were largely used by the American
armies during the Civil war of 1862-65. One over the Poto-
mac at Harper s Perry, Va., containing sixty boats, was built
February, 1862, in a period of only eight hours. The river
was in freshet condition, 15 feet above summer level, and was
filled with ice and drift, but the bridge, when finished, safely
carried the heavy army wagons, cavalry and artillery. The
Rapidan, Rappahannock and other rivers were similarly
crossed.
139. The bridge of boats over the Danube at Budapest
which existed previous to 1837, was removed in the winter
seasons because of danger from ice, and travel was taken over
the river, either in ferries or on the ice, which in 1838 was
6 to 8 feet thick. For several months of each year travel had
been accompanied with much uncertainty and risk, and as
these conditions were not satisfactory, the new suspension
bridge was erected in 1847- The pontoon bridge over the
Rhine at Maxau, Germany, had a portion 768 feet long sup-
ported on thirty-four pontoons, though the total length with
approaches is about 1,200 feet. It is 40 feet wide with a
single line of rail track in the middle and a highway on each
side, but only light train loads and an 18 ton locomotive are
permitted on the bridge. The wood pontoons are each 12 feet
wide, 4^ feet deep and 65 feet long. It was opened in 1865
after twelve months in construction. Another large pontoon
bridge, erected in 1873, crosses the Hoogly river at Calcutta,
India. It is 1530 feet long and the deqk is supported on twenty-
eight rectangular iron floats coupled together in pairs, and
held in position with 1%-inch chain cables, fastened to anchors
weighing three tons each. The anchors are placed on the up-
stream and downstream sides and each pontoon is divided
into eleven separate compartments, with the top three or four
feet above water. The pontoons are 10 feet wide. 8 to 11 feet
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110 BRIDGE ENGINEERING.
deep and 160 feet long, to prevent their oscillating or tipping
sideways. The deck is 63 feet wide and 27 feet above the sur-
face of the river, which has a current of six miles per hour. An
opening for the passage of boats can be made when desired
by removing four pontoons, which operation occupies a period
of 15 minutes.
140. A large pontoon railroad bridge in America over the
Mississippi river between Prairie du Chien, Wis., and North
MacGregor, Iowa (1874), crosses the river and an island which
divides the channel into two parts, the West channel being
1,500 feet wide, while the East one is 2,000 feet, each channel
being provided with a draw span 408 feet long. The total
length of bridge including the part over the island is 7,000
feet. The pontoon bridge at MacGregor was rebuilt in 1898
by Captain M. J. Godfrey, who designed and built many of
the best river steamers on the Mississippi river and its trib-
utaries, and in other countries. A few years previously, he
also built the Read's Landing pontoon bridge, owned by the
Chicago, Milwaukee and St. Paul Railroad, Mr. Onward Bates
being then chief engineer of the road. Another over the
Mississippi river at Nebraska City (1888) is 2,124 feet long,
and has a 528-foot draw span operated by the current, un-
der the control of one man. Other interesting ones cross
the Indus at Khushalgarh, and the Diena at Riga. A
temporary pontoon bridge was recently used at Chicago
during the construction of a permanent bascule, and the
revolving; draw span at. Weed Street (F'vj. 42), Chicago, is
supported at the outer end on a float, while the rear end is
hin^2:ed to the deck- The Weaver river swing bridge at North-
wich, England, is also supported on a floating center pier.
Many others might be mentioned, such as those at St. Peters-
l)uri^^, Presburg, Coblenz. Seville, Ehfenbreitstein, Carazoa,
Colombo in Ceylon, and Portsmouth in England.
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PONTOON BRIDGES.
Ill
Name.
Euphrates river.
Danube river.
Bosphorus.
Hellespont.
Ganges.
Oxus.
Bay.
Tigris.
Danube.
Rhine.
Rouen, France.
Lynn, Mass.
Port Hope, Ontario.
Potomac, Harpers Ferry.
Rhine.
Hoogly.
Mississippi, Prairie du Chien.
Missouri, Nebraska Citv.
Date. Builder.
536 B. C. Cyrus.
510 B. C. Darius.
495 B. C. Darius.
480 B. C. Xerxes.
330 B. C. Alexander.
327 B. C. Alexander.
40 A. D. Caligula.
4th Century. Julian.
14th Century. Servians.
1674.
18th Century
1802. Moses Brown.
19th Century. George Stewart.
1862. U. S. Army.
1865.
1873.
1874.
1888.
Fig. 42.
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112 BRIDGE ENGINEERING.
CHAPTER VII.
AQUEDUCT BRIDGES.
141. The most important of the old Roman bridges were
those in connection with their aqueducts. Remains of about
one hundred still exist in Italy, France, Spain and adjoining
countries, which were once part of the Roman Empire, and
these are evidence of their high state of civilization. For 440
years after its founding or until 313 B. C, Rome was de-
pendent for its water supply on wells and springs, but in the
following four centuries nine aqueducts were built, and five
others at a later period. Agrippa, who married the daughter
of Emperor Augustus, was the first regular superintendent
of the water supply of Rome, being installed 34 B. C, and in
addition to building and extending the water system, he con-
structed many other public works. Masonry aqueducts of a
similar kind had previously existed in other countries, prob-
ably in Greece, but not before had they been so extensive or
of so permanent a character.
142. Julius Frontinus or Sextus, who lived 35 to 104 A.
D., was a later engineer and superintendent of the water
works of Rome, and he was a great builder and leader as
well as a historian. He wrote two books on "The Water Sup-
ply of Rome" and six others on engineering subjects, some of
which have been translated in recent times. The inability of
the Romans to make pipes of sufficient strength to resist the
water pressure which would result from laying them across
the valley underground, may have been the reason for placing
them on high stone aqueducts, for they must have known
that water will seek its own level. The viaducts were built
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AQUEDUCT BRIDGES. 113
with accurate grade, showing that they understood and used
the level.
143. The nine aqueducts for the city of Rome were as
follows :
(1) Aqua Appia was started by Appius Claudius, 312 B. C,
who was also builder of the Appian Way, one of the great
roads of Rome. This aqueduct brought water from springs, 10
miles distant and still running, but only 300 feet of it was on
arches, the remainder being underground. It enters the city
60 feet above the sea level.
(2) Anio Vetus was built 272-264 B. C. Pont Lupo and
other parts of this magnificent aqueduct are made of arches
built of tufa and travertine. It brought water a distance of
43 miles from the river Anio and delivered it at the city 150
feet above the sea level, but only 1,100 feet is on masonry
above the ground, the water way being 3.7 feet wide and 8
feet high.
(3) The Martian aqueduct was built by Quintus Martins,
144-140 B. C. It was about 60 miles in length, 12 miles of
which was carried on masonry arches, and the original struc-
ture was so substantial that the two succeeding ones were
built upon it. The material used was red, brown and yellow
cut stone, 18x18x42 inches, laid in cement, and in some places,
the aqueduct is 70 feet high, in three tiers, delivering water to
the city 196 feet above the sea level. Having been recon-
structed in 1869, it is still in use.
(4) Aqua Tepula was finished in 125 B. C* and brought
water that was slightly warm, from volcanic springs in the
Alban hills.
(5) Aqua Julia was built by Agrippa, 33 B. C.
(6) Aqua Virgo, completed by Augustus, 19 B. C, brought
water from springs eight miles from Rome, which were only
80 feet above the sea level.
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114
BRIDGE ENGINEERING.
(7) Aqua Alsientina was completed by Augustus, 10 A. D^
and took water from a lake twenty miles from Rome.
(8 and 9) Aqua Claudius and Anio-Novus were beg^n by
Caligula, 38 A. D., and finished by Claudius, 52 A. D. These
had brick and stone arches of 20-foot span, lined with concrete.
Both aqueducts are carried on the same arches a distance of
over eight miles across the Campagna, much of the viaduct
being 105 feet above ground, and they are the highest in
Rome. The whole length of the Anio-Novius is 62 miles.
Flff. 44.
144. Pont-du-Gard (Fig. 44) is an old Roman aqueduct
built in the year 19 B. C, to supply water to the city of Nimes
in France, a place which has many remains of ancient Roman
civilization. It was built during the reign of Emperor Augus-
tus, probably under the direction of Agrippa. There are three
stories, the lower one containing six arches and the second
story eleven arches of the same span, while the upper or third
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AQUEDUCT BRIDGES. US
has thirty-six smaller arch openings supporting the water-
duct. The total length of the upper tier is 886 feet and its
greatest height above water is 160 feet. In the year 1743, ex-
tensive repairs were made and the lower tier of arches was
widened enough to carry a roadway on one side, so the present
structure serves the double purpose of aqueduct and bridge,
the length of roadway being 465 feet. The lower arcade was
originally made of four separate rings, side by side not bonded
together, and the second tier of three similar rings, the original
width of the lower being 20 feet 9 inches, and the second and
third tiers, 15 feet and 11 feet 9 inches, respectively. The
largest central arch over the Garden river has a clear span
of 80 feet 5 inches, while the adjoining ones on either side
vary from 51 to 63 feet. The smaller arches in the top story
have a uniform length of 15 feet 9 inches and all arches are
semi-circular. The structure carries a single waterway 4
feet wide and 4 feet 9 inches high, and is built of cut stones
tied together with iron clamps without cement excepting in
the water channel on top. It is said to have been partly
destroyed by the barbarians in the fifth century, but was sooil
repaired.
145. The Metz aqueduct is of Roman origin, before the
Christian era, and has a single row of arches 1,000 feet long
and 50 feet high. The Carthage aqueduct, 70 to 80 feet high,
is carried on a long series of cut stone arches on piers 12 to
15 feet square, and the Mytilene and Lyons aqueducts date
from about the same period.
146. The aqueduct of Segovia in Spain, was built by Em-
peror Trajan, 100 to 115 A. D. It is in two stories, 102 feet
high at the center and has one hundred and nine arches,
thirty of which are modern but similar to the old ones. The
material is squared stone put together without mortar, and
the total length of the structure is 2,500 feet.
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116
BRIDGE ENGINEERING.
147. The Tarragona aqueduct, similar to that of Segovia,
is 100 feet high and 876 feet long, with two series of semi-
circular arches, eleven in the lower and twenty-five in the
upper story.
148. The aqueduct at Antioch has one bridge of rude de-
sign, 200 feet high and 700 feet long. It has a single row of
uneven and varied arch openings in the upper part and a solid
wall beneath with only two small openings.
149. Between the years, 109 and 310 A. D., five other aque-
ducts were built for the city of Rome, many miles of which
were carried on masonry arches. There were, therefore, in the
Fiar.
aqueducts of that city not less than 63 linial miles of stone
arches, including the Alexandrina (226 A. D). Remains of
aqueducts at Mayence, 16,000 feet long, and others in Dacia,
Africa and Greece are still extant.
150. The aqueduct of Bourgas near Constantinople is car-
ried on a stone arch viaduct in two tiers, and was probably
built during the reign of Justinian (560 A. D.). It is 109 feet
high and 720 feet long, the arches of the lower tier having
spans of 52 feet, while those of the upper tier are 40 feet. They
are pointed, in both tiers, and the central piers which are
strengthened with buttresses are pierced with minor arches.
(Fig. 45.)
151. The aqueduct of Spoleto (741) in central Italy, 426
feet above the valley, was one of the highest masonry arch
bridges (Fig. 18). It had ten tall openings 70.2 feet in the
lower arcade, and thirty smaller ones above them, all pointed.
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AQUEDUCT BRIDGES. 117
and the piers were llj^ feet thick at the springs. This ac-
count, given by Gauthey, does not agree with the present
structure, which is only 250 feet high with ten openings in
a single tier, the piers being wider than the adjoining spans.
152. The Pyrgos aqueduct near Constantinople, built sub-
sequent to the tenth century, is in two branches at right angles
to each other, with length of 670 and 300 feet respectively.
The longer branch is in three tiers with a maximum height
of 106 feet, the lower arches being pointed, while those of the
two upper tiers are semi-circular. The width is 11 feet at the
top, increasing to 21 feet at the bottom, and piers in the lower
story have buttresses. The shorter branch contains twelve
semi-circular arches.
153. The most notable bridge structure of the period in
North America was the Tempoalo aqueduct, 1553-1570, seven
miles south of Huauchinango, Mexico. It was built under the
direction of the Franciscan Friars and contained sixty-eight
semi-circular arches of stone, the largest being 58 feet. It
was erected by Tembleque on two connecting tangents con-
taining an angle of 177 degrees. The maximum height was 124
feet and the waterway very small, being only 8jS4xl2 inches.
154. Another important stone aqueduct bridge in Mexico
is one built for the city of Queretaro, in the years 1726 to 1735,
by the Spaniards under Antonio Avana, with seventy-four
spans of 50 feet each. The masonry is 92 feet high and it cost
$125,000, of which $82,000 was donated by one person. Arches
3 to 4 feet in thickness are supported on stone piers about 10
feet square, which diminish from the springs to the width of
the arch at the top. The water is conveyed from mountain
springs five miles distant. Other structures of this kind in Mex-
ico and West Indies are at Cuernavaca, Guadalupe and Orizaba.
155. The stone aqueduct of Alcantara near Lisbon, was
projected from 1713 until construction began in 1731 from de-
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118 BRIDGE ENGINEERING.
signs by Mausel de Maya, but it was not completed until 1774.
Its origin has been attributed to Trajan, but no more than the
beginning was made in that day. There are thirty-five arches,
pointed, the center one being 108 feet in span with a rise of 88
feet. The height is 227 feet and total length 2,464 feet. It car-
ries the whole water supply for the city of Lisbon and success-
fully withstood the earthquake of 1775.
156. Others of about the same time are at Cazerta, Italy
(1763), in the reign of Charles III., under the architect Van-
vitelli, a beautiful work in three arcades, and Montpelier,
France (1760), by Pitot, chief engineer of Languedoc. Mr.
Telford built several aqueducts in England and Scotland,
including the Chirk aqueduct of the Ellesmere Canal over
the Ceriog river (1802) and the Cyssylte. Both of these were
partly of cast iron, the first having a bottom lining, and the
latter, a complete iron channel, supported on cast iron arch
ribs between stone piers.
157. .The Manhattan water supply is brought into the city
of New York in pipes on a series of stone arches known as
land, including the Chirk aqueduct of the Ellesmere Canal over
High Bridge (Fig. 36), a part of the Croton aqueduct. A tun-
nel under the river was not desired and the high bridge was
adopted instead. The demands of navigation made it neces-
sary to provide a clear head room of 100 feet beneath the bridge
with openings of not less than 80 feet in width. There are
therefore eight spans of 80 feet over the water, with six spans
of 50 feet at the end next the main land, and one span of 50
feet at the end adjoining Manhattan Island- The total length
of bridge is 1460 feet and height of parapet above the high
water 116 feet. The width is 21 feet over parapets and the
entire faces of the spandrels and piers batter out on each side
at the rate of 1 inch in 4 feet. The bridge originally carried
only two lines of cast iron water pipes, 36 inches in diameter,
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AQUEDUCT BRIDGES. II9
but a third line, 90 inches in diameter, was added later. At
high water the river had a width of 620 feet. The deck car-
ries a driveway and two foot walks, guarded by light and
ornamental railings. Above the arches the bridge is relieved
with belt courses and a coping supported on corbels, and at
the piers are pilasters extending from the arch springs to the
copings, the whole giving a very pleasing and satisfying effect.
The design and construction was under the direction of John
B. Jervis, Chief Engineer of the Croton Aqueduct, and the
erection took place during the years 1837 to 1842, at a cost of
$737,800. The Mohawk river aqueduct at Crescent, N. Y.,
designed by W. J. McAlpine, was constructed during the
years of 1838 to 1842 and contained twenty or more spans
having a total length of 1137 feet.
158. The Roquefavour Aqueduct near Aix, France, over
the Arc river on the canal from Durance to Marseilles, is a
masonry arch structure 1,290 feet long and 270 feet high, form-
ing part of a conduit of 67 miles by which water is supplied
to the city of Marseilles and its suburbs from the Durance
river. It is 48 feet wide at the top, the canal being 22 feet in
width at the bottom. Like Pont du Gard, there are three
arcades, the lower one having twelve arches of 49.2 feet, the
middle one fifteen arches of 52.5 feet and the upper 52 arches
of 16.4 feet. The Roquefavour is a fine example of recent
stone arch aqueducts, being built during 1841 to 1847, and it
was for many years the highest stone bridge in France.
159. Prior to the building of the High Bridge, a stone
aqueduct was commenced at Rochester, N. Y. (1820), to con-
vey water over the Genessee river, and was built of red sand-
stone with eleven arch spans in an entire length of 802 feet.
One at Washington over the Potomac was started in 1837, with
seven arch spans, contemporary with the building of the Cro-
ton aqueduct bridge. The present water supply for Washing-
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120 BRIDGE ENGINEERING.
ton is carried over the Cabin John bridge (Fig. 37), built by
General Meigs in 1857 to 1864. The span of 220 feet was the
longest masonry arch for many years. The roadway, with a
width of 20 feet over parapets, is 101 feet above the water.
The arch is a segment of 110 degrees, with a rise of 57 feet,
crown radius of 134 feet and a granite arch ring, 4 feet deep
at the crown and 6 feet thick at the springs. The spandrels
are of sandstone and the backing behind the arch ring is laid
with radial joints, thus adding greatly to its strength. The
entire work is very simple in character, the flatness of the
face being relieved by two projecting courses at the parapet.
Another notable aqueduct bridge (Fig. 38) is at Newton Lower
Falls, Mass., having been built by the Boston Water Com-
mission in 1876, under Mr. Fitzgerald's direction as Chief En-
gineer- It is known as Echo bridge and carries a conduit over
Charles river, with one span of 129 feet, 42-foot rise and five
other spans of 34 to 37 feet, at a height of 78 feet above the
water. It is within the Metropolitan Park system, and though
unsymmetrical in span arrangement, presents a very pleasing
aspect in summer, with the smaller spans screened by trees
and shrubbery.
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WOODEN BRIDGES. 121
CHAPTER VII.
WOODEN BRIDGES.
160. There are few wooden bridges now standing, more
than one hundred years old, all earlier ones having disap-
peared. The normal duration of those which were roofed
over and protected from the weather was generally thirty to
forty years, while the open ones without covering would last
about one-third as long; but fires were so frequent, especially
on railroad bridges, that many were burned before their timber
was decayed. Wooden bridges which escaped fire had parts
frequently renewed, and after many years might contain
none of their original timbers. Ikakuna bridge (Fig. 29) over
the Kintai river in Japan, with five arches, built in 1673, had
one span renewed every five years, and the whole bridge was,
therefore rebuilt four times every century. Pons Sublicius
(Fig. 4) over the Tiber river at Rome, Caesar's bridge over
the Rhine (Fig. 8) and Trajan's bridge over the Danube (Fig.
11) were all made of timber, and many others were doubt-
less built in ancient and mediaeval times, of which no account
appears in history. The remains of an old wooden bridge,
dating from the eighth century, were removed from the river
bed of the Rhine in 1883. The old bridge stood on twenty-
eight bents, but was struck by lightning and burned. The
fifty piles which were taken out were in good condition after
1100 years. Truss bridges were unknown until the sixteenth
century, when Leonardo da Vinci and Palladio, the Italian
architects, invented and built wood truss frames for bridges
and roofs which diflfer little from those used at the present
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122
BRIDGE ENGINEERING.
Fig, 47.
J \ a ft R ft ft ft v
Fig, 48.
time. Some of the forms used by Palladio are illustrated
in Figs. 46 to 48. He built a wooden bridge of five spans
over the Brenta near Bassano (Fig. 49) and another over
Fig. 49.
the Cismore at the same place with a span of 108 feet, but
his truss discovery was forgotten and not rediscovered until
the latter part of the eighteenth century, when Hale, Burr
and others again used truss construction for timber bridges.
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WOODEN BRIDGES. 123
A wooden bridge on the Palladio principle with a span of 87
feet, 13-foot rise and 20-feet wide, was built at Walton Park,
England, the country seat of the Marquis of Buckingham.
161. A curious but ingenious wood cantilever bridge at
Wandipore in Tibet, built about 1660 with a clear span of 112
feet between shore towers, was made of fir, pinned together
with wooden pegs, without iron of any kind. It had three
separate roadways, with entrance gates and side railings, and
lasted for one hundred and fifty years. Another old type over
the Kandel (Fig. 50) in the canton of Berne, had one span of
166 feet, designed by Joseph Ritter.
Fig. 50.
162. Prior to the nineteenth century, the size of framing
timbers was determined by judgment or from the study of
models and previous failures. Experienced builders became
very proficient and their work showed much skill. The "Great
Bridge" at Boston, Mass., built in 1662 on the site of the North
Harvard St. bridge, between Brighton and Cambridge, was
of timber on pile bents 15 to 20 feet apart, and was one of the
earliest in North America, but the most interesting ones of
the century were found in Europe. In 1738, a contract was
awarded to John King for building the Westminster bridge
across the Thames, to consist of thirteen timber arches, of
62 to 76 feet, on stone piers. Money for the purpose was
raised by lottery, but after the piers were nearly completed
the design was changed to stone arches according to a plan
by Labelye. King's plan showed a length of 1164 feet, and
a width of 44 feet, with arch timbers spreading out in fan
shape from the piers. After the contract was signed and the
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124
BRIDGE ENGINEERING.
piers nearly completed, Labelye published a pamphlet showing
how his design could still be substituted for the one with
wooden arches, and circulated this pamphlet in England among
the members of Parliament. He appealed to their pride, de-
claring that a wooden bridge across the river at the world's
metropolis was a disgrace to the nation and out of harmony
with the monumental buildings and wealth of London. La-
belye's efforts were successful, for John King, being liberally
paid, relinquished his contract and the stone arch was built
with Labelye as engineer.
163. Several of the finest early bridges were in Switzer-
land, where good timber was abundant, one of these being at
Schauffhausen over the Rhine (Fig. 51). It was built in
1758, at a cost of $40,000, by Ulrich Grubermann, an unedu-
cated village carpenter of Teufen. It was 18 feet wide and
had a clear length of 400 feet between abutments, but a central
Fig. 51.
pier of a former bridge divided the bridge span into two parts
of 172 and 193 feet. The arrangement of members and de-
tails was complicated, but they clearly show the intention of
making the whole length in one span, though the inclined
members to the center pier, probably inserted to gratify the
skeptical authorities, who doubted its strength, also show
provision for transmitting the loads to the central support.
When completed, the bridge had very little bearing on the
center piers, for pedestrians or other light loads would cause
it to spring from the bearing, but heavy loads were safely
carried for forty-two years. As the oak timbers, where they
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WOODEN" BRIDGES. 125
rested on the abutments, were found to be decayed, it was
repaired in 1783 by Spengler, and the whole bridge was
temporarily supported on jacks while these timbers were be-
ing renewed. Several stone bridges on the site had previously
been washed away, and this one, which occupied three years in
building, was destroyed by the French in 1799. The bridge
over the Limmat near the abbey of Wittengen at Baden was
also designed and built by Ulrich and John Grubermann in
1758, and was burned by the French army in 1800. It had a
clear opening of 390 feet and was the longest span wooden
bridge ever built. A similar one 240 feet long was erected by
John Grubermann at Ruichenau, and several years later the
two brothers built another near Baden over the Limmat with
a span of 200 feet, while others similar to the Schauflfhausen
were located at Landsberg and Zurich, the latter having a
span of 128 feet.
164. A wooden bridge on thirteen piers, with a length of
270 feet, was built by Samuel Sewell over the York river,
Maine, in 1761, and was rebuilt in 1793, but there are no
complete records of wooden bridges in America prior to the
Charlestown bridge over the Charles river at Boston, which
was commenced in 1785 by Samuel Sewell and completed
thirteen months later, at a cost of $50,000. This was the first
bridge connecting Boston with the main land and succeeded
the ferry which had been used since 1630, the new bridge re-
maining until 1899, when it was replaced by the present steel
one. It was 42 feet wide, 1,500 feet long, with a 30-foot draw
span, and was supported on seventy-five piers, 20 feet apart.
Being a toll bridge for many years, it was very profitable,
paying 30 to 40 per cent interest annually on the investment,
and similar ones were built at Beverly and Maiden in 1787.
Three years later (1790) when a bridge was required at
Londonderry, Ireland, the. services of Eugene Lemuel Cox
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126
BRIDGE ENGINEERING.
of Boston were secured, and he erected one 40 feet wide, 1068
feet long, with oak piers 16^ feet apart, like that over the
Charles river at Boston. A bridge at Hampton Court, Eng-
land, 500 feet long, had seven timber spans, three on each
side of a center draw, supported on six cribs filled with stone.
In 1789, a 100 foot model for a bridge with a single span of
980 feet, to cross the Neva river in Russia, was made by an
American engineer. It had four timber frames, two on each
side, with suspended roadway. In 1792, the West Boston
bridge over the Charles river was chartered and completed in
the following year on the site of the present new Cambridge
bridge. It was a wooden pile structure 3583 feet long and
40 feet wide, supported on one hundred and eighty bents, with
a 80-foot draw span, the whole costing $76,000, but it was
•rebuilt in 1854 with a width of 50 feet and has been immor-
talized by the poet Longfellow.
165. A bridge at Manchester, N. H., over the Amoskeag
river, constructed in 1792 by Col. William P. Riddle, had
six spans of 92 feet and a length of 656 feet, being completed
in the short space of two months.
Flff. 62.
Among the early American bridge builders, the most prom-
inent were Col. Enoch Hale, Timothy Palmer, Theodore Burr
and Lewis Wernwag. Timothy Palmer built bridges at Es-
sex, Andover, Portsmouth and Haverhill, N. H., the George-
town bridge over the Potomac, the Easton bridge over the
Delaware, and the "Permanent Bridge" at Philadelphia, while
Theodore Burr built bridges at Waterford (Fig. 52), Fort
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WOODEN BRIDGES.
127
Miller, Trenton, Schenectady, Harrisburg and Philadelphia.
Previous to the introduction of Mr. Burr's bridges, most long
spans were some form of arch. The scientific building of
wooden bridges in America dates back to 1792 when Col.
Enoch Hale designed a bridge to cross the Connecticut river
at Bellows Falls, Vt, with two spans of 175 feet and a length
of 368 feet, the center pier being founded on a natural rock
in the middle of the river. It was a combination of arch and
truss similar to that patented by Mr. Burr a few years later.
The MelHngen bridge with one span of 157 feet, built in Eu-
rope two years later, was somewhat like this, but was sup-
ported chiefly by the arch (Fig. 63).
Fiff. 63.
166. The Essex bridge over the Merrimac river at Deer
Island, three miles above Newburyport, was built by Timothy
Palmer in 1792 at a cost of $36,000, and was divided by the
island into two parts. The part on the Newbury side was
483 feet long with three deck wood spans and a through truss
of 160 feet in twelve panels, while the portion on the Salis-
bury side, 592 feet long, had one truss span of 113 feet and a
bank approach, both spans having a clearance of 40 feet be-
neath. The piers and abutments were heavy timber cribs filled
with stone, containing enough logs to reach 50 miles if laia
end to end. The larger of the two spans was replaced fti
1810 by John Templeton's chain suspension bridge, but the
smaller span remained until 1833. Timothy Palmer built an-
other bridge over the Merrimac river at Andover in 1793.
which was rebuilt ten years later.
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128 BRIDGE ENGINEERING.
167. Between 1795 and 180O a pile bridge about a mile
long was erected across Cayuga Lake in New York state, on
the road from Albany to Niagara, with two hundred and ten
bents 25 feet apart, each containing three posts standing on
the hard gravel bottom and connected with four sets of braces
and girths. But the length of all previous spans in America
was surpassed in 1794 by an arch in the Piscataqua river
bridge, seven miles from Portsmouth, N. H. The whole bridge
was about 2,400 feet long, composed chiefly of pile bents and
short spans, but a portion between the two islands in the
middle of the river over water 46 feet deep, was crossed by
a single timber arch of ^44 feet. It was desigfned by Timothy
Palmer, the arch being similar to one built by Palladio, the
Italian architect, in the sixteenth century. Three arch trusses
or ribs, with a rise of 27 feet and 18 feet deep, supported a
floor 38 feet wide, each rib having three concentric rings, the
center one supporting the floor. An English writer refers
to "a wood bridge over Portsmouth river in North America,
with 250-foot span, built by Mr. Bludgett, something similar to
those of Grubermann Brothers in Switzerland," particulars
concerning which are not available.
168. Palmer's bridge at Haverhill with three arches of
180 feet and a 30-foot draw span, had piers 40 feet square
"with defensive piers or sterlings extending above," patents
being issued to Mr. Palmer in 1797. Another bridge at Holt's
Rock betwen Haverhill and Newbury, 1000 feet long, built
in 1795, had four arches and a draw span, but was destroyed
by ice in 1818.
169. Over the Connecticut river at Hanover, N. H., a tim-
ber arch was built, 1796, with a 236-foot span, copied after
Palmer's arch at Portsmouth, some of the pine timbers being
18 inches square and 60 feet long. The roadway followed the
line of the arch, being 20 feet higher at the center than at
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WOODEN BRIDGES.
129
the sides, and vehicles had difficulty in crossing it, but eight
years after completion it collapsed from its own weight with-
out warning. It was built by Rufus Graves, who, after mak-
ing a failure as a clergyman and later as a merchant, tried
civil engineering, but failing in that also, entered the army
and afterwards became a physician.
170. Several wooden bridges in Scotland were erected by
James Burn of Haddington, in 1803, including a deck arch over
the Don, seven miles from Aberdeen, with a clear span of 109
feet and 18 feet wide. The arch frames were made of short
pieces of timber acting as voussoirs, but stiffened by bracing
in the spandrels. Another in Scotland was a 34D-foot arch
foot bridge, 7 feet wide, in one span, built by Peter Nicholson,
over the Clyde at Glasgow in 1803, on the site of the present
Albert bridge.
F\g. 54.
171. Two notable bridges in America built by Mr. Burr,
were those at Waterford and Trenton. The bridge at Water-
ford over the Hudson (Fig. 52), built in 1804 of hewn yellow
pine, was one of Mr. Burr's best designs. It remained un-
covered for ten years after completion, but was then en-
closed. It had four spans of 154, l6l, 176 and 180 feet, and
a total length of 797 feet, each span containing three lines
of combined truss and arch on wooden piers. Two roadways
11 feet wide lay between the trusses, and the outside width
was 30 feet. A similar structure was built by Mr. Burr at
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130 BRIDGE ENGINEERING.
Fort Miller over the Hudson. The Waterford bridge con-
tinued in use until 1909, when it was burned, and a steel truss
with concrete floor was erected on tfie site. The bridge over
the Delaware river at Trenton (Fig. 54) in 1804 had three
spans of 161, 186, 198, and two of 203 feet. Each span had
five through arch ribs with a rise of 30 feet, dividing the
width of 36 feet into two carriage ways and two foot walks,
and the roadway platform was suspended from the arch ribs
at intervals of 8 to 16 feet by adjustable rods. The framing
timber was white pine in lengths of 35 feet to 60 feet, and 4
inches thick, with joints staggered. The arch footings were
renewed in 1832, and in 1848 the space occupied by the walk
at one side was widened and used for a line of railroad, the
inner trusses being strengthened, and the outer ones replaced
by heavier ones. It was again strengthened in 1869, and re-«
placed by an iron bridge in 1876.
Pig. 55.
172. In 1777, when the English were in possession of
Philadelphia, a pontoon bridge was built across the Schuyl-
kill river at Market Street, which was replaced later by one of
plank on floating logs. A new one, known as the "Permanent
Bridge" (Fig. 55) was constructed by Timothy Palmer from
1801 to 1806, at a cost of $300,000. It had a central span of
195 feet with 12-foot rise and two side spans of 150 feet each,
with 10-foot rise, the total length of framing being 550 feet,
but as the abutments and wing walls were 750 feet long, the
extreme length was 1,300 feet. It was covered and had three
lines white pine trusses 20 feet deep at the center and 35 feet
deep at the ends, with framing arranged to represent voussoirs.
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WOODEN BRIDGES. 131
The space between trusses was divided into two separate
roadways, 13 feet wide, with an elevated sidewalk inside the
outer trusses, making a total width of 42 feet. The carriage
way had a camber of 8 feet, making the floor at the center
31 feet above the water. Piers were 20 by 60 feet at the top
and were built in coflfer dams, the depths of water being
24 feet at the east pier and 41 at the west. In 1850, the
timber work was rebuilt from a different plan and the bridge
widened for a car track. The Delaware river bridge at E^ton
built by Mr. Palmer in 1805, consisted of spans 163 feet clear
and 195 feet center to center, and lasted for at least ninety
years, only a small part of the original bridge being rebuilt.
It had two lines of trusses 20 feet deep at the center, 34 feet
at the ends, 27 feet apart and was enclosed. It was replaced
in 1896 by a steel cantilever designed by Madison Porter.
173. Two timber arches in Germany, one over the Isar at
Freysingen, and the other over the Regnitz at Bamberg, had
spans of 153 and 208 feet respectively. Two sets of curved
ribs, one above the other, were sheathed over on the face and
painted to represent voussoirs. The framing timber was
preserved by coating with oil and tar. A stone bridge for-
merly occupied the site of the Bamberg bridge, but its numer-
ous piers so dammed the water that it was washed out, after
which the timber arch was erected with a single span.
174. The bridge over the Connecticut river between
Woodsvillc and Wells River, Vt. (Fig. 56), had a single span
of 239 feet and carried a highway on the lower chord' and a
single track of the Boston and Maine Railroad on top above
the shingled roof. It was five times rebuilt in timber and
finally replaced in 1903 with a steel bridge. The first one on
the site was a pile bridge built in 1805 by Avery Sanders at
a cost of $2,700, but it was destroyed two years later and im-
mediately built again. It was washed out in 1812, and for
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BRIDGE ENGINEERING.
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WOODEN BRIDGES. 133
eight years there was no bridge, until in 1820, another which
remained for thirty years was built at a cost of $2,585. The
fourth bridge (1851) had timber trusses and wood piers, the
fifth on the Burr type costing $20,000, was reinforced in 1868
and again in 1886, to carry the railroad on the upper deck.
The timber trusses were 24 feet deep and 19 feet apart on
centers, and the reinforcing arches had a rise of 30 feet.
175. The most unusual timber bridge in America was one
over the Mohawk river at Schenectady, N. Y. (Fig. 57), built
by Theodore Burr in 1808. It was a wooden suspension con-
taining four spans of 167 to 190 feet, and was the second
bridge on the site, the first one, which is said to have con-
tained two spans of 450 feet, having collapsed during construc-
tion. In 1828, after twenty years' service, signs of weakness
became evident and it began to sag. Piers were built under
the center of each span, in which condition it remained until
1873, when replaced by an iron bridge. The curved ribs were
made of eight layers of 4 by 14-inch plank spiked together.
176. The Coliunbia bridge (Fig. 68) over the Susque-
hanna river was built in 1812 at a cost of $232,000, but it was
washed out in 1832 and immediately rebuilt at an additional
cost of $157,000. It had twenty-nine timber spans 200 feet
long of combined truss and arch without counter braces. The
main braces and tie rods were in pairs and the upper chords
were not continuous over the piers. It was burned during
the Civil war (1863) to stop the troops from crossing, and in
1869 the old piers were purchased by the Pennsylvania Rail-
road Company, which rebuilt the bridge with Howe trusses,
placing two iron spans as a fire guard in the middle. As re-
built by the railroad company, the bridge had one 150 foot
and twenty-five 198-foot Howe spans with two iron spans of
100 feet and one iron deck span 89 feet long, the whole hav-
ing a length of 5,285 feet. It was destroyed again by a wind
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134 BRIDGE ENGINEERING.
storm in 1896 and was rebuilt in the following year in steel.
The three span bridge at Bethlehem, Pa., which still remains
(1910), is another of Mr. Burr's, the north span dating from
1816. The site was first occupied by a pile trestle, erected
by Mr. Trucks in 1794 at a cost of $7,800. The truss bridge
was not roofed over at firsts and all spans remained intact until
1862, when the two south ones were washed out by a flood.
It was immediately rebuilt and toll was collected until 1892,
when it was purchased by the counties for $26,000 and made
free. The trusses are wood lattice reinforced with timber
arches, roofed over but open on the sides. The span lengths
beginning at the North end are 125,110 and 135 feet respect-
ively. It has a clear roadway of 18 feet, an outside width of
21.3 feet and trusses are 13 feet deep. Sidewalks were added
in 1885. After a lapse of ninety-four years, this old wooden
bridge is one of the best preserved of the early timber bridges,
and stands in striking contrast to some of the newer metal
ones in the vicinity.
177. The first bridge on the site of the old "Long Bridge"
over the Potomac river at Washington, was built in 1809 at
a cost of $100,000, but was destroyed by a freshet in 1831.
The tolls collected were 25 cents for a man on horseback and
$1.00 for a four-wheeled vehicle. Four years elapsed after its
fall without a bridge, and in 1835 a wooden one was erected at
a cost of $113,000. It was damaged in 1836 and again in 1840,
. but was re-opened for travel in 1843 and used to carry steam
cars in 1867, and electric cars sometime later. In 1870, the
Baltimore & Potomac Railroad Company secured it, keeping
a highway open at one side, but the whole bridge was finally
sold for the sum of $175, conditional on its removal. It had
a length of 4,677 feet, divided into three section, the first 700
feet, afterwards filled in, followed by 1,980 feet of earth bank
over the river flats. The bridge proper over the channel was
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WOODEN BRIDGES. 135
2,000 feet long, with thirteen fixed spans of 135 feet clear
length and one pivot span of 182 feet. Of the three lines of
trusses the two southern ones carrying the railroad were
reinforced with timber arches. The clear width for the rail-
road was 19 feet and for the highway, 13 feet, while the total
over all was 40 feet. Water several times rose two feet above
the bottom chords and in 1905 it was replaced.
178. In 1811, Thomas Pope made a 60-foot model for a
wooden cantilever bridge 1,800 feet long, to span the Hudson
river at New York. He proposed building it with light tim-
ber frames from anchor cribs on either shore, and wrote and
published a comprehensive description of his design.
179. Some of the finest bridges in America during the
first part of the nineteenth century were designed and built
by Lewis Wemwag, including those over Nashammony
Fiir. 69.
Creek, the Colossus bridge at Fairmount, the New Hope
bridge, costing $50,000 without covering, the Manoquay and
Harper's Ferry bridges. The wood cantilever over Nasham-
mony Creek of 1810, which had a movable panel at one end,
he called "Economy Bridge," claiming that it could be used
for spans up to 150 feet ; but his largest bridge was the "Colos-
sus" (Fig. 59), over the Schuylkill river at Fairmount, Phila-
delphia (1812). It was destroyed by fire in 1838 and was
succeeded by Col. Ellet's wire suspension bridge, on the site
now occupied by the Callowhill truss bridge. It was an
arched truss with a rise of 38 feet and clear span of 340 feet,
the same length as the Clyde bridge at Glasgow (1803), and
up to that time was the longest wooden span in America,
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136 BRIDGE ENGINEERING.
though since exceeded by one in Oregon. Five curved wood
frames 20 feet deep at the center, acted as truss and arch,
with two roadways and two sidewalks between them, the
bottom chords being composed of three sticks 6 by 13 inches.
The east abutment stood on rock, the west abutment on
piles driven to rock, and the whole bridge was roofed over
and enclosed with sheathing. After completion it was tested
by passing over it a wagon loaded with a stone weighing
22 tons and drawn by sixteen horses. This was Mr. Wern-
wag's third bridge, but between 1810 and 1836 he built about
thirty others, the last being over the Potomac and canal at
Harper's Ferry. Both the Permanent bridge at Market Street
(1805) and the Colossus (1812) were somewhat like Thomas
Paine's Wearmouth model for cast iron, made in 1787. In
1816 the Smithfield Street bridge at Pittsburg was built with
eight spans of 188 feet, but was burned in 1845.
List of Mr. Wemwag's Bridges:
Name. Date.
Nashammony Creek 1810
Bridesburg 1811
Colossus 1812
New Hope 1813-1814
Reading, Pa 1816-1816
Monongahela and Allegheny, Pittsburg 1816
Wilkesbury ; 1817
Falls of Schuylkill 1817
Conneswingo on the Susquehanna 1818
Jones* Falls, Baltimore 1818
Brandy wine Creek near Wilmington 1820
Paulding's Ford on Schuylkill 1823
Harper's Ferry 1823
Goose Creek, London County, Va 1824
Gunpowder Creek, Va 1824
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WOODEN BRIDGES.
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Monoquay river near Frederick City 1827-1830
Port Deposit 1827-1830
Cambridge, Ohio 1827-1830
Monoquay Railroad bridge, B. & 1830
Romney, over South Branch of Potomac 1834
Harper's Ferry, over Potomac and canal 1838
180. Previous to 1816, only fourteen bridge patents had
been granted by the United States. In 1820, an architect of
New Haven, Ithiel Town, invented and patented the Town
truss (Fig. 60), so many of which in spans up to 220 feet have
S ^'^Y^ ^^ ^^^^ ^^
1.. !■ 1 ■ 1.
Fig. 60.
been used all over the continent for both railways and high-
ways. The top and bottom chords were made of two or three
parallel timbers and the web, of diagonal planks spiked to-
gether with wooden pins. They were made with uniform sec-
tions and were frequently continuous over the piers. Mr. Town
published a pamphlet in 1831, describing his designs, claiming
that these bridges could be quickly made from common plank,
could be covered and protected from the weather and pro-
duced no overturning thrust on the piers, and the parts could
easily be inspected for dry rot. His first bridge was on the
New Haven and Hartford turnpike over Mill river near Lake
Whitney, a suburb of New Haven. It was 14 feet wide, 12
feet high and 100 feet long. In later years this truss became
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138 BRIDGE ENGINEERING.
a prototype for iron lattice bridges, such as those at Kiel and
Hamburg. An objection to the Town truss was its liability
to twist and warp, owing to the thinness of the web and the
lack of enough verticals near the end. This warping tendency
is well illustrated by the old wood lattice bridge over the
Jordan river at Salt Lake City, built under the direction of
Brigham Young, which was renewed in 1908. It was
recently examined by the writer and designs prepared for
a new one. An improved form of lattice truss was therefore
evolved which used a less number of a larger web members,
the inclination of which changed from 45 degrees at the center,
to vertical over the piers. Previous to 1820, most large spans
had been some form of arch, but soon after this numerous
wood trusses were invented, most of which were a combina-
tion or arch and truss with one or more systems.
181. In 1824 the Mill Dam bridge was built at Water-
town, Mass., and four years later the Warren toll bridge over
the Charles river at Boston. Tolls were discontinued on the
latter in 1836, whereupon the owners of the Cambridge
(Craig's) bridge removed the draw span and closed up theirs
for five years. Both were again subject to toll in 1841, but in
1843 were thrown open to free travel.
182. In 1830, Col. Stephen H. Long of the U. S. En-
gineers, took out patents on a timber truss connected with
wooden pins, and 1836, he published at Concord, N. H., a
pamphlet of seventy-five pages describing it. The top and
bottom boards were in three pieces, with double web posts
between, fastened with wooden keys. The skew blocks be-
tween the web members and chords were made of oak or
other hard wood, instead of iron, as on some later ones. The
first bridge on his patent was on the Washington road two
miles from Baltimore. Both the Town and Long trusses
were often combined with an arch in long spans.
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WOODEN BRIDGES.
139
183. A wooden bridge, Pont Ivry, designed by M. Em-
mery (1828), crossed the Seine near Paris, with five arch
spans, the maximum being 78 feet, and it remained until
1881, when replaced by metal.
184. In 1831, a timber street bridge was built by Robert
Stephenson between the Broomielaw and old Glasglow bridges,
over the Clyde at Glasgow. Fourteen spans of 34 feet each
were supported on timber bents with flat knee braces from
Fig. 61.
the bents, forming arch frames beneath the floor (Fig. 61)
Another by Mr. Stephenson was the foot bridge at Abbey St.
Bathans over Whitadder river, and one by William Bull over
the Calder and Hibble Navigation.
185. In America the progress of bridge building was slow
until the introduction of railroads in 1829, which gave an im-
petus to this branch of engineering. The first wooden rail-
road bridge in America was built by Wernwag'for the Balti-
more & Ohio Railroad at Monoquay in 1830. In 1834 the
Columbia covered bridge over the Schuylkill river at Phila-
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140 BRIDGE ENGINEERING.
delphia was built for the Columbia Railroad, afterwards sold
to the Philadelphia & Reading. This was the work of Mr.
Burr and continued in use for fifty years, when it was re-
placed by one of iron. Another bridge over the Susquehanna,
about five miles from Harrisburg, similar to the Columbia
bridge, had counter braces and was more rigid. It had twenty-
three spans of 160 feet, with .trusses 18 feet deep and 20-foot
arch rise. There were two lines of trusses and a covering, a
single line of railroad being on the deck. During erection,
after fourteen spans were placed, a violent windstorm blew
six spans completely oflf their piers.
Fig. 62.
186. The Cumberland Valley Railroad bridge over the
Susquehanna river at Harrisburg, with twenty-three spans
of 170 to 180 feet, built at a cost of $62,000, Was used until
1844, when all but four spans were burned. It was 4,277 feet
long and had four lines of double lattice trusses, with two
highways on the level of the lower chord and a single line
of railway on top, and wis rebuilt after the fire and roofed
over. The old Long bridge over the Potomac at Washing-
ton, which was destroyed in 1831, was rebuilt in 1836 as
previously described.
187. The Baltimore & Ohio Railroad built a number of
wooden bridges, among which are the covered ones over the
Patapsco river near Elysville (Fig. 62), eighteen miles from
Baltimore. They were designed by Benjamin H. Latrobe in
1838 and patterned after the SchaufFhausen bridge in Germany,
but had counter braces and were more rigid. One of them had
two spans of 150 feet on stone piers, while another over the
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WOODEN BRIDGES. 141
same river near by, had three spans of 110 feet, the two
bridges costing $140,000.
188. In 1834 a single span bridge was built by General
John Milroy over the Whitewater river at Richmond, Indiana,
with three white oak arch ribs and light trusses. It was
roofed over but open on the sides and carried two roadways
and two walks outside the trusses. In 1897 it was found to
have sagged five inches and was renewed,
189. A Town truss railroad bridge, over the James river
at Richmond, Virginia, was built in 1838 with nineteen tim-
ber spans of 130 to 153 feet on granite piers, 4 by 18 feet at
top, and standing 40 feet out of water. It had a length of
2,900 feet and was erected by Moncure Robinson at a cost
of $125,000. The truss was 26 feet deep and the roadway on
top was 60 feet above water. A similar Town truss bridge,
over the Susquehanna river, had 220-foot spans and a length
of 2,200 feet. Other similar trusses were at Nashua, Newbury-
port. Providence, Philadelphia and Trenton and one near New
York on the Harlem river railroad 736 feet long, four near
Troy, and one for the Baltimore & Ohio Railroad near
Philadelphia.
190. A timber bridge of eight spans over the Seine at
Eauplet, near Rouen, France, for the Rouen and Havre Rail-
road, was built by Joseph Lock with a length of 1,148 feet.
Each span was 133 feet long and was supported by four tim-
ber segmental arches with a rise of about 20 feet, on stone
piers. It had a width of 24 feet and carried two tracks, cost-
ing about one-third that of stone arches.
191. In the United States, Herman Haupt secured a pat-
ent in 1839 for a bridge truss, and the following year, William
Howe was granted a patent on a truss (Fig. 63) with timber
diagonals and vertical iron ties in single or double systems.
Many Howe truss spans are still in use, and in regions where
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BRIDGE ENGINEERING.
timber is plentiful this type is extensively used on new roads
for temporary work. Mr. Howe's first bridge was in 1840,
and the second one completed during the same year, carried
a railroad over the Connecticut river at Springfield, with
seven spans of 180 feet. It lasted for thirteen years, when
it was replaced by another Howe bridge which remained
until 1874, when it was removed for a double track wrought
iron structure.
192. In 1844 Caleb Pratt invented and patented a truss
(Fig. 64) similar in outline with the Howe truss, but differ-
ing from it in having the vertical web members in compres-
sion and the inclined diagonals in tension. This type was
little used in wooden construction, but later became the pre-
vailing one for trusses of iron and steel. Patents for timber
trusses were also granted in 1851 to D. C. McCallum.
Fig. 64.
193. In the early days of railroad building in England
many timber viaducts were built, one for the Newcastle,
North Shields & Tynemouth Railroad over Willington Dean
(Fig. 65) being typical of many others. The one mentioned
consisted of seven timber arches of 115 to 128 foot span be-
tween stone piers, the height being 82 feet and length 1,048
feet. It was designed by John and Benjamin Green, engineers.
Two similar bridges over Ouse Burn and Wellington • Brook,
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WOODEN BRIDGES.
143
completed in 1839 stood until 1868, when the arches were re-
moved by T. E. Harrison, engineer for the Northwestern Rail-
road, after building iron arches beneath them. The one over
Ouse Burn had wood arches, 114 to 116 feet and four approach
stone arches, a road 26 feet wide and a 5-foot walk on one
side. A somewhat similar arch of one 275-foot span on the
New York & Erie Railroad over Cascade Glen was built in
1848, from designs by Col. J. W. Adams. The chords have
a rise of 45 feet and the deck is 26 feet wide and covered
over, carrying a single line of railway in the middle. The
Fig. 65.
three timber hingeless arch trusses were 12 feet deep at the
center and 11 feet 9 inches apart, the center truss being double
width. The Glenury bridge in Scotland contained fourteen
timber arches of 60 feet, between masonry piers, each span
having six ribs.
194. The Havre de Grace bridge over the Susquehanna
river on the Philadelphia, Baltimore & Washington Railroad
contained thirteen spans of 250 feet and a draw of 176 feet,
making a total length of 3,500 feet. It was completed in 1850
after five years in building at a cost of $2,000,000. The original
bridge consisted of two. lines of wood Howe trusses 20 feet
apart, reinforced with arches carrying a single track, but was
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144 BRIDGE ENGINEERING.
replaced a few years later with an iron bridge, and again by
the steel one in 1906. Many other bridges similar to this were
scattered over the country. The usual practice was to re-
move the false work after the trusses were erected, allowing
the whole dead load to be carried by them, and afterwards to
place the arches. In course of time, as the bridge settled,
the weight was finally borne by the arch, with the trusses
only for stiffening.
196. A Burr truss of two spans, 148 and 164J4 feet, carried
the Pennsylvania Railroad over Sherman creek, and there was
another at Clark's Ferry over the Susquehanna.
196. A railroad bridge over the Connecticut river between
Windsor Locks and Warehouse Point (Fig. 66) was built in
Flff. 66.
1844, with seven spans of 180 feet, one small span at the east
end and three at the west adjoining the tow path and channel.
It had a total . length of 1,260 feet and carried one line of
railway between the trusses, which were of the Long type.
After two years the whole bridge was blown bodily off the
piers in a violent windstorm, but a new one like the old was
built in forty-five days, and it remained in use until replaced
by one of iron in 1864. The clearance over low water was 29
feet, and it was supported on stone piers with radial braces
from the piers spreading out at each side to the three lower
panel points. George Washington Whistler (1800-1849),
United States army engineer, was the designer, and a number
of others similar to this were designed and built by him when
engineer for the Petersburg & Moscow Railroad, all of which
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WOODEN BRIDGES.
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were of timber. One over the Msta river had nine spans of
200 feet and a total length of 1,927 feet, carrying two tracks
at a height of 101 feet above water. Three lines of wood
truss 21 feet deep rested on piers, the upper 70 feet of which
were timber on masonry bases. Two spans were burned in
1869 and replaced with steel.
197. An old highway bridge over Pine creek in Warren
County, Ind., built about 1850 of black walnut, had a single
span of 150 to 200 feet, and in recent years the timber became
so valuable that several bridge companies offered to replace
it in steel in return for the walnut.
Fig, 67.
198. Two bridges on the Utica and Syracuse Railroad,
made of plank and thin sawed timber in spans up to 100 feet,
are illustrated in Fig. 67. The Kennebec river bridge at
Skowhegan, Maine, had one span 124J4 feet long, built in the
middle of the last century and replaced by a steel bridge in
1904. It had two lines of combined truss and arch, 16 feet
deep in centers, with a clear road 21 feet wide and 5-foot pro-
jecting sidewalks, the whole being roofed over J[)ut not other-
wise enclosed. Immediately after its erection it showed signs
of weakness and a suspension rod was inserted in each one
to strengthen it. The floor supported on the bottom chord was
40 feet above the river, which was swift and deep.
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BRIDGE ENGINEERING.
199. Another covered wooden bridge of 1860 crossed the
Delaware at Narrowsburg, N. Y., with a single span of 262
feet and floor 40 feet above the water. It was roofed over and
Fig. 68.
shingled and the lower part of its sides enclosed, leaving the
upper part open for ventilation and light. The trusses were
a combination of arch and truss of the Howe type.
Fig. 69.
;;^00. A bridge, designed by William Tyrrell of Weston,
Ontario, the writer's father, to carry King Street, Toronto,
over the river Don, had three lines of combined truss and arch
(Fig. 69). The photograph is of a carefully made walnut
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WOODEN BRIDGES.
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model, about 10 feet long, put together with brass bolts and
pins, and, as far as known, is the only one of the kind.
201. A timber arch bridge (Fig. 70) for the Ladykirk and
Norham Railway over the Tweed river, designed by John
Blackmore, had two spans of 190 feet and 17-foot rise, on a
Fig. 70.
center pier 20 feet thick, carrying a road 18 feet wide. The
timber frames which act as arch and truss had a lower chord,
increasing in thickness towards the springs, and upper truss
chords increasing in thickness to the center, with web posts
radiating like parts of a voussoir arch. Another bridge, de-
signed by Mr. Blackmore for the Newcastle & Carlisle Rail-
way over the Tyne at Scotswood, had eleven spans of 60 feet,
35 feet above low water, each span having trussed ribs sup-
ported on pile piers. Many other railroads in England and on
the continent made extensive use of timber bridges. Five not-
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BRIDGE ENGINEERING.
able ones over the Aranyos river, on the Eastern Hungarian
Railway, completed in 1870, had lengths of 650 to 1,150 feet,
and a long pile and trestle bridge crossed the Danube at Vienna
and Linz in the middle of the nineteenth century. The Spreuer-
brucke, a covered wood bridge over the Reuss (Fig. 71) at
Lucerne, Switzerland, built in 1871, is a picturesque example.
Another very interesting timber bridge is one at Kanday,
Ceylon, with an arch span of 205 feet and 20-foot rise, sup-
Fig. 72.
porting a deck 20 feet wide; it has four wood arch ribs of
three double beams two feet apart. A triangular bamboo arch
at Java, in the Dutch East Indies, is illustrated in Fig. 68.
202. Other typical wooden bridges in America are those
at Grand Rapids, Minneapolis, St. Paul and Los Angeles.
The Grand Rapids bridge carries Leonard Street over the
Grand river (Fig. 72) and was built by William Seckel, city
engineer, in 1S79. It has eight spans of 104 feet each, the
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WOODEX BRIDGES. 149
trusses having six system Warren lattice, made of white pine
and fastened at intersections with wooden pins. It lately
showed signs of weakening by crushing over the piers, and in
1907 the whole bridge was strengthened by inserting addi-
tional vertical timbers at the supports and a system of diag-
onal rods, the work being carried on by G. J. Davis, Jr., under
the direction of L. W. Anderson, city engineer. The Min-
neapolis Howe truss bridge (1873) crossed the Mississippi
river with ten equal spans of about 160 feet.
203. A design was made by Tredgold (Fig. 73) for a 400-
foot timber arch, and similar but smaller ones were erected at
St. Paul and Los Angeles. The Mendota ravine near St. Paul
is crossed by a single arch of 192 feet, carrying a deck 95 feet
above the valley. It has two hingeless braced timber ribs, 15
Fig. 73.
feet deep and 18 feet apart, with 48-foot rise, the clear height
beneath the intrados being 77 feet. A bridge somewhat like
this may be found in Hollenbeck Park, Los Angeles, carrying
a foot path high above the lagoon. A very interesting and un-
usual example of rustic bridge construction has recently been
placed in the National Zoological Park at Washington, D. C.
It is a log arch of 75-foot span and 30-foot width. In this
wooded spot the rustic bridge corresponds well with the
natural surroundings and produces a satisfying effect. The
total length is 96 feet and the rise 11 feet. The cost, includ-
ing macadam roadway and footwalk, was $3,000. Mr. Glenn
Brown of Washington was the architect.
204. Small covered wooden bridges similar to Fig. 72
may still be seen in many parts of the United States, espe-
cially in the eastern portion of the country. One over the
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BRIDGE ENGINEERING.
McKenzie river near Coburg, Oregon, for the Southern Pa-
cific, contains a span of 380 feet. The old covered bridge at
Hartford, Conn., was burned in May, 1895, while a deter-
mined effort w^as being made by a local bridge building com-
pany to secure a contract for a new bridge at their proposed
price of about $280,000. Finding themselves without a bridge
WEBSTER AVENUE BRIDCE, CHICAGO
across the river, the city of Hartford contracted for a tem-
porary one of combined timber and steel, on pile piers, the
drawing of which were made by the author. The contract
called for its completion within two months time, and during
this period communication was maintained by ferries.*
♦Hartford Temporary Bridge. H. G. Tyrrell, in Railway and Ensrineerinff Review,
Auffust 31, 1901.
♦Comparative Cost of Combination and All Steel Bridcres. by H. G. Tyrrell. Scientific
American, Aufifust 11, 1900. Indian and Eastern Engineer, April, 1901. etc.
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CAST IRON BRIDGES. 151
CHAPTER IX.
CAST IRON BRIDGES.
205. Cast iron, though brittle and less reliable than steel,
has the merit of little or no corrosion from rust, and bridges
of this material are still in use, long after later ones of wrought
iron and steel have been destroyed. Cast iron was favored
also because of the opportunity for designing bridges which
were light and ornamental with architectural features. The
very earliest iron bridges were probably the chain suspensions
in China and Japan of mediaeval times, but the first modern
attempt at building one of cast iron was at Lyons, France, in
1755, when a single arch was erected at the foundry where it
was cast. The effort was not successful and the project was
abandoned as too expensive.
206. The most remarkable cast iron bridges were those
designed by the English engineers, Rennie, Telford, Brunei
and Stephenson, including the designs for bridges over the
Thames and those projected for spanning the Menai Straits.
In 1896, on the railroads of England and Wales (not including
Scotland and Ireland), there were twenty-eight hundred
bridges of cast iron, fifty-two hundred of wrought iron, four-
teen hundred of wood and one hundred and twenty-one of
steel. The cast iron were mostly girders, the longest being
less than 50 feet, but the number show to what extent they
were used previous to 1870.
207. In 1776 the cast iron bridge at Coalbrookdale (Fig.
74), over the Severn river between Medley and Brosely, near
the town of Iron Bridge, was built by Abraham Darby at his
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152
BRIDGE ENGINEERING.
Coalbrookdale iron works, and in 1900 was still in good con-
dition. It was designed in 1773 by Pritchard, an architect of
Eyton Turret, who planned several large ,arches with clear-
ance below for ships. It has one span of lOOJ^ feet with five
Flgr. 74.
segmental arch ribs nearly semi-circular, having a center rise
of 45 feet, and at one end are two similar but smaller arches.
Each rib has three concentric rings connected by radial pieces,
and they were cast in halves, meeting at the center. It con-
tains 378 tons of metal and was the first bridge in any coun-
try composed entirely of iron. The partial failure of the abut-
ments and their movement forward from earth pressure behind
them, caused the arch to rise slightly at the crown, giving it
a pointed appearance. The English Society of Arts awarded a
gold medal to Mr. Darby in 1788 for its construction.
In the year, 1787, Thomas Paine, the versatile author and
civil engineer, proposed building a cast iron bridge over the
Schuylkill river at Philadelphia, with a span of 400 feet. He
made models of the bridge in wood and cast iron and took the
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CAST IRON BRIDGES. 153
wood model to Paris, where he submitted it with his plans
to the Academy of Science for examination. As it was favor-
ably received and found satisfactory for a span of 400 feet,
Mr. Paine ordered two arch ribs of 90-foot span and 5-foot
rise to be cast at the Walker foundry in Rotheram, York-
shire, and tested them with double their own weight. As the
tests were also satisfactory, he ordered, at the same foundry,
the parts for a complete bridge with a span of 110 feet and
the small rise of 5 feet, and had them shipped to London for
a trial erection at Lisson Grove. Mr. Paine's project was,
however, abandoned because of the failure of his financial as-
sociates, and the cast iron was taken back by the foundry to
be used again in making the arch ribs for the bridge at Sunder-
land over the river Wear (Fig. 75). The designs for both the
Coalbrookdale and the Sunderland bridges show that they
were intended to act only as voussoirs arches, no reliance be-
ing placed on spandrel bracing.
208. The earliest iron bridge on the continent of Europe
was at Laasaiiy Silesia, over the Striegauer Wasser. It
has a single 60-foot cast iron arch with five parallel ribs,
built in the years 1794 to 1796, soon after the completion of
the one at Coalbrookdale, and was still in use in 1900.
209. Mr. Telford's first iron bridge was built in 1796,
over the Severn at Buildwas, with a span of 130 feet. It had a
width of 18 feet, contained 178 tons of iron and was cast at Mr.
Darby's Coalbrookdale foundry, at a cost of $30,000. It was
made with a small rise to better resist the earth pressure
on the abutment and thereby avoid any accident similar to
that which happened to the Coalbrookdale bridge. It was re-
moved in 1906. Mr. Telford's best bridges were those at
Tewksbury and Craigellachie, built about fifteen years later.
210. The Sunderland bridge over the Wear at Wearmouth,
England (Fig. 75), was designed by Thomas Paine, patented
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154
BRIDGE ENGINEERING.
by Rowland Burdon in 1795, and built in 1796, under the direc-
tion of Thomas Wilson, who designed its architectural fea-
tures. It has a single cast iron hingeless arch of 236 feet and
34:-foot rise, and the roadway is 100 feet above the river. The
six segmental arch ribs with open spandrels, the outer ones
ornamented with circles, each had one hundred and five cast
iron voussoirs like arch stones, 5 feet deep and 2 feet long,
connected with wrought iron bars, supporting a deck 32 feet
Fig. 75.
wide, which was planked over and covered with gravel and
limestone. It w^as cast from the metal in the discarded arches
of the Philadelphia bridge, and contained 214 tons of cast
iron, 46 tons of wrought iron, the cost, $135,000, being almost
entirely donated by Mr. Burdon. In 1861 it was sold by lot-
tery for $150,000. It was patterned after the model made by
Thomas Paine for the Schuylkill river bridge at Philadelphia
in 1787, and the Coalbrookdale and Sunderland arches, espe-
cially the latter (both of which act as voussoir arches), are
the prototypes of many modern ones of wrought iron and
steel. The bridge was widened in 1858-59 under the direction
of Robert Stephenson.
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CAST IRON BRIDGES. 155
211. In 1801 Mr. Telford and Mr. Douglas presented to
the British Parliament a plan for rebuilding the London
bridge with a single cast iron arch of 600-foot span and 65-foot
clear head room. Though it was referred to a committee of
twenty persons no action was taken. In the following year
Mr. Rennie proposed a single cast iron arch to span the entire
width of Menai Straits at the site of the present Britannia
tubular bridge, and at the same time made another design with
three 350-foot arch spans and a center head room of 160 feet,
both designs having many small approach arches at the ends,
and he revised them again in 1810. In the years, 1810-11, Mr.
Telford also prepared two plans for bridging the straits, the
plan for one site having a single 500-foot span, 40 feet wide,
while the other site required three cast iron arches of 260 feet
and two of 100 feet between piers 30 feet thick ; but neither de-
sign was accepted. His proposed Menai arch had a center
under clearance of 100 feet with 60-foot rise. He proposed
erecting the voussoirs by means of a system of guy ropes or
suspensions from the abutments. An aqueduct, Cys Sylte
bridge, designed by him, located over the River Dee at the
bottom of the vale of Llangallen, 1,007 feet long with nineteen
spans of 45 feet and 126 feet high, has a cast iron canal box
5 feet high and 12 feet wide, supported on cast iron arch ribs
and stone piers. It had a foot walk over the water at one
side, with a substantial railing. The bridge over the Conway
near Bettws-y-Coed (1815), also the design of Mr. Telford,
bears an inscription in large open cast iron letters below the
soffit, through its whole length, **This arch >vas constructed in
the same year that the battle of Waterloo was fought."
212. A bridge over the Cam river at Cambridge, England,
known as Gerrard's Hostel bridge, was designed by William
C. Milne, son of Robert Milne, architect of old Blackfriars
bridge, and was cast by the Butterfly Iron Company. It has
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156 BRIDGE ENGINEERING.
three ribs, a narrow roadway of only 9 feet and a span of 60
feet, slightly pointed, being patterned after Trinity Bridge in
Florence. The railing was ornamental cast iron of Gothic
design.
213. The earliest cast iron bridge in France was Pont-du-
Louvre, with nine spans of 57 feet, built in 1803 for pedestrian
travel. It was 30 feet wide, 616 feet long and each span had
five arch ribs, the whole weight of metal being 263 tons.
214. The Craigellachie bridge over the Spey, by Telford,
with a single span of 150 feet, was the first use of a cast iron
arch with braced spandrel. It crosses the river where the
road encountered a high bluff and makes a sharp turn. This
and the bridge at Tewksbury are the finest cast iron bridges
built by this distinguished engineer.
215. The Witham river bridge at Boston, Lincolnshire,
and the Southwark bridge in London, were the work of John
Rennie. The Southwark bridge over the Thames has three
cast iron hingeless arches on stone piers 24 feet thick, the cen-
ter arch being 240 feet and the two side arches 210 feet each,
with rise of one-tenth the span, the arch rings being made
in imitation of stone voussoirs. It is 710 feet long and each
span has eight ribs in thirteen separate pieces 2j4 inches
thick, and 6 feet deep at the center. It contains 5,780 tons of
metal and has the largest cast iron span ever built. In 1819,
after five years in building, it was completed at the cost of
$4,000,000. The widening of it is now (1910) being consid-
ered, at a prospective cost of $1,300,000. The Southwark and
London bridges are Mr. Rennie's finest works.
216. The Monk and Hunslet bridges over the Aire river at
Leeds, England, with single spans of 112 and 152 feet, built
by George Leather in 1827 and 1832, were the first instances
of a roadway suspended from overhead cast iron arches. A
crossing of the Birmingham canal at Galton (1829) has parallel
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CAST IRON BRIDGES. I57
chord lattice ribs and a deck covered with cast iron floor
plates. A cast iron bridge was built in 1835 over Dunlap
creek at Brownsville, Pa., by John Snowden of Brownsville,
from a design by John Herbertson, with a span of 85 feet and
width of 25 feet.
217. St. Peter's bridge over the Seine at Paris, known
also as Potit du Carrousel, built during the years 1832-1838
by Polonceau, has three cast iron arch spans of 150 feet each,
and a rise of 16 feet, each span having five arch ribs. The
method of filling the spandrels with cast iron circles is not
satisfactory or pleasing and will probably not be repeated in
good designs. The length of bridge does not harmonize with
the present condition of the docks, giving the impression of
being too great for the location, and the piers are too thin.
218. The Thornby cast iron girder bridge over the Tees
(1844) on the Stockton and Darlington railway, placed there
by Robert Stephenson beside the old suspension, has five
spans of 89 feet for double track. The girders of each span
were in three pieces, bolted together and trussed with wrought
iron bars, and all five spans were bolted together over the
piers. After the failure of a similar bridge at Chester, each
span was reinforced with inclined timber braces from the
girders to the pier base, in which condition it remained until
replaced by a steel bridge in 1906.
219. The Chester bridge over the Dee, which collapsed
in 1847 a few weeks after completion under a derailed train,
had three spans of 108 feet, with four lines of cast iron girders
in two parts for double track. The floor, on which an excess
amount of ballast had been piled, consisted of 4-inch plank
over transverse timbers, resting on the lower girder flanges.
The girder was 3 feet 9 inches deep, and the bridge was the
largest of its kind.
220. In 1844 R. B. Osborne made about twelve combina-
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158 BRIDGE ENGINEERING.
tion cast and wrought iron girder bridges in America, with
chords of wrought iron and intermediate braces of cast iron
in the form of rectangular tubes.
221. The cast iron arch near Thirsk over the River Swale
(Fig. 76), erected in 1847, carries two tracks of the Leeds
& Thirsk Railway, and in 1908 was still in service. To lighten
the dead load, an ornamental railing at the sides, together with
a great accumulation of ballast, was removed about 1890.
222. When designing the Britannia and Conway tubular
bridges in 1847, the engineers benefitted greatly by the sur-
veys, reports and experience of Messrs. Rennie and Telford,
Fig. 76.
made more than twenty years before when they were de-
signing the Menai suspension bridge. Mr. Brunei proposed
two cast iron spans of 350 feet each, 105 feet above high water,
for the Britannia bridge, and a similar 350-foot arch 20 feet
above high water over the strait at Conway, and he developed
a method of erecting them by cantilevering the voussoirs out
symmetrically from the piers with corresponding arch blocks
at each side, tied together over the piers with rods. The plan
necessitated the use of half arches or anchor arms at the
ends to balance the cantilever arms over the water, and
showed that the arches could remain disconnected at the span
center. The idea is doubtless the origin of the modern metal
cantilever bridge, a similar principle being used twenty years
later for erecting the arches of the Eads bridge at St. Louis.
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CAST IRON BRIDGES. 159
Mr. Stephenson proposed two cast iron arches of 450-foot span,
similar to Mr. Brunei's design, with 100 feet center clearance.
The design was not accepted however, because the clearance
which was sufficient at the center was diminished by the arch
towards the springs, and the flat tubular bridge was used in-
stead. Before proceeding with the construction, Mr. Stephen-
son ordered an elaborate series of experiments to be made on
the strength of cast and wrought iron under the direction of
two theoretical men, William Fairbairn and Eaton Hodg-
kinson, the conclusions from which, finally caused the aban-
donment of cast iron in favor of a more ductile metal.
223. Another bridge designed by Robert Stephenson in
1849 is that carrying three tracks of the Northeastern Railway
over the Tyne at Newcastle. It has six metal spans of 125
feet, with two approach arches at one end and six similar
arches at the other end, making a total length of 1,873 feet.
Two platforms are supported by four lines of trusses in pairs,
the upper deck carrying the railroads and the lower one the
highways. The main spans are bowstring trusses with cast
iron arch and top chords without diagonals, the arch thrust
being resisted by lines of wrought iron tie rods at the lower
roadway level. Piers and abutments are stone with a clear
head room beneath the trusses of 83 feet. It contains 4,730
tons of cast iron in the compression members, 320 tons of
wrought iron in the tension members and cost 243,000 pounds
sterling.
224. The new Westminster bridge at London was built
during 1854 to 1862 by Thomas Page, at a cost of $1,866,000,
and replaced the old stone arch bridge of 1760, which had thir-
teen small arch spans. The design was made to harmonize
with the architecture of the adjoining Parliament buildings.
225. The seven span cast iron arch bridge over the Neva
at St. Petersburg, which was in use in 1890, was designed and
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160 BRIDGE ENGINEERING.
built in 1854 by Joseph Harrison, Jr. of Philadelphia. Two
years later, Sir William Cubitt built a three-span cast iron
arch at Rochester, England, over the Medway to replace the
old stone one of the fourteenth century.
226. A very unusual bridge was completed over Rock
creek at Washington, D. C, in 1859, to carry the Washing-
ton aqueduct from Georgetown. It consisted of two lines of
cast iron water pipe 4 feet in diameter, through which the
water flows, arched between the two abutments and support-
ing a highway and car tracks on a deck above. It has a clear
span of 200 feet, a rise of 20 feet and was built under the
direction of General Meigs of the United States army. The
span is nearly as great as that of the Cabin John bridge in
the near vicinity, which also carries an aqueduct, and their
cost is an interesting comparison.
227. The site of the St. Louis bridge at Paris was orig-
inally occupied by an old suspension bridge connecting Isle
St. Louis with Quay Napoleon. The present bridge, built
1860-62, has a single cast iron arch with a clear span of 210
feet, designed by M. Georges Martin of Paris, and built by M.
Garnochot. The springs of the arch are 10 feet above low
water and the arch has a flat rise of 19 feet, the total clear-
ance beneath it at the center being only 29 feet. There are
nine parallel girders about 6 feet 7 inches apart, the inner
ribs being plain, 2 inches thick at the ends and lyi inches at
the crown, while the outer ribs are ornamental. The floor is
laid on brick arches carried on cast iron beams 6 feet 7 inches
apart, and the total width between parapets is 52 feet 6 inches,
consisting of a carriage way and two sidewalks. It contains
745 tons of cast iron, and cost $137,000, and when built was the
longest cast iron arch in France.
228. Duplicate cast iron bridges known as the Victoria
and Albert bridges over the Severn river, England, were de-
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CAST IRON BRIDGES. 161
signed by John Fowler and built in 1861. The Victoria
bridge, located at Areley near Bewdley, carries two lines of
railroad on arches, with a clear span of 200 feet and 20-foot
rise. There are four main curved ribs or girders 4 feet deep,
supporting a ballast deck on a solid plank floor 27J4 feet
wide, with clear head room beneath of 40 feet. Another small
but ornamental bridge planned by Mr. Fowler spans the canal
in Regent's Park, and is a model design for the location.
229. The largest cast iron bridge in America is at Chest-
nut Street in Philadelphia, crossing the Schuylkill river in
the central part of the city, with two cast iron spans of 185
feet clear length. The distance between abutments is 390 feet
and the total length over all is about 1,000 feet. The central
pier was located in line with the west pier of the Market Street
bridge. In addition to the central iron spans there are two
stone arch approach spans at each end, of 53 and 60 feet re-
spectively. The cast iron arch ribs are segmental and 4 feet
deep, in lengths of 12 feet 10 inches, with a rise of 20 feet. The
total width of bridge is 42 feet, consisting of a 26-foot road
and an 8-foot walk on each side. The masonry is faced with
cut granite and the original bridge cost $500,000, but in 1884
the foundations were underpinned and strengthened at a cost
of $40,000 more. It was designed by Strickland Kneas, city
engineer of Philadelphia, and built during 1861-66, its erec-
tion being seriously delayed by the Civil war. It adjoins the
site of Thomas Paine's proposed 400-foot cast iron bridge
at Market Street, but the Chestnut Street bridge has two
spans instead of one as proposed by Mr. Paine. In place of a
single span cast iron arch at Market Street, the river is crossed
at this point by a wrought iron cantilever.
230. The El Kantara bridge over the Rummel at Con-
stantine, Algeria, was designed in 1860 by M. Martin, with a
center cast iron arch of 188 feet, two masonry arches at one
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162 BRIDGE ENGINEERING.
side and one at the other. It has five arch ribs carrying a
highway 33 feet wide, over a ravine 394 feet deep and 414
tons of cast iron were used in its construction. The orna-
mental spandrels bear the letter "N," the initial of Napoleon.
An ancient Roman bridge which fell about the middle of the
nineteenth century, formerly occupied the site. Other cast
iron railroad arch bridges in Algeria are over the Chiffa (1868)
with four spans of 156 feet, over the Mina (1869) with one
span of 146 feet, and over the Habra (1869) with two spans
of 81 feet, all for single track.
231. Many other cast iron bridges of less importance were
built during the nineteenth century, chiefly in England, where
they were very popular. The old Blackfriars stone arch bridge
at London (1760-70) with thirteen spans, was replaced in 1865
by five longer spans of cast iron, designed by Joseph Cubitt.
It cost 270,000 pounds, and formed less obstruction to the
Flfir. 77.
water and to navigation, but was widened in 1908 by Sir Ben-
jamin Baker at an additional cost of 203,000 pounds sterling.
Another notable bridge is that at Chepstow (Fig. 77), over the
Wye, designed by Rastrick and Hazeldean, with cast iron ribs
and wrought iron railing, and with one arch of 112 feet, two
of 70 feet and two of 34 feet, the width being 21 feet.
232. The three span cast iron highway arch bridge over
the Marne in France (1899) has center and side spans of
15Sy2 and 132 feet, with ribs 36 inches deep, 7 feet 3 inches
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CAST IRON BRIDGES. 163
apart, and sections 13 feet 9 inches long. It has no crown
hinge and the temporary ones at the ends were wedged up
tight after erection. The stone piers go up to the grade and
the floor has wood blocks on buckle plates.
233. Other important ones are those at Haddlesley, York-
shire, over the Aire ; Ely bridge over the Ouse ; the Aberdeen,
Staines, Bristol, Galton, Lary, Tees, Barnes and Nevers. Still
others are the Tarascon, St. Denis, Austerlitz, Meuse, Lendal
and the new Rochester (N. Y) bridge.
234. The introduction of ductile wrought iron and steel
for structural purposes, following the experiments of Messrs.
Hodgkinson, Fairbairn and Stephenson, from 1840 to 1846,
and the failure of several cast iron bridges, led to a more gen-
eral use of the former materials in preference to brittle metal,
and in twenty-five years preceding 1900, not more than three
or four cast iron bridges of any importance were built, the
Eads bridge at St. Louis and the Alexander III. at Paris being
cast steel.
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164 BRIDGE ENGINEERIXG.
CHAPTER X.
SIMPLE TRUSS BRIDGES.
235. The first attempt at building iron bridges was made
in Italy in the middle of the sixteenth century, about the time
that Palladio began using timber trusses, but no further record
of them in that country appears until 1719. These bridges
were used in Japan and China during the seventeenth cen-
tury, two hundred years before coming into service in Amer-
ica, but authentic dates in those countries are not available,
though their existence is certainly known. Malleable iron for
other purposes has been used from very ancient times, for
it is frequently mentioned in the Bible, as in Genesis, where
reference is made to "artificers in brass and iron," B. C. 3875,
and in Job, where letters "were graven with an iron pen," B. C.
1520. In Exodus 20-25 when building an altar, -1491 B. C,
the use of tools was not permitted, and in the description of .
Solomon's Temple in Kings 6 :7, which was erected 1014 B. C,
it is stated that "no tool of iron was heard in the house while
it was building." Iron tools and implements as well as hel-
mets, chain armor, and other articles of iron, were found in
the excavations at Nineveh. Methods of forging iron in an-
cient times are described by Homer (about 800 B. C), but
in modern times iron was first rolled into structural shapes
in 1783 by Cort of England.
236. The first truss was probably a simple triangle, and
from this, modern trusses with many connected triangles have
developed. The first iron railroad bridge was a small one with
four spans, on the Stockton and Dailington railroad (1823)
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SIMPLE TRUSS BRIDGES. 165
crossing the Gaundless river near West Auckland, England.
The originator is supposed to have been George Stephenson.
It somewhat resembled a modern trestle, for the spans were
only 12y2 feet long, supported on cast iron bents. The road
was abandoned in 1856, and the bridge continued in use until
1842, but in 1901 was removed and placed on exhibition in the
car shops at Darlington. Lattice trusses with a span of 84
feet were used by George Smart in 1824, for crossing the
Dublin and Drogheda railway. His truss, known as "The
Patent Iron Bridge,*' had vertical framing, and diagonals in-
clined at an angle of eighteen degrees to the vertical. But the
first use of steel in bridge building was for the 300-foot sus-
pension bridge at Vienna (1828), the eye bars being puddled
steel. Fairbairn used riveted beams for the floors of build-
ings in 1832, and one year later the first American patent
on an iron bridge, was issued to August Canfield, but the first
iron girder bridge in America was at Frankford, N. Y. (1840),
over the Erie Canal with a span of 77 feet. The design was
made by Earl Trumbull of Little Falls, N. Y., the cast iron
girders being strengthened with wrought iron bars. It has
be^n described as a combination of truss and suspension
bridge.
In the same year, Mr. Whipple built his first bridge, a
bowstring with cast iron top chords and wrought iron ten-
sion members, and a patent was granted to him in 1841, but
in 1846 he adopted a trapezoidal form. The first iron truss
bridge in the United States with parallel chords and open web,
crossed a small creek near Manayunk^ Pa., (1845) on the Cata-
wissa branch of the Philadelphia and Reading Railroad, the
design of Richard Osborne. He made three other similar ones
34 feet long and Syi feet deep, with cast iron top chords and
wrought iron in the bottom. The two tracks were supported
between these trusses, which were fabricated by hand with-
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166 BRIDGE ENGINEERING.
out the use of machine tools. These bridges remained in
use until 1901, though for many years they had been reinforced
with timber bents. Patents were granted in 1846 to Fred-
erick Harbach, on an iron Howe truss with cast iron braces
and top chords, and wrought iron verticals and bottom chords,
the chords and main braces being pairs of hollow tubes. A
30-foot span, 6 feet deep, with four panels, was erected near
Pittsfield, Mass., on the Boston and Albany Railroad. A com-
bination cast and malleable iron girder with parallel chords
and multiple web system, similar to one used in France in
1844, was invented in 1846 by Mr. Rider of New York, and
a patent was granted to S. Moulton. The bridge had T-shaped
chords with wrought iron diagonals, which were connected to
the verticals but not to the chords. The failure of one of
these bridges in 1850 caused all similar ones on the road to
be removed and replaced with timber, and after that time they
were but little used.
237. The scientific and exact computation of stresses in
bridge frames originated in 1847 with the publication of Squire
Whipple's treatise, "A Work on Bridge Building," which was
followed in 1851 by Herman Haupt's book, **The General
Theory of Bridge Construction.'* These two books, written
independently of each other, are the foundation of the mod-
ern theory of framed structures. Before that time bridge
members were proportioned according to the judgment of
experienced builders, which was often defective. One of the
earliest double system Whipple bridges (Fig. 78) near Troy,
N. Y., (1852) had a single span of 146 feet. The type as
modified later by J. W. Murphy, and known as the Murphy-
Whipple truss, continued in use until 1885. A bowstring of
187-foot span and 25-foot rise was erected in 1849 by Mr.
Brunei, over the Thames at Windsor, for the Great Western
Railway. Two other notable ones are the Newcastle high
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SIMPLE TRUSS BRIDGES. 167
level bridge over the Tyne (1849) and the Newark Dyke
bridge over the Trent (1853). The Newcastle bridge (Fig. '79)
carries the Northwestern Railroad over a ravine and river be-
tween the towns of Newcastle and Gateshead, on six spans
of 125 feet, with four approach arches at each. end, making a
total length of 1873 feet, three lines of railroaid being on the
upper deck, and a highway and two walks at a lower l^vel
between the trusses. Piers and abutments are stone, allow-
ing a clear headroom of 83 feet beneath the bridge. The
four lines of bowstring trusses in two pairs have no diagorlals,
and 4,700 tons of cast iron were used in the compression
members and 320 tons of wrought iron in the tension miem-
bers. It was completed in 1849 at a cost of 243,000 pounds
sterling, and officially opened by Queen Victoria. It was
strengthened in 1894 and is still in use (1910). The transition
of bridges in Europe was from stone to metal, and this partly
accounts for the extensive use in European countries of cast
iron arches and bowstrings, for which masonry arches were
the prototype. But in America the change was more from
wood to iron, and the early metal bridges here; were modeled
after wooden ones, though many lattice trusses were also
used in Europe. Newark Dyke bridge carries two lines of the
Great Northern over a branch of the river Trent near Newark.
It is the earliest example of a Warren girder, and was erected
in 1851-53 under Joseph Cubitt^ from designs by Charles Wild.
Four lines of trusses, two under each track, with cast iron
pipes for compression members and wrought iron links in ten-
sion, have a clear span of 240 feet and a total length of 259
feet, the cost being 11,000 pounds.
238. Iron trusses of the Bollman and Fink type were ex-
tensively used on the Baltimore and Ohio Railroad from 1840
to 1850. Both types were of suspension truss form, without
stress in the bottom chords, and frequently without any bottom
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BRIDGE ENGINEERING.
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SIMPLE TRUSS BRIDGES. 169
chords whatever, the Bollman truss (Fig. 80) having diagonal
rods from each lower panel point to the ends. The Harper's
Ferry bridge of 1852 with a span of 124 feet was of this type.
Albert Fink, who was assistant to Wendell Bollman, in-
vented and patented a new and improved form, and while
the Bollman bridges were not long used, the Fink tjrpe (Fig.
81) continued in service until 1875. The first large Fink
bridge (1852) crossed the Monongahela river at Fairmount,
W. Va., with three spans of 205 feet. Both of these types
had chords and posts of cast iron with wrought iron tension
members. The first iron viaduct on the Baltimore and Ohio
Railroad, which was all of cast iron excepting the tie rods,
appeared in 1852, and in the same year, , Pratt trusses were
first built in iron. The Pratt truss (Fig. 64), invented in 1844,
was at first framed in timber, but it has since become the pre-
vailing type in iron and steel. One of the first firms to un-
dertake bridge building in the West was A. B. Stone and
L. B. Boomer of Chicago, who began business in 1851. With
them were afterwards associated Edward Hemberle and W. G.
croolidge as engineers.
239. A Whipple bridge of 165-foot span over the canal
at Phillipsburg, N. J. (1859), designed by J. W. Murphy for
the Lehigh Valley Railroad, was the first pin connected truss
bridge, pins being used instead of trunnions. It was removed
in 1869 and placed in the center of a long wooden bridge at
Towanda, Pa., as a safety provision in case of fire. A span
of 152 feet over Saucon Creek on an uncompleted branch of
the North Pennsylvania Railway, was never used and was
afterwards removed. A bridge 89 feet high and 1,122 feet
long in eleven spans (1857) was the first one designed by
F. C. Lowthorp, who afterwards made many others.
240. Among the longest early truss bridges in Europe
are the Chepstow (1852), with a 300-foot span, the Newark
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SIMPLE TRUSS BRIDGES. 171
Dyke (1853), with a clear span of 240 feet, and the Boyne
viaduct at Drogheda, Ireland (1855), with a center span of
267 feet and two end ones of 140 feet.
241. The Bessemer process for converting steel was in-
vented in 1855 and the Siemens-Martin process soon after-
wards, and though Bessemer steel was used for a bridge in
Holland in 1862, it was not favored nor again seriously consid-
ered for the purpose until 1880, when it was manufactured for
the Forth bridge. Structural metal was having a wider use
every year, and yet the great majority of bridges previous to
1860 were of timber. Twenty years later wrought iron was
generally used, but before 1890 it was replaced by steel for eye
bars, and in 1895 wrought iron was no longer rolled or ob-
tainable in structural shapes, as it had been entirely replaced
by steel.
242. Metal lattice trusses, of which the prototype was
the American Town wooden lattice, became very popular in
Europe, and many of this kind were built, including those at
Dirschau (1857), with six spans of 400 feet, the Bommel
bridge over the Waal with three similar spans, the Cologne
bridge (1859), the Passau bridge over the Inn (1861), with a
span of 420 feet, and the Berne bridge over the Aar (1857)
with three spans on tall stone piers. The piers of the Dirschau
bridge over the Vistula are continued above the metal work
in the form of round battlemented towers. The Offenburg
bridge over the Kinzig (1858) with a single span of 197 feet,
has three lines of lattice trusses for double track, with heavy
Gothic portal arches and a projecting foot walk on each side.
The Cologne bridge (Fig. 82) crosses the Rhine east of the Co-
logne cathedral with four spans of 322 feet, making a total
length of 1,362 feet. It carries railroad and highway travel
in separate spaces with three lines of lattice truss in each
span, and the floor is 47 feet above average water level. Over
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172 BRIDGE ENGINEERING.
the entrance at the Cologne end is an equestrian statue of
William IV., by Blazer, while at the other end is a similar
figure of William I., by Drake, erected in 1867. The bridge
connects Cologne on the left bank of the river with Deutz
on the right, and was built in the years 1855-59.
The Kehl railroad bridge carries two lines of the Baden
State railroad over the river Rhine, about two miles from
Strassburg, Germany, and was built during the years 1856-60
from designs by Keller. There are three main lattice girder
spans of 197 feet each, continuous over the piers, and at one end
are four additional spans of 85 feet and a draw. Each main
span has three girders with single lattice webs and foot paths
on brackets from the outer trusses. The bridge is 1,000 feet
long and the Gothic portals at the entrance are fine examples
of ornamental iron, the statues and crosses being suggestive
of Gothic cathedrals. In ancient times the building of bridges
was considered a sacred duty and the work was entrusted
to an order of priests who were called "Pontifeces." It ap-
pears appropriate, therefore, that decorative features should
perpetuate the memory and traditions of ancient bridge build-
ing.
243. Lenticular trusses of the Pauli system, on high stone
piers, were used in 1857 in the three-span bridge over the
Isar at Grosshesselote, but the best known one of the type
is the Saltash bridge on the Cornish Railroad over the Tamar
river near Plymouth (Fig. 83), designed by I. K. Brunei in
1859. The Saltash bridge has two spans of 455 feet with sus-
pended roadway, and was the first through lenticular bridge.
In addition to the two large spans there are seventeen smaller
ones of 69^4 feet, making a total length of 2,240 feet. Each
main truss was made complete on shore, floated out on pon-
toons and raised on jacks into position. The main piers are
circular masonry, 35 feet in diameter and 96 feet high, and
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SIMPLE TRUSS BRIDGES.
173
the approach piers are double masonry columns 11 feet square,
the rails being 100 feet above high water. The bridge is
chiefly remarkable for having a single large tube as upper
chord for both trusses. Over the end portals is the name of
the engineer in letters four feet high. The Mayence bridge,
similar in outline to the last, has four river spans of 345 feet
and twenty-eight smaller ones. It crosses the Rhine between
Frankfort and Mayence and carries two railroad tracks. The
channel spans have four lines of light trusses with curved top
and bottom chords, and the total length is 2,060 feet, and the
weight, 600 tons. It was commenced in 1859, but in 1871
similar trusses were added to carry the second track.
^^^^^^
a„
7'
1
a — ,
Fig. 88.
244. Wide forged eye bars were first introduced in 1861
by J. H. Linville in a bridge over the Schuylkill river for the
Pennsylvania Railroad, though flat plate bars had previously
been used in suspensions. The first bridges wholly of wrought
iron, were riveted lattice girders with spans of 40 to 90 feet,
designed in 1859 by Howard Carroll for the New York Central
Railroad. In 1863 J. W. Murphy designed the first pin con-
nected truss with wrought iron for both tension and compres-
sion members, to cross the Lehigh river at Mauch Chunk, on
the Lehigh Valley Railroad, the only cast iron being that in
the joint blocks. The first of the many long span bridges in
America was at Steubenville, Ohio, over the Ohio river, with
a channel span of 320 feet, -four deck spans of 231 feet, and
three of 205 feet, designed by J. H. Linville, who was after-
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174 BRIDGE ENGINEERING.
wards engineer on ether bridges over the same river at Park-
ersburg and Cincinnati. The Steubenville bridge was replaced
in 1889 and again in 1909. The Windsor Locks bridge over
the Connecticut river (1866), designed by the American en-
gineer James Laurie, is remarkable because the iron was
manufactured in England by the William Fairbairn Company,
and when erected in place cost $277 per ton, or more than
twelve cents per pound. It replaced Colonel Whistler's old
wood bridge of 1844, and was in turn replaced by a double
track deck plate girder on the old piers.
245. Turning attention to Europe, the Runcorn bridge
over the Mersey river near Liverpool for the London and
Northwestern Railway, was commenced in 1863 from designs
by William Baker, with three spans of 305 feet each, though
there are one hundred and one openings in the whole bridge
and viaduct. Beneath the channel span is a clearance of 75
feet for ships. Bridges at London with tubular piers are
those at Cannon Street (1863-66), with heavy Doric columns,
and the Wandsworth, Putnam, Blackfriars and Charing Cross
bridges, the last two being completed in 1864. Blackfriars
was built by Kennard, with three lines of lattice trusses for
four railroad tracks, and clusters of pillars under each line of
girders. The Charing Cross bridge, built from plans by Sir
John Hawkshaw, at a cost of 180,000 pounds, was widened
in 1882 under the direction of F. Brady. It replaced the
Hungerford suspension, the piers of which were allowed to
remain, standing out in contrast to the lighter ones. The
Orival bridge over the Seine for the Western Railway of
France, has six continuous lattice spans of 127 to 167 feet
on cylinders 12 feet in diameter filled with concrete. The
Mannheim bridge over the Rhine (1865-68) with three spans
of 295 feet, connects Mannheim with Ludwigshafen and has
space for railroad, highway and sidewalks, and the portals
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SIMPLE TRUSS BRIDGES.
175
designed by Durn, are adorned with groups of figures. The
length of all previous truss spans was exceeded by that at
Kuilenburg over the Leek river (Fig. 84), which has triple sys-
tem lattice girders with curved top chords, designed in 1868 by
G. Van Diesen. One span has a clear length of 492 feet, and
Fig. 84.
a total length of 515 feet, another span a clear length of 262
feet, and seven others are 189 feet long. A bridge Resign
of unusual interest was made in 1867 by Carl Von Ruppert
to cross the Bosphorus, with three lenticular spans, the center
and two side spans having openings of 650 and 513 Austrian
feet, and the project was again revived in 1890 and 1901.
Alternate plans for a suspension bridge were also prepared
by the American engineer John A. Roebling.
246. The first of Mr. S. S. Post's patent trusses (Fig. 85)
was at Washingtonville (1865) on the Erie Railroad, but many
others appeared in the next fifteen years, including those at
Omaha, Leavenworth and Boonville. The lower end of the
Fig. 85.
web posts were inclined half a panel length towards the ends,
an arrangement which marred the regularity of the truss.
The Omaha bridge over the Missouri river (1871), wijth eleven
spans of 250 feet, 28 feet deep, on 83/2-foot cast iron cylinder
piers 140 feet high, was 2,750 feet long and cost $2,000,000.
The Leavenworth bridge, completed a year later, carried both
railroad and highway travel, 130 feet above the river. Two
spans of 340 feet and one of 314 feet were supported on cylin-
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176
BRIDGE ENGINEERING.
der piers, the total cost being $1,000,000. But the combined
railroad and highway bridge over the Missouri at Kansas
City for the Chicago, Burlington and Quincy Railroad, first
built in 1869 and reconstructed in 1891, is the oldest one over
that river. It contains five fixed spans of 119 to 234 feet with
parallel chords and a draw adjoining the right bank.
Two Mississippi river bridges were completed in 1868 at
Dubuque and Quincy, the first having eight spans with a max-
imum of 240 feet, and the Quincy bridge eighteen spans of
151 to 250 feet and a 360-foot draw. The draw span is all
of wrought iron, but the fixed spans are a combination of
wrought and cast iron. The Louisville bridge (Fig. 86) over
the Ohio river, for a single track, was designed by Albert Fink
and finished in 1869. The largest spans are 400 and 370 feet
and the draw span 264 feet, but there are also twenty-four
shorter ones partly triangular and partly of the Fink type.
m
m
m
m
m
Fig. 86.
The track is above the trusses on all spans excepting the
largest one, which has an under clearance of 90 feet above low
water, or 50 feet above high water. The channel span was at
that time the longest in America. Mr. Linville's two bridges
over the Ohio at Partcersburg (1870) and Cincinnati (1872)
contain long spans, the first, for the Baltimore and Ohio Rail-
road, having two channel spans of 350 feet, and forty smaller
ones, the whole costing about $1,000,000. The Cincinnati
bridge has a central span of 420 feet and twenty-three shorter
ones, that over the channel exceeding by a few feet the cor-
responding one in the Louisville bridge. Mr. Linville designed
many others, including one over the Connecticut river at Mid-
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SIMPLE TRUSS BRIDGES.
177
dietown with four spans of 200 feet and a central 300-foot
draw, with a shore span of 54 feet at each end. An examina-
tion and report was made by the writer in 1896 for strength-
ening it (Railroad Gazette, August 2, 1901), but it has since
been replaced by a heavier structure. The company for which
Mr. Linville was engineer had, up to 1874, erected over twelve
lineal miles of iron bridges, and nine miles of wooden ones.
The combined railroad and highway bridge over the Missis-
sippi at Hannibal, Mo., (1871) was the seventh bridge over
the river below Dubuque. It was a low level structure with
six fixed spans and a 362-foot draw, and cost, with approaches,
$650,000, but was reconstructed in 1886. Another over the
same river was erected by the King Bridge Company at Min-
neapolis in 1874, with a length of 1,100 feet, in six deck metal
spans on stone piers, and the following year the same com-
fi?t5^^
5?SS
s
s
1
%
^
?
H
T"
"
Fig. 87.
pany erected one at Topeka with six bowstring spans of 150
feet. The Atcheson bridge over the Missouri (1873-75) had
three through fixed spans of 260 feet with parallel chord
Whipple trusses, and a 365-foot draw at one end with pro-
jecting sidewalks. It was used by seven different railroads
and had an 18-foot roadway which was floored over for high-
way travel, the whole work costing about $1,000,000.
247. The old Elbe river bridge (Fig. 87) at Hamburg
(1868-72) with three lens-shaped girders of the Lohse type
was widened in 1894 when a similar bridge was being erected
at the same place. The upper and lower braced arches are con-
nected with verticals without diagonals. Hamburg has two
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178 .BRIDGE ENGINEERING.
other bridges over the Elbe, the highway bridge of 1887, and
the railroad bridge of 1893, both of the Lohse type, the Gothic
portals on the latter being very heavy and elaborate. The
Stadtl'au bridge over the Danube (1870) has fifteen spans, five
of which are 249 feet long each. The Moerdyck bridge over
the Holland Diep (1871), with fourteen spans of 328 feet,
has double system trusses with curved top chords. The
trusses are disconnected at the piers according to the usual
practice in Holland, where foundations are too uncertain to
permit continuity, but continuous girders are used on the
large spans of the Danube river at Vienna, which has five
openings of 262 feet and four of 112 feet.
248. Prior to 1860, the railroad companies designed their
bridges in their own offices, and manufactured the parts in
their own shops, but in the next ten years the men who had
become proficient in designing, organized contracting and
engineering companies and took contracts for manufacturing
and erecting them, frequently on their own patented designs.
These companies at first undertook work chiefly in their own
districts, but competition was soon desired by the railroad
companies, and prices were then asked on competitive plans.
Until about 1875, plans continued to be made almost entirely
by the bridge companies, who took lump sum contracts, a
practice which tended to reduce the weight of metal to a
minimum. These designs were prepared according to the
railroad companies' general specifications, several of which
appeared after 1870. Among these were the specifications of
Clark, Reeves and Company (1891), the Erie Railroad by
George S. Morrison (1873), The Cincinnati Southern Rail-
road by G. Bouscaren (1875), the Lake Shore Railroad by
Charles Hilton (1877), the Chicago, Milwaukee and St. Paul
Railroad by C. Shaler Smith (1877), and the Erie Railroad by
Theodore Cooper (1879). Mr. Cooper's specifications were
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SIMPLE TRUSS BRIDGES. 179
afterwards adopted as standard by several companies, resulting
in a greater degree of uniformity. Previous to 1875, engine
loads were assumed uniformly distributed, but greater in
amount than the accompanying train loads or a locomotive
excess was applied to the train loads; but for twenty years
after 1880 the actual loads on the locomotive wheels was used
instead.
249. In the preparation for the Philadelphia Centennial
of 1876, two bridges were erected across the Schuylkill river
at Girard Avenue and Callowhill Street, 1874 and 1875. The
Girard Avenue bridge adjoining the Zoological gardens is one
of the finest examples of American city bridges. The abut-
ments and piers show careful design and artistic treatment,
though monumental features are absent. The three middle
spans are 197 feet long, and each of the end spans, 137 feet,
the whole having an outside length of 865 feet. The deck
is 100 feet in width and on the* roadway are eight refuge bays
with clusters of six lamps over each bay. The outer balus-
trade and cornice are cast iron with bronze open work panels,
and the roadway and sidewalks are separated by a lower but
substantial railing. At the ends are steps leading down from
the street to the level of the lower chords, where a sidewalk
through the bridge is reached by arches in the abutment walls.
At the abutments are drinking fountains, and the bridge is well
lighted, there being in addition to the lamp clusters over the
piers, intermediate lamps at the curbs. It was designed under
the direction of Samuel Smedley, city engineer, and was
completed at a cost of $267,000. The Callowhill Street bridge,
finished a year later, with a span of 350 feet, was severely
criticized because of the presence of artificial sheet metal facing
representing arcades on the lower roadway, but this has
since been removed. It has upper and lower decks and is a
fine example of city bridge construction. The Falls of Schuyl-
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180
BRIDGE ENGINEERING.
kill bridge at Philadelphia is of more than usual interest be-
cause of its upper floor. The failure of an iron Howe truss
in 1876 at Ashtabula, Ohio, with a span of 154 feet, in which
accident ninety people were killed, resulted in discarding cast
iron entirely by the railroad companies, and four or five years
later it was also abandoned for highway bridges. The failure
called attention to the need of better structures and shortly
afterwards independent bridge engineers began practicing as
specialists in this branch of civil engineering.
250. The Cincinati Southern Railroad bridge over the
Ohio river at Cincinnati (1876), with a channel span of 515
feet, and a lower chord 106 feet above low water, was the
largest simple span at the time, and the first to exceed 500
/NxUt«tim^
Fig. 88.
feet. It was designed by J. H. Linville, according to Mr.
Bouscaren's specifications, and cost $700,000. The Smith-
field Street bridge at Pittsburg, with two 360-foot spans, of the
Pauli system, is the work of Gustav Lindenthal, and replaced
Roebling's old eight-span suspension of 1845. Mr. Linden-
thal's bridge was widened about ten years later by the addi-
tion of other trusses. The Glasgow and Bismark bridges over
the Missouri river, and those at Henderson, Louisville and
Cairo over the Ohio, all contain one or more long spans.
The Glasgow bridge is notable for being 'the first all steel
bridge in the world, but it was rebuilt for heavier loads in
1889-1901. The Bismark bridge (1882) (Fig. 88) was designed
and built under the direction of George S. Morrison and C. C.
Schneider, the longest span having a double web system,
which was about the last of the type, as after 1885 they began
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SIMPLE TRUSS BRIDGES. 181
to disappear. It had a height of 40' feet above the water, and
was reconstructed in 1905. The Sioux City high level railroad
bridge over the Missouri (1888) with four spans of about 400
feet had parallel chords and an under clearance of 50 feet.
Henderson bridge (Fig. 89) over the Ohio for the Louisville and
Nashville Railroad, has a 525-foot channel span and eighteen
smaller ones connecting with two and one-half miles of timber
trestle. The Cairo bridge of the Illinois Central Railroad over
rig, 89.
the Ohio river (1889) is 10,560 feet long, including the twelve
spans and viaduct, and was then the longest bridge in Amer-
ica.
Since 1888 other simple span railroad bridges have been
erected over the OHio at Cincinnati, Ceredo, Brunot's Island,
Louisville, Benwood, and Point Pleasant. The Cincinnati
bridge of 1888 has one 550-foot and two 490-foot river spans
with double railroad, highway and footwalks, a total width
of 67 feet with 1,500 feet of approach on the Covington end,
and 2,300 feet on the Cincinnati end. It is the design
Fifir. 90.
of William H. Burr, and contains 10,180 tons of steel. The
Ceredo railroad bridge, with four spans of 304 feet and one
of 521 feet, is notable chiefly for the use of double bottom
chords. It is 34 feet wide between truss centers but carries
only one track, being designed by Messrs. Doane and Thom-
son. The Brunot's Island bridge, a few miles below Pitts-
burg, with twenty-nine spans, has one of 416 feet and another
of 525 feet. The one at Louisville (Fig. 90), of 1893, with
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BRIDGE ENGINEERING.
three spans of 550 feet, was designed and built by the Phoenix
Bridge Company, and during erection two of the large spans
weighing 1,000 tons each, collapsed, killing eleven people. Its
total length is 9,360 feet, including 4,075 feet of approach on
the Indiana side, and 2,740 feet in Kentucky. The Point
Pleasant bridge, first built 1882-84, was renewed in 1909 with
five main spans, one of 416 feet with a clearance under it of
90 feet.
251. The most important truss bridge of the time in
Great Britain was that over the Tay at Dundee, Scotland, com-
pleted in 1877 after six years in construction. It carried two
Fig. 91.
lines of railroad on eighty-five wrought iron spans with a to-
tal length of 10,350 feet. Some of the piers were brick, but
most of them were cast iron cylinders with wrought iron
struts and braces, and the clear headroom, beneath it is 85
feet. It was designed by Sir Thomas Bouch, and completed
after much delay caused by two different contracting firms
engaged in succession on the work. After only two years'
service, twelve spans were blown down with a train of passen-
ger cars, and about one hundred persons drowned. Con-
struction was again started by William Arrol and Company
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SIMPLE TRUSS BRIDGES. 183
of Glasgow from plans by W. H. Barlow, and was completed
in 1887. The new bridge contains 18,000 tons of steel, and of
the eighty-five piers, seventy-three are composed of double
cylinders. The Wear river bridge at Sunderland (Fig. 91),
with wrought iron girders 310 feet long and 42 feet deep, de-
signed in 1879 by T. E. Harrison, has a plate web without
diagonals, and large curved web openings in each panel. It
adjoins Burdon and Stephenson's cast iron arch. The bridge,
over the Dnieper at Jekaterinoslaid (1884), with fifteen spans,
is one of the longest in Eufope. Two bridges in India and
Australia, finished in 1888 and 1889, over the Ganges and
Hawkesbury rivers, possess more than usual interest. The
Ganges bridge at Benares, India, crosses the river where it
is 1,600 feet wide and 30 feet deep, and like other rivers in
Northern India, the water sometimes rises 40 to 60 feet, with
a current of 12 to 15 miles per hour. Seven spans are 356
feet between pier centers, and the remaining nine spans 114
feet. The lattice girders with parallel chords are 35 feet deep,
and 22 feet apart for single track, and piers are a combination
of brick and concrete. The bridge is 3,568 feet long, and piers
go down 141 feet below low water. It was under the direc-
tion of F. T. C. Walton, and construction occupied five and
one-half years. The Hawkesbury bridge, crossing a river of
the same name, seven miles from the sea, was one of the
first which was opened for world-wide competition, fourteen
designs being submitted by American and European firms. It
contains seven spans of about 416 feet, with trusses 28 feet
apart for double track. The floor is 42 feet above water which
is 40 feet deep, and the foundation bottoms are 227 feet below
the rails. Each span weighs 800 tons and was floated into
position on pontoons, and lowered on the piers. The founda-
tions were very expensive, and the whole structure cost up-
wards of $1,600,000.
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184 BRIDGE ENGINEERING.
In 1888 statistics showed that, for ten years or more,
truss bridges on American railroads had been failing at the
rate of twenty-five per year, which averaged one bridge per
year for every 5,000 miles of railroad. In 1890 the length of
iron and steel bridges on American railroads, estimated as
single track or equivalent, was two and one-half lineal miles
with spans exceeding 500 feet, four lineal miles with spans
of 500 to 400 feet, and five lineal miles with spans of 400 to
300 feet, or a total of eleven and one-half miles with spans
exceeding 300 feet. Many of these old bridges were strength-
ened from time to time, to carry the greater loads of inter-
urban cars or locomotives.*
253, Structural steel, with a safe working strength 20
per cent greater than wrought iron, came into general use
about 1890, and in less than five years it was exclusively used
for bridges, and wrought iron shapes were no longer rolled.
The years 1894-95 are, therefore, the beginning of the steel
period.
254. Several large bridges over the Missouri were built
or projected after 1890, including those at Kansas City, Belle-
fontaine, Nebraska City, and Omaha. The one at Kansas
City, known as the Winner bridge, with four spans of 423
feet, was commenced in 1890, and the piers and a mile of
timber trestle were completed, but work was then abandoned
and for twenty years the piers, standing seventy-five feet above
the water, have awaited the erection of the superstructure.
The Nebraska City and Bellefontaine bridges, both designed
by George S. Morrison, and completed in 1895, have chan-
nel spans exceeding 400 feet in length. The trusses in both
cases have parallel chords, and the one at Nebraska City
is probably the last of the double system Whipple type.
Trusses are 22. feet apart for single track and the deck which
'^Strensrthenins: Traction Bridges. H .( r .Tyrrell in Street Railway Review. April IS, 1905-
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SIMPLE TRUSS BRIDGES. 185
is 53 feet above high water, is floored over for carriage travel.
The Bellefontaine bridge (Fig. 92) has single system trusses,
with subdivided panels, and sub-ties to the upper panel points.
The Merchants' bridge over the Mississippi river at St. Louis,
completed in 1890 under the direction of George S. Morrison
and E. L. Corthel, contains three spans of 517J4 feet, with
trusses 30 feet apart and 75 feet deep for double track. On
the east side of the river are three additional spans of 125 feet.
Another over the same river at Hastings, Minn., (1895) has a
375-foot span, 55 feet above the water, and contains an unusual
feature in the way of a spiral approach at one end. The com-
bined railroad and highway bridge over the Missouri at Sioux
.^^^mtiym^f-ix
Fig. 92.
City, Iowa, (1896) has two central fixed spans of 490 feet, with
a 450-draw at each end.
255. The longest highway bridge in America was com-
pleted in 1893 across the bay at Galveston^ Texas, with eighty-
nine bowstring spans of 80 feet, and a draw, all supported on
concrete piers. The metal work was 7432 feet long, and the
pile trestle approach 3,877 feet, making a total length of
11,310 feet. The superstructure cost $13 per lineal foot, or
$1,040 per span, and the cedar pile approach cost $6 per foot,
the whole bridge costing $192,000. Piers stood on piles and
the spans were floated into position on barges. It was de-
stroyed September, 1990, in the hurricane which devastated
the city and district. An important bridge (Fig. 93) con-
taining the longest highway draw span in existence, was
erected across the Connecticut river at Middletown (1896).
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186
BRIDGE ENGINEERING.
Previous to building it, communication between the towns of
Middletown and Portland had been mantained by ferries. The
site selected was 850 feet upstream from the old railroad
bridge, and 300 feet below the end of Willow Island. It is
1,300 feet long, has a 26-foot roadway, and provision for two
sidewalks on brackets. Besides the 450-foot draw span, it
contains two spans of 200 feet, and two of 225 feet. The draw
is operated by electric power from two sources, and opens
^^V^Bf^^^^^^^V^
S!
5
■
li
iSS^^^I
*nwf ^
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^ Tf"""^
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Fig. 93.
against wind pressure in thirty seconds, the whole bridge*, in-
cluding substructure and superstructure, costing $180,000. The
superstructure and all machinery were designed by the writer.
The Sixth Street bridge at Pittsburg (1S97) (Fig. 94), with
two spans of UO and 415 feet, has lenticular trusses 44
*For full description and credits, see London Ensrineeringr. March 1, 1901. and Railroad
ani'Bn^neerins: Rev.ew. June 8. 1901.
* "Reports both false and malicious, conceminir the desism of this bridge, were pub-
lished through the medium of various journals of September. 1901. and February .1902, by
those who desired personal a^rsrrandisement. The writer of one of these reports is now
confined in an asylum, and another is no longrer connected with the construction of
bridires or civil engrineerin?.— M. K. T."
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SIMPLE TRUSS BRIDGES.
187
feet apart, with 10-foot projecting walks outside. The lower
chords are inverted, stiffened three-hinged arches, the center
line of tension lying midway between the stiffening cables.
256. The Delaware river bridge at Bridesburg (1896) has
three spans of 537 feet, and 330-foot draw for double track,
each of the long spans weighing 2,090 tons, while the draw
weighs 930 tons. The steel traveler used in erection was 110
feet high, 81 feet wide at the top, and 46 feet wide at the bot-
tom, weighing 146 tons. Two important bridges appeared
in Canada in 1897-98 at Montreal and Cornwall, the first being
the rebuilding of Stephenson's old tubular bridge over the
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— —4
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2
2
1
1
V
>;
g
1 r
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md
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Fig. 94.
St. Lawrence river after fifty years of continuous service.
The old piers were in excellent condition, and only required
extending on the down stream end. The new bridge has
twenty-four spans of 254 feet, and one of 348 feet, with two
lines of trusses 31 feet 2 inches apart on centers. Between
the trusses are two lines of railway, intended for both steam
and electric cars on the same rails. On outside brackets are
two 10-foot roadways, and two footwalks 6 feet wide, making
the total width of platform 65 feet. The whole bridge con-
tains 20,000 tons of steel. The other structure over the St.
Lawrence, at Cornwall, was designed and built by the Phoenix
Bridge Company, with three spans of 370 feet, and curved
top chords, but during erection two spans fell, killing seven
people, the accident being similar to that which happened to
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188 BRIDGE ENGINEERING.
the two spans of the Louisville bridge built by the same com-
pany, when eleven workmen were killed. The St. Francis river
bridge (Fig. 95), at Richmond, Quebec, with two spans of 371
feet, has the longest riveted simple truss highway span in
America. Trusses are double intersection Warren, with para-
llel chords, 40 feet deep, and panel lengths of 20 feet.
257. Structural work for bridges began to be extensively
exported to foreign countries about 1898, and since that time
many of the longest ones in China, Japan, Africa, South
America, and other countries that are without structural shops
of their own, were sent from Americst. One of the first was a
railroad bridge with ten spans of 200 feet for Korea (1899),
and another was the Athbara bridge in Egypt, with seven
Pig. 95.
spans of 150 feet, containing 800 tons of steel. The last
was of no especial interest in itself, but was largely advertised
because of the short time occupied in its manufacture and erec-
tion. The fabrication was completed in thirty-two days and
the material shipped from America in forty-two days after
commencing work, and the erection completed in forty-eight
days more. Each span was erected in succession by anchoring
back to the previous one, and cantilevering the parts out to the
next pier. It was originally designed for a live load of only
2,000 pounds per lineal foot, and the trusses are now (1910) be-
ing renewed, though the old floor system was sufficient. The
work is being done by an English company, and completion is
required within six months. The Godavari river bridge on the
East Coast Railway at Rajahmundry, India, completed in 1902,
contains fifty spans of 150 feet, with total length of 9,100 feet.
The Amou-Daris river bridge in Russia, with twenty-five
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SIMPLE TRUSS BRIDGES. 189
spans of 210 feet on stone piers, is the longest in that country
and replaced a wooden trestle. It carries a line of railroad and
was opened in July, 1901, the steel work being made by Rus-
sian firms. Another on the Trans-Siberian railroad over the
Yenesei river is 2,975 feet long, and contains a span of 469
feet.
258. Three long span highway bridges cross the Great
Miami at Hamilton, New Baltimore and Elizabethtown, Ohio.
The Columbia bridge (Fig. 96) at Hamilton (1899), with one
^^KSiga^
Fig. 96.
Span of 406 feet, has trusses 22 feet apart with cantilever walks
carrying an asphalt road and concrete sidewalks. Trusses are
50 feet deep, and the whole weight of steel, including buckle
plates, is 650 tons. The truss depth is unfortunately insuffi-
cient for the heavy floor, and the excessive vibration under
moving loads gives a feeling of insecurity. The New Balti-
more bridge (Fig. 97) over the same river (1901) with a span
of 465 feet, has deeper trusses and a more pleasing outline.
Fig. 97.
but the panels are too short for economy or proper appear-
ance. Trusses are 25 feet apart on centers, with wood floor
system proportioned for a six-ton load without cars.
259. A consolidation of twenty-four competing bridge
companies, with a capital of $70,000,000, was formed in 1900,
under the name of The American Bridge Company, a name
which had been adopted by Rust and Boomer of Chicago in
1851, and the new company, with branch offices in many
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190
BRIDGE ENGINEERING.
American cities, constructed many of the largest bridges.
The Davenport bridge over the Mississippi river (1900) con-
tains seven fixed spans, the longest being 365 feet, and a 4-42-
foot draw, with 850 feet of viaduct in spans of 30 to 70 feet,
the total length being 3,157 feet. Another over the same river
at Dubuque (1902) has two channel spans of 380 feet. Other
long span bridges are at Clarion (1904) (Fig. 98), for the
Pittsburg and Lake Erie Railroad, with 31-foot panels and a
Fig. 98.
span of 498 feet, the Ben wood bridge (1904) over the Ohio
with stiff bottom chords for cantilever erection, the Platts-
mouth bridge (1904), the South Tenth Street bridge, Pittsburg
(1904), the Mobridge high level railroad bridge over the Mis-
souri (1907), with three spans of 410 feet, and the Columbia
river bridge at Vancouver, Washington (1909). The Van-
couver bridge has forty-eight concrete piers, ten of which are
in the river and thirty-eight on the island. The camel back
Fig. 99.
trusses are 30 feet apart for double track, and over the channel
is a 464-foot draw, the whole bridge costing about $1,000,000.
The Donora bridge over the Monongahela (1910) for high-
way and electric railway travel has five spans, the longest
being 515 feet.
260. The length of all previous simple truss spans was sur-
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SIMPLE TRUSS BRIDGES. 191
passed in 1906 by the Elizabethtown bridge over the Great
•Miami river (Fig. 99)), which has a single span of 686 feet
between end pins. The trusses are 80 feet deep, with points
of the upper chord on a parabola, and they are placed 32J4
feet apart on centers. The main panels are 65 feet long, di-
vided by sub-panels at the center, making square ones for
the lateral system. It was built irgm designs by the writer,
and because of its great length many alternate plans were
prepared before the final one was selected.*
The McKinley bridge at St. Louis crosses the river at
an elevation of 90 feet above low water with three river spans
of 521 feet. Between the trugses are two lines of track for
75-ton electric cars, and at each side are 13-foot projecting
roadways, which have a plank floor on wood joists. False
work of the center span was washed out in December, 1909,
causing a loss of $40,000, but the bridge was opened a year
later. The other large bridge under construction at St. Louis,
to be known as the Municipal bridge, will have three spans
of 668 feet, 110 feet deep with trusses 35 feet apart on cen-
ters, and two decks, the upper one being a roadway and the
lower one for double lines of railroad. The floor system will
be of carbon steel, but the trusses nickel steel. Each span
will contain 85 tons of cast iron, 1,800 tons of carbon steel,
and 2.695 tons of nickel steel. The contract price for the
three river spans was $1,393,000, the same bid being made
for construction in either carbon or nickel steel, though the
pound price for carbon steel was 3.95 cents per pound, and
for nickel steel 5.6 cents per pound. The bids of other com-
panies were $40,000 to $100,000 higher for construction in
nickel steel. A. P. Boiler, engineer.
*Ellzabethtown Brldsre. by H. G. Tyrrell. 1909. Pamphlef . 22 pafires. DescriblnK the
longrest simple truss span In existence. Canadian Engineer. Nov. 5, 1909.
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192 BRIDGE ENGINEERING.
Foreign bridges of unusual proportions completed in t^e
year 1909, are those over the Wear at Sunderland, the Vistula
in Prussia, and the Nile at Khartoum. The double deck
bridge at Sunderland, for both railroad and highway, is 1,220
feet long between abutments in several spans, 85 feet above the
water. The piers are granite, and the whole, including 8,500
tons of steel, cost $2,225,000. The double track bridge over
the Vistula, in Western Prussia, was begun in 1905, and com-
pleted four lears later. It contains five spans of 256 feet with
parallel chords, and five others of 426 feet with curved upper
chords. The roadway is 37 feet wide, and accommodates two
tracks and a highway. The weight of steel is 13,000 tons, and
the cost $2,000,000. Two bridges on the Sedan Railway, in
Egypt, are also of unusual length. The first over the White
Nile, 192 miles above Khartoum, contains nine spans of 156
feet, and a 245-foot draw, giving two clear passages of 100
feet each. The masonry piers were built on caissons sunk by
compressed air. The other bridge, over the Blue Nile, at
Khartoum, is supported by twenty steel cylinders 16 feet in
diameter. In addition to the approach spans, there are seven
of 218 feet. A causeway which is proposed between the Isl-
ands of Masnedo and Falster, Denmark, would consist of a
series of 275-foot spans and two 150-foot draws, the spans
alternating with embankments, and the estimated cost is
$2,625,000.
261. Recent tendency in construction in England was to
use truss depths of about one-eighth of the span, which re-
sulted in heavy chords, accompanied sometimes with excessive
vibrations under moving loads. The American practice was
to use much deeper and stiffer trusses with correspondingly
lighter chords. During the last decade there was a much
greater use of solid floors with rock ballast, the greater weight
and mass tending to reduce vibrations. Double truss systems
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SIMPLE TRUSS BRIDGES. I93
were practically abandoned after 1900, and as the railroads
are best able to inspect and observe their bridges under serv-
ice, it became the custom to have railroad bridges designed by
the company's engineers. There was also a great increase in
the use of plate girders, and many of the railroads used
bridges of standard lengths, for which uniform designs and
detail drawings were prepared. This resulted in much saving,
for special plans and templets were no longer required. Riv-
eted trusses were generally preferred for span lengths up to
150 to 180 feet, and center lines of truss members were re-
quired to intersect at the panel points, thus eliminating in-
ternal or eccentric stresses. Stiff bracing was preferred and
panel lengths were increased up to a maximum of about 35
feet. Too much curvature of top chords was avoided, as web
posts would become light and subject to reversal of stress.
Assumed engine loadings increased in many cases up to an
equivalent of Cooper's E65 specification. The weight of loco-
motives and tenders, which in 1860 did not exceed 40, in-
creased in twenty years to 70 tons, and in 1890 to 100 tons.
By the year 1900, these weights had still further increased to
125 tons, and in 1910 to 150 tons or more. Bridge pins gen-
erally were made much larger than formerly, and trunnion and
other bascule forms almost entirely supplanted horizontal re-
volving spans with their objectionable center piers.
The widest of all highway bridges crosses the Erie
canal at Main Street, Lockport, N. Y., the floor being 270
feet across, supported on twenty-seven arch ribs. The widest
railroad bridges are at Fifty-first Street, Chicago, 433 feet
across, and at the Union Terminal Station in Washington,
D. C, over H Street, 790 feet wide, each supporting thirty-
three tracks. The Seventh Avenue bridge at New York City
is proportioned for heavier loads than any other, while the
longest truss in America with riveted joints is the 412-foot span
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194 BRIDGE ENGINEERING.
on the Canadian Pacific Railway, over French river, at Rum-
ford, Ontario. Since 1905 most important bridges have been
designed by independent and competent engineers, employed
by the purchasers or prospective owners, and construction and
fabrication contracts awarded on the plans on a tonnage basis.
On the 190,000 miles of railroad in the United States,
there are not less than 80,000 metal bridges, not including
wooden trestles, and these have an aggregate length of over
1,400 miles, or one bridge for every three miles of railroad.
There are at least thirty-one bridges over the Missouri and
forty-eight over the Mississippi below St. Paul. Not less than
fifty-five railroad bridges have simple spans exceeding 400
feet in length, and of these at least twenty-five have spans
greater than 500 feet. It has further been demonstrated that
simple spans are quite practicable in lengths up to SOO feet.
Tyrrell's Formulae for the welffht of bridfires, trusses, grlrders. trestles, etc . for rail-
ways and hififhway. See followlnfl: journals: London Enarineerlnsr. June 8» 1900; Street
Railroad Review. Dec. 1900 and July 15. 1901; Canadian Electrical News, May. 1901:
Canadian Engineer. Nov.. 1904: Railroad Gazette. Sept. 12. 1902, and Feb. 24. 1905:
EnsrineerlnfiT-Contractinsr, Sept. 23. 1908. etc.. etc.
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TUBULAR AND PLATE GIRDERS. 195
CHAPTER XI.
TUBULAR AND PLATE GIRDER BRIDGES.
262. The first wrought iron girder bridge, which had a
span of only 31J4 feet, was built by A. Thompson in 1841,
to carry a highway over the Pollock and Govan railroad near
Glasgow, Scotland. It was 25J4 feet wide, with six lines of
girders. In 1846 William Fairbairn of England erected a pony
tubular girder over the Leeds and Liverpool canal with a
span of 60 feet, to carry two tracks of the Blackburn and
Bolton railway. In the same year a tubular plate girder bridge
was built by James Millholland, on the Baltimore and Ohio
railroad near Bolton depot, with a span of 50 feet. The sides
and bottom of the last bridge were wholly of wrought iron, but
the top flange was reinforced with a 12x12 inch timber. The
plates used by Mr. Millholland was 38 inches wide and 6 feet
deep, the whole bridge weighing 14 tons and costing $2,200.
These small spans were the first of their kind, and the begin-
ning of plate girder bridges, which are now so common on
American railroads.
263. Experiments made by Mr. Hodgkinson in 1842, to
determine the strength of cast iron and wrought iron beams,
disclosed the weakness of the former, and it was proposed that
cast iron girders should in the future be trussed with wrought
iron bars. The first bridge of this kind was at Tottenham,
over the river Lea, the work of G. P. Bidder. The uncertainty
in reference to the strength of those materials caused George
Stephenson, when preparing to bridge the Menai Straits, to
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196 BRIDGE ENGINEERING.
have extensive experiments made on the strength of wrought
and cast iron. This work he entrusted to three men of known
ability, Messrs. William Fairbairn, Eaton Hodgkinson and
Edwin Clark, and the completion of their experiments, which
occupied more than a year, and cost upwards of $150,000,
marked an epoch in the history of bridge building. These
experiments showed conclusively the superiority of wrought
over cast iron, and after that time cast iron was but little
used. In 1847 Mr. Fairbairn secured patents on pony plate
girder tubular bridges with upper chords in box form, the
cost of which he estimated at $146 per ton.
264. In the next ten years, five large tubular bridges were
completed, the Conway, the Eritannia, the Brotherton over
the Aire, a bridge over the Damietta branch of the Nile, and
the St. Lawrence river bridge at Montreal. The Conway
bridge over the Menai Straits, with a single 400-foot span,
designed under the direction of George Stephenson, was open-
ened in 1848. It was at first proposed to span the straits with
a single 350-foot cast iron arch with springs 20 feet above the
water, but the under clearance was insufficient and the tubular
bridge was accepted instead. The portal towers, 90 feet high,
were made to resemble the near-by towers of Conway Castle,
now in partial ruins. In 1849 Mr. Fairbairn submittd two
alternate plans for bridging the Rhine at Cologne with tubu-
lar spans, provision being made for both railroad and high-
way travel. One plan had four fixed pony spans, two of
326 feet and two others of 244 feet, while the other plan pro-
posed two through tubular spans of 570 feet, with double
tubes for two lines of railroad and an open 24-foot highway
between them. Projecting brackets supported promenades
at the sides, and at each end were 200-foot draw spans with a
clear opening of 70 feet for boats, approached by a series of
land arches.
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TUBULAR AND PLATE GIRDERS. I97
265. In preparing to bridge the Menai Straits seventeen
miles from Conway, Sir Isambard Brunei proposed two cast
iron arches of 460-foot span with 230-foot half arches at each
end, and he developed a plan for erecting them by placing cor-
responding voussoirs at each side, held together with rods
above the piers. Stephenson had a similar plan, but arches
were not favored, because of the decreased headroom towards
the springs, and a girder bridge was therefore preferred. The
Britannia bridge, which is located a few hundred yards from
Telford's old suspension of 1826, was designed by Robert
Stephenson, and built in the years 1845-50. It carries two
tracks of the Chester and Holyhead railway at a height of 108
feet above the water. Each track has a separate tube, the
side girders of which are spaced 15 feet apart on centers. The
two middle spans are 460 feet each, and the end spans 230
feet, with depths of 30 and 23 feet, respectively. Towers were
extended above the tubes to carry suspension chains for re-
inforcing the girders, should such an expedient be found neces-
sary. The tops of the towers are 196 feet above high water
and their total height 230 feet. Each tube is 1,511 feet
long, and one tube of the central span weighs 1,600 tons, while
each of the 230-foot end tubes weighs 630 tons. The shore
spans were built on false work, but the center ones were floated
into place on pontoons and lifted with hydraulic jacks. At
each end are large figures of reclining lions, and enough at-
tention was given to its architectural treatment to win much
commendation. It cost about $3,000,000, and was the first
example of a large wrought iron girder bridge. (Fig. 101.)
266. The Brotherton bridge over the river Aire, carrying
the York and North Midland Railway, on a span of 225 feet,
was opened in 1850, the same year as the Britannia bridge. The
two tubes for double track were 20 feet deep, but the side
girders were only 11 feet apart, and it became necessary to
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198
BRIDGE ENGINEERING.
^ KU
SUM
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TUBULAR AND PLATE GIRDERS. 199
cut the tubes down the center and force them apart for
greater width. It was Mr. Stephenson's design, but no pro-
vision was made for chains like on the Menai bridge. It has
since been replaced with a modern truss. The bridge over the
Damietta branch of the Nile has the road above the tubes in-
stead of through them.
267. One of the earliest girder bridges in America was on
the Pennsylvania Railroad at South Fork, Pa., completed in
1853, and used for forty years; and another, designed by E.
S. Philbrick, was used in 1860 on the Boston and Albany rail-
road. But the largest tubular was the old Victoria bridge
over the St. Lawrence river, at Montreal. This notable struc-
ture was designed by Robert Stephenson and built during the
years 1854 to 1860 under his direction with the assistance of
James Hodges and A. M. Ross. It was similar to the Britannia
over the Menai Straits, the iron tubes being 6,592 feet long,
and the total length of bridge 9,144 feet. The piers are 18
feet thick at the water line, and piers and abutments contained
more than 100,000 cubic yards of masonry. The bridge car-
ried a single line of railway only and had a cross sectional area
of 16x20 feet. The tubes contained 9,044 tons of iron, the clear
headroom underneath for the passage of ships being 60 feet,
and they were built on scaffolding in their final position, all
the shop work of fabrication and punching having been done
in England. The floor and roof were of. stiffened plates. Ven-
tilation holes were provided in the sides, but as these were in-
sufficient to carry off the gas and smoke from the locomotives,
a strip of iron was removed from the roof and the edge of the
opening was reinforced with new angles. A permanent travel-
ing carriage on the roof was used for inspection and paint-
ing, the area for painting in each coat being 32 acres. The
water current in the river is 7 miles per hour, the greatest
depth being 22 feet. Peto, Brassey & Betts were contractors,
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200 BRIDGE ENGINEERING.
and the cost is said to have exceeded $5,000,000. Both the Bri-
tannia and the old Victoria bridges resulted in serious financial
loss to their builders. The latter was replaced in 1897 by a
new bridge, which weighs twice at much, and has five times
the capacity of the old one, but cost only $1,500,000. A
tubular bridge over the English Channel was proposed about
1858 by Mr. Boyd, with 500-foot spans on 190 towers 300
feet high, the estimated cost being $150,000,000. The con-
clusion, however, after much discussion, was that the best con-
nection between England and France was the open sea.
268. The Penrith bridge on the Great Western Railway,
over the Nepean river. New South Wales, 32 miles southeast
of Sydney, has three pony or open top tubular girder spans of
186-foot clear opening on piers, 12 feet thick at the top ancj
198 feet apart. The main girders are 28^^ feet apart on cen-
ters and the double webs are 13 feet deep, supporting cross
girders 3 feet apart, covered with close plank and ballast. The
total length of tubes is 594 feet, with an under clearance of
40 feet. Light angle arches on the outer face were added for
appearance only. It was designed by Mr. Whitton and com-
pleted in 1864. The Gainsborough bridge, carrying the Man-
chester, Sheffield and Lincolnshire Railway over the Trent
river, on two spans of 154 feet, was, in 1865, the largest pony
or half-through tubular bridge in England. The girders are
12 feet deep, and 26 feet apart for double track, supported on
a center pier and two abutments, each abutment having a
40-foot arch opening. John Fowler, engineer. A double track
through plate girder bridge, the length of which has probably
been exceeded by only one other, was erected in 1864 on the
Eastern Bengal Railway. It crossed the Piallee river with
a clear span of 170 feet between abutments. The two side
girders with single webs, were ISyi feet deep and 22 feet
apart. They were reinforced on the upper flange with cast
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TUBULAR AND PLATE GIRDERS. 201
iron, and were connected at intervals of 19 feet, with over-
head arched braces.
269. The longest simple plate girder spans in America are
at Hubbard, Ohio, and Towanda, Pa. The Hubbard bridge
carries the Erie railroad over Yankee river on a span of 128
feet 4 inches. The double track bridge over the Susquehanna
river at Towanda, on the Lehigh Valley railroad, has thirteen
spans of 1295^$ feet and one span of 120 feet. Another deck
bridge over the Beaver river, at Newport, has three spans
of 103 feet, with four lines of girders for double track, and
another at Bridgeport, Ohio, is 105 feet long, for single track.
270. The longest half-through plate girder bridge is on
the West Shore Railroad at Gardner, N. Y., with a span of
119 feet. Another long half-through girder bridge crosses the
Mattabessett river at East Berlin, Conn., with a span of 102
feet. The longest four-track girder bridge is on the New
York Central Railroad at Lyons, N. Y., with three lines of
girders and an opening of 107 feet.
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202 BRIDGE ENGINEERING.
CHAPTER XII.
SUSPENSION BRIDGES.
271. The suspension bridge is one of the earliest types, but
it has not been developed or adopted as rapidly as other forms,
owing chiefly to its lack of rigidity and the absence of correct
theory for proportioning stiffening trusses. It was used in re-
mote ages in China, Japan, India, Tibet, and by the Dyaks
of Borneo, the Aztecs of Mexico, and the natives of Peru and
other parts of South America. In all early forms the platform
was supported directly on the cables, which consisted of
twisted vines or straps of hide drawn tightly to remove floor
sag, the cable ends being fastened to trees or other perma-
nent objects on shore. Light bridges of this kind, requiring
no piers, were economical, and are still common in Peru and
in parts of China, India and Ireland. A more primitive bridge
consisted of a single rope with a basket suspended from it,
which was drawn back and forth by a smaller rope or cord.
Single tight ropes were also used with smaller ones at higher
levels, to form side support for the traveler. Definite in-
formation relating to the early history of bridges in China is
lacking, but enough is known to prove that suspensions were
used in that country in very remote times. The first one of
which the date is given was built A. D. 65 by order of Em-
peror Ming, in the province of Yunnan, and as described by
Kirchen, was 330 feet long, with a plank floor resting on the
chains. A similar one at Tchin-Chien was 140 feet long, and
another over the river Pei, several hundred feet in length. One
in China with the floor resting on the iron suspension chains.
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SUSPENSION BRIDGES. 203
resembling the rope bridges of South America, dates back to
remote times, and later records show that all in that country
before the sixteenth century had floors supported in this way.
Foot bridges of this kind crossing ravines and rivers, per-
mitted the Buddhist to reach his house or temple on the other
side.
Turner describes a bridge (Fig. 102) with a span of
160 feet and a mat floor on five chains over the Tehint-Chien
river near Chuka Castle, 18 miles from Murichom, East In-
dies, while more recent ones of this kind may be found at
Carrick-a-Rede, Ireland, and one over Taggart Creek in Car-
Fig. 102.
ter County, Kentucky, with a span of 140 feet and cables fas-
tened to trees. Iron chains were used for suspensions in Japan
500 years ago or more, at a period when iron was very valu-
able, and some of these are said to be still in use. Major Remel-
describes a suspension bridge in Hindustan over Sampoo with
a span of 600 feet, and one of rope over the Kishangauga,
Shardi, India, is also mentioned. Humbolt describes several
interesting suspension bridges in South America found by
him in 1802, one at Quito over the Chambo river having a
span of 131 feet. Cables four inches in diameter were sup-
ported on timber end frames and fastened to posts driven into
the ground, the road lying on the cables and conforming to
their curve. Another in Peru is said to have a span of 225
feet. A native bridge at Caucasus with a span of 80 feet and
a narrow suspended foot path, strong enough for loaded mules.
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204 BRIDGE ENGINEERING.
had two cables fastened to trees on shore, each cable being
made of three twisted creeper vines. The Padus river in
Italy was crossed by a suspension bridge, in 1515, built by
soldiers for transporting the army and artillery, and a rope
suspension to cross the Clain river was used in France at the
siege of Poitiers (1595). Iron suspensions were used in Eu-
rope as early as 1615 and several are reported in Switzerland
in 1650 and in Italy in 1742.
272. The first suspension bridge in England (1741) crossed
a chasm 60 feet deep and the river Tees near the High Force,
two miles from Middleton. It was 70 feet long, 2 feet wide,
and the floor lay directly on the cables, with a railing on each
side. It was used chiefly by miners, and fell in 1802, killing one
or two people, but was replaced by a similar one known as
Wynch bridge, which was standing in 1908. Suspensions
were used in America before any other kind of iron bridge,
the first scientific ones of the modern type, with horizontal
suspended floor, appearing at the beginning of the nineteenth
centufy, though rude ones like that at Caucasus may have
preceded them. James Jordan secured an American patent
in 1796 on a "suspension bridge," but it was really a bow-
string truss with a suspended floor. Those previous to 1810
were chiefly the work of James Finley, a native of Fayette
county, Pennsylvania, whose first bridge in 1801 over Ja-
cob's Creek on the turnpike between Uniontown and Greens-
burg, had a span of 70 feet, though he is said to have made
experiments with, or models of, smaller ones three or four
years before. As the Greensburg bridge was a success, many
others were made like it, and the type became the most ap-
proved form in the first half of the nineteenth century. The
Greensburg bridge had two iron chains, one on each side, with
links of the proper length to suit the distance between the
suspended floor joist. The chains had a sag of 10 feet, or
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SUSPENSION BRIDGES. 205
one-seventh of the span, and passed over masonry towers with
the same angle of inclination on each side, being bolted to four
large anchor stones on shore. The suspended wood floor was
12J^ feet wide without any stiffening trusses, the whole cost-
ing when finished about $600. Eight similar ones are said
to have been erected the same year, and about forty more
prior to 1808, when patents were granted to Mr. Finley on
his designs. He made the floors in one solid slab for the sake
of lateral stiffness, and used long joists to spread the floor
loads over several suspenders. Previous to 1808 he erected
one over the Potomac at Washington with a span of 130 feet
and a 15-foot roadway supported by two chains of l^^-inch
wrought iron bars ; another over Brandywine Creek at Wil-
mington, Del., with a span of 145 feet and a floor 30 feet
wide; two at Brownsville, Pa., with spans of 120 feet; and
one at Cumberland, Md., with a span of 130 feet. The one
at Wilmington over the Potomac was washed out by a freshet
about 1840 and was replaced by a wooden bridge.
273. One of Finley's earliest bridges, 306 feet long, was
erected in 1809 over the Schuylkill river at Fairmount, Phila-
delphia, on the site occupied by the Colossus twenty years
later. A description says that it was "aided by an inter-
mediate pier," and it is represented in an old illustration with
two spans of 153 feet each, being the first appearance of a sus-
pension bridge with more than one span. The cables were
made of long iron links from which the floor was hung with
rods. It collapsed in 1811 under a drove of crowding cattle,
but was replaced by another suspension, which fell January
17, 1816, under a weight of snow and ice. The third bridge
opened in June, 1816, had a single span of 408 feet, and a
passage way of only 18 inches, and was the work of White
and Hazard, who owned and operated a wire mill near by,
the cables being made of six ^-inch wires. It was notable
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206 BRIDGE ENGINEERING.
for being the first wire suspension bridge in any country,
all those in Europe having a later date. The wood floor was
without stiffening trusses, and the bridge was safe for
only eight persons at one time, and is said to have cost the
small sum of $125. A toll of one cent was levied on each
passenger. It fell in 1816 under a load of snow and ice soon
after its erection, and was replaced by the Colossus, a wooden
bridge designed by Wernwag, and opened in December, 1817.
274. One of Mr. Finley's most notable suspension bridges
crossed one channel of the Merrimac river at Deer Island, three
miles above Newburyport, Mass. It replaced Timothy Pal-
mer's old wooden one of 1792, and was built under the direction
of John Templeton in 1810, with a span of 244 feet between
tower centers. The two roads were 15 feet wide, each having
two sets of cables containing three chains in each, or a total
of twelve chains for both roadways. The links were one inch
square and 27 inches long, making a total area of six square
inches in each chain, and floor supports were 7 feet apart.
The anchorages are 100 feet from the towers and the shore
end of cables are not loaded, being supported on timber frames
47 feet wide and 37 feet high above the floor, sheathed over
and shingled, and standing on masonry abutments. One chain
broke in 1827 under a load of four oxen and a horse, but it
was repaired. It was sold to Essex county in 1868 for $30,000,
and in the following year the woodwork was wholly rebuilt. It
was again strengthened in 1900 by adding two pew wire cables
to one of the roadways, making the bridge strong enough for
a line of electric cars, the work being done without interfer-
ing with travel on the other roadway. It has no stiflFening
trusses, and although the first chain bridge in New England,
it still remains. Another suspension bridge with several
spans was erected at Newburyport in 1826, and is described
later. Mr. Finley designed two bridges crossing the Lehigh
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SUSPENSION BRIDGES. 207
river, one at Northampton, Pa., in 1811, and another at Allen-
town, in 1815. The Northampton bridge had a total length
of 475 feet and three towers supporting two intermediate and
two end spans with double roadways and two 6-foot walks,
and was the second suspension bridge with more than two
towers. The Allentown bridge had two spans of 230 feet, with
cables of iron bars carrying a roadway 30 feet wide. It was
damaged by fire in 1828 and carried away by a flood soon
afterwards. Another old bridge at Island Park, near Easton,
Pa., has two spans resting on a pier in the river and a flopr
following the sag of the cables.
275. Suspension bridges were of two kinds, (1) those
with towers on shore and cables loaded only between the
towers, and (2) those with towers in the river or valley, and
cables loaded over both central and end spans. When pre-
paring designs for a bridge at Runcorn Gap, in 1814, Mr.
Telford made« experiments and investigations which showed
that wire suspension bridges could be built in spans up to
1,000 feet, and while the wire bridge at Philadelphia two years
later was the first actually built, Mr. Telford's investigations
probably preceded it. The plan for this suspension over the
Mersey showed a center span of 1,000 feet with 600-foot spans
at each end and 30-foot roadway, the cable sag in the center
being only 45 feet. Each of the sixteen cables were to be
made of 36 square half-inch bars bound together with wire
The water beneath the bridge was 16 feet deep and the plan
showed a clear headroom above water of 70 feet, the floor
having a sag towards the center of 15 feet. In 1814 Mr. Dum-
bell, of Warrington, also proposed a bridge from Runcorn,
in Chester, across the Mersey to Liverpool.
276. Two foot bridges between different parts of a manu-
factory were erected at Galashid over the Galawater (1816)
and at King's Meadow, over the Tweed, in the following year.
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208 BRIDGE ENGINEERING.
The first was designed by Richard Lees, with a span of 112
feet and cables of slender wire, at a cost of only $200, while
the latter, designed by Redpath and Brown, with a span of
110 feet and 4-foot deck, had similar cables supported on cast
iron towers 9 feet high, and with stays, plank floor and rod
railing, cost $800. Others of about the same time were the
Kelso bridge over the Tweed, with 300-foot span and 18-foot
carriageway, and the Thirlstone Castle bridge, 125 feet long
with stays. The Dryburg Abbey suspension, over the Tweed,
was built by Messrs. Smith, with a 260-foot span and 4-foot
deck. It was owned by the Earl of Buchan, and cost 500
pounds sterling. In 1&18 it was blown down, but was soon
afterwards restored at an additional cost of 220 pounds. Auxil-
iary stay cables were used and the main ones were 12 feet
Fig. 103.
apart at the towers, sloping in to 4 feet apart at the span
center, this probably being the first use of this arrangement
(cradling).
277. Four years after Mr. Telford's investigations for the
Runcorn bridge, Mr. James Anderson, a civil engineer of Edin-
burg, made three designs for chain suspension bridges to
cross the Firth of Forth (Fig. 103), with three spans of 1,500 to
2,000 feet, and an under clearance for ships of 90 to 110 feet,
the estimated cost being $1,000,000. These designs showed two
intermediate piers corresponding with those afterwards used
for the Forth cantilever. One of the first engineers in Eng-
land to investigate and develop the suspension bridge was
Sir Samuel Brown, who in 1811 proposed the use of flat bars
or links for cables instead of the square and round bars pre-
viously used. During the years 1814 to 1830, although several
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SUSPENSION BRIDGES. 209
of his structures collapsed, Mr. Brown greatly improved the
design of suspension bridges, but neither he nor Mr. Telford
used stay cables. It was Mr. Brown who, in 1819-20, designed
and built the first large suspension in Great Britain, the Union
Bridge, over the river Tweed, at Berwick. It had a span of
449 feet and a road 18 feet wide supported by 12 cables, 6
on each side, with versed sine of 30 feet, passing over piers
17J4 feet thick at the road level. The cables hung in three
tiers above each other with two chains in each tier, and were
of round wrought iron, 2 inches in diameter, and 16 feet long,
united by coupling links IJ^-inch diameter and 7 inches long.
The road had wooden floor beams supported by round rods
attached alternately to the three cables, loading them equally.
Six months after its completion the bridge was blown down
by a violent wind storm. In 1823 Sir Samuel Brown de-
signed and built the Brighton Chain Pier, 1,136 feet long, with
four spans of 265 feet, at a cost of $150,000. The deck was
supported by four chains at each side of the roadway with
a cable sag of 18 feet in each span, each chain consisting of
links 10 feet long joined by double couplings and bolts. The
chains passed over four iron powers standing on piles, and at
the land end they were carried 64 feet into the cliffs. After
being used for thirteen years, the pier was damaged, in Novem-
ber, 1836, by the action of heavy waves during a great storm.
278. Suspension bridges were introduced on the continent
of Europe about 1820, one of the first being at Geneva, over
the Fosse (1823), with two equal spans of 132 J/$ feet, the work
of Colonel Dufour, a French engineer. It had a platform 7j4
feet wide and 300 feet long, supported by round rod hangers
from four wire cables, two at each side, the upper and the
lower cables being 1-inch and IJ^-inch diameter, respectively.
Several other wire suspension bridges were made in France
during the same year by Seguin Brothers, of Lyons. The
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210 BRIDGE ENGINEERING.
versed sine or cable sag used by the French engineer, Navier,
was one-twelfth to one-fifteenth of the span, while Finley's
bridges had a deflection of only one-seventh. Navier was sent
by the French Government to England in 1821 to study and
investigate suspension bridges, and two years later he pub-
lished a book on the subject, which was followed in 1824 by a
treatise written by the elder Seguin.
279. A project for bridging the Menai Straits, between
the Island of Anglesea and Carnarvonshire, in Wales, had
been considered in England for many years. As early as
1776, Mr. Golbourne proposed high embankments at each side
connected by a bridge, and in 1785 Mr. Nichols outlined a
plan for a great wooden viaduct. In 1810 Mr. Telford sub-
mitted designs for bridging the Straits with a single 500-foot
cast iron arch, but the arch design was not favored because
of the lessened headroom towards the springs, and a sus-
pension bridge with uniform clearance was accepted instead.
Actual construction on the bridge was begun in 1819 under
the direction of Thomas Telford as chief engineer, and the fol-
lowing year another suspension was started at Conway, both
of which were completed in 1826. The Menai bridge has a
central span of 580 feet, and two side spans of 280 feet with
four stone arches of 50 feet at one end, and three similar ones
at the other end, making a total length of 1,710 feet. It car-
ries a platform 30 feet wide divided into 12-foot driveways
with a 4-foot walk between them, at an elevation of 120 feet
above low water, the total suspended weight being 643 tons.
The sixteen main cables are arranged in four sets vertically
above each other, one set at each side of the roadway. The
cables have a versed sine of 43 feet and pass over stone towers
founded on rock, the top of towers being 152 feet above high
water and the thickness at the road level 29 feet. Each chain
contains five iron bars S% by 1 inch, 10 feet long, united by
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SUSPENSION BRIDGES. 211
8xl6-inch links and 3-inch pins, and they are secured in
anchor pits reached through tunnels. The total cross sec-
tional area of the main chains is 260 square inches and the
bridge with approaches cost 120,000 pounds sterling, and is
still in use. After the designs were completed and a contract
for the construction awarded, Mr. Telford increased the
amount of material over that shown on the original plans, and
made the towers higher, the extra quantities being paid for
at agreed unit prices. It is situated only a few hundred yards
from the Britannia tubular bridge, and when built was the
first great suspension. It was seriously injured by a wind
storm in January, 1839, when one-third of the hanger rods
were broken and both roadways made impassable, but it was
soon afterwards repaired. It crosses the channel at the nar-
rowest point, over water 40 feet deep. (Fig. 105.)
280. The Conway bridge, across a deep and rapid channel
in North Wales, adjoins the old Conway Castle, now in par-
tial ruins, and was completed in 1826 after six years' work.
It was designed by Thomas Telford and the stone work was
made to harmonize with the round towers and battlements of
the castle. It has a span between towers of 327 feet and has
four eye bar chains on each side 3J^xl inches by 9 feet long,
vertically above each other but not connected. The chains
have a center sag of about 22 feet and are anchored back into
the solid rock. The bridge continued in use in its original
condition for more than eighty years, but was then found
insufficient for modern loads and travel, and was strengthened
in 1904 by the addition of new anchorages, four new wire
cables, two on each gide, new suspension links and stiffening
girders 8J^ feet deep. A new 6-foot walk was also added on
the North side, the cost of reinforcing being $32,500.
281. In 1826-27, when Mr. Telford was completing the two
suspension bridges at Bangor and Conway, a notable one of
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BRIDGE ENGINEERING.
be
be
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SUSPENSION BRIDGES. 213
several spans was started under the direction of Thomas
Haven, at Ncwbur3rport, Mass. (Fig. 104), crossing the Merri-
mac river betwen Newburyport and Salisbury, below Carr
Island. It had three river and two shore spans supported on
four piers and two abutments. At the Newburyport end was
a small double leaf bascule draw span separate from the rest
of the bridge, but as the main river was about 1,000 feet wide,
Fls. 106.
the spans must have been 150 to 200 feet in length. The
cables were wrought iron links with four groups of three in
each, supported on timber towers 31 feet high standing on
log cribs filled with stone.
282. The old Hammersmith bridge (Fig. 106), over the
Thames at London, was designed by William Tierney Clark,
and erected in 1824-27, with a central span of 400 feet and
c:^ , UZD
Fig. 107.
two side spans of 147 feet. It was found in 1887 to be too
light, and was rebuilt on the old foundations under the direc-
tion of Sir J. Bazalgette at a cost of 82,100 pounds. It is orna-
mental and one of the most attractive objects in London.
283. The first use of steel for bridge building in any coun-
try was for the chain bridge at Vienna, over the Danube canal
(1828), with a span of 334 feet, the work of engineer Von
Mites. The cables were fiat eye bars of open hearth steel.
It was taken down in 1860 and another suspension (Fig. 107),
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214 BRIDGE, ENGINEERING.
designed by Schnirch, with a clear span of 255 feet, placed on
the site, the latter being remarkable for being the first and only
railroad suspension bridge in Europe, but in 1884-85 the sec-
ond one, which had two lines of braced chains at each side,
4 feet apart vertically, was replaced by an iron arch.
284. Two suspension bridges appeared in England (1829-
30) from the plans of Sir Samuel Brown, the first one at Mont-
rose having a span of 432 feet, and cables of flat wrought iron
bars. Nine years after it was opened it met the fate of Mr.
Brown's other bridges at Berwick and Brighton. It partly
collapsed in 1830 under a crowd of people viewing a boat race,
causing great loss of life, and was blown down and destroyed
in 1838. It was afterwards reconstructed by Rendel and stif-
fened with trussing. Mr. Brown's bridge over the Tees (1830),
carrying a railroad from the Durham coal fields into York-
shire, had stone towers and a clear span of 281 feet, with a
cable sag of 28 feet, the floor being 20 feet above high water.
The side trusses were entirely too light for engine loads, and
after being in use for some time, the deflection was so great
that piles were driven under the platform to support it, and
in 1841 nothing remained except the chains. It was replaced
in 1842 under the direction of George Stephenson by a cast
iron girder bridge of five spans for double track, the three
river openings having clear lengths of 89 feet each. It re-
mained until replaced in 1906 with steel. A bridge at Brough-
ton, near Manchester, failed in 1831 under the march of sixty
soldiers, and a similar accident happened at Angiers, in France.
A chain bridge over the Regnitz, at Bamberg (1829), with a
span of 210 feet, replaced an old timber arch of 1808, and in
1889 the suspension was in turn replaced by a cantilever. In
building suspension bridges, cables were at first made on land
and then transferred to the towers, but in 1831 M. Vicat, when
building a bridge over the Rhone, wove the cable in place.
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SUSPENSION BRIDGES. 215
and the same method was used for the Tours and Roche-
Bernard suspensions in 1840.
286. In 1832 a proposition was made to the United States
Congress by Charles Ellet, a young man only twenty-two years
of age, to cross the Potomac river at Washington with a wire
suspension bridge of 1,000-foot span. His proposal was not
accepted, but fifteen years later Mr. Ellet was recognized as
one of the leading bridge engineers of America, and built a
suspension at Wheeling with a span exceeding the one which
he proposed at Washington.
286. Two important bridges were erected in 1832 and
1834 at Fribourg, Switzerland, and until the end of the nine-
teenth century, the larger one remained the longest span of
Fig. 108.
any kind in Europe. The smaller bridge crossed the Saone
Valley with a span of 195.5 feet, the cables being anchored
into rock banks, while the larger one, designed by M. Chaley,
had a single span of 870 feet between tower centers, versed
sine of 63 feet, and carried a floor 810 feet long at an eleva-
tion of 167 feet above the Sarine Valley. (Fig. 108.) It orig-
inally had four iron wire cables, two on each side of the road-
way, each cable containing 1,056 wires, and the platform which
was two feet higher at the center than at the ends, had a 15-
foot roadway and two 3-foot sidewalks, with wood floor beams
hung from the cables with 1-inch wire suspenders, making a
total width of 21 feet. The piers are solid masonry 20 feet
thick at the road level, and rise 66 feet above it with Doric
porticos. The cables are securely anchored in the rock, the
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BRIDGE ENGINEERING.
anchor chambers being reached through tunnels. It was se-
verely tested by a detachment of 16 cannon, 50 horses and
300 people passing over it, the deflection under the combined
load being 39 inches. The original cost of the bridge was
24,000 pounds sterling, but in 1880 it was reinforced at con-
siderable expense by adding one more cable on each side.
M. Chaley also erected suspension bridges at Beaumont, over
Fig. 109.
the Sarthe, at Charite, over the Loire, Cormery, over the Indre,
at Percey, in the Jura Mountains, and at Paris.
?87. Mr. James Dredge evolved a new suspension bridge
principle (Fig. 109) in 1832, with floor rods inclined instead oi
veri.ical, and chains hanging in vertical planes increasing uni-
formly in sectional area from the span center to the towers,
combined with a compression member at the floor level. He
Fig. 110.
designed a bridge on this principle at Balloch Ferry, Loch
Lomond, with a total of 292 feet and 200 feet between towers,
which were 20 feet apart transversely. Each cable had thirteen
rods at the tower of J^-inch diameter, decreasing to a single
rod at the center of the span. Cables were loaded on both
sides of the tower, and as the two sides balanced each other.
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SUSPENSION BRIDGES.
217
the bridge was more cantilever than suspension. Mr. Dredge
designed a similar one with latticed side trusses and battle-
mented towers to cross the river Spey.
288. The Dordogne river bridge at Cubzac (1839) with five
equal spans of 357 feet (Fig. 110), supported on cast iron
towers, had a system of bracing between the towers above
the floor, and the cables at the ends slope down at an angle of
about 45 degrees to the masonry abutments, which are pierced
with transverse arches. The towers are 82 feet high, their
tops being 126 feet above water.
289. The Weser suspension bridge, near Hameln, by
Wendelstadt (1839), was the first use of triangular bracing be-
tween double chain cables. It was removed in 1899 to Hessich,
Oldendorf, and the Weser bridge rebuilt as a cantilever.
Fig. 111.
290. In 1840 the elder Seguin erected a railroad suspension
over the Saone with two spans of 137J4 feet each, and three
cables at each side with a sag of 16 feet 8 inches, stiffened with
girders about 8 feet deep. It was not a success, for after four
years it was replaced by a stone bridge.
291. The Neckar suspension at Mannheim, by Wendel-
stadt (1845), was replaced in 1890 by a cantilever with curved
upper chord resembling a suspension. A chain bridge over
the Ruhr at Muhlheim, Prussia (1850), by Malberg, also had
iron towers.
292. A wire suspension bridge at Roche-Bernard, France
(Fig. Ill), over the Velaine, had a span of 650 feet, 110 feet
above the water, with four wire cables having a sag of 50 feet.
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218 BRIDGE ENGINEERING.
* It was completed from designs by Le Blanc, but was wrecked
by a gale in October, 1852, and counter cables were added in
its restoration. The end cables are not loaded and have the
same angle of inclination at each side of the towers, being
made continuous around the anchorages in the end vaults,
similar to the Lorient bridge. Each approach was supported
on a series of three masonry arches of 31-foot span. Other
wire suspensions prior to 1842 were those of Lorient and Su-
resne, France, the former having a span of 600 feet. The
Suresne bridge over the Seine (Flachat and Petiet, Engineers)
has a center span of 203 feet, with a one-tenth cable sag, and
two side spans of 139 feet each. It has ornamental stone
towers and carries a roadway 22 feet wide and 500 feet long
at a height of 35 feet above the water. The Suresne bridge,
. Paris, has cables of thin flat iron, which is stiffer though not
as strong as wire. A double chain bridge over the Moldau,
at Prague (1842), designed by Schnirch, has center and side
spans of 433 and 109 feet, respectively, with stone towers.
The Douro river suspension bridge at Oporto (1842), with a
span of 568 feet, has eight cables, four on each side of the
road, with a sag of 45 feet, anchored at one end into the cliff
and into horizontal foundations at the other end. The stone
towers are 59 feet high and the road 20 feet wide, the con-
struction being under the direction .of M. Stanislan Bigot, and
costing $100,000. A bridge at Seraing, Belgium, over the
Maas (1843), with a center span of 344 feet, was one of the
first suspension bridges with cast iron towers, others being
the Dordogne at Cubzac (1839) and the Ruhr at Muhlheim
(1850). The Gotteron bridge (1840) with a span of 640
feet at a great height, had the ends at different elevations.
293. Ten years after proposing the span of 1,000 feet at
Washington, Charles Ellet designed and built a wire bridge
across the Schuylkill river at Fairmount, Philadelphia (1842),
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SUSPENSION BRIDGES. 219
to replace the Colossus, burned in 1838. From 1809 to 1816,
previous to building the Colossus, the site had been occupied
consecutively by two other suspension bridges, both of which
collapsed under excessive loads. Mr. Ellet's suspension had a
span of 358 feet, and was supported by wire cables, five at
each side. It had a clear width of 26 feet, and remained in
use until 1874, when it was replaced by the present double
deck truss bridge.
294. Two important bridges at Pittsburg (1844-47) were
the work of Mr. John A. Roebling, one of them being the sus-
pension aqueduct over the Allegheny river and the other the
Smithfield Street bridge over the Monongahela, replacing an
old wooden one burned in 1845.. The aqueduct had seven
spans of 162 feet with two 7-inch wire cables, supporting a
wood water flume. The project met with opposition and was
reported impracticable by other engineers, but was completed
by Mr. Roebling in 1845 and remained in use until the canal
was abandoned in 1861, when the bridge was removed. Mr.
Roebling was the first to use suspension aqueducts, and
previous to 1848 he built four others with openings of 116 to
170 feet. The Smithfield Street suspension bridge over the
Monongahela, stood on piers of an old wooden one which
had eight spans of 188 feet. It had two cables, 4.5 inches
diameter, and cast iron towers which were truncated pyramids,
7J4 feet square at the base and 16 feet high, standing on stone
piers. The road was 20 feet wide and had two lines of car
track, the total width of bridge being 36 feet. It was com-
pleted by Mr. Roebling in 1847 and continued in service for
35 years, carrying the heaviest kind of street traffic, electric
cars, steam rollers and eight-horse teams drawing heavy trucks
loaded with iron and machinery. A system of wire stay cables
was used, but the loaded span sometimes deflected as much
as 2 feet, with a corresponding rise of the adjoining unloaded
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220 BRIDGE ENGINEERING.
spans. It was taken down in 1882, and a contract entered
into for building a new suspension on the site with two river
spans of 360 feet and end ones of half this length. But a
change of management in the construction company caused
the contract to be nullified, and the present two-span lenticular
one was erected on the piers intended for the new suspension.
295. The older of the two chain bridges over the Danube
at Budapest was the work of W. Tierney Clark in the years
1839-49. This has a distance between tower centers of 666
feet, with a cable sag of 47 feet, and two side spans of 298
feet, with total waterway of 1,250 feet. The stone towers
rise to a height of 200 feet above the foundations and are very
artistic both in general outline and detail. It has four flat
eyebar cables and an outside width of 46 feet. It was very
severely tested when, for two days, the Hungarian army re-
treated across the bridge, followed by 30,000 Austrians, both
armies having cannon, heavy ammunition and supply wagons.
W. T. Clark died before the bridge was completed, but it was
finished by his brother, Adam Clark.
A design made in 1850 by Schwedler for a stiffened sus-
pension at Cologne, which received the first prize, had 620
foot spans and double center towers 138 feet apart, with a
double bascule draw between, and an elevated platform for
pedestrians 72 feet above the main deck similar to the later
Tower Bridge at London. The cables were stiffened by a
series of members from the towers.
296. The Hungerford foot bridge over the Thames, at
Charing Cross (1842-45), was the work of Isambard K. Brunei,
and was the longest chain suspension, having spans of 676
feet, versed sine of 50 feet, and two side spans of 329 feet.
The four main chains, two on each side, were composed of
7x1 inch flat links, 24 feet long, connected with 4^-inch pins.
The road was 14 feet wide and the wooden beams were sus-
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SUSPENSION BRIDGES. 221
pended from the chains with rods hung from small metal
levers, the two ends of which were supported separately from
each chain, to load both cables uniformly. Each chain was
connected to the saddles which rested on iron rollers over
brick towers, allowing a movement of 18 inches in either
direction from the center line. It was removed to make room
for the new Charing Cross railroad bridge, but was re-erected
at Clifton, England, in 1863. To provide for expansion Mr.
Brunei used pendulums or suspenders on one of his bridges, at
the top of towers, for supporting the cables, and a similar
arrangement was afterwards used for a bridge over the Alle-
gheny near Pittsburg. Mr. Brunei sometimes used inverted
or up-curving cables under the floor to stiffen it against up-
ward wind pressure, and the inverted cables on two bridges of
this form built by him on the Isle of Bourbon, had one-third
the capacity of the main cables.
297. It is well known that in designing the Britannia
tubular bridge provision was made for supporting the tubes
at the center with chains, and the towers were extended to
the proper height with openings for the cables, should they
be required. Mr. Stephenson investigated several suspension
bridge forms, including one in which the horizontal deck was
carried above the chains instead of below them. He proposed
wrapping the cables around the anchor masonry and reported
the plan suitable for spans up to 150 feet in length. He also
investigated a combination or double suspension system for
the Britannia, with cables supported on alternate towers.
Mr. Stephenson reported that the 300-foot suspension at Stock-
ton had excessive deflection and "a wave 2 feet high rose up
in front of the engine." His conclusion was, therefore, that
suspension bridges were unsuitable for railroad purposes, ex-
cepting for exceedingly long end heavy spans, a conclusion
which is confirmed by recent investigation and experience.
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222 BRIDGE ENGINEERING.
298. The wire bridge over the Ohio river at Wheeling,
(1846-49) with a central opening, 1,010 feet, was the longest
span of any kind in existence. It was the work of Col. Ellet,
and was somewhat similar to one which he proposed 14 years
before for the Potomac river at Washington. The Wheeling
bridge was 24 feet wide, the platform being 97 feet above low
water. On each side of the road were six separate cables
side by side, containing a total of 6,600 wires. It was dam-
aged by a tornado in 1854, when the floor was turned over
and all but two of the cables were broken in succession at the
anchorage, though one cable of 150 wires broke at the span
center. It was repaired the same. year by Roebling, the sepa-
rate strands on each side being united into solid cables and
placed farther apart at the towers than at the center, which
greatly assisted in making the bridge rigid against wind pres-
sure. It was again rebuilt in 1862. The failure and repairing
of this bridge brought the systems used by Ellet and Roebling
into sharp contrast. Mr. Ellet used wires in separate strands
side by side, with iron bars fastened across them from which
the suspenders hung, while Mr. Roebling used wire cables
in cylindrical form enclosed and wrapped with light wire
to protect them frohi the weather. In his system, the sus-
penders hung from clamps surrounding the cables, which
were generally in planes sloping at an angle from the vertical,
with systems of auxiliary stay cables radiating from the towers
to successive panel points of the floor system. The stays added
stiflPness to the floor and relieved the main cables of much
load, but the distribution of load on the main and auxiliary
cables was uncertain and their use was afterwards abandoned.
299. While the Wheeling bridge was being considered,
Mr. William Merritt of St. Catharines, Ontario, proposed in
1844, the construction of a suspension bridge across Niagara
gorge, and through his eflPorts the first charter was obtained
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SUSPENSION BRIDGES. 223
in 1846. Four prominent bridge engineers, Charles Ellet, John
Roebling, Samuel Keefer and Edward Serrell, were invited
to report on the feasibility and cost of such a work, and their
reports were all favorable. It is interesting to note that each
of these men in later years actually built a bridge across the
Niagara gorge. In 1847, a contract was given to Mr. Ellet
at $190,000 to erect a bridge with a span of 800 feet and two
7y2-ioot roads, two 4-foot sidewalks and a railroad track in
the center, but preliminary to starting work on the larger
bridge, which was not completed according to his plan, Mr.
Ellet made a smaller foot bridge, 7J4 feet wide, over the
gorge, at a cost of $30,000, which was strengthened the same
year to carry material and supplies for use in the larger one.
It had an opening of 770 feet and a kite was used to take the
first cord across, the light string drawing over a larger one,
which in turn pulled over a rope to which was attached the
first wire cable. Mr. Ellet was so proud of his achievement
when it was nearly completed that he mounted his horse and
rode triumphantly across the narrow unguarded platform on
horseback, at a height of 250 feet above the river, before the
side railings had been placed. The bridge remained in use
until the heavier one was finished in 1854, when the light
one was no longer needed and was removed. In March, 1848,
Mr. Ellet erected a basket ferry over the Niagara river about
two miles below the falls, on which a toll of $1.00 per pas-
senger was charged. The car or basket was made of light
iron work with seats on each side and was large enough for
four persons. It hung by a trolley from a single wire cable
and was drawn back and forth between the opposite banks.
300. Mr. Ellet made a report and plan in 1849 for a pro-
posed railroad suspension bridge to cross the Connecticut
river at Middletown, Conn., with a single span of 1,050 feet,
at an elevation of 140 feet above the water. The railroad
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224 BRIDGE ENGINEERING.
company was considering alternate plans for a low level bridge
with a draw span, and a fixed high level bridge, but the low
one with draw being the cheaper, was accepted and built. In
1896 it was found too light for the increased train and engine
loads and an examination and report was made by the writer
for strengthening it. (Railroad Gazette, August 2, 1901.)
301. The failure of Samuel Brown's suspension bridges at
Berwick, Brighton, Montrose and Durham, was a serious check
to the building of these bridges in England, and in 1850 a wire
bridge at Anglers, France, collapsed under a company of
marching soldiers, the wires having corroded at the anchor-
age. In the following year construction was started on the
Nicholas suspension bridge in Russia, crossing the Dnieper
river at KiefF, with four intermediate spans of 440 feet and two
€nd ones of 226 feet. The road is suspended from four chains
composed of eight rows of flat bars 11x1 inch, 12 feet long,
supported on fine stone towers. It was completed in 1853
and is still in use.
302. The next bridge over the Niagara gorge was started
in 1850 at Lewiston, two miles below the falls, under the direc-
tion of Captain Edward W. Serrell. The distance between
cable supports was 1,040 feet, the road was 860 feet long
and 21 feet wide, and the cable sag 87 feet. In 1861, when
the guy cables had been temporarily removed, the bridge was
wrecked by a wind storm and it was not repaired or rebuilt
until 1899, when a new one to carry a highway and one line
of electric cars in the middle was erected under the direction
of Mr. L. L. Buck. Other interesting suspension bridges in
Canada are those at St. John, New Brunswick, also designed
by Mr. Serrell, and one at Montmorency Falls, Quebec. The
St. John bridge dates from 1852 and carries a platform 100
feet above the river, with a span of 640 feet. It has ten
cables, and stone towers and was rebuilt in 1857. The Mont-
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SUSPENSION BRIDGES. 225
morency bridge was located just below the falls adjoining
the residence of the Duke of Kent, but it collapsed some years
ago carrying a wagon and its driver into the cataracf 260
feet below, and only the stone towers now remain. The old
Chaudiere highway suspension over the Ottawa river at Ot-
tawa, Canada, was removed in 1888.
303. One of the first to propose open web, deep stiffening
trusses braced together transversely for suspension bridges
was John C. Trautwine, who in 1851 designed a bridge to
cross the Delaware river at Market Street, Philadelphia, with
four river spans of 1,000 feet each, and two end spans of 500
feet, using wire cables, and trusses 20 feet deep. His plan was
exhibited for several months at tbe Franklin Institute in that
city, and later at the Merchants' Exchange, from which hall
it was removed without the owner's permission. Eighteen
months after this a similar arrangement was proposed and
used by John A. Roebling for thie railroad bridge over the
Niagara river. Lattice stiffening trusses, 6 feet deep, were
used also on a railroad suspension bridge over the Kentucky
river at Frankfort, Kentucky, which existed in 1852 and was
built some years before with spans of 100, 261 and 200 feet.
It had no stays and the floor was supported with rods 3 feet
apart. Mr. Stephenson's tubular railroad bridge over the
Menai Straits was also designed as a suspension with solid
web stiffening girders, instead of open trusses, but as the
girders were found to be strong enough in themselves, the
cables were omitted. The Niagara bridge had a span of 825
feet with two decks, the lower one carrying a highway 15
feet wide, partially enclosed at the side by the timber stiffen-
ing trusses. The upper deck, 24 feet wide and 245 feet above
high water, had a single track in the center and was floored
over, separating it from the road below. The floors were sus-
pended at intervals of 5 feet from the upper and lower cables.
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226 BRIDGE ENGINEERING.
the deflection of the lower one being 10 feet more than the
upper one. There were four cables 10^ inch diameter, con-
tainyig 620 wires in each or a total of 3,640, the wires of Mr.
Ellet's old foot bridge being incorporated with the others. The
masonry towers were 60 feet high above the road, 15 feet
square at the base, and 8 feet square at the top, and the bridge
was braced laterally against wind pressure by 66 wire guy
ropes, IJ^-inch diameter, fastened to rocks below, the guys
detracting considerably from its appearance. It was com-
menced in September, 1852, and completed in 1855, at a cost
of $400,000. In 1877 damaged wires in the cables were re-
placed with new ones and later the anchorages were strength-
ened, and in 1880 the old wood stiffening trusses and the floor
system were removed and replaced with steel. At a later date
some new stones were inserted in the towers, but in 1886-87
the stone towers showed further signs of weakness and were
renewed in steel. Ten years later the whole bridge was re-
placed by the present steel arch, with a span of 550 feet. The
history of railroad suspension bridges has not been satisfactory,
for all have lacked stiffness and rigidity, and those at Niagara,
Frankfort, Vienna and Durham over the Tees, have been re-
moved. The modern advocates of stiffened suspension bridges
declare their failure due to a lack of reliable theory for stiffen-
ing them, which theory has since been developed and explained.
The bridge over the Elk river at Lovell Street Charles-
ton, W. Va., which collapsed December 15th, 1904, dates from
1851-52, and was designed by W. O. Buchanan, with Wm.
Kuhn and Abraham Wright in charge of construction. After
its collapse a careful investigation and report was made by
H. G. Tyrrell (Engineering News, Jan. 5th, 1905), who made
plans, estimates and tenders for replacing it with either sim-
ple spans, suspension or cantilever. The distance between
tower centers was 478 feet and the floor, 17 feet wide, was on
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SUSPENSION BRIDGES. 227
a grade, being 7 feet higher at one end than at the other and
35 feet above water in the middle. The towers were 30 feet
high above the floor, 30 feet on centers transversely at the
low end, and 34 feet at the other end, supporting two 3j4-inch
wire cables on each side, the whole costing $19,000. It was
twice disabled by retreating armies during the Civil War and
the last time was completely wrecked. Tolls were collected
until 1886, but soon after being transferred to the city it was
reported unsafe and failed under a load of 4 inches of ice and
snow, carrying a large number of people and vehicles into
the river, killing two persons and seven horses, and seriously
injuring several other persons.* A similar suspension bridge
at Morgantown, W. Va. (1866), has a span of 608 feet, sup-
ported by two cables, and another over the Gauley river in
West Virginia, was used during the Civil War.
304. The first suspension bridge over the Mississippi river
at Minneapolis, was built in 1855, with a span of 620 feet,
connecting the west bank of the river with Nicollet Island,
and was under the direction of Thomas M. Griffith, who
was formerly associated with Mr. Serrell in the construction
of the one at Niagara. The four cables containing 2,000
strands of No. 10 wire were supported on wooden towers com-
posed of sixteen wooden posts of 12xl2-inch timber, with a
base 14 feet square. The cables had a sag of 47 feet and were
cradled 10 feet, supporting a total load (including their own
weight) of 92 tons. The floor was carried on white pine
beams, 3j4xl4 inches, spaced 3 feet 9 inches apart with light
stringers on top to support the plank. The width between
centers of trusses was 17 feet and the cost of the structure
$40,000. It is said to have been the first bridge of any kind
over the Mississippi.
•Engrineerlng News, Feb. 2, 1905.
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228 BRIDGE ENGINEERING.
305. A suspension bridge was started by Mr. Roebling in
1857, to carry the Cincinnati Southern Railroad over the Ken-
tucky river at an elevation of 275 feet above the water, on the
site of the present three span cantilever. The span of the
cables was 1,230 feet, but after the towers were completed,
building was discontinued, owing to the failure of the company.
Another Roebling bridge, over the Allegheny river at Pitts-
burg, replaced an old wooden one of 1818. It had two river
spans of 344 feet and two shore spans of 171 feet, or a total
length of 1,030 feet. The deck, including two 10-foot walks,
is 40 feet wide, with a floor on iron framing supported by
four cables, two 7 inches and two 4 inches in diameter, dipping
30 feet and resting on cast iron towers 45 feet high. No im-
portant new suspensions appeared in America during the next
ten years, until the opening of the bridge at Cincinnati in 1867,
but in Europe there was at least one each year worthy of
mention. The Victoria suspension bridge at Chelsea, by
Thomas Page, connecting Battersea Park with Pimlico (1854-
58), has central and end spans of 348 and 183 feet respectively,
with a cable sag of 29 feet, supported on cast iron towers. The
four flat eyebar chains support a deck 47 feet wide, with sus-
penders 8 feet apart. The road is 24 feet above high water
and is cambered 18 inches to the center and stiffened with
lattice girders 6 feet deep. It is 720 feet long, cost 112,100
pounds sterling, and is one of the cheapest and most attractive
bridges in London. In strong contrast with the Chelsea
bridge is the three span suspension bridge at Lambeth, de-
signed in 1862 by P. W. Barlow, and costing 48,900 pounds,
with a 20-foot road and two walks outside the trusses, or a
total width of 32 feet. It stands on cylinder piers and has
cables fixed at the top of towers, causing a pull on them from
uneven loading of adjoining spans. In suspension bridges of
several spans Mr. Barlow proposed to prevent deflection of
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SUSPENSION BRIDGES. 229
the loaded span by fixing chains rigidly to the towers and
designing them as cantilevers to resist the tension from the
chains. The Clifton bridge over the Avon at Bristol was fin-
ished by Messrs. Barlow and Hawkshaw in 1864, though it
was commenced and the towers built in 1829-30. It has a
single span of 703 feet, with a platform 31 feet wide and 252
feet above high water. Construction was resumed in 1840 by
Brunei, but was not continued until the old Hungerford bridge
at Charing Cross, London, was removed and the parts trans-
ferred to Bristol, and re-erected there in 1864 at a cost of
$500,000. It has six chains, three on each side and was the
longest span with flat eyebars in Europe.
306. In the years, 1860-64, two fine suspension bridges
appeared in Vienna over the Danube. The first one (1860,
Fig. 107) was the rebuilding of the old suspension in 1828,
which had been in service for 32 years. The new one had a
clear span of 255 feet and the cables were double lines of braced
chains 4 feet apart. It was the first and only railway sus-
pension in Europe, and continued in use for 25 years, when it
was again replaced by the present arch. The Aspen bridge
(1864) over the same canal at Vienna has a clear span of 200
feet, and braced chains similar to the last.
307. A new form of suspension (Fig. 112), which was
partly a modification of that devised by James Dredge in
1832, was developed by Rowland M. Ordish, and several were
built by him after 1868 on his principle. It had sloping rods
running directly from the panel points of the floor system
to the top of the towers, the direct tension members being
supported and held in position by catenary cables between the
towers, which have no other purpose than to sustain the
weight of the direct tension bars. Bridges of this kind were
built at Prague, London and Singapore. The Albert bridge
over the Thames at Chelsea has a center span of 400 feet and
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230 BRIDGE ENGINEERING.
N
two side spans of 155 feet on the Ordish-LeFeuvre principle,
begun in 1863 and finished 1873 at a cost of 117,^00 pounds.
The Franz Joseph bridge over the Moldau at Prague, de-
signed by Rowland Ordish, 1868, with a center span of 480
feet and two side spans of 156 feet, has twelve main and
two auxiliary chains with a sag of 60 feet, supporting a plat-
form 32 feet wide on piers 16^4 feet thick at the road level.
The straight bars'were replaced in 1898 by wire rope when the
bridge was otherwise strengthened. The suspension foot
bridge over the same river at Prague, Austria, erected by
Ordish (1869), is located between the old stone bridge and the
new suspension and succeeded a boat ferry. It has only one
tower in the middle of the river, and is really two half spans
of 305J4 feet, with a clear distance between shore abutments
of 629 feet. A single pier was believed to offer less obstruction
to ice than two piers as ordinarily used, and was therefore
adopted. The pier is of stone 18 feet thick at the floor level,
and is surmounted with ornamental cast iron towers. Each
column has four standards bolted to the piers and they are
connected at the top with open cast iron girders. The clear
width is 11 feet, the chains being placed a greater distance
apart over the tower than at the abutments. The floor and
tower top are 6yi and 63 feet respectively above high water.
The chains which rest on a saddle with rollers, are steel links
4yi by 1 inch, 21 feet long, with heads and 3j4-inch pins. The
floor is supported by cast iron girders, 21 feet apart, suspend-
ed by wrought iron rods from the cables, and two continuous
stiffening trusses add rigidity. The river banks are low, re-
quiring twenty steps leading up to the deck at each end. The
cost of the whole bridge was 18,500 pounds sterling. Mr.
Ordish and Col. G. Collyer also designed and built a rigid sus-
pension bridge on the Ordish plan at Singapore, capital of the
Straits Settlements, on the island of the same name. It has
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SUSPENSION BRIDGES. 231
a span of 200 feet, a roadway 21 feet wide, and two sidewalks
with wooden floor, and a total width of 31 feet. The stone
piers extend up to the road level and the stiffening girders
are 4 feet deep and 21 feet apart.
308. In 1840 Col. Charles Ellet made an offer to bridge
the Ohio river at Cincinnati with a 1,400-foot suspension, 112
feet above the water, and he made a similar proposal in 1849.
In 1846 John Roebling reported on a proposed bridge at the
site, with a span of 1,057 feet as finally built, but. his first plan
had a tower in the middle of the river, which was not accept-
able. The bridge was begun in 1856 by Roebling, but the
financial panic of 1857 and the war delayed it until 1863, after
which time construction was continued until its completion
in 1867. At low water the Ohio river has a width of 1,000
feet, but in 1832 the river rose 62 feet above low water, and at
this stage it had a width of 2,000 feet. The towers are 52x82
feet at the base and rise 75 feet above the floor, with transverse
arches 30 feet wide over the roadway. The side spans from
abutment to tower are 281 feet, making the total length of
bridge 1,619 feet, and the total length over abutments 2,252
feet. It was the longest suspension bridge previous to the
one at Brooklyn. The elevation of the floor above low water,
is 91 feet at the towers and 103 feet in the middle. It has two
wire cables 12J^ inches in diameter, with a versed sine of 90
feet, with numerous stay cables and stiffening trusses 10 feet
deep between the roadway and walks supporting a wood floor
on steel framing. The bridge originally had a 20-foot road
and two 7-foot sidewalks or a total width of 36 feet, and the
cost was $1,828,000. In 1897-98 it was strengthened under the
direction of Wm. Hildenbrand by the addition of two new
steel cables, lOJ^-inch diameter, directly over the old iron
ones, and increasing the width of road to 30 feet and the
walks to 9 feet each, the cost of reconstruction being $650,000.
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BRIDGE ENGINEERING.
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SUSPENSION BRIDGES. 233
In the same year when the Cincinnati bridge was completed,
Mr. Roebling made a report on bridging the North (Hudson)
river at New York, and declared an iron wire suspension of
3,000-foot span to be practicable. A year later he prepared
elaborate designs which were a combination of arch and sus-
pension, with stiffening trusses and stay cables, for a pro-
posed three span bridge over the Mississippi river at St. Louis,
with a center span of 800 feet (Fig. 113), and published a book
explaining and illustrating his design, but Mr. Eads arch
bridge was accepted instead.
309. The Niagara-Clifton suspension bridge, located a
short distance below the falls, was begun in 1867, under the
direction of Samuel Keefer, civil engineer of Ottawa, Can-
ada, and was completed by him twelve months later. It had
a span of 1,260 feet between centers of wooden towers, and
iron wire cables with a sag of 90 feet, 12 feet apart at the
middle of the bVidge and 42 feet apart at the towers, the cables
being imported from England. The floor was 190 feet above
water and was carried by vertical suspenders 6 feet apart.
The stiffening trusses were 6yi feet deep and the bridge was
further braced with 12 wire stays from each tower to the
floor. There were also side guys anchoring the bridge to the
shore and preventing excessive vibration from wind, and the
original cost was 22,000 pounds sterling. The roadway had a
clear width of only 10 feet, not great enough to permit car-
riages to pass, and in 1888 it was widened to 17 feet, altera-
tions being completed in December of that year. On January
5th, 1889, it was blown down, but was replaced in four months'
time by a new structure with steel wire cables, steel towers
and stiffening trusses, and was re-opened to travel on May
7th, 1889. The whole bridge was replaced ten years later with-
an 840-foot steel arch.
310. The only new suspension in Europe at this time was
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234 BRIDGE ENGINEERING.
a foot bridge (Fig. 114) over the Main, between Frankfort
and Sachsenhausen, designed by Schnirch in 1869, with stiff
riveted members having part cantilever action. The Angarten
bridge at Vienna, with a 202-foot span (1873), on the Fives-
Lille system, is an interesting work and highly ornamental.
In the years 1870 and 1871, two new suspensions, with spans
of 470 feet, appeared in the United States, the first, with two
cables, being at Waco, Texas, over the Brazos river, and the
second over the Allegheny in Warren County, Pennsylvania.
The Waco bridge was designed by Thomas Griffith, engineer
of the first one at Minneapolis in. 1855. The Minneapolis
bridge, after 20 years of service, was found insufficient for the
increased traffic, and in 1875 was replaced by Mr. Griffith with
a new and heavier one of 676-foot span. It had two main
cables 10 inches in diameter, containing 3,648 strands of -No. 9
wire, and two sidewalk cables 4 inches in diameter, containing
460 strands, with a sag of 58 feet and 6-foot cradling. The
two lines of wood Howe stiffening trusses at each side of the
roadway were 7 feet deep and two outer ones 6 feet deep,
with four stay cables in each quarter, the total weight of
suspension material being 350 tons. The cross floor beams
were 3J^xl3>^-inch white pine, 36 feet long, placed in pairs
6 feet apart. On these, stringers were placed covered with
plank and a wood block pavement. The masonry towers were
111 feet high and 35 feet apart on centers, and the width be-
tween main trusses was 20 feet, with 6-foot walks outside.
The two main anchors were solid stone, 10x10x40 feet, and
the cost of the bridge proper was $127,000, and the approaches
$72,000, or a total of $199,000. In 1888 a new steel arch was
erected beside the suspension, and in 1890, when the arch
was completed, the suspension bridge was removed at a cost
of $3,000. A very unusual design was carried out in 1871
in the Redheugh bridge, 850 feet long, over the Tyne near
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Newcastle, which is a combination of truss and suspension.
It is supported on three braced towers and the upper and
lower members of the truss are respectively gas and water
pipes.
311. The Point bridge (Fig. 115) at Pittsburg was de-
signed by Edward Hemberle, and built in 1876 with a center
span of 800 feet and two side spans of 145 feet each, making
a total length of 1,250 feet. It had a 20-foot roadway and two
7-foot walks with a clear height beneath of 80 feet and cost
Fig. 115.-
$526,000. The river piers were of stone and the towers of iron,
110 feet high. The 8-inch eyebar cables have stiflfening trusses
above the chains in the form of segmental chords, and the de-
sign is such that all uniform loads are carried by the cables,
causing no stress in the stiffening trusses. It was the longest
span with flat eyebars in America, and toll was collected upon
it till 1896. In 1906 it was repaired at a cost of $92,000. An-
other suspension over the Allegheny at Oil City was built the
same year, with a span of 500 feet, supported by two cables,
but was rebuilt in 1884 and again in 1905. At Franklin, Pa.,
an unusual failure of a suspension was caused by fire in an
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BRIDGE ENGINEERING.
adjoining building, melting the lead which secured the cables
into their iron sockets, and allowing them to pull out and
precipitate the bridge into the river. The Mill Street sus-
pension at Watertown, N. Y., with a span of 175 feet, was re-
placed in 1898 by a steel arch. The floor was 18 feet wide
without stiffening and. was supported by vertical rods from
four main cables, each of which was 2 inches twisted iron wire
rope, with a sag of 12J^ feet. The 3 by 6 inch wood joist were
carried on 9-inch beams.
312. Two bridges over the Allier river in France, which
were built in 1879-84, had some interesting and unusual fea-
tures. One at St. Ilpize (1879) had a center span of 232
Fig. 116.
feet and side ones of about 50 feet, crossing the river at an
elevation of 85 feet (Fig. 116). The floor load for a distance
of 50 feet at each side of the cast iron towers was carried
directly to the towers by inclined ways, and the main cables
support only a portion of the platform in the central span.
l*his arrangement of loading distorts the curve of cables from
the catenary, but greatly reduces the amount of load upon
them. The bridge is 13 feet wide, and the whole cost was
$14,000. Similar bridges are at Lamothe, France, 1883-84, with
a span of 377 feet, a width of 18 feet and cost $36,400; and
another over the Saone at Lyons by A^ijiodin (1888), with a
total length of 397 feet. A suspension foot bridge at Inverness
over the river Ness (1877) has center and end spans of 173.
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SUSPENSION BRIDGES. 237
and 60 feet, respectively, supported on steel towers founded
on cast iron piers filled with concrete. It has two wire rope
cables 6 inches in circumference from which a 6-foot road is
suspended with 5^-inch rods, the cables being attached to con-
crete anchor blocks 10x10x26 feet. The steel lattice stiffening
trusses are 4 feet 3 inches deep, and the whole bridge cost
only $5,000. Several designs were made for suspension
bridges to cross the Firth of Forth, and in 1880 a contract
for construction was awarded on a design (Fig. 117) by Sir
Fig. 117.
Thomas Bouch, with two spans of 1,600 feet, but the failure
of the Tay bridge designed by him caused the Forth project
on his plan to be abandoned, and a cantilever design by other
engineers accepted instead.
313. For many years the most prominent object about
New York was the old Brooklyn bridge (Fig. 118), crossing
the East river from Park Row to Sands and Washington St,
Brooklyn, and though there are now three others across the
East river, the first is the most conspicuous from lower New
York and from the harbor. The preliminary investigations
and designs were made (1850-56) under the direction of John
A Roebling, who died 1869, at the age of sixty, the same
year that construction work was commenced, but it was car-
ried to completion (1883) under the direction of his son. Col.
Washington Roebling. The towers are l,595J/2 feet on cen-
ters and each end span is 930 feet, with an approach on the
New York side of 1,562, and a corresponding one at the
Brooklyn side of 971 feet, making the total length 5,989 feet.
The platform, which is supported by forr main cables 15J^
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23S BRIDGE EXGINEERING.
inches in diameter with a sag of 128 feet, has provision for
two elevated railroad tracks, two trolley tracks on the two 18-
foot highways, and a center way of 15 feet for pedestrians,
the total width being 85 feet. The stone towers, which are 53
by 136 feet at the roadway level, stand 278 feet above high
water and the under clearance for ships is 135 feet. The
original cost of the strutture was $9,000,000, and of the land
$7,000,000, making a total cost of $16,000,000, a large portion
of which was incurred in financing the project, but many im-
provements and additions have since been made, increasing
the cost to about $21,000,000. The cars carry 300,000 pas-
sengers daily over the bridge in addition to the travel on the
carriage ways and foot paths, and plans have been developed
for strengthening it and increasing its capacity by adding
deeper stiffening trusses and an entirely new floor system.
While the Brooklyn bridge was under construction, another
one was projected to cross the East river at Blackwell's
Island, New York. Cantilever designs were prepared by W.
P. Trowbridge and Charles MacDonald, but a suspension
bridge designed by T. C. Clark and Adolph Bonzano was ac-
cepted and a construction contract in the amount of about
$5,000,000, was awarded in 1881 to Thomas Rainey of Ravens-
wood, Long Island. It had river spans of 734 and 620 feet
over the two channels, a clearance beneath it of 150 feet and a
total length of 9,000 feet, with suspension chains stiffened
similar to the Point bridge, Pittsburg. The deck had provision
for two tracks, two carriage ways and double foot walks, but
the project was never completed and the site is now occupied
by the Blackwell's Island or Queensboro cantilever bridge.
To avoid long and expensive approaches to high level bridges
in large cities, such as the East river bridges in New York,
a plan was prepared in 1885 in which the ascent to the bridge
floor was made on a street circling around outside of tower-
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SUSPENSION BRIDGES. 239
like abutments, the interior of which was arranged for shops,
warehouses or offices. A bridge with rudiments of this idea
was erected over the Mississippi river at Hastings, Minn.,
with a river clearance of 75 feet, and a spiral approach at one
end.
314. The Seventh Street bridge over the Allegheny river,
at Pittsburg, Pa., has three towers with two river spans of
330 feet and two shore spans of 165 feet with a 90-foot truss
over the railroad tracks. It was erected in 1884 from designs
by Gustav Lindenthal and has eyebar suspension chords com-
posed of two lines of eyebars with diagonals between them.
Its width is 42 feet and total length 1,080 feet, both chains
being in tension from uniform loads. In the same year a light
suspension bridge was built over the Elk river at Charleston,
W. Va., with a span of 273 feet, adjoining the one which col-
lapsed in 1904. It has twisted wire cables, back stays, lat-
tice trusses and iron towers on high stone piers. A few years
after it was completed, one anchor block moved slightly for-
ward, allowing the tower to slope towards the river, but it
was repaired by William Hildenbrand, who added new anchor
masonry. For several years it carried a single line of track
for light street car travel, but this was discontinued in Decem-
ber, 1904, when the adjoining suspension bridge fell. A care-
ful examination of the bridge was made in January, 1905, by
H. G. Tyrrell, and a report submitted to the city railroad
company. The corrosion of the cables where they entered
the masonry, which caused the wreck of the Lovell Street
bridge at Charleston, also caused a suspension bridge at
Ostrawitza, Austria, to fall in 1886.
315. Competitive plans submitted for the Washington
bridge over the Harlem river in 1886 called forth two sus-
pension designs by William J. McAlpine, with center spans
of 800 feet, one of which had end cables loaded and an esti-
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BRIDGE ENGINEERING.
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SUSPENSION BRIDGES. 241
mated cost of $1,500,000 (Fig. 119) ; and another with ends
unloaded and the road supported on masonry arches (Fig. 120)
somewhat like the Menai suspension, with an estimated cost
of $2,100,000. Other notable designs in 1886 were those pro-
posed by Col. P. C. Hains, Capt. T. W. Symons and Mr. Paul
Pelz, for crossing the Potomac at Washington with a span
of 1,100 feet and two shore arms of 662 feet, carrying a plat-
form of 64-foot width at a height of 105 feet above the river.
The name of the proposed bridge was the "Grant Memorial,"
and the estimated costs $3,000,000 to $6,000,000, but none of
the designs were ever built.
As suspension bridges can be quickly placed, they have
frequently been used as. temporary structures to replace
others which have been washed away. They were used at
Kansas City after the flood of 1904, and one was erected over
the Tiber at Rome where the two arches of Ponte Rotto were
swept out. Another at Rome (1889) has stiffened cables
somewhat like those of the Point bridge at Pittsburg, except-
ing that both chords of the bridge at Rome are in tension un-
der uniform loads, the curve of equilibrium passing half way
between them, while under those conditions the lower cable
only is in tension on the Pittsburg bridge.
316. Many of the largest suspension bridges in the United
States span the Ohio river, and a very attractive one over" one
of its tributaries is about two miles from Valley Junction,
crossing the Whitewater river with a span of 498 feet. It has
ornamental stone towers 12 feet square at the base and 86 feet
on centers, transversely, with a 20-foot clear roadway between
them. The end cables are unloaded and the floor is braced
with stays in the four quarters and held laterally with guys
fastened to anchor blocks on shore. In strong contrast to this
bridge was another over the same river at Richmond, Ind.
(1889), with a center span of 150 feet and a total length of
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242 BRIDGE ENGINEERING.
200 feet, costing complete only $2,160. The towers consisted
of iron pipe driven into the river bank, and the floor was sup-
ported by rods radiating from their tops, as in the Ordish
system. Light lattice trusses served as railing, but a person
at the center of the span could cause the bridge to spring a
foot or more. Several so-called economical types have ap-
peared in the United States in recent years, one of which on
the Eddy patent with a 300-foot span over the Mojave river
at Victor, California, the strength of which was questioned,
fell in 1890 under a test load. Another suspension bridge in
California, the design of J. M. Graham (1890), carr)ring a
timber flume over Kings river on a span of 461 feet between
towers, was first used without stiffening trusses, but when
Pig. 121.
water was turned into the flume the load caused so great a
waving motion of the floor that wood trusses at either side
were added. It had seven 1^-inch steel cables at each side,
which were covered with wood casing to prevent expansion
from the excessive heat. Crude suspensions with floor on
wire cables over temporary timber towers were used by con-
tractors on the Union Pacific Railroad, to carry the track over
ravines while embankments were being made. Car loads of
earth were run out on the bridge and dumped into the valley
below, the operation being repeated until the embankment
was completed. A suspension foot bridge was placed across
the Oapaaen river at the Odda works of the Alby Carbide
factory, being similar to a type much used in Norway for foot
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SUSPENSION BRIDGES. 243
travel. Its four spans, the longest being 102 feet, are sup-
ported by three lines of 1^-inch wire ropes passing over
three timber towers, the cables being drawn taut and the
wood floor laid directly thereon.
317. Grand Avenue suspension bridge at St. Louis (1890-
91) designed by Carl Gayler is worthy of special mention
(Fig. 121). It carries a street over the railroad yards with a
center span of 400 feet and two end spans of 150 feet each.
It is a three hinge inverted arch with two stiffened chains,
one on each side. The upper chord and all web members
are eyebars, while the lower chord consists of light riveted
sections for stiffening purposes only, all uniform loads being
carried by the upper bars. The width between center of
Fis. 122.
trusses is 42 feet, the total width 60 feet and the length over
abutments 1,600 feet, the whole costing $450,000. Another
long bridge over the railroad tracks at St. Louis, with a series
of shorter spans, is lacking in stiffness due to their suspension
or cantilever action. To avoid this lack of stiffness, Charles
Steiner proposed in 1892 a combination of suspension and
cantilever with short spans of 60 feet, supported by stiffened
cables running direct to the top of towers. In alternate main
spans were suspended trusses of 100 feet, and the arrangement
of piers and general outline was somewhat similar to T. C.
Clark's design of 1881 for the Blackwell Island bridge. Rigid-
ity was secured by G. Koepcke in the Loschwitz bridge (Fig.
122), near Dresden, by using stiff members, and it is therefore
sometimes called a cantilever. It has a central span of 481
feet and two side spans of 202 feet, with metal towers carry-
ing a platform 36 feet wide. The curve of the upper chord
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244 BRIDGE ENGINEERING.
IS a hyperbola, and as the center hinge transmits tension from
one half to the other, it may be called a three-hinged suspen-
sion. It is very heavy and would easily carry two lines of
railway. Conspicuous from its bright color of cobalt blue, it
is commonly called "the blue wonder." Other bridges are at
Vcrnaison over the Rhone, and Pont Lorois over the Etel.
The first is Syi miles below Lyons and is 1,283 feet long, with
a center span of 763 feet and end spans of 172 and 139 feet
suspended from wire cables. The platform, 17 feet wide, is
supported at each side of the stone towers directly by stays
from their tops, thus relieving the cables of much load.
Pont Lorois on the road from Port Louis to Auray has a
single span of 360 feet with stone piers and floor 40 feet above
the water, but it was blown down in 1894. A park suspension
bridge in the northeastern part of Paris, in the artisan dis-
trict, has a single span of 200 feet, with three wire cables
on each side supported on natural rock towers 17 feet high,
with 10-foot openings blasted through to form the roadway
portal. The towers are about 3 feet square at top and 8 by 20
feet at the bottom, and the cables are anchored back into
native rock. The road, which is 12 feet wide and 40 feet above
water, is stiffened with railing trusses Syi feet deep at each
side.
Suspension bridges are much in favor for park use, and
artistic ones are found in the parks of Boston, Chicago and
San Francisco. A small suspension in Mill Creek Park,
Youngstown, with stiff eye bar cables, is the work of C. E.
Fowler (1894). It has a span of 90 feet between towers, a
road 20 feet wide, and two walks 5 feet each. (H. G. Tyrrell
in American Architect, 1901.) The suspension bridge over a
lagoon in the public gardens of Boston, adjoining the Boston
Common, is probably as much seen as any object in the
downtown district and is very artistic, as are also the more
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SUSPENSION BRIDGES. 245
recent ones in Garfield Park, Chicago, built in 1893, and
Golden Gate Park, San Francisco. Oak Park, Illinois, had an
unusual kind of suspension foot bridge, with a span of 125
feet, crossing the Desplaines river, with four cables 5^-inch
diameter hung between two trees for towers on the opposite
banks, and was put up in 1887 by young men who at that
time had little special knowledge of bridge building.
As material for suspension bridges is comparatively
light and more easily transported than riveted structural
work, many bridges in foreign countries^ the parts for which
are imported, have been made of this type. One of the largest
of the kind is the Occidente suspension at Antioquia over
Cauca river, Colombia, South America, which has a span of
940 feet, with the small cable sag of only 30 feet. The bridge
is 12 feet wide, and has two 4-inch cables at each side with
hollow towers, the lower 12 feet of which are of brick sur-
mounted with timber frames. The height of saddles is only 22
feet, and as the bridge has a capacity of only 10 pounds per
square foot, it is one of the very lightest ever made, and is re-
markable for its extremely flat cables. Another bridge in Co-
lombia over the Guarino river at Honda has a span of 130 feet,
a road 12 feet wide and towers 16 feet high made of iron pipe
filled with concrete. In the years 1895 to 1900 designs for sev-
eral suspension bridges were made by the writer for export to
Mexico and South America, mostly in snmll spans up to 250
feet. One for the Spanish Silver Mines at Mampimi, Mexico,
over the Ojuela river (1900), has a span of 1,030 feet, supported
by two wire cables on timber towers 50 feet high, and 30 feet on
centers, with a 10-foot roadway. Each cable consists of three
2-inch steel wire ropes and in each quarter are four stays.
A very light suspension somewhat similar to one at Fribourg,
was placed across the Lehigh river at Mauch Chunk, Pa.
(1888), to carry a six-inch oil pipe. The tower on one side
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SUSPENSION BRIDGES. 247
of the river is 115 feet higher than the anchor masonry on the
other side, and the bridge floor, which is 360 feet long, is on
a steep grade. It was the design of William Hildenbrand.
318. In 1897 two important structures very similar in de-
sign were erected over the Ohio river at East Liverpool, Ohio,
and at Rochester, Pa., both having underneath clearances of
90 feet. The first (Fig. 123) has a center opening of 706 feet
and side spans of 860 and 420 feet, with masonry piers 47
feet above low water, surmounted with steel towers 106 feet
in height and 30 feet on centers transversely. It has a 20-
foot roadway and a 7-foot walk on one side, with stiffening
trusses 20 feet deep. The Rochester bridge has a center open-
ing of 800 feet with side spans of 400 and 416 feet. The road-
way is 22 feet wide with one 7-foot walk, and is stiffened with
steel trusses 18 feet deep and supported by wire cables, the
whole costing $175,000. The estimated cost of a cantilever
bridge of the same size and capacity was $230,000. Similar
to this was one proposed by Mr. Herman Laub in 1897, to
cross the Ohio at Bellaire, with a center span of 850 feet,
but it was not carried out. In the same year the competitive
designs for a proposed bridge across the St. Lawrence river
at Montreal brought forth two interesting suspension designs
by J. W. Balet and C. C. Wentworth, with spans of 1,400 and
1,300 feet, respectively, a platform 105 feet wide and towers
800 to 400 feet high.
819. The Langenargen suspension on Lake Constance by
Kubler (1898), 286 feet long, is a stiffened cable bridge with
two cables 5J4 inches diameter of six twisted wire ropes,
cradled from 22 feet apart at the center to 32 feet over the
stone towers. The floor is stiffened with light side trusses and
the end cables are not loaded. Floor stiffness is secured in
the Muhlenthor bridge over the Elbe-Trave Canal at Lubeck
(1899) by lattice ribs below the floor, and the Tower bridge
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BRIDGE ENGINEERING.
at London (1895) has stiffened end cables (Fig. 124). The com-
petition for bridges at Bonn, Cologne and Worms evolved
several interesting designs, one by M. Rieppel for Cologne hav-
ing stiffened cables.
320. In 1899 when the two suspension bridges over the
Niagara gorge, just below the falls, were replaced with steel
arches, it was decided to use some of the cables from these
r*:lrfc:^*
Flff. 124.
bridges for rebuilding the wrecked one two miles further
down the river at Lewiston, and work was commenced the
same year under the direction of L. L. Buck and his asso-
ciate, R. S. Buck. The Lewiston bridge (Fig. 125) was the ninth
to cross the gorge in the Niagara district, and is the only sus-
pension now remaining there. It has a span of 1,040 feet with
steel stiffening trusses 800 feet long, 14 feet deep and 28 feet
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SUSPENSION BRIDGES. 249
apart on centers, with a single electric car track in the middle
and carriage ways on either side. It has four 10-inch wire
cables, with g^y ropes beneath the floor to prevent uplift from
wind. The towers stand on rock cliffs high above the roadway,
giving the bridge an unusual appearance. Another small orna-
mental suspension bridge crosses the rapid water between the
two Sister Islands.
321. Two suspension foot bridges of the last decade, 6
feet wide, crossing the New river in West Virginia, are at
Nuttallburg and Caperton. The first has a span of 340 feet
supported by four cables 1^-inch diameter, with masonry
towers 22 feet high and 5 feet -square at the floor level ; while
that at Caperton has a span of 610 feet and wood towers 19>^
feet on centers transversely, 8 feet square at the base and 30
feet high, sheathed over and shingled. The platform is 50
feet above the water, which has a current of 10 miles per hour.
The bridge has one cable lj4-inch diameter on each side.
322. A suspension bridge of very unusual design was
erected over the Lehigh river and canal at Easton, Pa., in
1900 (Fig. 126), from designs by H. G. Tyrrell. It is for
pedestrian travel only and joins Dock Street on the lower
side of the river with Glendon Avenue on the upper side, 90
feet above it. To overcome this difference in elevation of the
two ends without incurring excessive expense for approach, the
bridge floor was made to descend on a g^ade of 7.2 per cent
from the upper bank to meet stairs rising from Dock Street
at the lower side. The available revenue from tolls and the
corresponding permissible investment were the governing con-
siderations, and left no opportunity for artistic or architectural
treatment. The bridge has two river spans of 279 feet, sup-
ported on steel towers 108 feet high, and a small tower at the
upper end from which the cables pass over Glendon Avenue
to their anchorages, the total length being 804 feet. It has
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SUSPENSION BRIDGES. 251
light stiffening trusses 6 feet 3 inches deep, suspended at in-
tervals of 12 feet from the 2^-inch cables, which have a sag
of one-tenth the span, the lowest point of the cables being 24
feet from the span centers. (Engineering News, Nov. 22, 1900,
Scientific American Supplement, Sept. 28, 1901.)
323. Four years later another interesting one known as
the Ticonic suspension foot bridge was erected at Waterville,
Maine, at a cost of $18,000, carrying East Temple Street over
the Kennebec river, with a center span of 400 feet. The plat-
form was 6 feet wide and the distance between the towers
transversely was 20 feet. It has a 2J^-inch cable on each side,
and the tower top is 72 feet above the water, the under clear-
ance of the bridge being 30 feet. Two years previously the
writer submitted several competitive designs for this bridge
both with loaded and with unloaded cables. Another light
bridge of this type was placed across the Merrimac river near
Lowell, with a span of 550 feet. The cables, 2^-inch diameter,
cradled from 24 feet apart over the timber towers to 6 feet at
the center, leaving a clear foot walk of 4^4 feet. Towers are
45 and 50 feet high and the cable sag is 36J4 feet. It is the de-
sign of J. R. Worcester.
324. The new Elizabeth suspension bridge at Budapest
(1905) is a model of elegance and simplicity. It has a single
span of 951 J4 feet, a distance face to face of abutments of
1,235 feet and a total length over approaches of 3,014 feet,
with piers 212 feet above zero water Hnfe. It has eyebar cables
in vertical planes and steel towers 66 feet apart, pivoted at the
base, enclosed by masonry, and was designed by Aurelius
Czekelius, engineer, and M. Nagy, architect. A design which
was submitted in 1897 by Kubler for this bridge had 120 feet
of the river span adjoining each tower, supported on girders
independent of the cables, the outer end of girders being hung
from the towers. A suspension design submitted in 1904 for
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252 BRIDGE ENGINEERING.
the Sydney harbor bridge had 1,300 feet stiffened center span,
with end cables unloaded and approach spans on metal towers.
After several efforts to bridge the Mersey river at Run-
corn, including suspension plans by Thomas Telford and Mr.
Dumbell, and more recent arch designs of long span, a trans*
porter bridge was erected there in 1904, with a clear span
of 1,000 feet, and a clear height beneath it sufficient to allow
the passage of ships with masts. Several other transporter
bridges have their trolley ways and trusses suspended from
cables, including several in France. The Runcorn bridge has
cast iron towers 190 feet high on each side of the river, and
the final cost of the structure, including power house and
equipment, was $650,000, which was only one-third the esti-
mated cost of a permanent high-level bridge of the same ca-
pacity and span, with the necessary approaches. A 70-foot
car accommodating 300 people and four double horse wagons
makes ten trips across the river per hour, or a single passage
in 2yi minutes. The new Borsig suspension over the Spree
at Berlin, with stone towers of unusual design and eye bar
chain cables is the work of Bruno Mohring, and leads to a
new land tract that was lately opened.
326. Another recent electric railroad bridge, at Ville-
franche-de-Conflent, with a central span of 166 meters, and two
end spans of 39 meters, has a platform supported by a sjrstem
of cables running straight from the panel points of the floor
to the top of the tower, somewhat similar to the Ordish prin-
ciple. It has steel towers on masoniy piers built up to the
roadway level, and cost $76,000. Several similar to this, of
the Gisclard type (Fig. 127), in spans up to 42 meters, have
been exported and erected in the French Congo.
326. The Williamsburg bridge (Fig. 128), over the East
river at New York, is the longest suspension, having a span
of 1,600 feet between tower centers, and about 6 feet greater
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SUSPENSION BRIDGES.
253
than the old Brooklyn bridge. Its totaj length is 7,200
feet and width 118 feet. The underneath clearance for the
passage of ships in the central 400 feet is 135 feet. It has
two decks with provision for four trolley tracks, two elevated
tracks, two foot walks and two carriage ways on projecting
brackets. The two riveted stiffening trusses are 40 feet deep
and 72 feet apart on centers, while the apprpaches have grades
of 3 per cent, and the elevated tracks grades of 2 per cent
There are four main cables 18 inches in diameter, which are
Elevation ofTcMver
Fig. 128.
336 feet above mean water at the top of towers, and the
end spans are not. loaded. The bridge passes from Delancy
street in Manhattan to Broadway in Brooklyn, the distance
from center of steel towers to anchor masonry at each end
being 600 feet, divided into two spans of 800 feet each. The
approaches cross over one and a half miles of streets and build-
ings. The 1,600-foot span weighs 8,000 tons, its greatest live
load is 4,500 tons, and in each of the towers are 3,000 tons of
steel. It has the largest traffic of any bridge in existence.
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254 BRIDGE ENGINEERING.
and is surpassed in length only by the Forth bridge in Scot-
land. The bridge proper cost about $8,000,000, and the land
$12,000,000 more, or a total of $20,000,000. The chief engi-
neer on construction was L. L. Buck, and O. F. Nichols, prin-
cipal assistant.
327. The Manhattan bridge (Fig. 129), situated one-quar-
ter of a mile east of the first Brooklyn bridge, has the largest
carrying capacity of any bridge in existence. It was originally
designed as a stiffened chain cable suspension, but a change
of administration caused the eyebar cable plan to be aban-
doned, and wire cables adopted instead. The center and side
spans are 1,470 and 725 feet, respectively, and the total length
over approaches 6,855 feet, total width 120 feet, and towers
322 feet above high water. Each tower is composed of only
two legs, approaching the condition of rocker towers, as on
the new bridge at Budapest. The lower deck has provision for
four surface tracks, one 36-foot carriage way, and two 11-foot
walks, and the upper deck has space for four elevated railroad
tracks. The cables are 21J4 inches diameter, hanging verti-
cally, and the total cost about $26,000,000. It was openea
to travel in December, 1909. All the East river bridges are
crowded with travel, and it was proposed by Mr. T. K. Thom-
son that the approaches in Manhattan be connected to avoid
the terminal features. Mr. Lindenthal's proposed design for
the Manhattan bridge (Fig. 130) had four lines of stiffened
cables fastened to the top of steel rocker towers 300 feet high,
with one highway, four tracks and two walks on the lower
deck, and four lines of elevated track on the second deck. He
made a similar design for the Quebec bridge with end and
center spans of 680 and 1,800 feet.
328. The proposed North or Hudson river bridge, with a
span of 3,100 feet, which was seriously considered for fifteen
years or more, would exceed any suspension yet projected,
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( S
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though a cable span of 4,427 feet between towers, consist-
ing of four %-inch galvanized steel wire cables, is in use at
the Straits of Carquinez, California, 140 miles from Oakland,
for the transmission of power, with a clear headroom beneath
it of 200 feet. A commission of army engineers reported in
1894 that a span of 4,335 feet was practicable for bridges, and
Mr. Lindenthal considers that this length may safely be in-
creased to 6,000 feet for a bridge to carry heavy trains at high
speed. At least five designs for the proposed North river
bridge have appeared, with estimated costs of seventeen to
thirty-seven million dollars. The one by Gustav Lindenthal,
with stiflFened eyebar cables (Fig. 131), and center and end
spans of 3,100 and 1,800 feet, respectively, had upper and lower
decks, and towers 600 feet high, carrying fourteen lines of
railway track. The estimated cost of the bridge alone, without
land, is $26,000,000. More careful investigations of the sites
for foundations, show that solid bottom could be reached only
at so great a depth as to make the project impracticable, and
tunnels have been constructed under the river instead.
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CANTILEVER BRIDGES. 257
CHAPTER XIII.
CANTILEVER BRIDGES.
329. An essential difference between suspension bridges
and cantilevers is that the former transmit tension across from
one half to the other, while the halves of cantilever bridges are
self-supporting. The earliest recorded cantilever bridge is at
the sacred city of Nikko, in Japan, and dates back to the fourth
century, A. D. It is known as Shogun's Bridge, and records
state that "the abutments are of hewn stone, the shore piers of
hewn granite, octagonal, monolithic, mortised for stone gird-
ers, and monolithic plate beams receive the wooden superstruc-
ture. The stringers, which are fastened into the abutments,
balance over the stone beams, but do not reach by a consider-
able distance, the gap being fitted by middle stringers let into
the stone stringers. It is not used by the laiety." A timber can-
tilever, also in Japan, in the province of Etchin, dating from
1665, had six lines of slanting timbers, cantilevering out from
the opposite sides of the river, with intermediate stringers
supported between the projected ends. The banks on either
side were protected by large stones held in place by bamboo
lattice work. A somewhat similar cantilever bridge (Fig. 132)
at Wandipore, Tibet, (1650) had a span of 112 feet and lasted
for one hundred and fifty years. It was made of fir, fastened
together with wooden pegs without nails or metal of any
kind. The cantilevers projecting about 40 feet out from
either side were layers of timber keyed together, the upper
courses in each case projecting out past the one beneath it.
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BRIDGE ENGINEERING.
and the space between the cantilever ends was spanned by
simple timber beams. A smaller opening at one side had a
single cantilever only, with end towers and entrance gates.
Another biit ruder bridge of this type spans a gorge in the
Fig, 132.
Himalayas near Darjeeling, India, on the border of Tibet,
and still another is located near Opdal in Norway. Several
interesting rustic cantilever bridges made by the Canadian
Indians have been found in British Columbia, one of them
Fiff. 133.
over the Bulkley river (Fig. 133), two hundred miles from
Prince Rupert, containing a suspended span. A native canti-
lever bridge near Ona, Ecuador, has a floor of logs supported
on projecting brackets at either side of the ravine.
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CANTILEVER BRIDGES. 259
In Colima, Mexico, a bridge (Fig. 134) was found span-
ning the Armeria river with a length of 175 feet. It was made
by a native Mexican peon, who is reported to have seen a
picture of a suspension bridge in an illustrated paper, and
after examining the picture carefully concluded that he could
build a similar one. His was a combination of cantilever and
suspension with a clear span of 70 feet, the joints being put
together without nails. The cables were made of twisted vines,
and lighter or smaller vines were used in making the joints.
Poles with natural forks or crotches driven into the river
bank constituted the towers, and these were protected by a
square enclosure of other poles and stakes tied together with
rods and vines, the enclosure being filled up solid with loose
Fi«r. 134.
stones and gravel. The two main stringers were spliced at the
middle, and supported at the center from the cables, and at
the ends in crotches of the shore towers. The stringers
were further supported at the quarter points by cantilever
poles bearing, on the towers and anchored with stones on
shore. The bridge was strong enough to carry loaded mules
and men on horseback, but was washed out by a freshet with-
in a year after its completion. Undaunted by its failure^ the
peon bridge builder replaced it with another, which lasted
eighteen months when it, too, was destroyed.
330. In 1810, Thomas Pope, a clever and ingenious car-
penter of New York, made a 60-foot model to the scale of
}i inch to 1 foot for a proposed "Flying Lever Bridge" of
1,800-foot span to cross the Hudson river near that city. He
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260 BRIDGE ENGINEERING.
made elaborate plans and estimates and the- following year
wrote and published a book describing his invention. In
1833 patents were granted to Mr. A. Canfield on a bridge
which contained elements of the cantilever principle. Twelve
years later, when designing the Britannia bridge over the
Menai Straits, 1846-47, Robert Stephenson evolved a plan
with two cast iron arches of 460 feet flanked with half arches
at the shore ends, and proposed erecting them from the three
piers by placing sections symmetrically on either side, cacnti-
levered out from the piers and tied together above them
with ropes or rods, similar to the method proposed by Mr.
Brunei for erecting masonry arches without falsework. The
plan was not adopted for the Britannia bridge, but a similar
method was used in 1867-70 in erecting the steel arches of the
Mississippi river bridge at St. Louis. This was the first
practical application of the cantilever principle in modern
bridge building. It was used with the evident purpose of
avoiding the expense of temporary staging, a reason which
is still the governing factor in the selection of a cantilever
bridge.
331. In the year 1850, Sir John Fowler had a wooden
model made of a continuous girder with the chords cut at the
points of contraflexure for the purpose of showing the merits
of continuous girders and avoiding the uncertainty of their
reactions. The Boyne river viaduct at Drogheda, Ireland
(1866), had three continuous lattice spans with center and end
openings of 267 and 141 feet respectively. The upper chords
of the middle span were disconnected after erection, at the two
points of contraflexure, 170 feet apart, but were afterwards riv-
eted together again. In connection with Sir Benjamin Baker,
Mr. Fowler made a design, in 1864, for a' metal cantilever
bridge with a span of 1,000 feet to cross the Severn. The span
length was afterward reduced to 600 feet and a contract
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CANTILEVER BRIDGES.
261
awarded for its construction, but the failure of the company
caused the project to be abandoned. Two years previous to
this, Professor Ritter of Hanover computed the stresses for
a 625-foot cantilever, and proposed, as did Mr. Fowler, to
avoid the uncertainty of continuity by cutting the chords.
During the same year Mr. Baker wrote his book, entitled
"Long Span Bridges/* in which the cantilever principle was
considered. Messrs. Baker and Fowler designed another
Flff. 186.
bridge, in 1871, to cross the Severn, this one having two
cantilever spans 800 feet long, and two years later Mr. Baker
designed a ferry bridge over the Tees, including a 650-foot
cantilever.
332. In 1867 the three span cantilever bridge was built
over the Main at Hassfurt (Fig. 135) from designs by Herr
Gerber, with a central opening of 124 feet. During the years
1865-70 many combination cantilever and suspension bridges
Fig. 186.
were built by Mr. A. Smedley, an English engineer,
the bridges being known as "the Smedley System," one at
Calcutta (Fig. 136) having a span of 76 feet In the same
years pamphlets were circulated by a company in America
showing bridges in course of erection (Fig. 187), the parts
being built out from shore without the use of falsework.
Many crude ones were built throughout New England and
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262
BRIDGE ENGINEERING.
New Brunswick (1867-70) by the "Solid Lever Bridge Co.,"
of which C. H. Parker was engineer, the company being suc-
ceeded by the National Bridge and Iron Works.
In 1868 Prof. W. P. Trowbridge of Columbia College
designed a cantilever bridge to cross the East river and
T\g. 137.
Blackwell's Island, New York, with channel spans of 600 and
720 feet and a clearance for ships of 135 feet. I^s plan
showed stone abutments and metal towers, with numerous
stays supporting the floor, and intermediate spans between
Fig, 188.
the cantilever parts. His design was revised in 1870, and
in 1872, when an effort was made to finance the enterprise, the
competition, for which prizes were offered, resulted in the
acceptance of a design (Fig. 138) by Charles MacDonald,
r^^^^^^^^^^< ^^
^^g^
n n
Fig. 189.
president of the Delaware Bridge Co. It had two channel
spans of 734 and 618 feet and an estimated cost of $3,000,000.
The Wrsowic bridge on the Francis Joseph line of railway,
designed by Joseph Langer in 1870, has three continuous
lattice girder spans, stiffened by an upper member, following
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CANTILEVER BRIDGES. 263
the line of a suspension cable, but the first railroad cantilever
bridge (Fig. 139) really built was over the river Warth at
Posen, Poland, in 1876, with five spans, the center one 148
feet long.
383. In the same year, the Kentucky river bridge at
Dixville, Ky., (Fig. 140) was completed for the Cincinnati,
Southern R. R. from designs by Charles Shaler Smith. It
had three spans of 375 feet on metal towers, with a deck 276
feet above water. It is located at a place where a suspension
bridge was started by John A. Roebling, twenty-two years
before. To avoid the use of expensive falsework, the first
section and the end spans was cantilevered out from shore
Flff. 140.
by tying the top chords back through the old piers of the
proposed suspension bridge. Single timber towers were then
built up from the valley in the middle of the end spans, the
timbers being lowered from the overhanging trusses, and the
erection of the girders was continued, cantilevering them over
the timber towers to the permanent metal ones, and on
further, to meet in the center of the middle span. After com-
pletion, the chords were cut 76 feet shoreward from each
towfer, making end spans of 300 feet and a center continuous
girder 526 feet long. The girders are 37 feet 3 inches deep,
18 feet apart and 1,138 feet long. The heights of the towers
and masonry piers are 177 feet and 71 feet respectively. There
were 1,426 tons of iron in the spans and 400 tons in the
towers. The trusses were 'replaced in 1910 by heavier ones
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264 BRIDGE ENGINEERING.
70 feet deep for double track, on wider towers and foundations,
the deck being 30 feet higher than the old one, thus elimin-
ating approach grades of one per cent at each side. On the
reconstruction, a single lune-shaped two-hinged arch of 864
feet and 162-foot rise was considered, and partial plans pre-
pared for erection at a new location, but the government re-
quirements, that the old piers should be removed if not re-
quired, made the cost of the arch project greater than re-
newal with trusses on the old site. The rebuilding was under
the direction of Gustav Lindenthal. Mr. Smith designed and
built, in 1880, a similar but smaller bridge (Fig. 141) over the
Mississippi river at St. Paul, with two end spans of 272 feet,
and a center span of 324 feet, on iron towers. The trusses were
18 feet apart, 30 feet deep, and carried a single track at an ele-
Fig. 141.
vation of 100 feet above the water. The chords were cut in the
middle of the cenier span, and there were, therefore, no sus-
pended trusses. This bridge was replaced in 1901 under the
direction of Mr. Onward Bates, by a double track bridge on
stone piers. A highway bridge was built the same year over
the Mississippi river at Fort Snelling with the largest span
suspended from cantilever brackets on the two adjoining ones.
The work was done under the direction of John S. Sewell, en-
gineer of St Paul, at a cost of $108,000. But Shaler Smith's
largest cantilever bridge was the steel one over the St
Lawrence river at Lachine, Canada, carrying a single track
of the Canadian Pacific Railroad (1888). It is 3,535 feet long,
or only a little more than half as long as the Victoria bridge
for the Grand Trunk Railroad, a few miles farther down the
river.
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CANTILEVER BRIDGES.
265
334. The Lachine bridge at Montreal is notable chiefly for
the method used in securing clearance over the channel, by
changing two spans from deck to through trusses with grace-
ful curves at the point of junction over the piers. The two
center spans of 408 feet and the adjoining ones of 269 feet are
continuous over five piers and were erected as cantilevers;
but the remaining eight spans of 240 feet are simple trusses.
The river has a depth of 20 to 90 feet and a current of eight
to twelve miles per hour, making the foundations expensive,
the whole bridge costing $1,250,000, or $354 per lineal foot.
The continuous trusses are 20 feet apart on centers, and until
recently were the longest of their kind, but the fixed spans
are decreased to 16 feet for single track. It is now (1910) being
replaced by a double track structure with simple trusses.
Flff. 142.
335. The first example of the modern metal cantilever
bridge with suspended span was at Niagara (1883), to carry
two tracks of the Michigan Central Railroad over the Niagara
river at a height of 245 feet above the water (Fig. 142). It
is two miles below the Falls, at a place where the gorge is
850 feet, and the river 425 feet in width. There were originally
only two vertical and parjillel trusses 28 feet apart, sup-
ported on iron towers. The top chord eyebars are of iron,
and the bottom chord compression members of high carbon
steel. In 1899, the bridge was strengthened by the addition
of a third line of trusses placed midway between the others,
supported on additional columns in the towers. The distance
between centers of towers is 495 feet, and from the center
of each tower to the end of shore arm is 207 feet 6 inches,
making the total length 910 feet, the center suspended span
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266 BRIDGE ENGINEERING.
being 120 feet in length. The original cost without ap-
proaches was $600,000. It was designed by C. C. Schneider,
but the reconstruction was done under the direction of Alfred
Noble, consulting engineer, and A. Torrey and Benjamin
Douglas, engineers for the railroad company. A simfilar
bridge was designed by Mr. Schneider in 1884 to carry a
single track of the Canadian Pacific Railroad at a height of
FUr. 143.
125 feet above the Prazer river in British Columbia (Fig. 143).
The anchor and cantilever arms are each 105 feet long, with
suspended span of the same length in the middle, making the
distance between stone piers 316 feet. The superstructure
containing 612 tons of metal was brought from England and
erected under the supervision of Joseph Tomlinson, bridge
engineer of the Department of Railways and Canals of Canada.
The Grouritz bridge, Cape Colony, by Sir Benjamin Baker, is
Ficr. 144.
almost identical in outline to the Niagara cantilever, but with
fewer panels and metal piers instead of wide braced towers.
The bridge at St. John, New Brunsvidck (1885) is similar to
that at Niagara, but with trusses inverted, making it a through
instead of a deck bridge (Fig. 144). It carries a single track
of the Canadian Pacific Railroad at an elevation of 96 feet
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CANTILEVER BRIDGES. 267
above low water. The cantilevers are of different length,
making the bridge as a whole unsymmetrical, and the appear-
ance is further injured by the presence of several trestle
bents at the west end. It is 813 feet long and 477 feet be-
tween centers of stone piers. The trusses are 20 feet apart,
with depths of 65 and 80 feet. It was built by the Dominion
Bridge Co., of Montreal, G. H. Duggan, chief engineer.
The long viaduct carrying Eighteenth Street at St.
Louis over the railroad yards near the Union Depot was de-
signed on the cantilever principle. It has iron towers on stone
piers with intermediate suspended spans and was completed
in 1884, but has always been lacking in rigidity and is not satis-
factory for heavy loads.
336. Many of the largest cantilever bridges such as those
at Louisville, Poughkeepsie, Cernavoda, Memphis, Forsmo,
Fig. 145.
and Thebes have a series of alternate anchor and cantilever
spans. The Louisville bridge (Fig. 145) carries both rail-
road and highway travel and was completed in 1886. The
central 360-foot span, 65 feet deep, serves as anchor for the
cantilever arms, and the two adjoining spans which are 480
feet between piers, each contain a suspended span 160 feet
long and 28 feet deep. The cantilever portion is symmetrical
about the center, but the bridge contains also a 370-foot
draw and a 240-foot fixed span. The width is 24^4 feet be-
tween trusses and 49 feet extreme. It was rebuilt for double
track in 1910, to sustain live loads equal to Cooper's E 65
specification, the work being under the direction of W. M.
Mitchel. The Poughkeepsie bridge over the Hudson (Fig.
146) was completed in 1889 and is owned by the Central New
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BRIDGE ENGINEERING.
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CANTILEVER BRIDGES. 269
England Railroad Company, but leased to the New York, New
Haven and Hartford Railroad Company. It has two anchor
spans of 525 feet and three alternate cantilever spans of 548
feet, with a 200-foot shore span at each end. The total length
is 6,747 feet, including approaches of 2,640 feet at the east and
1,033 feet at the west end, with the deck 212 feet above water.
There were two tracks and originally only two lines of trusses
30 feet apart, but in 1906 it was strengthened by inserting
another line of trusses midway between the original ones and
adding new columns in the towers. The longer approach
spans were also reinforced and the shorter ones replaced with
new plate girders. The towers are 100 feet in height, standing
on stone piers, supporting trusses 37 to 57 feet in depth. Water
Flff. 149.
under the long spans is 60 feet deep, making the cost of false-
work excessive, and the reinforcing required 15,000 tons of
steel, and cost $1,300,000, the work being done under Mr.
Mace Moulton.
337. Many of the most interesting cantilever bridge de-
signs are the result of competitions. Among these are the
bridges over the Harlem river and at Blackwell's Island, New
York, at Mannheim and Budapest in Europe, and at Detroit,
Montreal and Sydney, Australia. The Harlem river (Wash-
ington) bridge competition in 1886 brought forth four canti-
lever designs deserving of special mention, made by Messrs.
A. P. Boiler (Fig. 147), W. J. McAlpine (Fig. 148), Edward
Shaw (Fig. 149), and Wilson Brothers, with estimated costs
of about one million dollars. These designs, while unsym-
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270
BRIDGE ENGINEERING.
metrical as a whole, owing to the contour of the ground, con-
tained symmetrical cantilevers. A design made by Mr. Schnei-
der in 1887 for the proposed Blackwell's Island bridge (Fig.
150), between 64th and 65th Streets, had two channel spans
Fig. 160.
of 810 feet on metal towers 110 feet high, with a clearance
beneath the spans of 135 feet for ships. The promoter of
the enterprise was Dr. Rainey of Ravenswood, who had it
proportioned for two lines of railway only. The cantilever
Fig. 151.
proper was 2,760 feet long and the whole bridge including
approaches contained 26,000 tons of steel, 25,000 cubic yards of
masonry and 3,000,000 feet of lumber. A very different de-
sign to the rest was submitted by George E. Harding, with a
Fig. 152.
parabolic center span somewhat similar to the Hassfurt bridge.
(Fig. 151).
338. Two notable cantilever bridges were built in British
India 1886-1890, one over the Hoogly river and the other over
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CANTILEVER BRIDGES. 271
the Indus. The Hoogly or JubUec Bridge (Fig. 16!^), by Sir
Bradford Leslie, carries two tracks of the East India Rail-
way at a height of 63 feet above the water. The central con-
tinuous trusses are 360 feet long and 50 feet deep, on cylinder
piers 11^0 feet apart on centers, the cost complete being
$1,305,000. The ancient and barbarous custom of offering
sacrifices to rivers when bridging them continued in many
countries and until the nineteenth century. When building
the Hoogly bridge over the Ganges, the natives believed that
mother Ganges had consented to be bridged only on condition
that each pier be founded on a layer of infants' skulls. But
when a new bridge was placed over the Arcen, twelve sheep
were slain and their heads placed under the foundations. The
Sukkur bridge (Fig. 163), over a branch of the Indus river, was
designed by Sir. A. M. Rendel, engineer for the Indian Govern-
FlfiT. 153.
ment, with single 81^0-foot cantilever and a suspended span of
200 feet between 310-foot arms. It carries a 6j4-foot gage
track from Kurrachee to Attock, and cost $926,000, the high
cost being partly due to the supposed necessity of erecting
it at the shops in England before shipping to its destination.
339. The Stephanie bridge over the Danube Canal at
Vienna is a cantilever with flat arched center span of 197 feet,
and side anchor arms of 49 feet concealed in the abutments.
The Warnow bridge near Rostock (1886) has a parallel truss
over center piers with a single hinged panel at each end.
340. A bridge of unusual interest on account of its historic
site is the cantilever (1886) carrying Market Street over the
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272
BRIDGE ENGINEERING.
Schuylkill river at Philadelphia. It replaced an old wooden
truss of 1876, which succeeded Timothy Palmer's three span
"Permanent Bridge." For this location, Thomas Paine, the
noted writer, designed a 400-foot cast iron arch, the model of
which he submitted (1787) to the Academy of Science in
Paris. The cantilever bridge has a length of 538 feet, and
extreme width of 77 feet and a buckle plate and asphalt floor.
The river piers are 214 feet apart on centers and stand on
the old "Permanent Bridge" foundations.
341. Cantilever highway bridges over the Mississippi river
were built at Muscatine, Iowa (Fig. 154) (1889), with a span
of 442 feet ; Wabasha Street, St. Paul, the same year, with a
Tig. 164.
span of 280 feet,. and one three years later at Clinton, Iowa
(Fig. 156), with curved top chords over the piers. The Broad-
way bridge at St. Paul has a three span cantilever with two
simple spans at one end, and one at the other, in addition to
Fig. 166.
some approach viaduct. The deck has a central roadway 31
feet wide with 11-foot walks on each side. The center trusses
which are 55 feet deep are continuous over the middle pier,
with extension arms supporting simple spans at the sides.
342. Several notable railroad cantilevers appearing be-
tween 1888 and 1892 are those at Point Pleasant, Tyrone,
Red Rock, and two over the Verrugas and Pecos rivers. The
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CANTILEVER BRIDGES.
273
Point Pleasant bridge (Fig. 156), over the Kenawha river at
Parkersburg, West Virginia (1888), is a through railroad
Fiir. 156.
cantilever with a center span of 485 feet. It has 240-foot
anchor arms, 200-foot suspended span and a total length of
960 feet, the whole containing 1,000 tons of steel. The bridge
at Tyrone, Ky. (Fig. 157), over the Kentucky river (1889),
conveys a single line of the Louisville and Southern Railway
FUr. 167.
on a deck structure similar to that at Niagara, with a span
between towers of 561 feet. Up to the date of its construction
it was the largest and highest cantilever in America. The
trusses are 24 feet on centers, the cantilever portion 998 feet
long, with 210 feet of trestle approach at one end, and 390
feet at the other end, making the total length with approaches
KKS
Fig. 158.
1,598 feet. J. W. MacLeod was engineer. The Red Rock
cantilever (Fig. 158) carries a single line of railway over the
Colorado river and connects Arizona and California. The
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BRIDGE EXGINEERIXG.
shore and river arms of the cantilever are each 165 feet in
length and the center suspended span 330 feet, making the
total length of bridge 990 feet. The clear underneath head-
room is 41 feet above high water and the trusses are 25 feet
apart on centers. It contains 750 tons of steel and was erected
in eighty days, the design and construction being under the
direction of J. A. L. Waddell. At the time it was the largest
cantilever in the United States. It has recently been strength-
ened for increased loads by placing under it some additional
river piers.
343. The new Verrugas viaduct (1890) replaced an old
iron trestle of 1872, which had Fink trusses on three double
towers, over which the Lima and Oroya Railway crosses the
Verrugas valley and river, 52 miles from Callao, Peru. The
length is 575 feet, and the deck is 250 feet above water. In
the renewal (Fig. 159) the center and highest tower was
omitted, and the distance between the side towers spanned
^^iSK^|2PK|3^2S^
Flgr. 159.
with a cantilever. The new bridge has two lines of trusses
17 feet apart, supported on towers 146 and 179 feet high, 265
feet between centers. L. L. Buck, engineer. The Pecos via-
duct (1891), with forty-eight spans and a length of 2,180
feet, contains a central cantilever (Fig. 160), with 185 feet
clear opening, on towers of regular design founded on separate
stone piers, with the longest diameter of the pier parallel with
the river. The bridge carries a sinj^le track on trusses 10 feet
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CANTILEVER BRIDGES.
275
apart, at a height of 320 feet above the water, and was de-
signed by Adolphus Bonzano for a branch of the Southern
Pacific, the average cost of the viaduct being $119 per lineal
foot. It was strengthened (1910) by adding a center line of
trusses and girders supported on new cross girders between
the columns. The regular columns were reinforced by the
addition of angles and flats to the old zee bar sections, and
in the cantilever bents were placed new central uprights. At
the West end nineteen spans were removed and the bank sup-
ported temporarily on timber, while an embankment was made
The reconstruction required 1,100 tons of metal, 80,000 drilled
holes and 135.000 field rivets.
Fig. 160.
344. Three special achievements in cantilever bridge de-
sign were completed in Europe in the years 1890-91. The
bridge over the Firth of Forth in Scotland, the Neckar at
Mannheim, and the Danube at Cernavoda.
As early as 1818, James Anderson of Edinburgh, made
plans for a suspension bridge (Fig. 103) to cross the Firth of
Forth with three spans of 1,600 to 2,000 feet and an estimated
cost of $1,000,000, but active work was not begun until 1880,
when new designs were made by Sir Thomas Bouch for a
stiffened suspension with two spans of 1,600 feet each and an
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BRIDGE ENGINEERING.
estimated cost of $10,000,000. On these plans* (Fig. 117), a
contract for construction was awarded, but the failure of the
Tay bridge, designed by him, caused the plans to be aban-
doned and new ones begun in 1881 by Sir John Fowler and
Sir Benjamin Baker, on the cantilever principle. The bridge
has three cantilevers, the center one founded on an island,
with two spans of 171 feet and a clearance of 152 feet beneath
it. The trusses are not parallel, but lie in warped planes ,120
Fig. 161.
feet apart at the piers and 31^ feet at the ends. The arms
were at first 615 feet, with suspended spans of 500 feet (Fig.
161), but weie changed to 680 and 350 feet, respectively
(Fig. 162). The two end cantilevers stand on piers 155 feet
apart logitudinally and the center one on similar piers 270 feet
apart. The center tower is 343 feet high, tapering out to 41
feet at the end of arms. The whole bridge, including twenty
approach spans, is 8,300 feet long and cost $16,000,000, equal
Fig. 162.
to six and one-half cents per pound, or $2,400 per lineal foot.
The cantilever part, 5,360 feet long, weighs two tons per foot
at the center and thirteen and one-half tons per foot at the
piers, or an average of about ten tons per lineal foot of bridge,
containing 51,000 tons of steel costing $13,000,000. Most of
the compression members are hollow tubes, the largest being
12 feet in diameter and in the light of more recent experience
are not the most economical and will probably not be re-
peated. The bridge carries two lines of rail track over which
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CANTILEVER BRIDGES. 277
trains pass at maximum speed, and the two channels have a
maximum water depth of 218 feet. Seven years were oc-
cupied in building it and the services of 4,000 to 5,000 work-
men were employed at different times. It is said that a
bridge across the Forth was proposed in 1740, but no authen-
tic accounts are obtainable of its exact position or the type
of bridge considered.
345. Competition for the Frederick bridge over the Neckar
at Mannheim was invited in 1887, and it evolved four inter-
esting designs, one of which, 620 feet in length, was accepted,
and construction completed in 1890. The upper chord fol-
lows the line of a suspension, with false members joining the
cantilever and suspended spans to complete the continuity.
Fig. 163.
It replaced an old suspension bridge of 1845 and is one of the
most interesting and artistic cantilevers in Europe. The
bridge over the Danube at Cernavoda, Roumania, is divided
into two parts by an island, the smaller of the two channels
being known as the Borcea river. The bridge over the main
channel (the Cernavoda bridge) is 2,460 feet long in five
spans (Fig. 163), while the Borcea in three spans is 1,380
feet long. The total metal work including both approaches
and 4,770 feet of island viaduct is 13,450 feet long, or about
two and one-half miles. The floor is 121 feet above high
water on the larger bridge and 62 feet on the Borcea. A
single line of railway lies between the trusses, which have a
batter of 1 in 10. The Cernavoda bridge contains two anchor
spans of 467 feet between tower centers with overhanging
arms 164 feet long and suspended span of 295 feet, making
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BRIDGE ENGINEERING.
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CANTILEVER BRIDGES. 279
the distance between middle piers 623 feet. The length is
2,460 feet, the cost $1,570,000 (or $135 per lineal foot), while
the total cost of both bridges and approaches (13,450 feet)
is $6,000,000. The larger is quite similar in outline to the
Poughkeepsie, Memphis and Thebes bridges in America.
346. Two cantilever highway bridges in the western
states, which are worthy of special notice, are at Spokane,
Wash., and Roseburgh, Ore. The one at Spokane carries
Monroe Street at a height of 140 feet above the Spokane
river. It is 1,300 feet in length and was completed in 1892,
but is now being replaced by an arch of solid concrete. The
Roseburgh bridge over the North Umpqua river is a com-
bination bridge with metal tension bars and timber com-
pression members. The two anchor arms of 147 feet, and
105-foot projecting cantilevers, support an 80-foot suspended
span, making a distance of 290 feet between towers and a total
length of 584 feet. The trusses are 19J4 feet apart on centers
with 20-foot panels, and are 40 feet deep over the piers. At
the time of its completion this was the only combination canti-
lever of large proportions.
347. The Central bridge (1891) over the Ohio river be-
tween Cincinnati and Newport (Fig. 164) accommodates a
highway, two sidewalks, and two lines of trolley track on a
deck 100 feet above low water at the center. The anchor
and cantilever arms are 250 feet and 156 feet long, with 208-
foot suspended span, making a clear distance of 520 feet be-
tween towers. The two 7-foot walks- are outside the trusses,
the road 24 feet wide (total width 42 feet), and the length,
including fixed spans and viaduct, is 2,966 feet. One of the
largest bridges of this type in America was completed in
1892 over the Mississippi river at Memphis, Tcnn. (Fig. 165),
from designs by George S. Morrison. He states in his report
that his preference was for a symmetrical arrangement, with
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BRIDGE ENGINEERING.
three equal spans of 675 feet or, if one span must be longer
than the rest, to place the longest one in the center, but the
War Department required the longest span at one side. The
bridge has a highway and single line of railroad, with clear-
ance beneath it of 110 feet above low water. The approach
viaduct is 2,600 feet long, and the central portion is 2,258
feet, with two lines of trusses 30 feet apart and 78 feet deep.
This depth of truss is not economical, but was made small to
Fig. 166.
facilitate erection. The continuous span has cantilever arms
of 170 feet at each end with suspended spans 450 feet long
in the adjoining panels. The weight of steel is 8,160 tons,
averaging three and one-half tons per lineal foot, and costing
5.9 cents per pound in place.
348. Cantilever bridges are not ordinarily used in parks,
but one of this type in the fornj of an arch-cantilever was
built for a foot bridge in 1894 over the lagoon in Lincoln
Park, Chicago (Fig. 166), with a central span of 180 feet
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and 99-foot anchor arms. The panels are 18 feet and the
floor 20 feet wide, of reinforced concrete, with 3J/^-inch slabs
on 23^x8-inch joist, 1 foot apart on centers. The deck is
high enough to leave clearance under it for small sail boats
with masts which enter the lagoon from the lake, and the
elevated floor with a steep grade is reached at each end by
stairs. The bridge was designed by W. L. Stebbings of
Chicago, and is ornamental to suit its location.
349. Two highway bridges with outlines which cannot be
commended are the ones over the Mississippi river at Winona,
Minn. (Fig. 167), and at Davis Ave., Allegheny City, Pa. The
Winona bridge (1894) is not on the direct line of the highways
which it connects, but is several hundred feet west of them
near the railroad bridge, and is approached at either end by
Fig. 167.
viaducts parallel with the river, one of which passes over a very
attractive little park on the levee. The width of the river at
low water is crossed by a three-span cantilever, and at the
north end is a 250-foot fixed span over the high water channel.
A center clearance of 75 feet above low water was demanded
for navigation, and the floor, which is 23 feet wide, was
sloped up to the center on a 4 per cent grade. The top of the
stone piers are at high water level, and the two center ones
are surmounted with iron towers. At the sides, where under-
neath clearance is not required, the bridge changes from
through to deck construction, and the anchor arms curve
downward to the piers, making a more stable connection to
them and avoiding the use of extra towers. The suspended
span over the channel is connected to the cantilever arms by
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BRIDGE ENGINEERING.
false members with sliding joints which completes the con-
tinuity of the upper chord. The cantilever portion is 810
feet long, but the whole, including the approach viaduct, has
a length of 2,700 feet, and, contains 500 tons of metal. It
was designed by George T. Baker of Davenport, and built
in 1894 by Horace E. Horton at a cost of $100,000. The
Davis Ave. cantilever (Fig. 168), referred to above, has two
lines of trusses 22 feet apart, with 20-foot panels and a road
Fig. 168.
36 feet wide, paved with asphalt on buckle plates.
It is
about 400 feet long with 156-foot center span and cost $26,700.
350. In Paris (1895-96) were built two interesting street
bridges, the first, known as the "'Mirabeau Cantilever" over
the Seine, connecting the industrial district of Grenelle-
Laval with the residential quarter of Auteuil. The bridge
is a very artistic design and is remarkable for the shallow
Fig. 169.
depth of the metal ribs, which are 17^^ feet over the piers,
decreasing to about 3 feet at the center, seven of which are
placed about 10 feet apart beneath the roadway. The design
was by M. Resal, the center span having provision for arch
action and the structure cost $413,000. Tolbiac street bridge
(1896) over the station yards of the Orleans Railway, in
Paris, has three spans (Fig. 169), the center trusses projecting
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CANTILEVER BRIDGES. 283
39 feet over the piers and supporting the end of the shore
spans. Instead of making the chords continuous, the con-
struction is emphasized by omitting chords in. the junction
panels, showing clearly the cantilever feature. The end and
center spans are 167 feet and 197 feet long respectively, with
trusses 52 feet apart containing between them a 32-foot road
and two sidewalks.
351. Two bridges in South America of unusual interest
are those at Cachoeira in Brazil and Honda in Colombia. The
former is a heavy street bridge with solid paving on metal
trough floors, and was designed by Max Ende of Paris and
opened in Sept., 1895. An unusual feature is the two equal
anchor and cantilever arms balanced over the piers, with con-
Fig. 170.
tinuous top chords but without a suspended span, and an ap-
proach span at each end. The road is 34 feet wide with a
5-foot projecting walk outside of each truss. Piers consist
of double cylinders 10 feet in diameter, framed together and
filled with concrete, and the whole bridge, which is 524 feet
long, contains 722 tons of metal which was exported from
England to Brazil and all excepting the center span erected
on falsework. The Magdalena river bridge at Honda, Co-
lombia, has a center span of 366 feet with through trusses 17
feet apart, and is proportioned to carry a live load of only
500 pounds per lineal foot.
352. One of the best and most artistic bridges in Europe
is the Franz- Joseph cantilever (Fig. 170) over the Danube
at Budapest. Several very interesting designs were submitted
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284 BRIDGE ENGINEERING.
in 1894, in the competition for this bridge. They provided a
clear waterway of 1,000 feet and a deck 52 feet wide, at esti-
mated costs of one to two million dollars. One design has a
single cantilever span of 1,000 feet without piers and shore
towers 130 feet high, the upper chord following the catenary
curve of suspension cables. The design of Aurel Czekelius,
which was accepted, has two river piers 175 meters apart
supporting cantilevers which project 64 meters over the piers,
from the ends of which a center span 46 meters long is sus-
pended. The anchor arms are counterweighted with 600
tons of cast iron at each end. The road is llj/^ meters wide
with wood block paving, and outside the trusses are foot walks
3 meters wide paved with asphalt. The bridge contains 6,000
tons of iron, including the 1,200 tons of counterweight, and
was completed in 1896 at a cost of $950,000. Another, in
Hungary, over the Theiss river at Tokaj, contains several
new and interesting features. The framing has riveted con-
nections, and the upper suspension members bearing on rocker
towers are separate from the stiffening trusses, emphasizing
their purpose and making all stresses determinate. The anchor
arms are loaded with 81 tons of masonry counterweight below
the floor, similar to the bridge at Budapest, except that mason-
ry is used for counterweight instead of iron. The clear width
between trusses is 40 feet, the distance between piers, 351
feet, and total length 690 feet, the whole containing 770 tons
of iron. The Forsmo bridge is a railroad cantilever with five
spans crossing the Angerman river in Sweden, north of the
G7th parallel of latitude, within the Arctic Circle. The deck,
133 feet above high water, is supported by trusses on steel
towers and granite piers. Two anchor spans at the right
and left of the center have projecting arms supporting the
ends of the center and shore spans. The center span is 251
feet between pier centers, and the total length of bridge with
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CANTILEVER BRIDGES.
285
approaches is 964 feet. It contains 688 tons of iron, 208 tons
of which is in the towers, and the whole bridge including
foundations cost $133,000. A bridge somewhat similar to
the one at Budapest was completed in 1895 from designs by
J. Madison Porter, crossing the Delaware river at Easton, Pa.,
to replace Timothy Palmer's old covered wooden bridge of
1805. It has equal anchor and cantilever arms of 125 feet
with a 50-foot suspended span, making the total length 550
feet. The bridge has no upper lateral system excepting at
the towers, and the eyebar upper chords are in tension under
all conditions. A long bridge at Point Pleasant, N. J., with
Fig. 171.
thirty-three spans, has the truss frame of alternate spans pro-
jecting one panel length over the piers, supporting short sus-
pended spans. The bridge has thirty-two fixed spans 44 to
56 feet long, and 137 feet draw (total length, 1,910 feet).
The road is 20 feet wide, with a 5-foot walk on one side, with
lattice trusses 7 feet deep supporting floor beams on the
bottom chord gusset plates. Each pier is composed of two
steel cylinders 3 feet in diameter with three piles in each, the
space around the piles being filled with concrete. It was com-
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286 BRIDGE ENGINEERING.
pleted in 1897 from designs by D. E. Bradley and the writer.
353. In the years 1892 to 1897 designs appeared for several
proposed cantilever bridges, the largest being one over the
English Channel (1892), between France and England (Fig.
171), with a length of 21 miles. The plan showed alternate
spans 400 and 500 meters long at a height of 60 meters above
the surface, supported on double cylinder piers in water 50 to
60 meters deep, the suspended spans being 125 meters long.
The two lines of trusses would be 25 meters apart at the
piers tapering to 10 meters at the cantilever ends next to the
suspended spans, with provision for two tracks, and the design
had an estimated weight of 760,000 tons of steel and an esti-
mated cost of $170,000,000. Other interesting designs were
those for the proposed bridge over the St. Lawrence at
Montreal, the Ohio at Bellaire and the Canadian channel at
Detroit. In January, 1895, Walter Shanley of Montreal and
Ottawa, consulting engineer for the bridge company, offered
prizes and called for competitive designs for a bridge to
cross the St. Lawrence, with one cantilever span of 1,250
feet and two side spans of 500 feet, with provision for two
steam railroad tracks, two electric railroad tracks, a highway
and two foot walks. In response eight cantilever designs were
submitted by Messrs. A. L. Bowman, H. E. Mertens, J.
Ritchie, Edward S. Shaw, Henry Szlapka, T. K. Thomson,
J. Welsh and C. H. Wright, with estimated costs of one and a
half to six million dollars. The first and second prizes were
awarded to Edward S. Shaw and A. L. Bowman respectively.
Mr. Bowman's design had double towers with legs battered
1 in 10 and bottom chords in center and end spans curved
for better appearance. The designs of Messrs. Ritchie, Welsh
and Wright also had double towers, but the truss depth used
by Mr. Welsh was too small for economy or appearance. Mr.
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CANTILEVER BRIDGES. 287
Shaw's design had four lines of trusses in vertical planes with
25-foot panels, a deck 80 feet wide, and outer trusses 70 feet
apart, with curved bottom chords and steel towers 230 feet
high on granite piers. Grades of two and four per cent re-
spectively were used for the steam and electric railways, and
the upper chords on the cantilever arms were approximately
catenary curves. Mr. Szlapka's design was shorter than the
length specified, with width of only 44 feet between trusses,
equal to 1/27 of the span, and had, therefore, a lower cost.
The estimated costs for the several designs are as follows :
A. L. Bowman $3,436,000 Henry Szlapka $1,500,000
H. E. Mertens. . . . 3,200,000 T. K. Thomson. . .. 3,140,000
J. Ritchie 6,250,000 J. Welsh 5,632,000
Edward S. Shaw. . 3,514,000 C H. Wright 1,900,000
354. In the early part of 1897 several designs appeared
for a proposed cantilever bridge over the Canadian channel
of the Detroit river with a central span of 1,100 to 1,300 feet,
and a clear height of 120 to 140 feet above the water. In the
same year a design appeared for a highway bridge over the
Ohio river at Bellaire, with provision for electric car tracks,
central span of 825 feet, and two lines of trusses 40 feet apart.
Three years later Mr. Boiler prepared plans for the proposed
Hell Gate cantilever carrying two tracks of the New York
Connecting Railway over the East River, with a central span
of 800 feet on steel towers. In addition to the cantilever, his
design shows about three miles of approach viaduct.
355. Two highway bridges over the Connecticut river
at Northfield, Mass., were completed 1899 and 1904 from de-
signs by Edward S. Shaw of Boston. The first (Fig. 172)
has center and side spans of 360 and 108 feet respectively, with
trusses in the center span continuous over the piers, and slip
joints in the shore spans at the fourth panel point from the
abutments. The shore spans were erected on false work and
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BRIDGE ENGINEERING.
loaded down with sand, forming anchor arms for the center
span which was built out without centering over 30 feet of
water. To assist in the erection, temporary timber towers
were placed over the piers with guy ropes on either side.
The trusses are 22 feet apart and 45 feet deep at the middle,
with 18-foot panels and curved top chords, and the whole
Fig, 172.
bridge contains 280 tons of steel. The other bridge at North-
field is a memorial erected by Francis Robert Schell in memory
of his father and mother, bearing bronze tablets on the piers
with inscriptions (Fig. 173). As water under the bridge was 25
to 30 feet deep, a form was selected that would act as canti-
lever during erection. The length of the shore span at the East
end was fixed by natural conditions at 80 feet, and for sym-
S^S^Sfe&3--— • -^5^-?^^ 4.2-
^Bofj^rCay
Hzii^s:::±j^::::::zzi^^
Fiff. 173.
metry the West span was made the same, leaving a remain-
ing distance of 352 feet between piers. The trusses are con-
tinuous and dead load is at all times transferred to the central
piers, with reactions on the abutments from moving loads
only. A rope tramway between temporary towers was used
for handling and placing the parts in position. Another
bridge for which Mr. Shaw prepared an alternate plan crosses
the Snake river between Lewiston, Idaho, and Concord, Wash-
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CANTILEVER BRIDGES. 289
ington. The method of securing the required clearance of
70 feet above low water is similar to that used on the Winona
bridge (1894) by changing from deck to through construction
over the channel, and sloping the anchor arms down to the
side piers. The cantilevers stand on rocker bents with anchor
arms 238 feet long, which have sufficient dead load in them-
selves to balance the 119 feet cantilever arm and the 136-
foot suspended span, without depending on pier anchorage.
The channel span is 374 feet between towers with trusses 22
feet apart on centers. Mr. Shaw's plan had curved bottom
chords on the approach spans, giving a better appearance.
The bridge is for highway travel only and has a total length
of 1,485 feet.
>^a^^^P^y^
Fig. 174.
356. In the years J899 and 1900 two notable bridges were
erected in Canada at Cornwall and Ottawa. The South
channel of the St. Lawrence river at Cornwall Island is
crossed by a series of simple fixed spans, but the North
channel has a cantilever bridge 843 feet long with main piers
420 feet apart on centers, and a draw span over the canal. It
has "provision for one railroad track with trusses- 20 feet
apart, and is proportioned for a train load of 3,500 pounds per
lineal foot. While being erected by the Phoenix Bridge Co.,
two of the fixed spans over the South channel fell (Sept.
1898), killing thirty people, but the spans were rebuilt and
the bridge opened in 1899. The bridge over the Ottawa river
at Ottawa (Fig. 174) has a cantilever span due to a collection
of logs and sawdust from neighboring saw mills which is 50
to 60 feet deep on the river bottom. It was found impractica-
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290 BRIDGE ENGINEERING.
ble to sink piers through this bed of timber and sawdust, and
the channel was therefore spanned with a cantilever on piers
555. feet apart, with an under clearance of 45 feet. The
trusses are vertical and 24 feet apart, with a single steam
railroad track and two walks between them, and highways
21 feet wide with electric railway tracks on outside canti-
lever brackets, making the deck 66 feet wide. The central
bridge is 1,053 feet long, but the whole including two fixed
spans and viaduct has a length of 2,286 feet between abut-
ments. The cantilevers are 90 feet deep above the piers, with
247-foot anchor arms, and suspended span is 308 feet long,
between the 123j4-foot projecting arms. It crosses the river
at Nepean Point near the parliament buildings, and was
named the Royal Alexandria r>ridge in honor of the English
queen. It was designed by G. H. Duggan, chief engineer of
the Dominion Bridge Co., of Montreal.
357. The Kaisersteg foot bridge over the river Spree, near
Berlin, is a three span cantilever 282 feet long between center
towers, with four equal arms of 141 feet and center hinge, but
without a suspended span. It has a clear height above water
of 32 feet and a floor rise of 5 feet between the piers. The
center span is stiflFened with arch ribs overhead, connected
with lateral bracing, thus avoiding the use of long diagonal
members in the trusses near the towers. The four cantilever
arms were floated into position and connected, and the arches
placed afterwards. The towers and portals are ornamented
and the complete bridge cost $27,600.
358. The Highland Park bridge (Fig. 175), crossing the
Allegheny river from Pittsburg to Sharpsburg, resembles
somewhat the Francis Joseph bridge at Budapest. The dis-
tance between towers is 450 feet, divided into three equal parts
of 150 feet, while the shore or anchor arms are each 200 feet.
The two trusses are 24 feet apart with space for a highway,
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CANTILEVER BRIDGES.
291
two car tracks, and two foot walks with an outside width of 36
feet and a total length of 1,850 feet. The 850-foot cantilever
has 700 tons of steel, while the whole bridge contains 1,250
tons, costing with substructure $175,000. Herman Laub was
engineer. Another over the Allegheny between Reno and Oil
City, finished 1903, has a central span of 413 feet. The Boston
Figr; 175.
highway bridge over the Youghiogheny river near McKees-
port for the Versailles Traction Co was raised 24 feet at one
end, under the direction of Herman Laub, at a cost of $20,000,
to provide under clearance for another road.
359. A three span bridge (Fig. 176) of unusual form
was placed across Tygart's river near Fairmount, West Vir-
^ - -m'jjt >k-— ^ a'4r H *
^jk I jrfl!¥J!lL.*?'fi?«*i???* ^^^i.
y!Epi fM
ginia, with a center span of 260 feet, between piers one-half
of which with eight panels, is suspended. The two lines of
trusses are 18 feet apart with riveted joints, and the steel
towers stand on masonry piers with their tops at high water
level. The bridge has an under clearance of 50 feet and waa
designed by Charles Worthington, engineer.
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BRIDGE ENGINEERING.
360. A suspension cantilever (Fig. 177), which is similar
to a form proposed in America in 1869 and to a design sub-
mitted in 1895 for the Danube river bridge at Budapest, was
erected in 1901 at Long Lake, Hamilton County, N. Y., with
a single span of 525 feet. The central portion of 175 feet is
suspended between cantilever arms of the same length, and
two lines of trusses standing in vertical planes are 24 feet
r-kis^i^i-^'i^^T^i^
a^X
¥ ■»■■■ ^.S g JJ * --'JL1=
Fig. 177.
apart at the ends, tapering to 16 feet at the center span, an
arrangement which adds greatly to the lateral stiffness. It
contained 220 tons of steel, the erection of which cost $15 per
ton and was designed by C. S. Mallory, engineer.
361. The second largest cantilever bridge in Great Britain
is at Connel Ferry, Scotland, over Loch Etive (Fig 178).
The design was made by Sir John Wolfe Barry, and the bridge
Fig. 178.
manufactured and erected in 1903 by William Arrol and Co.
The channel is 690 feet wide and very deep at the center with
a current of twelve miles per hour,* making it impracticable
to use a center pier, but two were placed in shallow water at
the sides, 524 feet apart. The approach at each end contains
three masonry arches with spans of 38J4 feet ending with
curved wing walls. The bridge has a single line of rail track
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. CANTILEVER BRIDGES. 293
and contains 2,600 tons of steel. A notable feature of the
design is the triangular anchor arms with sloping and bat-
tered towers.
362. Four of the largest and heaviest cantilever bridges
in America were built in the years 1903 to 1905, at Marietta,
Pittsburg, Mingo Junction and Thebes. The .Marietta high-
way cantilever (Fig. 179), over the Ohio river, with a 650-foot
opening, was finished in 1903 from designs by C. L. Strobel.
The lack of symmetry is said to be due to the necessity for
two channel spans and a pier in the shallow part of the river.
The north and south anchor arms are 130 feet and 600 feet,
with two lines of pin connected trusses 28 feet apart, the whole
length including two simple spans and 640 feet of viaduct, be-
ing 2,460 feet. It is proportioned for 30-ton electric cars and
a steam roller. The 650-foot portion contains 755 tons of
steel, of which 220 tons is in the suspended span, and the
600-foot anchor span has 1,000 tons of steel, the whole with
viaduct approach containing 2,400 tons, and costing $800,000.
The Wabash Railroad Company in 1904 built two very sim-
ilar double track bridges over the Ohio river, from designs by
Boiler and Hodge. The one at Pittsburg (Fig. 180) has a
center span of 812 feet, and a length, with approaches, of 1,404
feet, with shore arms 346 feet and towers 126 feet high. The
suspended span is 360 feet between cantilevers and 60 feet
deep, with trusses 32 feet apart and 30 and 40-foot panels.
The bridge contains about 7,000 tons of steel, which is equal
to 9,300 pounds per lineal foot. It has a clear height of 70
feet above the river, and was completed at a cost of $800,000,
equal to $533 per foot of bridge. The bridge at Mingo Junc-
tion, Ohio, like the one previously described, has a 700-
foot center span and 298-foot anchor arms, and a total length
with approaches of 1,296 feet. The towers are 109 feet high,
and the suspended span 51 feet deep. It contains 6,000 tons of
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BRIDGE ENGINEERING.
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CANTILEVER BRIDGES. 295
steel and cost, with the substructure, $750,000, equal to $677
per lineal foot, of which $200,000 was the cost of four main
piers. The bridge over the Mississippi river between Thebes,
111., and Grey's Point, Mo. (Fig. 182), has five spans arranged
symmetrically about the center, and a total length of 2,750
feet without the approaches. The distance between center
piers is 671 feet and the two adjacent anchor spans are each
521 feet, with cantilevers overhanging the piers 152^ feet,
supporting three suspended spans of 366 feet. The two lines
of trusses are 32 feet apart on centers, for double track. The
superstructure contains 12,000 tons of steel, or about five tons
per lineal foot, and cost $1,400,000, which is equal to 5^ cents
per pound. The substructure cost •$600,000, the total cost
being equivalent to $800 per lineal foot. The water beneath
the bridge is 20 feet deep and the concrete piers, which are
faced with stone, have an average height of 115 feet. The
1,200 feet of concrete viaduct, 100 feet high, cost $300,000, or
$250 per lineal foot. The trusses are pin connected, with
panels 30J4 feet long. The free span and cantilever arms
weigh 11,600 pounds per lineal foot, and the suspended span
7,800 pounds per foot. The small truss depth above the piers
was selected to permit the use of overhead travelers and facil-
itate erection. The bridge was completed in 1905 from designs
by and under the direction of Messrs. Alfred Noble and Ralph
Modjeski, engineers. Other smaller bridges in America are at
Moline, 111., and Croton Lake, N. Y. The Moline highway
bridge (Fig. 183), over Rock river, is a three span cantilever
with a simple span at one end. The new bridge was placed on
the piers of an old combination wooden bridge and the river
interests required a clearance in the center of at least 35 feet.
These conditions, with the small appropriation of $25,000 for
construction, account for the design. The trusses are riveted
and 19J4 feet apart on centers, with anchor spans fastened
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BRIDGE ENGINEERING.
4^
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CANTILEVER BRIDGES. 297
at the shore end and standing on rocker bents over the river
piers. All spans excepting the center one were erected on
false work. The floor rises on a 6 per cent grade with truss
chords parallel to the floor, excepting the four lower panels of
each anchor span adjoining shore, which are raised nearer to
the horizontal to clear high water. It was designed by F. C.
Moore of Milwaukee, Wis. The Pines bridge, over a part of
Croton Lake, has center and side spans of 384 and 160 feet,
respectively, with two lines of trusses 22 feet apart and 51
feet deep at the center, and a plank floor on steel joist. The
suspended span is 160 feet long and 24 feet deep, and the
whole bridge, though a cantilever, was erected on false work.
The top chord is curved somewhat like that at Clinton, Iowa,
in the eflFort to give it a more pleasing appearance.
363. Two cantilevers in France of this decade are those
at Villefranche, over the Saone (1904), which replaced an old
suspension bridge with a single span of 528 feet, and the
Passy viaduct, over the Seine (1906). The Villefranche bridge
Figr. 181.
(Fig. 181) is unusual in having no suspended span, the canti-
lever arms meeting at the center with sliding joints. The end
and center spans are 150 and 220 feet, making the whole
bridge o20*feet in length. The bottom chord of the center span
is the segment of a circle with 5-foot rise, and the chords of side
spans are curved to correspond. The trusses have a depth of
32 feet over the piers and 9 feet at the center, with a 23-
foot road and 10-foot cantilever walks outside. It contains
740 tons of steel and was finished in 1904 at a cost of $110,-
500. The Passy viaduct crosses two arms of the Seine at an
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298 BRIDGE ENGINEERING.
island, and carries street travel on the main deck, and two
tracks of the Metropolitan Railway of Paris on a center ele-
vated viaduct. Each bridge is a three span cantilever, with
total lengths of 288 and 367 feet, respectively.
364. The new bridge between Homberg and Ruhrort (Fig.
184) is the largest of its kind in Germany, and crosses two
canals and a harbor basin in addition to the river Rhine. It
contains five spans with lengths of 296, 405, 678, 427 and 279
feet, with a total length of 2,085 feet, and is not symmetrical
with reference to span lengths. The road is nearly level, with
a 38-foot carriageway, two lines of electric car track, and two
8-foot walks, making an outside width of 54 feet. In the
center opening, 667 feet long, the suspended span of 450 feet
hangs freely between the 114-foot cantilever arms. The super-
Fig. 185.
structure cost $445,000 and the substructure $315,000, or a
total, with approaches, of $1,092,000. The central spans are
paved with wood, and the end ones with stone. Other inter-
esting bridges in Europe are those across the Mattig river,
Austria, the Weser in Hameln, the Wiedendammer bridge in
Berlin, Tunxdorf over the Ems (Fig. 186), a bridge over the
Tanaro, and one over the Main kt Frankfort. The Mattig
-■■i*3ggg^lX»XlXIXIXg?Ra!w
Fig. 186.
bridge is unusual in having short girder extension arms at
either end of the central 100-foot truss span. The Weser in
Hameln (Fig. 185) has a distance between piers of 150 feet
without suspended span, curved top chord similar to a sus-
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CANTILEVER BRIDGES.
299
pension, and anchor arms at either side 47J4 feet long, with
straight top chords. The stiffened suspension footbridge over
the Main at Frankfort, designed by Schnirch in 1869, has
anchor arms one-half the length of the center span, with
trusses standing vertical and 15 feet apart, and a total length
of 550 feet, and has part cantilever action. The deck is ap-
proached at either end by a series of steps.
365. A design was prepared for the proposed bridge
across the St. Lawrence river at Quebec, 1885, by T. Claxton
Fidler and Sir James Brunless, with a clear distance of 1,440
feet between towers and 1,550 feet on centers. The top chords
were curved, and the depth at towers was 258 feet (Fig. 187).
The design showed four lines of trusses in pairs, or two
separate bridges braced together, 90 feet apart on centers,
Fig. 188.
with extreme width of 108 feet. Each approach had six 40-
foot masonry arches with deck 150 feet above the river,
which is 180 feet deep in the middle. Twelve years later Ed-
ward S. Shaw of Boston prepared a design with towers 1,440
feet apart on centers and general features similar to his de-
sign for the proposed bridge at Montreal, submitted in the
same year (1897). The anchor spans on his design were 560
feet, with 2f20-foot simple spans at each end. The cantilevers
were 300 feet deep over the piers, and the outside width 90
feet, with an estimated cost of $3,000,000 to $4,000,000. Other
proposed designs are shown in the Figs. 1S8, 189 and 190. In
1900 a contract was awarded to the Phoenix Bridge Co., on
their own design (Fig. 189), for a bridge 67 feet wide, with
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300
BRIDGE ENGINEERING.
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CANTILEVER BRIDGES.
301
center piers 1,800 feet apart, a 675-foot suspended span 120
feet deep, and 500-foot anchor arms, and a total length of
3,300 feet, containing approximately 13 tons of steel per lineal
foot, at a proposed cost of 6.6 cents per pound. The trusses
were 315 feet deep above the towers, with 50 and 56-foot
panels in the anchor and cantilever spans, respectively. When
one cantilever was nearing completion, the bridge fell on the
Flff. 189.
29th of August, 1907, because of the crippling of bottom
chords near the piers, killing eighty workmen and causing a
loss of 20,000 tons of metal. Investigation of the cause of
its collapse was made by a commission appointed by the
Canadian Government, headed by Professor John Galbraith of
Toronto University, and in 1909 the project was taken over by
the Dominion Parliament and a board of engineers appointed
to prepare designs and superintend its construction. The de-
Fig. 190.
sign proposed by the board (Fig. 191) showed a central span
of 1,758 feet, necessitating moving one of the main piers about
50 feet out into the river. Trusses are 88 feet apart, and the
estimated weight of metal is 65,000 tons, as compared to
35,000 tons in the bridge that failed. Another proposed long
span cantilever bridge in America is that over the Mississippi
river at New Orleans, with a center span of 1,066 feet and
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302
BRIDGE ENGINEERING.
440-foot suspended span. The plans made in 1906 showed 606-
foot anchor arms with trusses 40 feet on centers and 72 to
160 feet deep, and floor 105 feet above low water, which has
a maximum rise of 20 feet. It was proposed to grade the ap-
proaches IJ^ in 100, using seventy-four alternate spans of 60
Ftff. 192.
and 120 feet, and a total length, including the cantilever, of
10,630 feet. The estimated weight of steel was 11,850 tons, and
cost $6,000,000. A design and tender was prepared and sub-
mitted by the writer in February, 1905, for a cantilever
bridge (Fig. 192) 500 feet long over the Elk river at Charles-
Fig. 193.
ton, West Virginia, with curved top chord, to replace the
old suspension, which collapsed a few months before. In
the following year several outline designs (Figs. 193, 194 and
11)5) were made by H. G. Tyrrell, for cantilever bridges to
cross mountain j^or^cs in western America, one of the gorges
having a depth of I'^O feet.
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Cantilever bridges.
303
366. The Blackweirs Island (Fig. 196) or Queensboro
bridge (1901-09) is a continuous cantilever with unequal chan-
nel spans of 1,182 and 984 feet at either side of the island
anchor span of 630 feet, and shore arms of 469 and 459 feet.
-^^f^^
Fig. 194.
The channel openings are connected at the center without
suspended span, thus making the stresses indeterminate. Two
lines of vertical and parallel trusses 60 feet apart on centers
support on the lower deck a center carriage way with two
Fig. 195.
car tracks on each side, the outer track being on a cantilever
extension of the floor beams outside the trusses, making the
deck 86 feet wide. The upper platform has provision for
four elevated railroad tracks between the trusses, with a canti-
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304
BRIDGE ENGINEERi:
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CANTILEVER BRIDGES.
305
lever prominade at each side. It is the first instance in which
nickel steel has been extensively used for tension members
and pins, and it contains approximately 13^ tons of steel
per lineal foot, costing 6.5 cents per pound in place. It was
designed by the bridge department of the city of New York,
contains the longest cantilever span in America, and is pro-
portioned for heavier loads than any other bridge.
367. Two cantilevers of original design by European
engineers appeared in '1908 over the Indus river at Khushal-
garh, India (Fig. 197), and at Westerburg over the Hoelzbach,
Prussia. The first was designed by Rendel and Robertson,
to cross the Indus where it is 175 feet deep. An approach span
Fl^. 197.
with projecting arm forms the cantilever at one end, while
at the other end a bracket is supported on the abutment and
anchored back into it. It replaced a pontoon bridge and has
a railroad track on the upper deck and a highway between
the trusses on solid trough floor. The Westerburg bridge
(Fig. 198), on the Prussian State Railway, is a five span canti-
lever viaduct on rocker bents, with 110-foot suspended spans
in the second and fourth openings.
868. The Daumer bridge (Fig. 199) on the Yunnan rail-
road system over the Red River in China, completed 1909,
has nineteen spans and a total length of 6,544 feet. Nine
anchor spans 246 feet between piers have overhanging 90-foot
arms supporting the eight intermediate and two end spans
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306
BRIDGE ENGINEERING.
of 168 feet. The anchor spans are 56 feet deep over the piers,
tapering to 20 feet deep at the cantilever ends. Trusses are
vertical and about 16 feet apart on centers for single track
railroad, with a 5-foot walk outside each truss, making a total
width of 26^ feet. The bridge contains 6,700 tons of steel
and 2,225,000 cubic feet of masonry. Another interesting one
was built during the last decade by Sir William Arrol and
Flgr. 198.
Company, crossing the river Nile in Egypt between Ghizeh
and Rodah Island, with a total length of 1,755 feet. It con-
tains ten spans of 140 feet, two of 70 feet, and a 220-foot
draw. The total width is 66 feet, with asphalt floor on con-
crete and buckle plates, and accommodation for two lines of
electric railway, the foot walks being on extension brackets.
For the sake of better appearance the bottom chords are
Fig. 200.
curved, and the trusses are continuous over the piers, being
cut at the points of contraflexure in alternate spans, the de-
sign being similar in this respect to the 1,500-foot viaduct in
Algoma designed by the writer in 1901.
369. The latest cantilever bridge in America is one for
the Pittsburg and Lake Erie Railroad over the Ohio river at
Beaver, Pa. (Fig. 200), with a length between center piers
of 769 feet, and 320-foot anchor arms, or 1,409 feet extreme,
not including the 370-foot fixed span at the Beaver end.
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CANTILEVER BRIDGES.
307
The clearance under is 90 feet and towers have a height of
145 or 235 feet above low water. Trusses are 34J/2 feet apart
for double track, and the bridge was designed by Mr. A. R.
Raymer, engineer for the railroad company. Another one is
proposed over the Straits of Canso, between Port Hastings
and Cape Porcupine, Nova Scotia, Canada, with a central span
— pfls^^^awj^
Fls. 201.
of 1,000 to 1,800 feet, while other large proposed ones of the
same type in Europe are at Kent, England, and Jutland, Den-
mark.
370. The bridging of the channel at Sydney, Australia,
has been seriously considered since 1880, a design prepared
by Pollitzer in one of the early competitions resembling the
Fig. 202.
Forth bridge. Competitive plans were again invited in 1904,
at which time twenty different designs were received, rang-
ing in price from eight to fifteen million dollars, one (Fig.
201) by A. Rieppel of Germany receiving the first prize. It
showed a center cantilever span 1,350 feet* between towers,
with anchor arms of 500 and 580 feet, and trusses battered 1
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308
BRIDGE ENGINEERING.
in 8, with two approach spans at each end. It had a clearance
of 180 feet below, with an estimated cost, including approaches,
of $10,000,000. The second prize design (Fig. 202) was sub-
mitted by Sir William Arrol and Company, and a third re-
ceived special mention. But the largest projected cantilever
bridge is that over the Hudson river at New York City. Com-
parative designs were made in 1894-98 for spans of 2,000 and
3,100 feet in length, showing the relative cost, including both
superstructure and foundations to be $27,000,000 and $51,-
000,000, the estimate for the 2,000-foot bridge containing 1,780
F!g. 20S.
feet of trestle approach to make its whole length the same as
the 3,100-foot span. The shorter design (Fig. 203) had a
distance of 2,300 feet between tower centers, which were 534
feet high, with truss web members arranged to transfer loads
in the shortest and most direct course to the points of support.
The conclusion from the comparisons was that cantilevers
are economical for highway bridges in spans up to 1,400 or
1,600 feet, and for railroad bridges up to 2,000 feet. Of the
seventy-seven bridges herewith described, seven were built
prior to 1880, eighteen between 1880 and 1890, twenty-nine
between 1890 and and 1900, and twenty-three since 1900, with
about equal numbers for railroad and highway use.
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WROUGHT IRON AND STEEL ARCHES. 309
CHAPTER XIV.
WROUGHT IRON AND STEEL ARCHES.
371. The first appearance of a wrought iron arch design
was in France in 1779, three years after the completion of the
first cast iron arch at Coalbrookdale, England (Fig. 74). It
was made by M. Califfe with the unprecedented span of 656
feet, and in 1782 another French engineer proposed a bridge
with two spans of 213J4 feet to cross the Seine. The next
record is in 1796, when James Jordan secured a patent for a
so-called suspension bridge which was really an arch with sus-
pended floor, the arch thrust being resisted by ties at the floor
level. But the first wrought iron arch actually built was a
foot bridge over the river Crou at St. Denis, in 1808, from a
design by the French engineer Bruyere. It was a braced arch
with straight upper chord and crossed diagonals, and had a
clear span of only 39 feet. The new material did not meet
with great favor, for cast iron continued in almost exclusive
use until the middle of the nineteenth century, and it was not
until 1853 that the next wrought iron arch was started, for
the Swiss Central Railroad, to cross the river Aare at Olten.
It wais designed by Etzel and Riggenbach with three plate
girder deck arches of 103 feet, and a roadway supported on
spandrel columns. In the same year appeared Pont d'Arcole
with a single span of 262 feet, designed by M. Oudry. Each
span had twelve plate girder ribs with cast iron spandrel-
braces beneath the floor. The first use of hinges in a wrought
iron arch was for a bridge over the St. Denis canal on the
Paris-Aire Railway (1854), with one span of 148 feet. The
Theiss river bridge at Szegedin, Hungary, with eight spans of
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310 BRIDGE ENGINEERING.
139 feet, was completed in 1858, and the railroad bridge over
the Rhine at Cologne, by Hartwich, was finished a year later.
Pont d' Arcole, which had a small rise of only 6.16 meters,
was strengthened by anchoring the top chords back into the
masonry to produce combined arch and cantilever action,
but the anchors all snapped at once, causing partial failure.
It was again repaired and in 1888, was still in use.
372. England has few very large metal arch bridges but
many smaller and artistic ones. The original Victoria bridge '
at Pimlico (1860) near the Chelsea suspension, was designed
by Sir John Fowler with four segmental deck arches and was
widened in 1866 by Sir Charles Fox, to 132 feet between para-
pets, and until recently was the widest of all bridges. It
Yig. 204.
was originally only 30 feet between parapets, for two lines
of railway with three ribs in each span, but the additional
width of 98 feet required eight ribs more. The only other
important bridge of the kind and time in England was the
Westminster bridge over the Thames at London, designed
by Thomas Page, 1861, with seven spans from 95 to 120
feet. This was an unusual combination of materials, for the
central 52 feet of each rib was wrought iron, while the re-
mainder was cast iron.
373. The three-span deck arch bridge over the Rhine at
Constance-Baden, designed by Gerwig, 1862, has solid plate
ribs without hinges, the upper chord in the spandrels being
in three straight lines instead of a curve parallel with the
intrados. A somewhat similar one crosses the Ruhr at Dus-
sern (Fig. 204), and they have also been used for arches
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WROUGHT IRON AND STEEL ARCHES. ?11
in America, but the contrast of intrados curve and straight
mitred chord in the spandrels is not satisfactory. The Con-
stance bridge had provision for both railroad and highway
travel with artificial adjustment for changes of temperature,
and was followed two years later by a plate girder three-
hinged arch over the Wien river in Germany, designed by
Hermann. The three-span Coblenz bridge of 1864, the Rhein-
hausen bridge of 1873 and the two-span Coblenz bridge of 1879
are similar railroad bridges with square end towers. The first
Coblenz bridge (Fig. 205) has often been described and has
^served as a pattern for many later ones. Each of its three
Fig. 205.
spans has end hinges, used only during erection and after-
wards made square ended. It was the first braced arch with
parallel curved chords and end hinges, and is probably the
most important and best known of all the early wrought iron
arches. The ribs have segmental flanges with open lattice,
Fig. 206.
and the deck carries a double line of railway. The Muhlheim
bridge over the Ruhr (1865), also designed by Hartwich,
consists of three river spans and seven smaller ones, with
four-braced parabolic open-web ribs in each span for double
track. In the following two years appeared a foot bridge (Fig.
206) over the Bollatfall at Hohenschwangan, by Gerber, a
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312
BRIDGE ENGINEERING.
railroad bridge over the Neckar at Jaxtfeld, by Becker, and
a highway bridge over the St. Denis canal at Villette.
374. The Albert bridge over the Clyde at Glasgow (1870),
designed by Bell and Miller, engineers, had arch ribs 3 feet
deep at the center and 4 feet at the springs. It replaced Rob-
ert Stephenson's old Hutcheson stone bridge of 1829, the site
of which was first occupied by Peter Nicholson's timber arch
foot bridge (1803), which had the large span of 340 feet and
was only 7 feet wide. The modern iron bridge with its three-
PIjT. 207.
deck arches and stone piers on cast iron cylinders, cost $240,-
000. In each span are eight wrought iron riveted plate girder
arch ribs, the outer ones being ornamented with cast iron
facings.
375. The St. Louis bridge over the Mississippi river (Fig.
207) is the first steel arch and the first and largest railroad
arch in America. Its construction was started in 1869 and
continued to completion in 1874. The center span has a clear
length of 520 feet and the two side spans, 502 feet each, with
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WROUGHT IRON AND STEEL ARCHES.
313
a rise of 47 and 44 feet, respectively. Piers go down to solid
rock, and above low water are faced with Maine granite with
limestone filling. Each span has four segmental arch trusses
in vertical planes with parallel chords 12 feet apart. The
chords are made of chrome steel tubes 16 inches in diameter,
each being formed of six separate staves bound together. The
sections are in 12-foot straight lengths with blocks at the joints
to form the curve. The upper deck is 54 feet wide and is
used for carriage and pedestrian travel, while the lower deck
has two lines of railroad between the two outer trusses with a
clear height underneath the bridge of 144 feet at the center.
The arch ribs having fixed ends without hinges, are well
braced together with struts and diagonals. The bridge proper
Fls. 208.
is 1580 feet long, and including the approaches is 1,700 feet,
the cost of the bridge alone being $5,300,000, or $3,150 per
lineal foot, and the whole cost, including the tunnel under the
city, $9,000,000 to $10,000,000. It is the longest arch with
fixed ends and the first extensive use of steel for bridges. It
was erected on the cantilever principle, without falsework, by
placing corresponding pieces symmetrically at either side of
the river piers, in a manner similar to that suggested by Brunei
and Telford for their proposed arches over the Menai Straits.
The St. Louis bridge, containing 2,200 tons of steel and 3,400
tons of iron, was severely tested after completion with a line
of fourteen locomotives on one track. The bridge was de-
signed by Capt. James B. Eads, and was erected under his
direction with Col. Henry Flad in charge of construction. Mr.
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314
BRIDGE ENGINEERING.
Eads considered several other forms, including a three-hinged
bridge with two lenticular ribs meeting on a center hinge,
with suspended floor (Fig. 208). Many other arch designs
were made by him, including one for a proposed bridge over
the Bosphorus. In the same year (1874) a single arch was
completed at Pittsburg, Pa., with a span of 150 feet, to carry
Forbes Street over two lines of railway. The segmental
arch ribs were 61 inches deep with parallel chords and open
web, having a center rise of 23 feet. It was a well-designed
arch and continued in use until 1898, when it was replaced by
a heavier one with plate girder ribs. In the following year
(1875) an interesting but very light railroad arch viaduct
was erected over the Retiro river in Brazil (Fig. 209), 165
Fig. 209.
miles from Rio de Janeiro. The five metal arch openings of
49 feet 2 inches have a 20-foot stone arch approach at each
end, the entire length being 357 feet. The arch ribs are each
made of two old rails riveted together with a plate between
them.
376. The Rheinhausen railroad bridge over the Rhine
(1873), designed by Hartwich, similar to the old Coblenz
bridge, has side spans and a swing truss in addition to its four
river spans. The Margaret bridge over the Danube at Buda-
pest (1875) is unusual in having three separate sections meet-
ing at a center pier in the middle of the river. Each of
these sections contains three arch spans with vertical and
diagonal spandrel bracing supported on light intermediate
piers. A similar concrete Y bridge has recently been built
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WROUGHT IRON AND STEEL ARCHES. 315
at Zanesville, Ohio. The Pia Maria bridge over the Douro
river at Oporto, Portugal (1877) (Fig. 210), the work of T.
Seyrig, is one of the boldest metal arch designs executed, rank-
ing with the later one at Oporto, the Garabit, and the Kaiser
Wilhelm at Mungsten. The deck is supported on two crescent-
shaped ribs of 625-foot span and 33-foot center depth, bearing
on hinges at the end. The ribs, 13 feet apart on centers at
the crown, slope out to 49 feet apart at the shoes. The rise
of the lower chord is 123 feet, which is 200 feet above the
water. At the ends are five approach spans of 94 feet each,
two at one end and three at the other. The arch contains
500 tons of iron and the total weight of center structure in-
Flgr. 210.
eluding arch and floor supports, is 720 tons. The arch was
erected by the cantilever method without falsework, and a
single line of railway passes over it at a height of 251 feet
above water. Other interesting bridges of this time in Europe
are those over the Tauber at Weikersheim (1869), over the
Neckar at Heidelberg (1876), and the Main at Frankfort
(1877), the Erdre near Nantes (1877), and the Moselle river
bridge at Guls, in 1878. The Ferdinand bridge over the Mur
at Graz (1881) has a single span, through tied arch, without
center hinge, with floor suspended and stiflFened with lattice
girders. The city of Berne, Switzerland, has at least three
fine metal arch bridges, one of which is the Schwarzwasser
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BRIDGE ENGINEERING.
(1882), carrying the Berne and Schwarzenberg road 197 feet
above the valley (Fig. 211). It is a hingeless wrought iron
parabolic arch span of 374 feet, and is the largest metal arch in
Fig. 211.
Switzerland. The two ribs have a rise of 70 feet and vary in
depth from 6 feet at the crown to llj^ feet at the springs.
It frequently happens that the building of a bridge is the
means of increasing land values sufficiently, not only to pay
for the cost of the bridge, but also to enrich its projectors.
Land that has remained unused because inaccessible, will
often after the building of a bridge become very valuable.
This was the case with the Kirchenfeld at Bcmc (Fig. 212),
built in 1882 for the purpose of opening up an outlying and un-
Flg. 212.
developed district. The bridge contains two deck arch spans
with short lattice trusses at each end, and is 750 feet long,
with deck 115 feet above water. The framing is very light
and lacking in stiffness, but the design is artistic and presents
an attractive appearance. The third metal arch at Berne is
the Kornhaus (Cornhouse) bridge over the Aar, 1897, de-
scribed later. The city of Berlin has a number of ornamental
wrought iron bridges, including the Michael (1879), the Mar-
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WROUGHT IRON AND STEEL ARCHES.
317
schall (1882), the Sandkrug (1883), the Lutzon bridge (1884),
and one near the Muhlendamm (1894) over a branch of the
Spree. The Franzens bridge over the Danube canal at Vien-
na (1885) with a span of 174 feet, is a three-hinged steel arch
of small rise with a 27-foot opening through each abutment,
for streets parallel with the canal. It has a solid steel trough
Flff. 218.
floor, cost $160,000 without approaches, and replaced an old
suspension bridge. The upper or Wettstein bridge at Basle,
with three deck spans, was completed in 1882.
377. At Bedford, in England, are two very interesting
metal bridges over the river Ouse, one being a foot bridge
(Fig. 213) with a span of 100 feet, with open lattice arch ribs
Fig, 214.
rising above the floor and an underneath clearance of 15 feet
for boats. The other is a larger one at the same place, with a
length between abutments of 200 feet and a width of 35 feet,
ornamented on the face with cast iron panel work. M. Max
Ende, and R. E. Cooper, 1884, designed the Blaauw Krantz
viaduct (Fig. 214) over a ravine at Cape Colony, Africa, which
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BRIDGE ENGINEERING.
has a center 230-foot opening of very unusual form. The
two truss frames are united at the middle but at the ends they
separate to bear on four individual masonry pedestals. The
designer states that *'while the plan has quite an uncouth
appearance on paper, the bridge is imposing when observed
from underneath." In any case the design shows much orig-
inality.
378. The Garabit arch over the Truyere (Fig. 215), in
the south of France (1885), is similar to the Pia Maria arch at
Oporto, and was designed by the same engineer. The span
Flgr. 215.
is 540 feet, with the deck 406 feet above the water, and is the
highest iron arch in the world. The two parabolic, two-hinged
arch ribs are crescent shaped, 33 feet deep at the center, 20^
feet apart at the crown, and 65>^ feet at the shoes, and the
center line is the parabola for uniform loads. A single line
of railroad is supported on cross beams between lattice
girders 17 feet deep and ISyi feet apart, and below the track
is a foot walk for inspection. The whole structure contains
3667 tons of metal and cost $620,000. One-eighth of the span
at each side was erected on falsework, and the remainder can-
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WROUGHT IRON AND STEEL ARCHES.
319
tilevered out from the adjoining spans. Erection was greatly
facilitated by constructing a temporary wood bridge, 100 feet
high and 600 feet long, under the arch at a cost of $4,000.
Besides the central span, it contains three others of 182 feet
and two of 170 feet, with 2,460 feet of masonry approach. All
towers have a batter of 4 per cent longitudinally, and 12 per
cent transversely. The method of using half through, instead
of the usual deck construction, prevents a train from leav-
ing the bridge in case of derailment, and has since been used
on the Leithbridge viaduct in Western Canada. The Luiz I.
bridge over the Douro (1885) has a clear span of 566 feet,
with upper and lower roadways (Fig. 216). It differs from
all previous arches by having the ends tied together with
bars under the lower floor, thereby eliminating side pressure
Fig, 216.
on the abutments. The bridge is 1,278 feet long, and the upper
road is 160 feet above the lower one and 204 feet above the
water. The ribs are 26 feet deep and 20 feet apart at the
crown, increasing to 52^ feet apart at the shoes. The lower
platform with two lines of lattice girder 10^ feet deep and
2dy2 feet apart, is supported from the arch at the ends and
at four intermediate points. This method of tying the arch
ends together has since been used on several bridges in Ger-
many, as those at Worms, Harburg and Mainz. The Luiz I.
bridge cost $500,000 and both of the Oporto arches and the
Garabit in France were designed by T. Seyrig. Competitive
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BRIDGE ENGINEERING.
designs were received in 1881 for the highway bridge over the
Rhine at Mayence and one by Lauter with two-hinge seg-
mental ribs was accepted. It has five deck metal arches with
one of masonry at each end, and was completed in I8869 on
the site once occupied by an old Roman bridge. A single
arch of 291 feet was placed across the Adige river at Verona
in 1885, replacing an old stone bridge of the fourteenth cen-
tury which was destroyed in 1882. It was a through arch
with suspended floor and deck 38 feet wide, the whole with
its foundations costing 20,000 pounds sterling.
Pig. 217.
379. Arch bridges in America from 1886 to 1890 are those
at Lockport over the Erie canal; Richmond, Indiana; St.
Louis; Minneapolis; British Columbia; Pulaski, N. Y. ; New
York City; New Haven; Baltimore; Buffalo, and Rochester.
An impetus was given to arch design in America? by the ap-
pearance of those prepared in 1886 by Captain T. W. Sy-
monds and Mr. Paul Pelz for the proposed Grant Memorial
bridge over the Potomac at Washington (Figs. 217, 218, 219).
These are among the finest bridge designs produced in this or
any other country. One of them (Fig. 217) had two central
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towers 230 feet above water and 160 feet apart, with a double
bascule span between them and a series of steel deck arch
spans at each side. The proposed site was midway between
the Long Bridge and the aqueduct, and Congress proposed a
Fig. 218.
$500,000 appropriation as a start, but the project was post-
poned. The Whitewater river bridge at Richmond (1886)
has a 400-foot three-hinged open web arch, with spandrel-
bracing, designed by F. C. Doran, and a total length of 576
feet, including two end spans of 64 feet each. The two ribs
•{ ^X^r^'t-f* >• ■
Fig. 219.
are in vertical planes 25 feet apart and all web members are
inclined to the vertical.
380. The first bridge to cross the Mississippi river is said
to be the suspension at Main Street, Minneapolis, in 1855. 6e-
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BRIDGE ENGINEERING.
coming too narrow to accommodate the increased travel, it
was widened in 1888 by the addition of a three-hinged deck
steel plate girder arch beside the old one, with a foot walk on
one side only (Fig. 220). After the new bridge was com-
pleted, the suspension was removed and the other half of the
new arch bridge completed in 1891. The first part with three-
rB.ei5
Flff. 220.
hinge ribs had a wood floor and was lacking in stiffness, and
the other half was therefore made much heavier with solid
floor and hinges at the springs only. Mr. K. G. Hilgard made
a design for a bridge at this site in 1886 with a single arch of
520 feet and ribs rising above the roadway from which the
floor was suspended. The second large arch bridge to cross
•nrri'o'oift toM^ofSMt/-
45$'0'''
->i/^- SS'ff'-^^ft
Fl«r. 221.
the Mississippi river at Minneapolis was begun in 1888 at
Lake Street with two spandrel-braced, three-hinged arch spans
of 456 feet (Fig. 221). It forms a connection between the
riverside parkway systems of Minneapolis and St. Paul. The
two arch ribs are vertical and were erected over the ice dur-
ing the winter season with full timber centering. Diagonals
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WROUGHT IRON AND STEEL ARCHES.
323
^T^
bo
tu
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324 BRIDGE ENGINEERING.
are pin-connected, but other members are riveted. The two
spans are disconnected from the adjoining framing, thus pre-
venting cantilever action, and it is still the largest three-hinge
arch in America. In 1906 the road was widened from 18 to
33 feet to carry two lines of electric car tracks, and a new
center truss was added midway between the original ones
without moving them.
381. Competitive designs were invited in 1886 for the
Washington bridge, to cross the Harlem river at 181st Street,
New York, and nineteen designs were presented, including
several arches, one of which, by Mr. Hutton, was accepted. A
design by C. C. Schneider (Fig. 222) had two central spans
of 410 feet and open web parallel chord arch ribs. It had a
series of small arches below the cornice between the spandrel
columns, and an estimated cost of $2,076,000, being awarded
the first prize in the competition. The second prize was given
on a design by William Hildebrand, which had twin parallel
chord open web arches of 640 feet (Fig. 223), exceeding those
at St. Louis. A design very different from the others, proposed
by George Harding (Fig. 151), had a central span of 460
feet, and side spans of half that length, but was not seriously
considered. The bridge as built (Fig. 224) has two 610-foot
steel arch spans with three 60-foot stone arches at each end,
and a 66-foot flat stone arch over a driveway on the east side.
The total width of 80 feet consists of a 60-foot road and 16-
foot walks. The whole length is 2,376 feet, and the deck is 141
feet above water, with a clearance of 133 feet beneath. The
building of the bridge was commenced in 1886 and completed
three years later. The center opening has six steel plate
girder two-hinged arch ribs in each span 13 feet deep, spaced
14 feet apart, with 92-foot rise. It contains 3,342 tons of steel
and cost $2,850,000, which is equivalent to $1,200 per lineal
foot. Other bridges of 1890 in America are those at Rock
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Lane, New Haven ; Cedar Avenue, Baltimore ; two park bridges
at Buffalo, and the Gcnessee river bridge at Rochester. The
Rock Lane bridge has two vertical plate ribs 16 to 20 inches
deep without spandrel diagonals, and an asphalt floor on two
layers of plank. The Cedar Avenue bridge has three ribs
12 feet apart with bottom chords bent to a continuous curve
and plank floor on wood joist. Panels are open web lattice,
excepting in the center, which has a plate web. The Driving
Park bridge (Fig. 225) over the Genessee river at Roches-
ter, N. Y. (1890), is the work of L. L. Buck, and
Fiff. 226.
the prototype of his larger railroad arch at Niagara. The
two open web spandrel-braced arch ribs of 416 feet and 67-
foot rise, have top chords rising slightly towards the center.
Trusses are 20 feet apart at the crown, sloping to 46 feet at
the shoes, and although the intention at first was to erect the
arches cantilever, false work was finally used. All material is
wrought iron with riveted connections and the total weight, in-
cluding approach spans, is 700 tons. The floor is of 3j4-inch
oak on the road and 2j4-inch on the sidewalks.
382. The first appearance of the cantilever arch was in
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BRIDGE ENGINEERING.
1890, in the Hawk Street viaduct (Fig. 226), at Albany,
N. Y., which is a three-hinge spandrel-braced arch with a
Flff. 226.
360-foot central span carrying a highway over a guUey and
three other streets, on twin arch ribs. The deck has granite
block paving on the roadway and asphalt sidewalks, and the
entire cost was $90,000. The 180-foot shore spans have each
a 114-foot cantilever arm and a 66-foot end span. Other canti-
lever arches are those over the Viaur river in France, the Elbe
canal at Molln, the Paris Exposition bridge, over the Seine,
and railroad bridges in Alaska and Costa Rica.
383. Pont du Midi (1888) over the Rhone at Lyons,
France (Fig. 227), forming a connection between La Mouche
and Perrache depots is very ornate, with three flat deck arch
^^^^"^
Fig. 227.
spans 66 feet wide and 205 feet long. Each span has eight
plate girder ribs rising 15 feet. The Morand bridge over the
Rhone at Lyons replaced an old wooden pile bridge of 1774.
Beneath the arch at one side is space for a tow path 40 feet
wide, with 8-foot head room, and at the other side is a similar
but narrower path only 9 feet wide. The Garibaldi bridge
over the Tiber at Rome, near the Island, has two spans 174
feet long and 66 feet wide, with granite columns at the ends,
a central pier 39 feet thick, and stone pavement. The cost
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WROUGHT IRON AND STEEL ARCHES. 327
of the bridge is said to be $720,000, of which $200,000 was
for the 1,680 tons of metal work. In contrast to this is the
similar bridge of Commerce at Liege, with two spans sup-
ported on a slender center pier, with arches thrusting against
each other rather than against the pier. The single span para-
bolic open web arch over the Adda river at Pademo (1889)
(Fig. 228) is one of the longest and highest, with a span of
492 feet and deck 265 feet above water. The arch ribs, 16>4
feet apart on center at the crown, are battered two inches
per foot, to 66 feet apart at the shoes, each of the two ribs
being composed of double members one meter apart. The deck
trusses are vertical, 20^ feet deep and 16 feet apart, sup-
porting two roadways, the upper one with macadam pave-
ment for highway and pedestrian travel, and the lower with
solid trough floor for a single line of railroad. The spandrel
towers are battered in both directions according to the usual
European practice. It weighs 1,320 tons and is the largest
iron bridge in Italy, the erection occupying 10 months and the
whole work 18 months, and cost $370,000. Two of the highest
bridges in Europe, both built in 1890, are the St. Guistina
arch over Noce Schlucht, and another over Cerveyrette
gorge in Southern Tyrol. The St. Guistina arch (Fig. 229),
460 feet above the valley, is the highest bridge in existence.
A cableway was used in its erection, and the stringers are
anchored back into solid rock with a temperature adjustment
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BRIDGE ENGINEERING.
at one end, the anchor chamber being reached through tun-
nels from the face of the cliff. The two ribs are vertical and
15 feet apart and the deck has a plank floor on steel joist, the
whole weight of metal being 105 tons. The bridge over Ccr-
vcyrettc gorge near Briancon, is 279 feet above the valley
and supports a 13-foot roadway on two light parabolic arch
FUr. 229
ribs. The bridge contains 120 tons of metal, of which 80 tons
is in the arch. The wrought iron arch (Fig. 230) over the
Wear near Sherburn House, with a single span of 130 feet
(1892) is the work of Mr. G. A. Harrison.
384. Among the many bridges over Loop canal at Belle
Isle Park, Detroit, is a small three-hinge metal arch with solid
Flir. 280.
ribs which is worthy of mention. Some similar ornamental
bridges (1893) were placed in Lake Park, Milwaukee, the de-
signs of Mr. Oscar Sanne. One with a clear span of 50 feet
and length of 90 feet, has a 26-foot roadway paved with as-
phalt on buckle plates, and two 7-foot walks covered with cast
iron plates. Six steel ribs with end hinges, the outer one be-
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WROUGHT IRON AND STEEL ARCHES.
329
ing faced with ornamental cast iron, support the deck, which
is protected with iron railings. The total cost, including ma-
sonry, metal and paving, was $10,800. Over the North and
South Ravines near the Government lighthouse in the same
park are two bridges of artistic design, each having a span of
87 feet, and the two costing $36,500. Each bridge has six
two-hinge steel arch ribs supporting asphalt roadways and
cement sidewalks on beams and buckle plates. The abutments
are of fine coursed ashlar, surmounted with a Bedford stone
railing, but over the arches the railing is of ornamental iron.
At the four abutment corners adjoining the opening are orna-
mental posts, supporting a cluster of lamps, and at the abut-
ment ends are pedestals with figures of lions.
385. Several interesting arch bridges were used by the
Canadian Pacific railroad in rebuilding its line through the
mountains of British Columbia. Of these, the Stony Creek
bridge (Fig. 231) is probably the best known. It crosses the
creek and valley on a high deck steel arch- 300 feet above the
FUr. 281.
valley in a very picturesque place. The sides of the valley
are so steep and rocky that the site was naturally inviting for
an arch design. When first building the road in 1885 th^
engineers, Messrs. W. A. Doane, G. H. Duggan and T. K.
Thomson, carried the track on a wooden bridge with four
spans of Howe truss on timber towers, and the wood re-
mained in use for about ten years, when it was replaced.
The steel arch has a span of 336 feet and a rise to the under
chord of 80 feet. The curved arch trusses are 26 feet deep at
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330 BRIDGE ENGINEERING.
the ends and 20 feet at the center, 24 feet apart at the crown
battering out 1 in 10 to the shoes. The trusses are pin con-
nected, but all bracing is stiflf and riveted. The riveted deck
trusses carrying the track are 9 feet deep, and 9 feet apart on
centers, and the total length, including the two end spans,
is 485 feet. The weight of steel in the arch is 524 tons and
in the entire structure 771 tons. The chief engineer for the
railroad company was P. A. Peterson, and H. E. Vautelet,
bridge engineer. The bridge over Salmon river (Fig. 232) —
a branch of the Fraser — ^near Keefers Station, British Colum- '
Fig. 232.
bia (1893), is located 34 feet south of the old wooden Howe
truss bridge, which was designed by the same engineers who
built the Stony Creek bridge. The old bridge had a center
span of 210 feet with a 90-foot span at each end supported
on two high timber towers. The new steel arch has a center
span of 2'}'0 feet and a rise of 50 feet to the under side of
arch, with the deck 123 feet above water. The ribs are 60
feet deep at the ends and 10^ at the center and at each end
are two steel plate girder spans. The arches are three hinged,
16 feet apart at the upper chords, battered out 1 in 10 to the
ashlar masonry abutments, which are placed in seats cut into
the rock. The use of rod lateral bracing to avoid the expense
of bending the lateral plates was considered, but was not
adopted because of its insufficient stiffness. Surprise Creek
bridge (Fig. 233) is similar to that at Salmon river excepting
that the shoes are at different levels, making the arch ribs
unsymmetrical. It is a single span spandrel-braced steel arch,
290 feet between end pins, 70 feet deep at one end and 92
feet at the other, with a center depth of 16 feet. At one end is
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a plate girder^ span of 56 feet and a similar one of 108 feet
at the other end. The upper chords are 16 feet apart for
single track, battering out towards the shoes at the rate of
1 in 8. Shoes have ball and socket bearing, similar to other
larger spans on the same railroad. The arch is three-hinged.
Fig. 233.
pin-connected, with riveted bracing, and the deck is 180 feet
above the valley. The reported weight of steel in the main
span is 520 tons, which is much heavier than other similar
bridges.
Fig. 234.
386. Two of the largest iron arches in Europe are the
Grunenthal and Levensau bridges over the North Sea Baltic
Canal, completed in 1892 and 1894, respectively, with space
for both railway and highway, both bridges having high level
roadways and clearance beneath for ships. The Grunenthal
(Fig.234) has two crescent-shaped ribs of 513-foot span and the
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332 BRIDGE ENGINEERING.
Levensau arch has a 536-foot span supportecj on a pair of
segmental two-hinge open web ribs in vertical planes, the
whole containing 2,800 tons. The unusual feature of the
Levensau bridge is the provision for resisting wind pressure.
The floor is suspended, allowing wind stresses to be freely
transmitted to the upper truss, and the whole was erected on
full timber centers. Provision was made for two tracks, but
only one was placed at first, the place for the other one be-
ing used temporarily for a highway. The arch foot bridge
over a branch of the Spree near the Muhlendamm at Berlin
(1894) has a single through tied arch with suspended floor and
a span of 190 feet.
387. In 1893 a high-level bridge over the river Mer-
sey at Liverpool, was proposed by J. J. Webster and J. T.
Wood, with three through arch spans of 1,150 feet and a deck
150 above the water. In addition to the regular approaches
they proposed six lifts or elevators at each end from the lower
street to the upper bridge level. The main arch ribs were
shown of eight octagonal steel tubes braced together, with
hinges at spring and crown, the whole bridge having an esti-
mated cost including land of $8,650,000.
388. In the four years preceding the opening of the large
arch bridges at Niagara, about fifteen other steel arch bridges
were completed in America. The Brooklyn-Brighton bridge
over Big Creek at Cleveland, Ohio (1894), composed chiefly
of alternate trestle spans of 28 and 56 feet, contains an open
web three-hinge steel arch with 168-foot span. The center
line of the lower chord is a parabola, but the upper panel
points are on three straight lines. The trusses are 26 feet
apart on centers atid the total cost of the viaduct, including
land, was $170,000. An arch bridge (Fig. 235) over a pond
in Riverside Cemetery, Cleveland (1896) has two crescent-
shaped parabolic ribs 142 feet long with a rise of 27 feet and
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333
5 feet crown thickness. The middle half has an open lattice
web, while the two end quarters have solid web plate. The
arch ribs are in vertical planes and support the roadway
girders at only two points. The Walden highway arch bridge
at Lake Forest, 111. (1896), crosses a drive and valley with
E- 57W-H^-- J7«'-i^- SnO^-if J7»--Jf J7»*4'
- J7t6--* 40' — ^ 4C
"^
Fig. 235.
solid plate girder arch ribs and radial posts from the arch to
the floor beams. The Grand River arch bridge at Lansing,
Mich. (Fig. 236), is deserving of special notice, chiefly for its
great width of 116 feet and for its heavy floor. Each of the
FUr. ttt.
two spans has six steel plate girder ribs 4 feet deep and 18
feet apart. The brick pavement is laid on concrete over brick
arches between steel floor beams, but the walks have a plank
floor. It was designed by E. J. Landor and completed in
Fig. 237.
1895 at a cost of $60,000. Panther Hollow bridge in Schen-
ley Park, Pittsburg, Pa. (Fig. 237), carries a roadway over
Panther Hollow, a ravine 120 feet deep. It crosses from the
Phipps Conservatory to the Speedway, with a 360-foot steel
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BRIDGE ENGINEERING.
arch and two 28-foot stone arches at each end. The center
span has four steel three-hinged vertical ribs 13% feet apart
on centers, supporting a 60-foot deck, with 10-foot walks on
cantilever brackets, paved with asphalt on steel trough floor-
ing. The parabolic arch ribs have a rise of 45 feet and a
crown thickness of 5 feet, making- end heights of 50 feet. The
whole bridge is 615 feet long, and at the ends are pedestals
mounted with bronze figures of panthers. It was completed
in 1896 at a cost of $170,000. The other bridge in Schenley
Park, known as Schenley Park bridge, is quite similar to the
last-named one and crosses a ravine 100 feet deep with a 360-
foot steel arch and a 50-foot stone arch at each end. It is 620
feet long, 80 feet wide, with asphalt road and cement walks,
Fig. 238.
and was completed in 1897, under the direction of H. B. Rust,
at a cost of $240,000. The South Twenty-second Street bridge
(Fig. 238) was the first free bridge over the Monongahela
river at Pittsburg. The central 520-foot span consists of a
pair of three-hinged arched trusses of the Bonn type, 60 feet
deep at the ends and 30 feet at the center, with a lower chord
rise of 44 feet. At each side of the center is a 260-foot span
connected by false members with the larger span, the upper
outline resembling somewhat the Northfield cantilevers.
Trusses are 32 feet on centers, giving space for two lines of
car tracks and a paved road of concrete on trough floor. The
8-foot walks at each side have asphalt over concrete and
buckle plates. It was opened in 1897, but ten years later the
piers required very extensive repairs. A bridge over the Black
river at Watertown, N. Y., has two spandrel-braced ribs
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335
between rock side walls, and was erected with three hinges,
but the crown hinge, which was on the line of the upper
chord, was afterward discarded and the parts riveted up solid
with splice plates. The center 100 feet has solid webs, while
the remaining quarters have two panels of open lattice at
Fig. 289.
each end. It carries a solid pavement on buckle plates and
replaced an old suspension which had a span of 175 feet.
389. In the competition for a bridge over the St. Law-
rence river at Montreal (1897), three designs were submitted
by Messrs. Francois Bicheroux, Charles Steiner, and C. R.
Grimm, for high level arch bridges with single spans of 1,200
Fig, 240.
to 1,300 feet, and floors 160 feet above the water. The first
of these (Fig. 239) had high metal towers at each end of the
main span dividing the central bridge from the viaduct ap-
proach, and it, and the second design (Fig. 240) had hinges
at the ends and center, while Mr. Grimm used two-hinge para-
bolic arch ribs of crescent form. Three years previous, Mr.
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BRIDGE ENGINEERING.
Steiner prepared a somewhat similar arch design for a pro-
posed bridge to cross the North river in New York City, and
Max Ende, the French engineer, designed a 783-foot arch span
to cross the Thames at London, with an under clearance of
90 feet. M. Ende proposed elevating street traffic to the
bridge on moving cars or elevators somewhat like those on
the inclined railways at Cincinnati, Pittsburg, and Hamilton,
Ont., the last of which was built under the direction of J. W.
Tyrrell, engineer. The estimated cost of the Thames bridge,
including abutments, platforms, and machinery, was $1,210,000.
A similar bridge was proposed for crossing the Garonne at
Bordeaux (Fig. 241), with a span of 400 meters, and another,
with a span of 735 feet, proposed by Clark Reeves and Co.
Pig. 241.
A design for a proposed metal arch, with a central span of
1,000 feet and 250-foot spans at each side, was made in 1898
by Sir Bradford Leslie, to cross the Hoogly river at Calcutta.
The intention was to have two decks and a 200-foot double
bascule opening beneath the central arch, which was high
enough above it to give ample clearance for ships. In 1897,
W. B. Parsons made preliminary plans for a viaduct 3,000 feet
long over Sherman's creek, from Fort Washington to Kings-
bridge, N. Y., including a 516-foot crescent arch, with an esti-
mated cost for the whole viaduct of $1,400,000. Other bridges
of the period in America are those at Spokane (1893), Bentley-
ville and Youngstown, Ohio (1895), Forest Hills, Boston
(1896), Niagara Falls canal (1896), Six Mile Creek at Ithaca
(1896), and those over the canals at Buffalo, N. Y., and Ham-
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WROUGHT IRON AND STEEL ARCHES. 337
ilton, Ont. (1897). The proposed Hoogly arch was quite
similar to a design made by R. M. Ordish in 1885, for the
proposed Tower bridge at London.
390. During the three years previous to opening the Bonn
bridge in 1898, Europe produced several large arch bridges,
the principal ones being those at Mungsten, Viaur and Berne.
The Queen Carola bridge over the Elbe at Dresden (1896),
with three arch spans over the river and stone approaches at
each end, has very heavy piers with elaborate and heavy detail,
and bronze figures at the north end, placed in 1899. A road
bridge over the wild mountain Versam Gorge (1897), on the
road from Bonadiz to Ilanz, is 230 feet above the valley and
has two spandrel-braced ribs supporting a macadam floor on
Fl«r. 242.
solid metal troughs. The almost vertical rock cliffs made the
arch an economical type for the location. The Kaiser Wil-
helm bridge over the Wupper river at Mungsten, Prussia (Fig.
242), is one of the largest in Europe. It was completed in
1896 from designs by A. Rieppel, at a cost of $687,600. The
viaduct carries a double track railroad between Remscheid
and Solingen, on lattice girders with a solid trough floor, and
cantilever walks at each side, the deck being 350 feet above
the vallej^. The main arch, which has a span of 557J/$ feet
between tower centers, has two parabolic ribs 16 feet apart
at the crown, sloping out to 83 feet at the base. The Ger-
man government invited designs for crossing the valley either
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BRIDGE ENGINEERING.
on trestle, cantilever or arch, the last being adopted. The
erection occupied twenty-two months and was very expensive.
Towers were erected from temporary wooden staging inside
of each, and the 148-foot spans were built on platforms made
of light bridges hoisted bodily up between the adjoining
towers. Temporary shops were also ^uilt at the site, and the
center arch was cantilevered from each side and anchored
back to the adjoining framing. The whole bridge contains
5,600 tons of steel and is equipped with three permanent in-
spection travelers, giving access to all parts. The arch at
the end is built into the towers, and was first -erected with
three-hinge bearings, but the center and end hinges were re-
moved in turn, and the whole made fixed and square bearing.
It is now the longest fixed end arch in Europe. The Viaur
viaduct (Fig. 243), on the road from Carmaux to Rodez in
France, carries a single track at a height of 385 feet above
^
s
Fiff. 248.
the valley. The center span is 721 feet and the two end
spans 311 feet each, with a clear length between abutments
of 1,345 feet, and a total length of 1,509 feet. At the ends of
each side span are short suspended spans of 85 feet, bearing
on the abutments and on the cantilever brackets. The arch
ribs are 19^ feet apart at the crown and they slope out on
a 25 per cent batter to 109 feet at the shoes. A permanent
walk and tramway beneath the floor afford opportunity for
inspection. Compression members are tapering, and larger at
the center than at the ends. The trusses are all riveted, the
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WROUGHT IRON AND STEEL ARCHES.
339
total weight of the metal 4,290 tons, and the entire structure
cost $490,000, of which $47,000 was for the masonry. Sev-
eral preliminary studies were made, resulting in the selection
of a cantilever arch, as built. The Komhaus bridge (Fig.
244), the third large arch over the Aare at Berne, has a cen-
ter open web lattice arch of 384 feet, with five smaller plate
girder arches at the side. The main span contains 1,000 tons
of steel with 500 tons more in the smaller spans, and the whole
bridge, complete, cost $426,000. The ribs are parabolic, with-
out hinges, varying in depth from 5 feet at the crown to
Fifir. 245.
15 feet at the springs. The floor is on a grade of 2.7 per cent
and is made of wood block pavement on galvanized buckle
plates. The ribs are 26 feet apart at the crown and batter
out 1 inch per foot to 43J4 feet apart at the shoes. Other
European bridges of this time are those over the Danube at
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BRIDGE ENGINEERING.
Straubing (1896) and the Carlsburg viaduct (Fig. 245) in
Denmark, with two arch spans.
891. The opening of the Niagara railroad arch marked a
new period in American bridge design (Fig. 246). The remark-
able example of modern engineering was completed in 1896 at
a cost of $600,000. It replaced the old suspension built by
Fig, 246.
Roebling in 1855 with wooden stiffening trusses and stone
towers. The arch has end hinges and a span of 550 feet with
114-foot rise, and carries two lines of railroad on the upper
deck, with three lines of board walk for the convenience of
workmen. The lower deck has a 25-foot highway with 6-foot
sidewalks of wood joist and flooring on cantilever brackets.
The width between arches at the crown is 31 feet, and they
batter out to 57 feet apart at the shoes. The ribs are 20
feet deep at the center and 134 feet at the ends. The upper
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WROUGHT IRON AND STEEL ARCHES.
341
deck, 225 feet above the water, is protected by iron railings,
as is also the lower deck. The bridge contains 3,600 tons of
steel with riveted connections and was erected cantilever
with parts guyed back to shore. A three-hinge bridge (Fig.
247) with bottom members in a straight line from shoe to
crown was computed by Mr. Schaub, and found to contain
Fig. 247.
less metal than the arch form, though it was less pleasing in
appearance.
392. The Niagara-Clifton bridge over the Niagara river
1,000 feet below the falls (Fig. 248), has a center arch span
of 840 feet with approach spans at each end, and is the long-
Fig. 248.
est arch span in existence, though several larger ones have
been projected. The two arch ribs 'have parallel chords 26
feet apart with pin bearing at the ends. It replaced the old
suspension bridge of 1868, which had a span of 1,268 feet, and
it is the third bridge to occupy the site. It has a deck 46
feet wide, and 200 feet above the water, with two car tracks
in the center. The ribs are 30 feet apart at the crown, slop-
ing out to 69 feet at the shoes. The main arch contains 1,825
tons of steel and the whole bridge 2,260 tons. It was erected
cantilever, similar to the method adopted for the Mungsten
bridge, and opened for travel in August, 1898. Water under
it is believed to be about 180 feet deep. The Fairmount
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arch bridge (1898), over the Schuylkill river at Philadelphia,
had four three-hinged spandrel-braced arches of 200 feet,
flanked at each end with three girder spans. The arches
thrust against cast iron shoe boxes on the piers, the thrusts
tending to counteract each other. Two lines of electric rail-
way pass over one side with a wood floor beneath, the re-
mainder of the deck, which is 80 feet in total width, being oc-
cupied by a carriage way and footwalk with solid pavement.
Each span has three vertical ribs 28 feet apart with rigid
bracing and buckle plate floor. The bridge contains 3,000 tons
of steel, cost $375,000, and was designed by the Phoenix
Bridge Company, their design being accepted against much
opposition, in preference to a very superior one by C. C.
Schneider (Fig. 249). The long arch bridge on Riverside
Drive, New York, has twenty-two arch spans of 65 feet and
one of 130 feet, with a total length of 1,564 feet. It has a
deck 80 feet wide with a solid pavement on buckle plates, 75
feet above the valley. The design was not economical, cost-
ing $570,000, but was adopted because of its supposed better
appearance. The competition of 1898 for the Connecticut
Avenue viaduct at Washington evolved three designs with
steel arches, one by Mr. Breithaupt having 410-foot center
span with 282-foot arches at each side and Melan shore spans.
The length was 1,320 feet and width 70 feet, with an esti-
mated cost of $4,00 per square foot of roadway. Another
design by Mr. Buck had five similar arches, while the third
proposed a central steel arch of 544 feet with four ribs, and
95-^foot rise, and four Melan arches with asphalt floor, at an
estimated cost of $450,000. A competition the same year for
the Massachusetts Avenue bridge over Rock creek at Wash-
ington, brought forth an arch -design by E. Marburg for an
arch cantilever (Fig. 250) 500 feet long and 80 feet wide,
with an estimated cost of $200,000. Mr. Marburg proposed
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BRIDGE ENGINEERING.
three lines of trusses 28 feet on centers, with asphalt and
buckle plate floor. The Fall Creek arch at Ithaca, N. Y., near
Cornell College, spans a gorge 160 feet deep, with steep,
rocky sides, and an arch was therefore an economical type,
as artificial abutments were not required. It has a span of
170 feet with 20-foot approach spans at each end. The two
plate girder arch ribs are 5 feet deep and 20 feet apart on
centers, made in two straight sections between the loaded
points rather than in a continuous curve, and was erected on
temporary timber false work. The South Market Street bridge
over the Mahoning river at Youngstown, Ohio, 1899, has one
segmental two-hinge plate girder arch of 210-foot span and
60-foot rise, with two ribs 28 feet apart, and truss spans of
165 feet at each end. The whole viaduct is 1,610 feet long,
composed of trestle spans of 30 to 90 feet on towers 28 feet
Fig, 260.
wide and 30 feet long with vertical columns. It was designed
by C. E. Fowler and the arch was erected on full timber
false work. The city of Pittsburg, Pa., erected two solid web
arch bridges in 1899 and 1900 carrying Forbes Street over
ravines. The first replaced a lighter 150-foot arch^of 1874,
and has four two-hinge arch ribs of 144-foot span and 6 feet
deep, supporting a road 56 feet wide with asphalt pavement
and buckle plates, and a double line of electric car tracks.
The other bridge, erected in 1900, carries Forbes Street at a
height of 94 feet over Nine Mile Run on a three-hinge arch
of 190-foot span, with three approach spans of 24 feet at each
end. It was designed by Willis Whited, who gives his reasons
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345
for selecting this type. He says that "a braced arch with
parallel chords is not suitable for spans less than 300 feet
and was, therefore, not considered. Preference was for a
stone arch, but the cost was prohibitive and a continuous
trestle or combination of trestle and truss span was not ar-
tistic enough for the location. A cantilever with curved chords
was considered, but its deflection would be excessive, there-
fore not desirable, and the arch is false. The purpose of a
spandrel-braced arch is not so evident as a simple one, for
sincerity, which is an essential of good design, is lacking. An
arch without hinges, or with only two hinges at the ends,
has less material and looks better than a three-hinge arch.
Fig. 251.
but there is usually difliculty in securing an even bearing, and
a three-hinge plate girder arch was therefore adopted." It
has two vertical arch ribs 6J<2 feet deep and 36 feet apart,
supporting asphalt pavement on buckle plates, with a 3.3 per
cent grade. The whole bridge contains 760 tons of iron and
steel, and cost $86,000, the center span being erected canti-
lever, with guys from the adjoining framing. An unusual
form of cantilever arch, of the type used at Hawk Street,
Albany, and for the Viaur viaduct in France, carries the
White Pass and Yukon Railway over a mountain gorge with
a center opening of 240 feet (Fig. 251). It differs from these
bridges in having the bottom chord straight instead of curved
and the profile area suggests a surplus amount of web mem-
bers for economy. It was erected as a cantilever and the ends
afterward blocked up tight. It is quite similar in outline to
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346 BRIDGE ENGINEERING.
a design proposed in 1891, by J. W. Schaub with a span of
500 feet, for crossing the Niagara gorge.
393. In the six years following 1899, several new bridges
were erected across the Seine at Paris, the first of which is an
ornamental one at the Exposition grounds, connecting the
Champs des Elysees and the Esplanade des Invalides. It is 131
feet across and is the widest bridge in Paris, one-half of its
width being occupied by the roadway and the remaining half
by the two sidewalks or promenades. The bridge is remarkable
for its large span of 353 feet and its small rise of only 20
feet, and for the use of cast steel in its fifteen lines of arch
ribs, which are slightly less than 9yi feet apart. The erec-
FifiT. 253.
tion centers were suspended from overhead trusses, leaving
the river unobstructed. Another notable feature was the use
of steel caissons which were sunk by the pneumatic process.
At each end are ornamental towers, the tops of which are 76
feet above the roadway. The faces and spandrel are orna-
mented with festoons and panel work in iron, and the balus-
trade is rich and heavy with round balusters and moulded
top. At each end is a profusion of sculpture and on the posts
of the balustrades are ornamental standards supporting clus-
ters of lights. The bridge was opened in 1899 and was called
Alexander III. (Fig. 252) in honor of the czar of Russia.
The foot bridge (Fig. 253) over the Seine at Paris (1909)
between the Alma and Jena bridges, contains unusual and
original features, resulting from special requirements. It was
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WROUGHT IRON AND STEEL ARCHES.
347
imperative that the central 240 feet of the river should not be
obstructed with piers or falsework, and a clear height of 28
feet beneath the floor was required for river craft. A through
arch with suspended floor was therefore adopted for the
central span, and cantilever arms at each side served to
anchor back the arch, which was erected with falsework.
The bridge is for pedestrians only, has wood joist and floor,
and was a part of the improvement for the Paris Exposition
of 1900. The parabolic arch ribs are crescent shaped, 6J4
feet deep at the center, with open lattice work web through
the central portion, and solid web plate at the ends. All con-
nections are riveted, and over the central part is transverse
cross bracing.
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Fig. 254.
394. The Passy viaduct ovCr the Seine had a crescent-
shaped arch of 281 feet with suspended floor, over one; arm
of the river. It carried two tracks of the Western Railway
of Paris on a curve and on a 1 per cent grade, causing the
bridge to have a slight skew. The center line of the arch
rib was a parabolic curve and the suspended platform, which
was covered with flat plates, was so arranged that it could
resist none of the arch thrust. The Austerlitz bridge (Fig.
254) over the Seine (1905) carries two tracks of the Metro-
politan Railway of Paris on a three-hinged 460-fodt arch, which
is the longest span of any kind in Paris. A single span with-
out piers, with a clearance of 36 feet beneath the bridge for
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BRIDGE ENGINEERING.
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WROUGHT IRON AND STEEL ARCHES. 349
boats, was required by the authorities, and these stipulations
determined its outline. An earlier design showed arch ribs
with hinges at the piers and crown, but this was revised and
the lower hinges placed at the floor level, which shortened the
distance between them to 107 meters, and made square ended
sections between the piers and the floor. The deck, which is
independent of the arch and which carries all wind pressure
to the abutment, is covered with flat steel plates. At one
end is a single through span and at the other, two deck spans.
The cost of the substructure was $200,000, and the super-
structure $90,000 more.
395. The cantilever arch (Fig. 255) over the Elbe-Trave
at Molln (1899) has a 44-foot cantilever arm at each end
Flff. 265.
of the central arch, which has 106-foot span and 25-foot rise.
A center hinge was used during, erection, but the two halves
were afterwards riveted solidly together. Another bridge over
the same canal at Lubeck has a single through tied arch, sim-
ilar to the Spree bridge at Berlin, of 1894.
396. The building of two bridges over the Rhine at Bonn
and Dusseldorf marked the beginning of a new system of
bridge building in Europe. In the competition for the Bonn
bridge sixteen different designs were submitted, and the one
which was accepted and completed in 1898 (Fig. 266) has a
center 614-foot arch span, which is the longest one in Europe,
and second only to the highway arch at Niagara. The trusses
are vertical and 29^ feet apart, with a 23-foot roadway be-
tween them and 11-foot cantilever walks outside. At each
side of the central span are smaller deck arches 307 feet long.
The floor has wood block pavement on galvanized iron buckle
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BRIDGE ENGINEERING.
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WROUGHT IRON AND STEEL ARCHES. 35 1
plates. Chord sections are formed to a continuous curve,
which adds considerably to the amount of metal. The ribs
of the main arch vary in depth from 15 feet at the crown to
34 feet at the springs, with a lower chord rise of 97 feet.
The structure contains 3,330 tons of metal, was erected on
falsework and all joints riveted. It has heavy and elaborate
detail on the metal portal, which would hardly be appropriate
for other bridges. The engineer was Prof. R. Krohn,- who
was assisted by B. Moehring, architect. The Dusseldorf
bridge (Fig. 257), also designed by Prof. Krohn (1898), has
two central spans of 595 feet with smaller sides ones of 189
to 205 feet, and a total length of 2,100 feet. The roadway is
27 feet wide and the two cantilever walks 62 feet above the
water. The chords of the main span are cicrular arcs IQj/i
feet apart at the crown and 40 feet at the enBs, with a rise of
90 feet on the under side. Trusses are 31 feet 9 inches apart
on centers and the bridge contains 5,130 tons of metal and
cost, complete, $905,000,- The Moselle bridge at Trarbach,
the Elbe bridges at Harburg and Magdeburg, and the Rhine
bridges at Worms and Mainz, have arch trusses similar to
those of Bonn and Dusseldorf, except that the arch ends are
tied together by members below the floor and there is, there-
fore, no lateral thrust on the piers, but vertical reaction only.
In this respect the bridges are similar to the Luiz I. at Oporto,
which has a second low level platform above the arch ties.
These five are arched trusses rather than true arches, but are
included here because of their resemblance to those at Bonn
and Dusseldorf. The Moselle bridge at Trarbach (1899) has
four spans and the Harburg bridge (Fig. 258) over the South-
ern Elbe to Wilhelmsburg has four river spans and six smaller
ones of 102 feet each. It has two lines of street railway, with
stone block pavement on buckle plates, and cost $428,000.
The ends of the central bridge are marked by ornamental
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BRIDGE ENGINEERING.
portal towers. The Elbe highway bridge at Magdeburg (1901)
has a central span similar to the last with a stone arch at
each end.
The Worms railway bridge (Fig. 269), built the same year
from designs by Schneider and Frintzen for double track,
has three river spans with seventeen smaller deck spans of
113 feet at one end, and a total length of 3,054 feet. The
trusses rest at one end on expansion rollers and beneath the
bridge is a clear height of 41 feet above the water. The floor
is planked over and at one side is a foot walk on cantilever
brackets. The piers have concrete centers faced with stone,
and the bridge framing contains 5,430 tons of steel, the
whole costing $800,000. The highway bridge over the river
Fig. 259.
Rhine at Worms (1900) is a three-span deck arch, the
center one being slightly longer than the other two, and stone
arches at each end. The ribs are two-hinged, braced, crescent
shaped with chords curved to a circle and the whole fram-
ing contains 2,000 tons of steel. The Mainz railroad bridge
over the Rhine, similar to those at Trarbach, Magdeburg and
Worms, has three river spans, with arch trusses, the ends of
which are tied together with members under the floor. It
crosses two arms of the Rhine and an island, having three
spans over one channel and two over the other, with six sus-
pended deck trusses of 130 feet on metal towers between the
channels. It has provision for two tracks and two foot walks,
and was completed in 1904 at a cost of $1,300,000. An arched
truss bridge of the Bonn type on the Indo-China Railway
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WROUGHT IRON AND STEEL ARCHES.
353
over the Song-Ma river, has a single three-hinge arch of 532
feet, with trusses 33 feet apart and suspended floor. The
1,200 tons of metal was erected on the cantilever method, with
the assistance of a cableway.
397. The highest bridge in America crosses the Rio Grande
in Costa Rica» 26 miles from San Jose, with its deck 340 feet
above water (Fig. 260). It carries a single line of narrow
gage (3j4-foot) railroad over a 448-foot, two-hinged, spandrel-
braced cantilever arch, with 118-foot end spans. The main
ribs are 16 feet apart at the center and batter out two inches
per foot to 40 feet apart at the shoes. It was erected in
1902, as a cantilever, with the assistance of a 900-foot cable-
Fig. 260.
way with a 2J/$-inch rope, and contains 932 tons of steel.
The connection of the lower chord of the suspended span
to the cantilever, was made with bolts in slotted holes. Two
other railroad arches were completed during the same year
at New York City, and near Birmingham, Ohio. The first
is the Rapid Transit Railway viaduct between 125th and
133rd Streets, which contains a span of 168^ feet, with two-
hinge parabolic arch ribs 6 feet deep at the center, one end
being 5 feet higher than the other, but the same number of
different length panels are used on each side of the center.
The other is the Vermilion river bridge at Birmingham, with
twin deck spans carrying the Cleveland and Southwestern
Traction line over a picturesque valley. It has a much better
appearance than an ordinary truss, and the type is suitable
where water and other natural conditions will permit. A very
much heavier three-hinged arch over the Menominee river
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BRIDGE ENGINEERING.
south of Iron Mountain, Mich., has two lines of trusses in
vertical planes 22 feet apart, with the center hinge midway
between the upper and lower chords, and the panel points
of the lower chord on a hyperbolic curve. The center pin
was raised to avoid the large reversing stresses in the web,
and the design is said to be lighter than one with a parabolic
curve. It was proportioned for Cooper's E 50 engines, and
a train load of 7,000 pounds per foot, for iron ore traffic. The
weight of steel in the arch span is 240 tons and in the ap-
proaches, 75 tons more. It replaced a deck Pratt truss span
255 feet long, built in 1885, which was too light for the loads.
398. A new departure in American arch design was insti-
tuted in the building of the highway bridge over the Con-
necticut river at Bellows Falls (1905) between Rockingham,
Vt., and North Walpole, N. H. (Fig; 261), with a span of 540
feet, the longest in America. It crosses the river just above the
hpQffhedMf^ if/x-sr
Fig. 261.
railroad bridge and the dam, which adjoins the entrance to
the canal. A single span was adopted because of the canal
company's objection to piers or other obstruction in the river.
The parabolic ribs have parallel chords 14 feet apart, with
the floor suspended from 33 panels, on a grade of 3.3 per cent
ascending to the Rockingham side, where the shore road is
crossed by a through bowstring span of 104 feet. It was de-
signed by J. R. Worcester, contains 450 tons of steel, and
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WROUGHT IRON AND STEEL ARCHES. 355
cost $47,000. An arch which is proportionately much heavier
than the last, crosses the summit of Croton dam, where it
was first intended to place a masonry arch. It has two solid
plate girder ribs 36 inches deep at the crown, and 42 at
the shoes, supporting the spandrel columns, and a floor with
solid pavement. The balustrade has a solid plate without
openings, and the face below the cornice is ornamented with
spandrel arches. It was designed by Albert Lucius, and is
very heavy, containing 360 tons of steel. The Croton river
arch near the dam has a shorter span of 159 feet without
hinges. Another open web arch is the Rio Fiscal bridge
(1906) on the Guatemala Railway in Central America, which
was designed by V. G. Bogue and erected cantilever similar
to those at Niagara. Heavy arch bridges were built at Wash-
ington, Pittsburg and Boston in 1906 and 1907, which show
clearly the tendency towards a better degree of bridge archi-
tecture in American cities. The first of these is the Anacosta
bridge over the Potomac river at 11th Street, Washington,
D. C, containing six fixed low level arch spans and a central
double bascule draw, the clear length between face of abut-
ments being 1,000 feet. This was under the direction of the
United States government and from designs by W. J. Doug-
las, government engineer. Each of the fixed spans has six
three-hinged plate girder arch ribs, 4J/^ feet deep, and a deck
48 feet wide, with asphalt and buckle plate floor, and two
lines of railway. The weight of the draw span and machinery
is 380 tons, and the total weight of metal in the bridge is
1,815 tons. Another fine arch bridge in Pittsburg, known as
the Oakland bridge (1907), crosses the Pittsburg Junction
railroad tracks and the ravine separating Oakland from Schen-
ley Park (Fig. 262). The arch is 440 feet long with 30 and 40-
foot end spans and a total length of 800 feet between abut-
ments. The road is paved with asphalt and the walks with
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WROUGHT IRON AND STEEL ARCHES. 357
granolithic on buckle pjates. The ribs are curved lattice girders
without hinges, 10 feet deep at the center, increasing to 14
feet at the springs. It was designed by Willis Whited and
cost $138,000, equal to $4.50 per square foot of deck.
399. The new bridge at Cambridge occupied more time
in preliminaries than any other in America. The commission
having it in charge prepared not less than thirty-seven differ-
ent designs and made special trips to Europe before evolving
the accepted plan. It crosses the Charles river on the site
of the old West Boston bridge on eleven steel arch spans from
101 to 188 feet long, and a deck 106 feet wide between rail-
ings, the distance between abutment faces being 1,768 feet.
Each span has twelve steel plate girder ribs supporting four
lines of car track, two highways and two foot walks. It was
constructed under the direction of William Jackson, city en-
gineer, and Edmund Wheelwright, architect, at a cost of
$2,500,000 and opened in 1907. The Part Snclling bridge
over the Mississippi river near St. Paul (1909) has two span-
drel-braced deck arch spans of 364 feet with a 105-foot deck
span at each end. It has two lines of vertical trusses and
was erected on false work under the direction of F. R. Shunk,
at a cost of $250,000. It is quite similar in outline to the old
Lake Street bridge at Minneapolis. A design and proposal
was submitted for building it in reinforced concrete at a cost
which did not exceed that of steel.
400. The first decade of the twentieth century witnessed
the origin or rebuilding of several important bridges by Eng-
lish engineers. One of these over the Waverly railway station
at Edinburgh (1900) has three spans with six vertical plate
arch ribs in each, the outer spandrels being ornamented ac-
cording to the usual European practice with cast iron fascia.
It has granite paving on brick arches between rolled steel
floor beams. The bridge of Commerce (1905) over the Meuse
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BRIDGE ENGINEERING.
at Liege, has twin flat arches, the ribs of which bear on the
center pier and thrust against each other, like the Grand
river bridge at Lansing, Mich. (1896), rather than against
the pier. The road is 48 feet wide with solid pavement.
The great Zambesi river bridge (1905) (Fig. 263), construct-
ed under the direction of the Canadian engineer Sir Percival
Girourard of Montreal, has a central arch of 600 feet sim-
ilar to the railroad arch at Niagara, with approach lattice
girders at each side, making a total length of 650 feet. The
deck is 30 feet wide, planked over, and carries a single nar-
row-gage line of the Rhodesia Railway at a height of 420
feet above water. The bridge is situated about 700 yards be-
Fis. 263.
low the Zambesi Falls, giving travelers a view of the cataract.
The two spandrel-braced arch ribs have their lower panel
points on a parabolic curve, and are 27J4 feet apart at top, bat-
tering out 1 in 8 to 53 feet at the base. The arches are riveted,
and they thrust against solid basaltic walls. It was designed
by G. A. Hobson and contains 1,650 tons of steel, which was
exported from England, the total cost being $340,000.
401. Many of the Thames river bridges have been
widened and rebuilt during the last century to meet the de-
mands of increased travel, the two most recent ones being
the Vauxhall and the Blackfriars. The temporary arch at
Vauxhall, which was used for ten years, during the time of
rebuilding, was removed in 1907, when the new one was com-
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WROUGHT IRON AND STEEL ARCHES.
359
pleted. The first bridge for the site was designed by John
Rennie, with stone arches, but the cost appeared excessive
and the design was changed to cast iron, with James Walker
as engineer, and it was completed in 1816, being the first
iron bridge over the Thames. It continued as a toll 'bridge
for sixty-three years and was then purchased by the city of
London. The short spans with eight piers were found to be
an obstruction to river travel, and it was rebuilt in 1898-1907
with only four piers and longer spans. Each span now has
thirteen steel plate ribs 3 feet deep, with the. floor supported
on spandrel columns. It is ornamented with groups of sculp-
Flg. 264.
ture on the piers and is otherwise highly artistic. M. Fitz-
maurice, engineer. The widening of Blackfriars bridge was
begun in 1907 under the direction of Basil Mott and E. M.
Wood, from the plans of Sir Benjamin Baker. The old bridge
was completed in 1868 with nine spans of 70 to 100 feet. In
widening it, the piers were extended on the up-stream end to
carry three new lines of steel arch ribs, 10 feet apart, in-
creasing the width to 105 feet, which makes it the widest
one over the Thames.
An original type of three-hinged arch (Fig. 264) in the
Assopos viaduct near Thermopylae, Greece, has a river span
of 262 feet with four 86-foot lattice spans on stone piers at
one side and a single span at the other end. The two arch
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BRIDGE ENGINEERING.
ribs lie in planes inclined to the vertical. It was designed
by the French engineer Paul Bodin, and was under construc-
tion for thirteen months previous to August, 1906. The
track is 330 feet above the valley, and the road enters moun-
tain tunnels at each end of the viaduct. Four hundred and
forty tons of steel and 606 cubic yards of masonry were used
in its construction.
402. A somewhat similar three-hinged arch bridge (Fig.
266) has lately been completed (1909) over the Nami-Ti
Gorge on the Yunnan Railway in China, the design of
Fig. 266.
French engineers. The bridge is approached at each end
through tunnels, the floor of which is 335 feet above the
canyon. It has a span of 180 feet between side bearings and
was tilted into place by means of ropes from the hillside above.
403. Preliminary designs and estimates were made in
1906 by H. G. Tyrrell for two large bridges of unusual pro-
portions to carry a single line of railroad with heavy loads
equal to Cooper's E 60 specification, over gorges in the Rocky
Mountains. For one of these locations, nine alternate designs
were made, the acceptable one being a single span braced steel
arch of 760-foot span, with its deck 370 feet above the water
(Fig. 266). For the other crossing, ten preliminary designs
were considered, with single span of 476 to 600 feet (Fig.
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WROUGHT IRON AND STEEL ARCHES.
361
267) and deck 420 feet above the valley. A double bridge
with two roads, in the form of the letter X, was proposed
(1910) to cross the Seine at Paris just above Pont Neuf, and
the island, with arches meeting on a center pier.
404 Designs for two proposed large arch bridges over
the East River at New York, have recently been made but
Fig. 266.
not yet executed — the Hudson Memorial bridge and another
at Hell Gate. The first design for the Hudson Memorial
bridge, to cross the Harlem near its junction with the Hud-
son, made by Messrs. Boiler and Hodge, of New York, con-
templates the use of a 400-foot steel span, but the design was
Flff. 267.
rejected by the Municipal Art Commission of New York be-
cause no steel structure was considered suitable for a great
memorial. The plan showed three 80-foot semi-circular ap-
proach arches at the south end and five at the north, and
massive piers with interior chambers, the two principal piers
extending above the deck as monumental features. The ma*
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362 BRIDGE ENGINEERING.
sonry was proposed in either stone or concrete or a combina-
-tion of both. The central span is shown with two pairs of
three-hinged steel arches supporting a roadway 150 feet above
the water, the total cost of structure, including the arches
over the roadway and other decorative features, would not
exceed $2,500,000. Another design for the Hudson Memorial
bridge contains a central arch 825 feet in length, framed with
two pairs of three-hinged arch ribs carrying a roadway 100
feet in width and 170 feet above the water. The whole length
of 2,600 feet included seven masonry approach spans of 90
feet and two through the main abutments with spans of 65
feet, and a clear height of 120 feet. A statue of Hudson was
intended to stand on a massive pedestal in a plaza at the
southern end of the bridge. A design for one of the largest
steel arches ever projected has recently been made by Gus-
tav Lindenthal, with a clear span of 1,000 feet and road
140 feet above the water, to carry four lines of railroad over
the East river at. Hell Gate, New York. The project includes
about three miles of viaduct, requiring 80,000 tons of steel.
The position of the central span was emphasized by end tow-
ers 200 feet high, but this feature did not meet with the ap-
proval of the Alunicipal Art Commission. A street bridge over
the Weser at Nienburg is typical of many recent ones in Eu-
rope. The Kremlin Palace bridge at Moscow, with two river
piers, has a heavy balustrade extending out of the key walls.
405. The largest metal arch bridge ever projected was
one proposed in May, 1910, by Charles Worthington, for
crossing the St. Lawrence river at Quebec, Canada, with a
single span of 1,800 feet (Fig. 268). His plan shows a deck
88 feet wide with two 23-foot carriageways and two lines of
railway, all supported on four rectangular steel voussoir arch
ribs, 9 feet wide and varying in depth from 21 feet at the
center to 42 feet at the springs, with a rise of 164 feet. The
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WROUGHT IRON AND STEEL ARCHES. 363
essential structural parts of the bridge would be accessible
for inspection and painting, and not buried in masonry, as
with suspension and cantilever bridges. The voussoirs are
shown in 9-foot lengths interlocking, built up of nickel steel
plates and angles with interior bracing, and a sectional area
of 27 square feet at the crown and 53 square feet at the
springs. In determining, the sectional area of the ribs, a com-
pressive unit of 28,000 pounds per square inch was adopted,
but if a smaller unit of 24,000 pounds were used, the cost of
the bridge would be increased by about $500,000. Mr. Worth-
ington proposes to erect the arches by suspending the vous-
soirs from cables, and when all are approximately in place,
lowering them to their bearing. The abutments are shown
130 feet thick and the arch thrust on them is partly resisted
by concrete struts 98 feet wide and 20 feet deep, extending
back 800 feet to the cliffs. At one end are four approach
truss spans of 155 feet on stone piers, and three similar ones
at the other end. The estimated weight of the span is 36,000
tons, of which 22,500 tons is the weight of ribs and bracing.
Several features of the design are patented by the originator,
who reports that the bridge would compare favorably in cost
with a suspension or cantilever.
A list of iron and steel arches with spans of 400 feet or
more, in the order of their length, is given in the following
table:
Name. Date. Span.
Niagara-Clifton 1898 840
Viaur 1898 721
Bonn 1898 668
Dusscldorf 1898 595
Oporto-Luiz 1 1885 566
Mungsten 1897 557
Niagara 1897 550
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364 BRIDGE ENISINEERING.
Garabit ; 1885 541
Bellows Falls 1905 640
Levensau 1893 633
Oporto-Pia Maria 1877 626
St. Louis 1874 620
Grunenthal 1892 613
Washington , 1889 610
Zambesi 1906 600
Paderno 1889 492
Austerlitz 1905 459
Minneapolis 1889 466
Costa Rica 1902 448
Magdeburg 1900 443
Pittsburg 1907 440
Rochester 1890 416
Richmond, Ind 1886 400
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TRESTLES AND VIADUCTS.
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CHAPTER XV.
TRESTLES AND VIADUCTS.
406. A distinction is made in these pages between trestles
and viaducts, the former term referring to those structures
which support a deck on numerous bents, either separate or
braced together in pairs, while the term "viaducts" refers to
bridges in which a series of longer spans are borne on indi-
vidual towers composed of two or more bents braced together.
Trestles are essentially an American type and are not used
generally by the engineers of other countries.
Fig. 269.
Timber Trestles.
407. Timber trestles have been used ever since Caesar built
his bridge over the Rhine, A. D. 55, but came into gen-
eral use after the beginning of railroad building in 1830.
Among the first were a number for the Little Schuylkill and
Susquehanna Railway, designed by James F. Smith in 1840,
with heights of 30 to 130 feet. The most notable of the early
ones was the old Portage viaduct (Fig. 269) over the Gene-
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366
BRIDGE ENGINEERING.
see river (1852), carrying one track of the Erie Railroad at
a height of 234 feet above the water. It was SYG feet long
with two lines of Howe truss 14 feet deep on timber towers.
Each tower was composed of three bents braced together, and
united with longitudinal girths at intervals of 40 feet ver-
tically. The towers were spaced 50 feet apart on centers,
and had a maximum height of 190 feet on stone piers 30 feet
high. The timber bents were 25 feet wide on top, sloping
out to 75 feet at the bottom. This trestle, designed in 1851
by Silas Seymour and completed the following year after
eighteen months' work, cost $140,000. It contained 1,600
feet of timber, 60 tons of iron and 9,200 cubic yards of masonry,
teisssA
and was the boldest timber trestle ever built. Being burned
in 1875, it was immediately replaced by one of metal. Fol-
lowing the building of the Portage bridge, the use of timber
trestles began in England. One over the Dearness river
(1857), by T. E. Harrison (Fig. 270), for the York, Newcastle
and Berwick Railroad, 83 feet high with eight spans of 57 feet,
had bents on masonry bases spreading out at the top into
fan-shape like those used by Brunei on lines in the West of
England, which were not expensive. This type was not the
one generally used by Mr. Harrison, but it remained in
use till 1900, when it was replaced by a brick arch viaduct
Another similar timber trestle on the Cornish branch of the
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TRESTLES AND VIADUCTS. 367
Great Western Railway of England had a series of spans,
with masonry piers about 60 feet apart and 70 feet high, each
pier being surmounted by four bents spread out in fan shape
to support the deck, the height of which was 100 feet or more
above the ground. A bridge like this, but lower, crosses the
water at Victoria, British Columbia. Few of these timber
viaducts now remain in England, for most of them have been
replaced by brick arches. Temporary wooden trestles have
been extensively used for military purposes, as those in the
civil war of 1863. A notable one is the Potomac trestle, 80
feet high and 400 feet long, built by the United States army
in nine days under the direction of Herman Haupt, and made
mostly of round timber. The rapid building and develop-
ment of American railways, especially in the West, where
timber is plentiful, has brought into existence a large num-
ber of timber trestles too numerous to describe, and a few
only can be mentioned. The Marent Gulch bridge on the
Northern Pacific Railway, ten miles west of Missoula, Mon-
tana, was designed in 1883 by C. C. Schneider as a timber
trestle with eight braced piers 226 feet high, consistiilg of dou-
ble bents 20 feet apart supporting spans of 50 feet. Longi-
tudinally the bents were vertical, but transversely they were
10 feet apart at the top, sloping out two inches per foot to the
foundations. They supported wooden Howe trusses 10 feet
deep and 10 feet apart, carrying a single track. The longi-
tudinal tower bracing consisted of 6 by 10-inch timber and
horizontal tie rods 16 feet apart, but the transverse bracing
was more complex. The wooden trestle was replaced a year
or two later by a steel one with 116-foot truss spans between
towers 140 feet apart on centers. Some very large timber
trestles were used in the building of the Canadian Pacific
Railway through the Rocky Mountains in 1885, one at Moun-
tain Creek, designed by W. A. Doane, having a length of
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368 BRIDGE ENGINEERING.
1,070 feet and a height of 160 feet. Bents were spaced 15
feet apart up to 75 feet in height, and 30 feet apart for greater
heights, with a central 150-foot span over the river on triple
bent, timber towers at each side. The whole bridge cost
$67,300. The center span was afterwards replaced by steel
on double steel towers, and much of the timber trestle at the
ends filled in with earth by means of a hydraulic jet. The
Bellevue trestle on the Algoma Central Railway, 1,500 feet
longf and 169 feet high, is one of the largest in that region.
The Two Medicine bridge (1890) on the St. Paul, Minneapolis
and Manitoba Railway was 211 feet high and 750 feet long
for single track, and contained one span of 120 feet and four
of 40 feet, in addition to the regular 16-foot spans toward the
ends. The timber pier at each side of the larger span had
triple bents braced together. A trestle on the Esquimault
and Nanaimo Railway (1890) over Niagara Canyon on Van-
couver Island, 14 miles north of Victoria, is 585 feet long on a
10-degree curve. The bents, which are 120 feet high, stand
on a 60-foot rock fill, making the deck 195 feet above the
water. Other notable ones in the West are those on the
Pacific extension of the Chicago, Milwaukee and St Paul
Railroad (1908), which are joined together with spikes, the
only bolts being those through the guard rails. The largest
ones are those at Mine Creek, 155 feet high; Change Creek,
160 feet high, and Heason Creek, 190 feet high. Erection
was facilitated by the use of an aerial cableway. A similar
electric railway trestle over a ravine near Boone, Iowa, is
165 feet high and 800 feet long, with forty-eight bays in four-
ten stories. Among the numerous timber trestles in the
South, in a region of abundant timber, are those for the North
Alabama Railway, one of which, at New Found Creek, is 684
feet long and 115 feet high, with uniform 12-foot bent spac-
ing, and continuous longitudinal girths. Alternate pairs of
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TRESTLES AND VIADUCTS. 369
bents were braced together with diagonals. Several timber
trestles of great length have been used in recent years to
carry lines of railroad over swamps and shallow water, among
which are those at Lake Pontchartrain, near New Orleans,
La.; Great Salt Lake, Utah; and Albermarle Sound. The
Pontchartrain trestles crosses six miles of lake and 16 miles
of swamp on pile bents 15 feet apart, all of which, excepting
80,000 feet, was afterwards filled in. It included two draw
spans of 250 feet and was the longest bridge of any kind in
existence. The later one on the Lucin Cut Off over Great
Salt Lake has a gravel deck and is now (1910) being raised
above flood level. A similar one of the Norfolk and Southern
Railway over Albemarle Saund, where the water is 21 feet
deep, has an open deck and a length of 26,668 feet, with bents
12% feet apart. Five plate girders, 50 feet long, on pile piers
at occasional intervals, afford clear openings of 35 feet for
the passage of motor boats, and one rolling lift span gives a
clear space of 140 feet for ships with masts, while a 94-foot
plate girder swing span provides double passage ways for
other craft. Timber trestles in other countries do not corre-
spond exactly with American practice, as is illustrated by
one at Manawater, New Zealand (1890), 463 feet long and
68 feet high, which has bents 29^^ feet apart and continuous
longitudinal bracing in all bays, with additional deck bracing
in the upper story. In 1896 the Government of Ceylon pro-
posed connecting that island with the mainland by means of
a railroad over Polk's Straits, containing a bridge forty-one
miles long. The water in the Straits is usually not over
6 feet deep.
Steel Trestles.
408. The first iron trestle (Fig. 271) was on the Stockton
and Darlington Railroad over the Gaunless river near West
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BRIDGE ENGINEERING.
Auckland, erected by George Stephenson, 1823. The first
change of type from single disconnected piers like those
at Portage was in the Carey Street trestle (Fig. 272) at
Fl«. 271.
Baltimore, designed by Wendell Bollman (1851), the
same year in which Mr. Seymour designed the Portage
bridge. The framing was all wood and the bents were con-
nected by continuous lines of timber girths, all panels having
Fig. 272.
diagonal longitudinal iron rods connecting to pins in the shoe
castings under the columns. This was the first time that
bents were braced together with iron rods. TKe first all-iron
trestles in America were on the Baltimore and Ohio Railroad,
Fig. 27S.
the work of Albert Fink in 1853. They were the Tray Run
and the Buckeye viaducts (Fig. 273) over Cheat river, which
were entirely of cast iron, excepting the bracing rods. The
first of these was 58 feet high and 445 feet long, while the
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TRESTLES AND VIADUCTS.
371
second was 46 feet high and 350 feet long, both having 28-
foot decks. They were founded on continuous masonry walls,
with expansion points at intervals of 125 feet. The intention
at first was to build the walls up to grade, but cast iron tres-
tles were used instead. The Tray Run viaduct was replaced
in 1887 by a modern steel trestle and in 1885 the Buckeye via-
duct was removed and side walls built up. Columns had a
slight transverse batter, and column bases were tied together
with rods.
409. In 1853 a design was made by Liddell and Gordon,
engineers, for a viaduct (Fig. 274) differing from those used
in America, to support two tracks of the Great Western Rail-
Fig. 274.
way over a mountain gorge and the Ebbw valley, near the
village of Crumlin, in Monmouthshire, South Wales. The
bridge is divided by a natural ridge into two parts, one of
which has three spans and the other seven spans of 150 feet
each, having a total length of 1,800 feet and a maximum
height of 210 feet above the valley. Four lines of Warren
wrought iron lattice trusses 14^/^ feet deep and 9 feet apart
in pairs are supported on. towers made of fourteen lines of
hollow cast iron columns, 12-inch diameter, with 1-inch metal,
in 17-foot lengths The columns taper in towards the top,
giving the piers their greatest width at the base. It was
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372
BRIDGE ENGINEERING.
completed in 1857 by T. W. Kennard, contractor, at a cost of
$195,000, and was the first iron viaduct with independent tow-
ers. The design was original and it has served as a pattern
for many later ones in other countries.
410. In 1856-57 the American engineer, P. C. Lowthorp,
designed and built an iron viaduct (Fig. 275) over Jordan
Creek on the Catasauqua and Fogelsville Railway with nine
spans of 100 feet and two of 110 feet, with a total length of
1,122 feet. The towers were 89 feet high, made of clusters
of cast iron columns assembled in double piers on large ma-
sonry bases, and braced together with adjustable wrought
Fig. 275.
iron rods. The bridge continued in use till 1889, when it
was replaced by a heavier one.
411. A new system of trestle building was begun in Eng-
land about 1860 by Sir Thomas Bouch, who used short bays
with bents on small individual piers, instead of cluster towers
on large masonry foundations. The cost of the Crumlin type
appeared to be excessive, and one designed by Mr. Bouch at
Bclah (Fig. 276), with a height of 180 feet for double track,
had towers composed of double bents, 15 feet apart, braced
together, supporting 45 intermediate spans similar in outline
to the latest type in America. The bents, with three lines
of cast iron columns, were battered one per cent longitudinally
and one inch per foot transversely, and the 12-inch diameter
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TRESTLES AND VIADUCTS.
373
hollow columns were connected by cast iron struts and
wrought iron diagonal rods with cotters. The deck was laid
on three lines of continuous lattice trusses 11 feet apart, the
continuity adding greatly to its rigidity. The whole viaduct
was completed in the short space of four months and was
Fiar. 276.
hastened to the utmost, as other construction was dependent
on its completion. In comparing the cost of this type with
the cost of brick viaducts, Mr. Bouch found the brick ones to
cost 25 per cent more than iron. The lattice girders of this
viaduct were strengthened in 1898 to carry the increased
^^^- — ^H H S S H fl
- —
lELLLB
J"U'1_M_1U
■%
r
Fig. 277.
loads from ore traffic. When building the Grand Trunk
Railway of Canada about 1860, English and Canadian engi-
neers made general use of plate girders on high masonry
piers like that over the Humber at Weston, Ontario. This
bridge (Fig. 277) is 650 feet long and 70 feet high, with nine
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374 BRIDGE ENGINEERING.
spans 72 feet long. Two lines of girders 4 feet 4 inches deep
support 8 by 12-inch ties 18 feet long and the deck was
guarded on each side by two lines of light chain in iron rail-
ing posts. The lower 12 feet of the piers are stone, but above
they are faced with brick. The piers are 7 feet thick and 15
feet wide at top and are capped with stone with cast iron
bed plates under the girders. Bridges of simlar type were
much used in England and Scotland, an example being the
Daff viaduct on the Wemyss Bay Railway near Iverkip, Scot-
land, which is 360 feet long, and 89 feet high.
412. European practice, especially that in continental
Europe, differs greatly in viaduct design from that in America,
and is well illustrated by structures at Fribourg, Tarente,
Busseau, Assenheim and Angelroda. The Saone viaduct at
Fribourg, Switzerland (1863), has 157- foot petal towers on
stone piers 93 feet high and 158 feet apart on centers, the
total height being 250 feet. The towers have twelve lines of
13-inch columns, the outer ones having a slope in four direc-
tions, and being united by lattice bracing. The bridge has
two tracks on four lines of trusses and it was designed by
Mathieu, the metal costing $355,000, while the whole bridge
cost $480,000, or $2.16 per square foot of profile area. The
Castelleneta viaduct near Tarente, the highest metal bridge in
Italy, has four spans, with a deck 270 feet above water, sup-
ported on three metal towers 177 feet apart, .founded on
masonry bases (Fig. 282). The lattice girders are 14.8 feet
apart and the towers, with four lines of columns, slope out in
four planes to the foundations. The lattice bracing is simi-
lar to that on the Fribourg viaduct. Two other similar ones
are the Creuse and the La Cere viaducts, both of which were
designed by Nordling. The Creuse railroad viaduct (1865),
185 feet high, is located at Busseau, and is 940 feet long, simi-
lar to the Fribourg viaduct. It has metal towers standing
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TRESTLES AND VIADUCTS.
375
on high masonry piers and cost $255 per lineal foot, or $2.20
per square foot of vertical profile. La Cere viaduct (1866),
on the Orleans railway, is 175 feet high and 775 feet long
and cost $138 per lineal foot, or $1.58 per square foot of pro-
file area. The Nidda viaduct at Assenheim has a series of
nine deck spans with curved bottom chords. The trusses
have pin bearings on the piers, which were made wide enough
to support a second track (Fig. 284). The Thalubergang via-
duct at Angelroda, for single-track railroad, has three deck
spans of 100 feet on towers with trusses 11.2 feet deep and 9.8
feet apart, and walks at each side on brackets.
413. With the building of the Bulloch Pcnn viaduct in
1868 on the Cincinnati and Louisville Railway, a new kind of
Fig. 2^8.
trestle was started in America with separate bents on indi-
vidual piers. In this respect it was similar to those in Eng-
land by Sir Thomas Bouch prior to 1861. It was 470 feet
long and 60 feet high, with separate bents at the ends and
braced towers in the middle, and was planned by Frederick
H. Smith in 1867 and manufactured by Smith and Latrobe in
1868, who made five similar ones about the same time. These
were the first of their kind in America and the beginning of
modern iron trestle building there. The Lyon Brook via-
duct (Fig. 278) on the New York, Oswego and Midland
Railway (1869) was the highest of the early metal trestles in
America, with its deck 162 feet above water. The regular
wrought iron bents were 30 feet apart and were united with
continuous lines of wood girth, wood being used instead of
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376 BRIDGE ENGINEERING.
iron to avoid trouble from expansion. In all longitudinal
bays were diagonal wrought iron tie rods. The brook was
crossed by a 100-foot truss span 20 feet deep, supported on
a pair of iron bents at each end, united with a system of iron
bracing, iron struts being used in these two towers instead
of the regular wooden ones. Columns were battered one in
eight transversely and they stood in cast iron foot boxes on
isolated pedestals. The whole trestle contained twenty-four
spans of 30 feet, in addition to the center span, and cost
$49,000. Other similar ones built by Smith and Latrobe about
the same time were the Arequipa viaduct in South America,
1,500 feet long and 55 feet high ; the Running Water viaduct,
692 feet long and 115 feet high ; Clark Run viaduct, 460 feet
long; Sidney Center viaduct, 1,500 feet long and 100 feet
FIsr. 279.
high, and the St. Charles bridge trestle, 4,318 feet long. The
Rapallo viaduct (1869), from the shops of the Phoenix Bridge
Company, for the New Haven, Middletown and Willimantic
Railway, with forty-six spans of 30 feet and a height of 30
to 60 feet, had towers with three bents braced together, and
bracing omitted in every third panel. In the same year, 1869,
a proposed design by T. C. Clark for the Blackwell's Island
bridge at New York, contained approach trestle with alter-
nate spans of 25 and 50 feet, and bents braced together to
form towers. In the following year Charles Shaler Smith
designed and built trestles similar to those by Mr. Clark,
which were probably the first ones of the modern type actu-
ally erected in America. In 1870 Charles Bender was granted
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TR£STLES AND VIADUCTS.
377
patents on a form of trestle (Fig. 279) with supporting mem-
bers spreading out in fan-shape from the piers, similar to the
wood trestles used by T. E. Harrison and others in England
previous to 1857, but none of Mr. Bender's trestles were ever
built. In the following year Edward Serrell, of New York,
patented a form of trestle with the center bent of triplicate
towers rigidly fixed to the piers, and the base of the other two
bents in cast iron expansion shoes. The St. Charles bridge
over the Mississippi, first erected in 1871, with Fink trusses,
was rebuilt (1880-85) with double intersection Whipple
trusses, and a long trestle approach with Phoenix columns.
Fig. 280.
designed for loads equivalent to Cooper's E. 25. It remained
in its original condition until 1910, when the trestle was
strengthened by encasing the columns and struts in concrete,
and made secure for E. 50 loading, work being done in three
months, from May to August, at a cost of $17,000.
414. Four viaducts on the Commentry-Gannat line in
France have lattice girders on metal towers with spread bases
and four lines of columns in each tower. La Bouble viaduct
(Fig. 280) is 216 feet high with 160-foot spans on towers which
batter 1 in 40 longitudinally and 1 in 28 transversely. The
trusses and columns are 13.1 feet apart at top and the towers
are divided into vettical bays of 16J4 feet. It is 1,300 feet
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378
BRIDGE ENGINEERING.
long, and cost $1.10 per square foot of vertical profile. The .
Bellon viaduct, on the same line, is 160 feet high with lattice
girders 15 feet deep and 131 feet long, spaced 13.1 feet apart
on similar towers, with longitudinal widths of 9.S feet at top
and 14 feet at the bottom. The steel work terminates at the
ends on masonry arches, and the whole viaduct cost $1.25 per
square foot of area between base of rail and bottom of valley.
Others on the same line are the Neuvial and the Sioule via-
ducts of 1871, both for single track. The towers of these four
viaducts differ from those previously designed by Nordling
at Creuse and La Cere, by having only four columns in each
Fis. 281.
tower instead of many. Two others of 1873 are those at Olter
oyer the Aar, and St. Gall over the Sitter.
415. The Verrugas viaduct (Fig. 281) on the Lima and
Oroya railroad over a gorge in the Cordilleras, 50 miles from
Lima in Peru, is 575 feet long and 256 feet high with trusses
supported on three triplicate bent towers, with bents 25 feet
apart. The deck was carried on four Fink truss spans, three
of 110 feet and one of 125 feet. Towers were 50 feet long and
15 feet wide on top, and contained wrought iron columns bat-
tered transversely one inch per foot with cast iron joint
blocks, the height of the three towers being 145, 252 and 178
feet respectively. It was designed by C. H. Latrobe and built
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TRESTLES AND VIADUCTS.
379
by the Baltimore Bridge Company in 1872, the manufacture
occupying 88 days and the erection 3^4 months. In the five
previous years, the same company built about three lineal
miles of iron railroad trestle. The Verrugas viaduct was the
first large one of wrought iron, with independent braced
piers. It collapsed in 1889 and was replaced by a steel three-
F\g. 282.
span cantilever. The Cincinnati Southern Railroad was one
of the largest users of iron trestles, and a number of impor-
tant ones were built on that line from designs by G. Bous-
caren, its chief engineer. He considered that continuous
lines of longitudinal bracing should run from the top of bents
to the bottom of the adjoining ones, and to secure this he
Fig. 283.
continued the longitudinal diagonals through several adjoin-
ing bays. The Horse Shoe Run and Cumberland Railroad
viaducts (Fig. 283) were of this form, the former being 89
feet high and 900 feet long, and the latter 100 feet high with
35-foot bays and Fink trussing. Fishing Creek viaduct, by
Bouscaren (1876), was the first with double towers of the
modern type, with towers and intermediate spans of the same
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380 BRIDGE ENGINEERING.
length. It was 79 feet high with 20-foot spans and short 'Fink
trusses. In 1878 Mr. Bouscareh first proportioned the length
of the intermediate spans to their height, using this arrange-
ment for McKees Branch viaduct, which was 128 feet high
at the center. In 1881 he first made use of hinged bents bear-
ing on pins at the shoes. Viaducts in Norway with rocker
bents appeared about the same time or a little earlier, and
were used at Lysedalen in 1877 and at Thomter over the Sol-
bergthal in 1881, both of which have 65-foot deck spans on
rocker bents 100 feet high. The Solbergthal viaduct has nine
spans of 38 to 65 feet with parallel chord trusses, while the
other has horizontal upper chords and curved lower ones. In
both cases the bents have a transverse batter and the columns
fV^^^^^M^^ - ^VS^^^
L
Fig. 284.
taper longitudinally, being wider at the middle than at the
ends. Another railroad viaduct with rocker bents is that over
the Oschutzbach valley, near Weida (1884), with three lattice
trusses 118 feet long and a platform 66 feet above the valley.
416. The modern type of railroad trestle reached its pres-
ent stage of development with the building of the first iron
Portage bridge in 1875 and has not greatly changed since that
time. The new Portage bridge on the Erie Railroad replaced
the timber one of 1852 and was designed by George S. Mor-
rison, bridge engineer for that company. The old wooden
structure had uniform spans of 50 feet, but when renewing
it alternate spans of 50 and 100 feet were used over the high-
est part, and some of the foundation piers discarded. It con-
tained ten spans of 50 feet, two of 100 feet and one of 118
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TRESTLES AND VIADUCTS. 381
feet with six towers, the highest being 203 feet. The towers
were made heavy and wide enough for two tracks, though
only one track was laid. The intention was to add two more
lines of intermediate trusses for the second track, which, how-
ever, was never required. Trusses were pin connected and
20 feet apart, with track on 8 by 16-inch ties, 22 feet long and
14 inches apart, resting on the top chords, and the bridge con-
tained 655 tons of structural steel, 14 tons of bolts and 130,-
000 feet of timber. It was rebuilt again in 1903 (Fig. 285)
and the deck replaced by heavier single-track girders. Oak
Orchard viaduct on the Rome, Watertown and Ogdensburg
Railroad near Rochester, N. Y., with a height of 80 feet and
a length of 690 feet, had twenty-three spans of 30 feet, with
short Fink trusses 9 feet deep and 10 feet apart, and alternate
pairs of bents braced together in towers. It was propor-
tioned for a live load of 75 tons on each 50 feet, and con-
tained 182 tons of steel.
417. The first Kinzua viaduct on the Bradford branch of
the New York, Lake Erie and Western Railway (1882) was
a light iron structure 302 feet high and 2,052 feet long, built
by Clark, Reeves and Co. It contained twenty-one alternate
apart for s,ingle track. The deck had an extreme width of
18 feet and the whole bridge contained 1,400 tons of iron.
Bents had a transverse batter of two inches per foot, and alter-
nate pairs of bents 38J4 feet apart were united into towers.
In order to use girders of the proper and yet different depths
in the tower and intermediate spans with strong connection
to the columns, the Ontario and Quebec Railway Company
adopted in 1882 a form of girder for the intermediate spans
with curved bottom chords, like those on their Rosedale via-
duct over the Don at Toronto. The intermediate girders
varied from the depth of the tower girders at the ends to
their required economic depth in the middle. The Rosedale
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BRIDGE ENGINEERING.
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TRESTLES AND VIADUCTS.
383
viaduct has 30 and 60-foot spans with girder depth of 25^ feet
in the towers and 4^^ feet in the other spans.
418. The Dowery Dell viaduct on the Halesowen branch
of the Midland Railway is similar to others in England, with
lattice girder spans on metal towers, each tower containing
six lines of columns braced together. Another type in Eng-
land differing from the Dowery Dell and from the Crumlin
and later ones by Sir Thomas Bouch was designed in 1880
by J. Dixon for the Whitby and Loftus Railway. Several of
this kind were built, among them the Staithes viaduct, 690
feet long and 150 feet high. The bents, which were 60 feet
Fiff. 286.
apart through the central part, consist of pairs of wrought
iron cylinders filled with concrete and united with transverse
bracing. The piers originally had no longitudinal connection
below the deck, but were strengthened in 1883 under the
direction of T. E. Harrison by the addition of two lines of
longitudinal struts. The floor is carried in the 30-foot spans
on plate girders, and in the 60-foot spans on lattice trusses
irontinuous over the piers. This and similar viaducts were
erected from the deck without false work by lowering pieces
into position, as is done in the modern American practice.
419. The Marent Gulch viaduct in Montana on the North-
ern Pacific Railway, which, when first built in 1883, was of
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384 BRIDGE ENGINEERING.
timber, was renewed a year or two later in steel (Fig. 286),
with five truss spans of 116 feet between towers 24 feet long
at top, battering out longitudinally and transversely to the
foundations. It is 200 feet high and 800 feet long, with two
approach spans of 30 feet at each end. Trusses and columns
are 20 feet apart transversely, with a system of stringers and
floor beams. The piers contain 544 cubic yards of concrete
and the superstructure 843 tons of steel, equal to 2,133 pounds
per lineal foot, the complete cost being $178,000. It is one
of the best proportioned and most satisfactory designs in
America.
420. Two unusually large highway viaducts are those at
St. Paul over the Mississippi, and at Cleveland over the Cuya-
hoga. One at St. Paul contains twenty-eight spans of 40 to 250
feet, the greatest under clearance being 129 feet. The viaduct
portion has the bents of every fourth bay braced together,
the remaining bents standing independently. A somewhat
similar one at Cleveland, known as the Cleveland Central Via-
duct (1888) has a length of 5,228 feet, with 40-foot road and two
8-foot sidewalks, 101 feet above the valley. It has 30-foot
tower spans, with intermediate ones of 43 to 135 feet. The
road had block pavement on pine plank, and the sidewalk
three-inch pine, the whole containing 5,370 tons of steel and
costing $675,000. The Lfoa, Malleco and Pecos viaducts
(1888-92) are among the largest ever built. The Loa in
Bolivia is 336 feet high, carrying a narrow (2^4 feet) gage
track of the Antofagasta Railroad. The Malleco viaduct in
the southern part of Chili (1891) is 310 feet high, with mul-
tiple system lattice girders on four metal towers. It was
designed by Aurilio Lasterria, and the metal was exported to
Chili from France. The type is the prevailing continental one,
with long spans between piers 225 feet apart. Other notable
ones are the Souleuvre viaduct in France, 1,200 feet long and
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TRESTLES AND VIADUCTS. 385
247 feet high, and the Moldau viaduct in Bohemia, 886 feet
long and 214 feet high. A railroad trestle in Mittweida val-
ley near Schwarzenberg, Saxony (1889), has a series of trusses
with curved bottom chords between braced towers, the floor
above the towers being supported by a system of Fink trusses,
above the tower bracing. It is said to be patterned after the
American type, but the resemblance is not striking. The
Pecos viaduct (1894) is one of the largest in America, and is
unusual in having a pair of cantilevers with a clear span of
185 feet above the river, each cantilever being supported on a
tower of regular outline. Other towers have 36-foot plate
girders with lattice trusses in the intervening spans. It was
proportioned for an assumed wind pressure of 50 pounds per
square foot, and erected by sixty-seven men in eighty-seven
days. The west end, 1,070 feet long, has an average height
of 57 feet, and 600 feet of the east end an average height of
260 feet, with a total average through the whole length of 129
feet. The profile area between base of rail and top of piers
is 280,000 square feet, and the whole viaduct cost $238,000,
equal to $119 per lineal foot. Panther Creek viaduct (1893)
on the Wilkesbarre and Eastern Railway, 154 feet high and
1,650 feet long, has alternate spans of 30 and 65-foot plate
girders on towers with rigid bracing, and was erected in a
period of six weeks. An unusual type of viaduct with only
a single line of center columns having wide spread footings
somewhat similar to parts of the New York City elevated
railway, was erected at San Fernando Street, Los Angeles,
in 1891. It was 1535 feet long and 26 feet high, and carried
two lines of cable cars.
421. A movement towards better and more artistic design
was started in 1896 by the construction of several viaducts in
which due consideration was given to their appearance.
Among these were highway viaducts near Cleveland, Ohio;
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386 BRIDGE ENGINEERING.
Knoxville, Tennessee; and Snodland, England. The one on
Loraine Street near Cleveland, Ohio, over the South Rocky
river, has nine spans on metal towers, with a street 32 feet
wide, 130 feet above the valley. The trusses, with curved bot-
tom chords, are without arch action, and their center depth
is slightly less than ordinarily used for trusses with parallel
chords. The towers, which are 18 feet long on top, have a
batter of one-half inch per foot longitudinally and one inch
per foot transversely. The framing is riveted and gussets or
connection plates are curved and projecting brackets and
railing are artistic. A brick pavement on buckle plates, with
two lines of car tracks, constitute the floor. Towers were
erected from below and the trusses assembled and connected
on the ground and afterwards hoisted into place. The Osborn
Company of Cleveland were engineers, and the finished cost
of their work was $160,000. Another artistic design is the
Knoxville bridge over the Tennessee river, an arched canti-
lever viaduct, with curved bottom chords on stone piers. It
is 43 feet wide with a 30-foot paved roadway and two walks
with a double line of street railway. It was designed by C. E.
Fowler, with five main spans, each about 280 feet in lengt/i,
and half spans at the ends. The Snodland bridge over the
Mersey, England, is a long arched viaduct with nineteen
spans of 120 feet and one of 240 feet, with a maximum under
clearance of 95 feet above the water. The two lines of arch
ribs have tubes for the bottom chords, 24 inches diameter in
the shorter spans, and 36 inch for the longer one. The regular
piers consist of steel tubes 3^^ feet diameter, braced together,
while the two adjoining the river are 65^ feet diameter and 60
feet high to the springs. The bridge has an 18-foot road and
two walks on cantilever brackets, with a total width of 30 feet,
and contains 1,600 tons of steel with an average cost of $33
per lineal foot of viaduct. H. Woodhousen engineer.
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TRESTLES AND VIADUCTS. 387
422. The rolling mills producing structural shapes were
so crowded in 1899 that it was difficult to secure steel in any'
reasonable time, and when building the Grasshopper creek
trestle on the Chicago and Eastern Illinois Railroad it was im-
practicable to wait for mill delivery, and other sections
were substituted. The columns are composed of double chan-
nels with a beam between them, and the 25-foot tower
spans have six lines of 24-inch beams at 100 pounds, three
under each rail, while the 47J/$-foot intermediate spans have
four 24-inch beams at 80 pounds trussed with double chan-
nels and a web system of 15-inch beams.
423. Trestles and viaducts have frequently been renewed
because of the increased weight of locomotives and train load-
ing, and several in America have thus been replaced, including
those at Verrugas, Lyon Brook, Kinzua and Portage. The
rebuilding of the Verrugas viaduct as a cantilever has pre-
viously been mentioned. The Lyon Brook trestle on the New
York, Ontario and Western Railway originated in 1869, was
rebuilt in 1894, with square towers, under E. Canfield, the
new trestle being placed outside the old one, at a cost which
was less than the cost of the original bridge. The Kinzua
viaduct of 1882 continued in use for eighteen years, when it
too was reconstructed (1900) for heavier loads, under the
direction of C. R. Grimm. It contains twenty-one spans of
60 feet between double bent towers 38J^ feet long with gir-
ders 654 and 5 feet deep respectively, and all joints riveted.
A feature of the reconstruction is the absence of transverse
diagonals in the bents, which are strengthened by corner brac-
mg at the cross struts. Girders are framed into the columns
instead of resting on them, and expansion is provided for by
sliding pockets or girder seats on the columns at occasional
intervals,
424. Two of the largest viaducts ever made were pro-
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388
BRIDGE ENGINEERING.
duced in American shops in 1900, one for export to Burmah
and the other for erection at Boone, Iowa. The Gokteik via-
duct in Burmah (Fig. 287) is 2,260 feet long and 320 feet high,
with fourteen single 40-foot towers and one double tower,
supporting ten spans of 120 feet, and seven of 60 feet. Bents
are 245^ feet wide at top, for double track, but girders for one
track only were placed at first. Columns have a batter of
2>4 inches per foot transversely, which is more than is usual
on similar structures. To stiffen the deck laterally the top
flange of truss, floorbeams and stringers are all at one level,
and where they join are covered with 5/16-inch plates. It
was built under the direction of Sir Arthur Rendel, engineer
for the Burmah Railroad Company. The most favorable con-
Fig. 287.
struction tender submitted by a European firm was $130 per
ton for the steel, with completion in three years, while the
American firm which was awarded the contract received $75
per ton for completion in one year. It was erected by the
use of a traveler with a boom 150 feet long. The Boone via-
duct (Fig. 288) on the Chicago and Northwestern Railway,
over the Des Moines river, is 185 feet high with eighteen tower
spans of 45 feet, and twenty-one intermediate spans of 75 feet,
with a 300-foot span over the river, on special towers. It has
four lines of plate girders with a uniform depth of 7 feet and
is the longest double-track viaduct in the world. Towers
have stiff diagonal bracing without horizontal struts, except-
ing at the bottom, and each column consists of two 20-inch
beams and one 15-inch beam standing on cast iron shoes.
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TRESTLES AND VIADUCTS. 389
Girders have four angles in the upper flange and ov^r the col-
umns the girders are halved together, the lower half of one
girder end forming a seat for the upper half of the adjoining
one. Tracks are 13 feet apart on center and column legs
19y2 feet apart at top, while the whole deck is 36 feet wide,
protected at each side by strong iron railings. It was designed
by George S. Morrison. Another large viaduct over the Des
Moines river for the Mason City and Fort Dodge Railway,
at Fort Dodge, Iowa, is 138 feet high with 38-foot towers and
75-foot spans, and' four spans of 200 feet on mitered towers.
425. Designs with general drawings and specifications
were made by the writer in 1901 for a steel railroad via-
duct (Fig, 289) for the Algoma Central Railway to cross the
Montreal river and valley north of Lake Superior. The via-
duct was 125 feet high and 1,500 feet long, and the design
showed a series of trusses with curved bottom chords be-
tween towers battered both longitudinally and transversely.
It was arranged for cantilever erection with a short boom
traveler.*
426. The partial reconstruction of another American via-
duct was made in 1903, when the deck of the Portage viaduct
of 1875. which had been used for 28 years, was replaced by a
heavier one on the old towers, which were originally propor-
tioned for double track. The bridge (Fig. 285) has six 50-foot
towers with two truss spans of 100 feet and one of 118 feet
•with trusses and girders 14 feet apart and ties on the top
chords. In the original viaduct the trusses rested directly
on the columns, which were about 20 feet apart at top, but in
the reconstruction the new trusses were placed inside the old,
and work continued without interfering with the regular traf-
fic. New cross girders to support the longitudinal trusses
•Economic Length of Trestle Spans. H. G. Tyxrell. In Railroad Gazette. Dec.30. 1904.
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BRIDGE ENGINEERING.
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TRESTLES AND VIADUCTS.
391
were inserted between the column tops. The reconstruction
of the deck required 500 tons of new steel. A somewhat simi-
lar bridge over Caneadea gorge, 175 feet high, has 40-foot
towers and 100-foot truss spans, which were erected with a
derrick car. The Erie Railroad, which twice rebuilt its Port-
age viaduct, began in 1907 the construction of another over
Moodna creek, 182 feet high and 3,200 feet long, on a 2 per
cent grade, with alternate spans of 40 and 80 feet and girders
5yi and 9 feet deep respectively. Towers are 1954 feet wide
at top for future double track, but only one pair of girders,
654 feet apart, were placed at first. The Stony Brook Glen
viaduct, 242 feet high with 40 and 80-foot spans, has all gird-
ers 7 feet apart, and a uniform girder depth of 8 feet, the
girders being erected by a derrick with lOO-foot boom. The
rig. 290.
Richland Creek viaduct (1906), near Bloomfield, Indiana, 168
feet high with 40 and 75-foot spans, has girders with a uni-
form depth of 7 feet like the last one mentioned and the
Boone viaduct, Iowa, The one at Bloomfield is 2,215 feet
long for single track, contains 3,000 tons of steel, and was
erected in 50 days by a force of forty men.
427. Designs were made in 1906 by H. G. Tyrrell for
two viaducts to cross gorges in the Rocky Mountains (Fig.
290), one of which had a height of 420 feet, higher than any
other in America, and exceeded only by the recently completed
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392 BRIDGE ENGINEERING.
Fades viaduct in France. In both designs towers with trans-
verse and longitudinal batter supported truss spans for canti-
liver erection. These designs were made in connection with an
investigation of the economic and most suitable type of struc-
ture for the proposed crossings. In the following year several
bridges of this type with shorter spans were erected on the
Guatemala Railroad, those at El Rodeo and Las Vegas design-
ed for cantilever erection with short-arm travelers, and inter-
mediate 75-foot spans 12 feet deep and 10 feet apart. The tow-
ers have stiff diagonal bracing without horizontal struts, and
4-foot box girders at top, 18 feet long. In the same year com-
plete designs with details, estimates and specifications were
prepared by the writer for a street viaduct of very unusual
Fiff. 291.
proportions over the railroad yards at Ogden, Utah (Fig. 291).
The main viaduct was 2,260 feet long with thirty-one arch
spans, and at one end was a double trestle approach 620 feet
long leading up to the deck, with five more arches parallel to
the tracks. The whole bridge, therefore, contained thirty-six
arches of about 60 feet and a length of 2,880 feet. A Somewhat
similar one with one end approach at right angles to the main
viaduct, was outlined by him, to cross the railroad yards at
Pocatello, Idaho.
428. Two viaducts of 1908, which were erected by cable-
way, are those at Colfax, California; and Makatote, N. Z.
The Colfax bridge over the Bear river is 190 feet high and
810 feet long, with a pair of central cantilevers over the river
similar to the Pecos viaduct on the Southern Pacific. The
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TRESTLES AND VIADUCTS. 393
trusses of the cantilever, which have pin connections and rod
bracing, are in the plane of the sloping columns rather than
the vertical, and the remaining part, with 40 and 60-foot spans,
have girders 7 feet apart with a uniform depth of 5 feet. The
span of cableway was 830 feet. It was proportioned for only
twenty-ton locomotives, but provision was made for increas-
ing its capacity. Makatote gorge. New Zealand, 300 feet
deep, is crossed by a single-track viaduct 840 feet long, with
five towers 36 feet long supporting 100-foot truss spans, the
whole being erected similar to the one at Colfax. Columns are
9 feet apart at top and are battered two inches per foot at each
side. It contains 1,000 tons of steel and is the design of P. S.
Hay.
429. Three large and unusual trestles were erected in
Canada in 1908 and 1909. The Cap Rouge viaduct on the
Transcontinental Railway is 173 feet high, with alternate
spans of 40 and 60 feet, and three-deck truss spans. The two
columns of each bent, 9 feet apart at top, are made of two
rolled steel beams latticed together, and the longitudinal
tower bracing is arranged with a minimum number of heavy
members. The Battle River viaduct on the Grand Trunk
Pacific Railway in Alberta, 184 feet high and more than half
a mile long, has plate girder spans with uniform bent spacing
of 50 feet in all bays, and a single, deck-truss span of 150 feet.
But the largest one in Canada is the new Leithbridge viaduct
(Fig. 292) on the Canadian Pacific Railway over the Belly
river and valley in Alberta. It consists of alternate spans of
67 and 100 feet half through plate girder spans with girders
16 feet apart on centers and 8 feet deep. Half-through con-
struction was adopted to prevent a train from leaving the
track in case of derailment, a plan which was previously used
on the Garabit viaduct in France, and later on trestles in New
Brunswick. The great tower width of 67 feet made it eco-
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394
BRIDGE ENGINEERING.
nomical to use horizontal struts and diagonal tension mem-
bers, rather than diagonal struts without horizontal members.
Each 100-foot girder weighs 30 tons, and the 67-foot girders
15 tons each. They were erected with a steel traveler, the
weight of which was 356 tons. Columns are 26 inches square,
built up of plate and angles with cover plate, and rfie structure
contains 17,000 cubic yards of concrete, 1,700 concrete piles,
and 12,200 tons of steel. Manufacture was done by the Can-
adian Bridge Co., under the direction of J. E. Schwitzer, engi-
neer for the railroad company. A trestle with a different
style of tower (Fig. 293) was erected near Greenville, Maine,
1909.
-..Af»/.4...._ «ir#'
ne. 293.
430. The Fades viaduct, 1,231 feet long, in three spans,
has the longest continuous spans in the world, and is remark-
able for its great height, and its large masonry piers. It
crosses the valley of the Sioule river near Vauriat, France,
with the rail 435 feet above the water, which is 8 feet higher
than the Spoleto stone viaduct, which was formerly the high-
est of all. The center span of 472 feet has one 378-foot span
at each side» terminating at one end with a masonry abutment
and 78-foot arch, and at the other end with a girder span,
which was substituted instead of an intended arch because
of the yielding foundation. The two lines of lattice girder,
22 feet apart and 38 feet deep, are supported on two hollow
masonry piers 303 feet high, which cost $130,000, or about
twice as much as steel piers. The side spans were erected on
false work and continued over the piers to meet in the center.
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TRESTLES AND VIADUCTS. 395
431. A table of the largest viaducts described, with their
heights and lengths, in order of date, is as follows :
Date.
Crumlin, England 1857
Belah, England 1861
Fribourg, Switzerland . . 1863
La Bouble, France 1872
Verrugas, Peru 1872
Portage, New York 1875
Kinzua 1882
Marent Gulch, Montana . . 1884
Loa, Bolivia 1888
Malleco, Chili 1891
Pecos, California 1892
Boone, Iowa 1901
Gokteik, Burmah 1900
Makatote, New Zealand. . . 1909
Fades, France 1909
Leithbridge, Canada 1909
[eight
Length
Weight
feet.
feet.
tons.
210
1,800
180
960
250
1,300
216
1,300
256
575
203
818
655
301
2,053
1,400
200
800
843
336
800
1,115
310
1,200
320
2,180
1,820
185
2,685
6,200
335
2,260
4,850
300
860
1,000
435
1,228
314
5,327
12,200
From the above it appears that the Fades viaduct is the
highest, and the Leithbridge the longest and heaviest, while
the Boone and Gokteik are the next largest. Their relative
artistic merits and economic proportions are discussed else-
where.
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396 BRIDGE ENGINEERING.
CHAPTER XVI.
SOLID CONCRETE BRIDGES.
432. Many of the largest masonry bridges of recent years
have arch rings of solid concrete without reinforcing, or if
metal was introduced it was for uniting the material into a
solid monolith rather for resisting tensile stresses. Bridges
of solid concrete are similar in principle to thcfee of stone
masonry, and in the transition from one kind of material to
the other, plain concrete without reinforcing antedates the
later combination of concrete and metal. A concrete foot
bridge at Amalfi, Italy, on the Gulf of Salerno, said to have
originated with the Moors about the sixth century, is still in
fairly good condition. It is 5 feet wide, 10 feet above water,
and 23 feet long, the arch ring being perforated with a series
of transverse circular openings. Many old Roman bridges
and aqueducts which were faced with stone had concrete 'back-
ing and filling, but it was not till the middle of the nineteenth
century that solid concrete was extensively used without stone
facing. The Grand Maitre Aqueduct (1850-65), which con-
veys water from the river Vanne, 94 miles distant, through
the Forest of Fontainebleau, and over the Loing river to the
city of Paris, is borne on a long series of concrete arches with-
out stone facing, and this work was the beginning of modern
concrete bridge building. Ten years after the completion of
the Paris Aqueduct, some concrete bridges were built in
Switzerland, but it was not till 1890 that the new material
came into general use. In the last decade of the nineteenth
century concrete bridges appeared at Munderkingen, Verdun,
Kirchheim, Inzighofen, Imnau, and Miltenburg, the last three
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SOLID CONCRETE BRIDGES. 397
having hinges at the springs and crown. A small concrete )
bridge of 31-foot span was placed in Prospect Park, Brooklyn, y
in 1871, but the first important concrete bridge design in
America was one proposed in 1886 by Thos. C. Clark for cross- \
ing the Harlem river at New York City, with three semi-circu- .
lar arches of 285 feet. Mr. Clark outlined a bridge 160 feet ^
high, 100 feet wide, and 1,200 feet long with stone facing, at an •
estimated cost of $3,500,000. But the present twin steel arch ,
was accepted instead, and the first solid concrete arch bridge
actually built in America was a small one, 34 feet wide, over
Pennypack Creek at Philadelphia, with two spans of 25 feet,
wire mesh Weing embedded in the concrete for extra security.
Two years later a 40-foot span appeared over Richmond Creek
at Belleville, Illinois, which was at that time the largest of its
kind in the United States.* Soon after this several of the large
railroad systems, including the Pennsylvania, the Lake Shore
and Michigan Southern, and parts of the New York Central*
began renewing their old steel bridges in masonry, at first
using stone facing on the piers and spandrels. Among the im-
portant railroad bridges of the time are those over the Susque-
hanna at Rockviile, over Big Muddy river at Grand Tower, Illi-
nois, and others at Mechanicsville, Thebes, Ashtabula, River-
side, Long Key, and the Danville and Terre Haute bridges of
the Big Four Railroad. Similar construction was adopted on
the West Highland Railway in Scotland (1898), when many of
their bridges, most of which had spans of 30 to 50 feet, were
built in concrete. One, however, at Borrodale, had a span
of 127 feet. In contrast to the many hinged concrete bridges
in Europe, all heavy ones in America have fixed ends. The
Rockviile bridge over the Susquehanna, with 48 spans of 70
feet, cost upwards of $1,000,000 and is the largest of its kind.
*In 1881, three concrete railroad viaducts were erected on the Bwarton branch of the
Jamaica Railway, one of them having: four full centered arches of 50 feet, without rein-
forcement.
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398
BRIDGE ENGINEERING.
Piers and spandrels are faced with stone, but the centers and
arch rings are concrete. The Big Muddy River bridge (1903),
near Grand Tower, Illinois, for two tracks of the Illinois Cen-
tral Railway, is a three-span concrete bridge replacing an old
steel one, the piers of which were allowed to remain. The
old piers were 9 feet thick and new ones, 22 feet thick, were
built around them. The three main arches are solid concrete,
elliptical, with semi-minor axes of 30 feet. The only reinforc-
ing is in the spandrel arches supporting the floor and this was
introduced for convenience of erection. The spandrel construc-
tion, with arch openings, cost more than solid filling, but was
Fig. 294.
preferred because of its less load on the foundations. The
Riverside bridge, carrying the San Pedro, Los Angeles and
Salt Lake Railrpad over Santa Ana River, was designed and
erected under the direction of Henry Hawgood, chief engi-
neer for the railroad company. The distance between pier
centers is 100 feet, and as the piers are 14 feet thick, the cen-
tral arches are 86 feet, and the two end ones 38 feet. It is all
solid concrete without reinforcing, contains 12,500 cubic yards
of concrete and cost $185,000. The Long Key Viaduct (Fig
294) is one of several similar structures, carrying the Florida
East Coast Railway from the main land to the port of Key
West. The aggregate length of the viaducts is six miles, and
this one, which is the longest, contains 180 semi-circular
arches of 50 feet clear span, with a total length of 10,500 feet.
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SOLID CONCRETE BRIDGES.
399
The regular piers are 9 feet thick, but every fifth one is an
abutment pier 12 feet thick at the springs and all piers bat-
ter out 1 inch per foot at each side. The bridge is 15 feet
wide at top for single track, and is made of solid concrete with
metal reinforcement, the spandrels being filled with earth.
The deck is 30 feet above mean water, the depth of which is
13 to 25 feet, underlaid with coral rock. The concrete railway
viaduct over Finnan Valley, Scotland (1898) is 1250 feet
long and 100 feet high, containing twenty-one semicircular
arches of 50 feet each. All piers excepting two are 20 feet
Fisr. 295.
long and 6 feet thick at the top, the other two being 21 feet long
and 15 feet thick, with hollow centers. The bridge is on a curve,
and has three lines of longitudinal spandrel walls.
433. A great increase in span length was made in the
Gruenwald bridge over the Isar river at Munich (1904),
which has a 230-foot opening with three steel hinges, being the
longest span up to that time. In the two following years
other bridges were built at Ulm and Kempton, Germany, with
spans of 210 feet, the latter having three hinges. The main
arch of Gruenwald bridge was designed independent of rein-
forcing, though metal was afterwards added. The ring has a
thickness of 30 inches at the crown, 36 at the springs and 48
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400
BRIDGE ENGINEERING.
at the quarter points. Spandrel columns supporting the floor
system are two meters apart transversely, and four meters
apart longitudinally. The Danville (Fig. 296) and Terre
Haute (Fig. 297) arches of the Big Four Railroad are simi-
^i^r^ -^^. - . .i^a^MT is:
Zi J*_.B.._*^ l/- ^
Fig. 296.
larly proportioned as solid masonry arches with reinforcing
added, simply to unite the concrete.
434. The first American hinged concrete arch is in Brook-
Fig. 297.
side Park, Cleveland, over Big Creek. It has steel hinges
and is without reinforcing, the intrados being a semi-ellipse
92 feet long and 9 feet rise. As the hinges were placed at
the points of rupture the real arch span and rise were reduced
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SOLID CONCRETE BRIDGES.
401
to 86 and 5^4 feet respectively. Hinges were similarly placed
on the Kempton bridges in Bavaria, over the Iller river, where
the span between hinges was reduced to 166 feet (Fig. 295).
The two bridges at Kempton differ only in width, one having
a deck 54 feet wide for four tracks, while the other is 25 feet
wide for only two tracks, the wider bridge having two sepa-
rate rings 4 inches apart.
435. Four large street bridges of the last decade in Amer-
ica, at Washington, Philadelphia, Cleveland and Spokane, are
designed with twin arch rings similar to the Luxemburg stone
arch in Germany (Fig. 32). The bridge at Washington, car-
rying Sixteenth Street over Piney Creek, has a parabolic arch
Fiff. 298.
5 feet thick at the crown without reinforcement, only one of
the twin arches being erected at first. The platform is sup-
ported dn a series of spandrel columns, the construction being
obscured by solid spandrel walls. The second arch ring was
added in 1909, making the bridge 65 feet wide. Each of the
two ribs are 25 feet wide, the space of 15 feet between them
being bridged with 24-inch steel beams, 10 feet apart. The
original work cost $50,000, and the addition $85,000 more.
Walnut Lane bridge, Philadelphia (Fig. 298), connecting the
residential suburbs of Roxboro and Germantown, crosses the
Wissahickon valley at a height of 147 feet above the river,
and when completed was the longest solid concrete bridge,
having a clear span of 233 feet. It consists of two separate
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402 BRIDGE ENGINEERING.
arch rings 18 feet wide at the crown, increasing to 21J4 feet
at the springs, the two rings being separated at the crown by.
a space of 16 feet. The centering, which was a combination
of wood and steel, was first used for one arch rib, and then
moved over for the other rib. The main arch ring, which is
an approximate ellipse, carries ten cross walls which support
the floor system. At the ends are five semicircular arches of
63 feet. The bridge is solid concrete without reinforcing, ex-
cepting in minor details. The surface is rough, similar to peb-
ble dash, but of coarser grain, exposing stone chips }i inch
diameter, formed by surface washing before the cement was
hardened. The bridge is 585 feet long, 60 feet wide, and cost
$259,000. George S. Webster, chief engineer. H. H. Quimby,
bridge engineer. In addition to this bridge Philadelphia has
more than fifty other concrete bridges, either solid or rein-
forced.
The longest masonry span in America is the new con-
crete arch bridge over Rocky River on Detroit Avenue, Cleve-
land, Ohio, with a central span of 280 feet and five end spans
of 44 feet each. The main span, with two separate arch rings
18 feet wide, and 16 feet apart at the crown, support cross
spandrel walls carrying the roadway. The brick pavement
with two lines of interurban track for heavy cars, is 94 feet
above low water. Beneath the floor are two subway cham-
bers 3 by 11 feet for pipes and wires. The main arch rings
contain no steel reinforcement, as calculations show that
tension cannot occur in any part of the arch. Sidewalks pro-
ject out about five feet over the face walls, and are supported
on brackets. The central arch is similar to and 47 feet longer
than the Walnut Lane bridge at Philadelphia, and the only
longer masonry arches are those at Plauen, Germany, of hard
slate, with a span of 296 feet, and the Auckland concrete
arch of 320 feet. Plans are under way for replacing the
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SOLID CONCRETE BRIDGES.
403
steel cantilever at Spokane with a four-span concrete arch
bridge to carry Monroe Street at a height of 140 feet above
Spokane river. The 281-foot segmental arch will have twin
ribs 16 feet wide and 6 feet deep at the crown, with over-
hanging sidewalks, and cross spandrel walls 20 feet apart.
At the ends will stand ornamental Dutch towers for public
service and convenience. The ground on the north side of
the river is naturally suited for an arch bridge, but on the
south side the plan proposes an abutment carried down to
140 feet below street level, with four parallel walls each 4 feet
thick, joined by numerous cross struts and braces.
436. The Lautrach three-hinged arch was quite economi-
cal, for its cost was only $21,600, while the estimated cost of a
„iim i.i",'"'
mi9lf^.
!f W^.l ' J.ypNi^»^..^l^f ?7H!»! i^ . ' ^yw»f ^ p» ftP | ip ^wjffjp<s
Fiff. 299.
steel bridge for the same place was $26,200. Two solid con-
crete railroad bridges for double track, the design of Mr. Lin-
coln Bush, were completed in 1908 at Hainsburg, N. J., and
Portland, Pa. (Fig. 299), with spandrel arches and U abut-
ments, the last having seven spans and elliptical intrados and
a skew of 65 degrees. Temporary three-hinge steel arches
for centering were used on the Portland and Rocky River
bridges, the cost in steel being less than in timber. The
Wiesen bridge in Switzerland (1908) is made of concrete
blocks cast in place, with a facing of rough natural stone, and
is remarkable for its long span and great height of 325 feet.
The four-track bridge over Grand river at Painsville, Ohio,
replaced a four-span stone arch bridge which was considered
too light, and like several other concrete railroad bridges, was
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404 BRIDGE ENGINEERING.
proportioned as a solid masonry arch, and reinforcing metal
added afterwards, not, however, for resisting direct tensile
stresses. A bridge over Gwynns river at Edmondson Avenue,
Baltimore, has three spans with solid arch rings and a floor
with asphalt pavement and double car tracks supported on
spandrel columns. Other long spans are proposed at Larimer
Avenue, Pittsburg, over Beechwood Boulevard, with a span
of 300 feet, and one at Mannheim, Germany, over the Neckar
river, with a span of 365 feet.
437. Connecticut Avenue, one of the chief thoroughfares
of Washington, is carried over Rock Creek valley near its
junction with the Potomac, about three miles from the Capitol
building, on a concrete arch bridge 120 feet above the valley.
It has five semicircular arches of 150 feet, and two of 82 feet,
with a length between abutments of 1,068 feet, and a total
length of 1,341 feet. The main arches are hingeless without
reinforcing, but the spandrel arches contain metal bars. As
the bridge is located in a fine residential district, its aesthetic
appearance was a matter of considerable importance. The face
rings of the arch, pier corners, mouldings and all trimmings
below the granite coping are moulded concrete blocks. Othei
exposed concrete surfaces are bush hammered, presenting a
uniform and pleasing appearance. The false work cost about
$50,000, on which there was salvage of $15,000. Framing
the falsework cost $9.00 per thousand feet of lumber, and
molded cement blocks cost $15.00 per cubic yard. The whole
bridge cost $850,000, equal to $639 per lineal foot, or $12.30
per square foot of floor surface. The design was a modifica-
tion of one submitted by the late George S. Morison, and it
was built under the direction of W. J. Douglas, bridge engi-
neer, and E. P. Casey, architect.
438. The concrete arch at Auckland, New Zealand (Fig.
303), with a central span of 320 feet, is the longest on record.
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SOLID CONCRETE BRIDGES. 405
and replaced a light suspension bridge. Larger ones have been
projected, including one over the Mississippi river at Fort
Snelling, Minn., with two spans of 350 feet, but none have ma-
terialized. In addition to the central span, the Auckland
bridge has several concrete girder spans of 35 to 81 feet, the
longer ones having open webs. The approach at one end is
305 feet long. The bridge is 40 feet wide, including two
6-foot sidewalks, 147 feet high above the valley and 910 feet
long, and the two arch rings are hinged at the springs and cen-
ter. The floor is paved with asphalt and the walks with ce-
ment. It was designed by R. F. Moore, engineer for the Ferro-
concrete Co. of Australasia, and built under the direction of
W. E. Bush, city engineer of Auckland. Construction was
commenced in February, 1908, and work completed in April,
1910, at a cost of $170,000. Two parallel arch rings support-
ing the spandrel columns are connected by wide reinforced
concrete ties. The bridge adjoins a residential district, and
beneath it at one end are the graves of New Zealand pioneers.
439. The construction of a great memorial bridge at the
city of New York to commemorate the explorations and dis-
coveries of Henry Hudson has been seriously considered for
several years. The location selected is on an extension of
Riverside Drive over Spuyten Du3rvil Creek. Several alter-
nate plans were prepared, but the one accepted by the Munici-
pal Art Commission was a concrete arch. Metal was con-
sidered inappropriate for a great memorial structure, and all
steel designs were therefore rejected. The accepted design
shows a central 703-foot arch with seven semicircular end
spans of 108 feet, and a clearance at the center of 183. The
main arch would contain 8,500 tons of steel in its twelve arch
ribs, not merely as concrete reinforcement, to resist bending
stresses, but to assist in resisting compression, and thereby
reduce the amount of masonry. There would be two decks,
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406
BRIDGE ENGINEERING.
the upper one with a 50-foot driveway and two 15-foot side-
walks, while the lower deck, 70 feet wide, would carry" four
lines of electric railway, but it is intended to omit the lower
deck until needed. The main piers would be 180 feet wide,
and the estimated cost of the whole structure is $3,800,000.
The weight which the falsework would have to support dur-
ing construction would be 100,000 tons, and this would cause
a pressure on the entire ground area beneath the arch of two
tons per square foot.
440. Solid concrete bridges with spans over 200 feet in
length are given in the following table :
Name. Span in feet. Date.
Rome, Italy 328 1911
Auckland, New Zealand. 320 1910
Spokane, Washington 281 1909
Cleveland, Ohio 280 1909
Philadelphia, Pennsylvania 233 1906
Gruenwald, Bavaria 230 1904
Kempton, Germany 211 1906
Ulm, Germany 210 1905
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REINFORCED CONCRETE BRIDGES. 407
CHAPTER XVII.
REINFORCED CONCRETE BRIDGES.
441. The existence of bridges in a good state of preserva-
tion, which were built many centuries ago, some of them be-
fore the Christian era, is the basis of faith and confidence in
concrete bridges. Among the early bridges are those on the
aqueducts of Rome, Nimes, Carthage, Antioch and Segovia,
dating from the first century, and the Bourgas (Fig. 45) and
Spoleto aqueducts of the sixth and eighth centuries. Pont
du Gard (Fig. 44), a bridge over the Garden river in the
Nimes aqueduct, is perhaps the best preserved of all and has
lasted for about 1,900 years. Many old road bridges of stone
and concrete remaining from ancient times are further evi-
dence of the superiority of concrete and masonry over all
other kinds of building material. These road bridges include
Ponte Rotto (142 B. C.) (Fig. 6), Pons Fabricius (62 B. C),
the bridge of St. Angelo at Rome, and one at Rimini, Italy
(19 B. C.) (Fig. 9), as well as many of a later period through-
out Europe and Asia, many of which are well preserved and
still in use.
442. In the construction of masonry arches it has long
been observed that the arches settle at the crown when the
temporary centers are removed, and the extrados joints tend
to open at the haunches, these points being known as the
points of rupture. To prevent these joints from opening, rods
and iron bands have often been used in the extrados of the
arch rings extending from the piers and abutments up to or
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408 BRIDGE ENGINEERING.
beyond the points of rupture. Brunei, when experimenting
with arches, built a semi-arch of brick 60 feet long with hoop
iron bond, which supported itself by cantilever action.
443. The building of modern reinforced concrete bridges
began in Germany in 1867, when Jein Monier, an inventive
and ingenious gardener, made large cement flower pots and
urns strengthened with a single layer of wire mesh. In the
next few years he extended the construction to tanks, bins
and arches, and protected his inventions by German patents.
His arches had a single layer of wire mesh near the extrados
only, with wire of the same size in both directions. These
patents were introduced into the United States in 1884, and
the same year rolled iron shapes were first used for reinforce-
ment by R. Wunsch. Sir Shafto Adair built a concrete bridge
in 1871 over the Waveney at Homersfield, England, with metal
reinforcing frames, from designs by H. M. Eyton of Ipswich.
The arch had a span of 50 feet, a rise of 5 feet 3 inches, and
the skeleton iron frames were embedded in Portland cement
concrete, over 100 tons of concrete being used.
444. The first reinforced concrete arch in the United
States was in Golden Gate Park, San Francisco, in 1889. It
was a sinjgle 20-foot span, 454-foot rise and 64 feet wide, with
curved and ornamental wing walls, and imitation rough stone
finish. Another one was placed in the same park two years
later, and a somewhat similar ornamental bridge was built in
Union Park, Chicago, in the year 1890. The latter crosses
the park lagoon and is approached at either side by steps, the
side wall of the steps being a continuation of the wall enclos-
ing the pond. It is apparently more of a park ornament than
for real use, though it serves both purposes. It has ornamental
lamps and railing and in the summer season is further orna-
mented with large urns filled with growing plants and flowers.
445. Lack of definite knowledge in reference to the be-
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REINFORCED CONCRETE BRIDGES. 409
havior of reinforced concrete arches under live loads was a
serious obstacle to their development, and during the years
1890-95 the Austrian government conducted extensive experi-
ments on full size concrete arches. The result of the ex-
periments was satisfactory, and complete reports of the investi-
gations were published in many of the engineering and scien-
tific journals of America and Europe. Previous to this time,
no exact or scientific methods of proportioning them were
known, and progress was slow, but from the completion of the
Austrian experiments in 1895 to the present time, the building
of reinforced concrete bridges has greatly increased. Other
valuable tests were made at Albany, N. Y., in 1910. Cast iron
bridges with wrought iron ties were the prototype for rein-
forced concrete construction, for cast iron, which was strong
in compression, but weak in tension, was supplemented with
wrought iron tension bars. Professor Melan saw that wire
mesh reinforcement with wires of the same size in both direc-
tions was faulty in principle, and he patented another and im-
proved method of reinforcing arches by placing structural
shapes lengthwise of the arch embedded in the concrete, using
curved rolled beams two to three feet apart for small spans, and
deeper lattice frames three to five feet apart for larger ones.
His patents were introduced into the United States in 1893
by Von Emperger, and under these patents many of the best
concrete bridges are built. There were at that time about 200
concrete bridges in Europe, most of them on the Monier pat-
ents, and during the next ten years, 1894-1904, about 100
concrete bridges were erected in the United States, in spans
up to 125 feet. The reinforcing was at first used only in the
' arch ring, but in later years metal was inserted throughout
the whole bridge or wherever there was possibility of tension
in the concrete. Mr. Thacher was the first in America to
use the elastic method for proportioning arches, and in 1894
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410
BRIDGE ENGINEERING.
he built a 30-foot highway bridge at Rock Rapids, Iowa, which
was the first for heavy road travel in America. When it be-
came evident that ordinary iron and steel bridges seldom
lasted longer than twenty to forty years, the more general
adoption of concrete was rapid. Several American railroads,
after repeatedly renewing their metal bridges for increased
loads and rolling stock, substituted concrete and masonry for
later renewals, knowing that when properly built they would
last for centuries.
Fig: too.
446. Concrete arches with steel reinforcing to resist ten-
sile stresses in the arch ring from bending are confined almost
entirely to highway and foot bridges, heavier and solid arch
rings being used for train and engine loads. The heavier
bridges with greater mass better absorb the shock from rapidly
moving locomotives. Reinforced concrete bridges are ex-
tensively used in parks and private estates where architectural
treatment is desired, and they may be found in the parks of
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REINFORCED CONCRETE BRIDGES. 411
San Francisco, Chicago, New York, Boston and other large
cities. The Eden Park and Stockbridge bridges by Emperger,
both completed in 1895, demonstrate some possibilities in con-
crete. The one at Eden Park^ Cincinnati (Fig. 300), is a hand-
some 70-foot Melan arch 33 feet wide, crossing Park Avenue,
one of the main park drives. It has an 18-foot roadway and
two 5-foot walks with an arch rise of 10 feet and ring thick-
ness of 15 inches at the crown, and 48 inches at the springs.
The reinforcement consists of 9-inch curved beams 3 feet
apart. The whole bridge is ornamental, for the soffit is
paneled and the balustrade heavy and artistic, while the span-
drels and abutments have heavy panels and moldings. Tenders
received for a stone bridge were as high at $12,000, while the
contract price for the concrete bridge was only $7,130, which
probably did not include all items of expense, for the original
plan had urns and other ornamentation above the railing.
One of the lightest concrete bridges ever built is the foot-
bridge at Stockbridge, Mass., over the Housatonic river, con-
necting Laurel Hill with Ice Glen. It has a clear span of
100 feet, a total length of 124 feet, a rise of 10 feet, and a
clear roadway of 7 feet. The crown thickness is only 9 inches,
increasing to 30 inches at the springs, and it is reinforced with
7-inch curved steel beams 28 inches apart. It stands on rock
foundation and contains only 22 cubic yards of concrete.
After completion in 1894, at a cost of $1,475, it was tested
with a load of 25 tons.
447. The introduction of this new construction marks one
of the most important forward movements in bridge archi-
tecture, since the Romans discarded wood and built the Tiber
bridges of stone, and there is little doubt that concrete bridges
will gradually replace metal ones for ordinary spans. When
preparing for the California Midwinter Exposition of 1896,
the City of San Francisco placed several ornamental bridges at
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412 BRIDGE ENGINEERING.
the Fair Grounds in Golden Gate Park, among which are two
rustic bridges with two spans in each, a Roman bridge at
Stow Lake, Alvord Lakelet bridge at Haight Street entrance,
and two on the main drive near the museum. The rustic
street bridge with twin spans fits well into the landscape,
though a single span or three shorter ones would have looked
better. The exposed arch rings are of stone, but the soffits
are of other material, the rustic features occurring only on
the spandrel faces, wing walls and parapets. It was started
in 1893 and carries a drive over the lake. Another two-span
rustic bridge carries a double line of electric railway over the
drive at Ocean Beach, appearing like a natural bridge, and the
semi-tropical plants growing on and about it are characteristic
of the region. The Roman bridge carries a park drive over
Stow Lake, the characteristic feature of the bridge being its
plain surface with flat arch and curved parapet. It is solid
and heavy in contrast to many of the very light ones often
used for carriage and pedestrian travel. The Alvord Lakelet
bridge carries the driveway over the main foot walk at the
Haight Street Park entrance. It is almost buried in the
foliage and the soflit is thickly hung with artificial stalactites.
A bridge on the main drive grossing a foot walk near the mu-
seum is very beautiful, and displays a high degree of deco-
rative work on the spandrels and along the roadway where
lines of stone and concrete railing separate the foot walk from
the carriageway. When examined and photographed by the
author after the earthquake of 1906,* the barrel of the arch
was damaged and broken, but the upper part and railings were
uninjured, though the museum building close by was seriously
shaken and broken. Another bridge near the museum, sur-
rounded by semi-tropical vegetation, has wide drafts on the
stone courses, curved wing walls and other ornamental feat-
ures. Other park bridges of 1896-97 are those at Champlain,
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REINFORCED CONCRETE BRIDGES.
413
111., St. Louis and Hyde Park. The Champlain bridge, on
the state college grounds, is the work of Professor A. N.
Talbot. Franklin bridge, in Forest Park, St. Louis, is a single-
span Melan arch, the thickness of ring varying from 11 inches
at the crown to 30 at the springs, with ornamental lamp posts
at the four corners. The Hyde Park bridge on the Vander-
bilt estate, crossing Crum Elbow Creek, is very artistic, with
elliptical arch and curved wing walls and a railing of beautiful
design. (Fig. 314.)
448. Three of the largest early concrete bridges are those
at Maryborough, Australia (1896), Paterson, N. J., and To-
peka, Kan. (1897), the last two being the work of Mr. Thacher.
Fig. 301.
In the previous year Mr. Thacher submitted designs for two
bridges in Schenley Park, Pittsburg, with openings of 150
(Fig. 301) and 300 feet, and reported that spans up to 500
feet were economical and practicable. These designs showed
reinforced side arches with floors supported on a system of
steel beams and columns in open chambers, extending out
into the abutments, the face of spandrels and abutments being
enclosed with thin curtain walls. The Maryborough bridge,
with eleven spans, was the largest at the time, but its length
was exceeded in 1897 by the Topeka bridge (Figs. 302, 308),
over the Kansas river, which contained a central arch of
125 feet, though this span was soon after exceeded by others.
A vertical curve on the roadway of the Topeka bridge would
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414
BRIDGE ENGINEERING.
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REINFORCED CONCRETE BRIDGES.
415
have looked much better than the break of grade at the
center, which is very evident. The Maryborough bridge was
designed to be submerged 20 feet during floods, and it is
therefore much shorter than if placed at a higher level. It
contains eleven arches of 50 feet and is 613 feet long with
a clear road of 21 feet. On account of being occasionally
Pkrl. PmZ.
Fis. 802.
submerged, the balustrade is solid and the lamp posts are
removable.
449. Reinforced concrete has been used to cover and
preserve the structural steel of overhead bridges, as on the
foot bridge at Cedar Rapids, Iowa, which is 341 feet long
and 6 feet wide, with stairs at each end. The steel girders
were first enclosed with %-inch boards on which wire mesh
\dOnxwi9
Secrton oct Crown of Arch,
Fis. S04.
or expanded metal was fastened with a J^-inch space between
the boards and metal. The surface was then covered with
1 inch of cement plaster. The whole bridge cost $7,500. The
VanBuren Street Bridge, over the Illinois Central tracks, at
Chicago, was similarly protected in 1897 with tile.
450. A Y bridge with three arms, over the Muskingum
and Licking rivers, at ZanesviUe, Ohio (Figs. 304, 306), is
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416 BRIDGE ENGINEERING.
the fourth one on the same site, former ones having been either
wrecked or removed. In spanning the two rivers at their
junction, the bridge was built with three arms meeting at a
center pier. The east arm is 400 feet long with three spans of
122 feet, the west arm 250 feet long with two spans of 122
and 90 feet, and the north arm 250 feet long with three spans
of 81 feet. The foundations rest on rock, and a flat arch ris6
was used because of the small distance between the desired
grade and high-water level. A somewhat similar metal arch
bridge over the Danube at Budapest was erected in 1875, and
the Genoa bridge, with arches in two arms, has a suspension
in the third arm. The X bridge over the Sarthe at Mans,
Fig, S06.
France, just below the Ysoir bridge, carries an electric rail-
road on one branch and a steam railroad on the other. The
platform, which has an outside width of about 13 feet, con-
sists of a concrete slab reinforced with old rails supported on
a pair of steel plate girders about 5 feet apart, the whole
standing on a series of small single piers. The combined
length of the two parts is 360 feet, and the total cost was less
than $1.25 per square foot of deck.
451. Hinged masonry arches have been more favored by
European than by American engineers. One of the first of
this kind, crossing the Laibach river, is faced with ornamental
molded concrete slabs, and the concrete balustrade is relieved
by bronze candelabra and portal figures. Other hinged arches
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REINFORCED CONCRETE BRIDGES. 417
in Europe were erected at Chatellerault, France, 1899, and
at Soissons, 1903. The piers of the Chatellerault bridge (Fig.
306) stand on concrete steel grillage and each pier has four
vertical metal supports fastened to the foundation. The exterior
5 inches of the piers is fine concrete with ordinary concrete
center. It was completed in the remarkably short space oi
three months. A reinforced concrete bridge over the Taglia-
niento river near Pinzano, Italy, is in two stories somewhat
like Pont du Gard, with the deck 86 feet above the water.
Its total length with approach is 600 feet, and in the loWer
story are three twin arch rings of 160 feet, between piers
13 feet 3 inches thick, while the upper story consists of a
series of 35-foot arches supporting the 17-foot roadway.
462. In the year 1900 the United States government asked
for competitive designs for a memorial bridge to cross the
Potomac river at Washington, and several of the designs
submitted were of reinforced concrete. One, by Mr. Burr, had
a width of 60 feet, a length between abutments of 3,400 feet,
and one deck, without provision for car tracks. There were
six segmental reinforced concrete arch spans of 192 feet and
29-foot rise with 53-foot clearance underneath. A double leaf
bascule draw span centrally located between the arch spans
had an opening of 159 feet and a distance between trunnions
of 170 feet. The Washington approach consisted of twelve
semicircular reinforced concrete arch spans of 60 feet and 550
feet of embankment, while the Arlington approach had fifteen
similar spans and 1,350 feet of embankment. The face rings
of the main spans were 5J4 feet deep at the crown and 9J4
feet at the springs, with granite on the whole exterior face.
In each main span were five concrete steel arch ribs 30 inches
deep at the crown and 7 feet 3 inches at the springs, sup-
porting a system of interior steel columns carrying the floor
beams. Spandrel curtain walls with expansion joints rest upon
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418
BRIDGE ENGINEERING.
the arch rings and were shown faced with granite. Con-
crete floor arches between steel beams supported an asphalt
road and granolithic walks. The estimated cost was $3,680,000.
A number of large American cities began about 1900 to
adopt concrete deck arches for their new bridges, and among
them were the cities of Indianapolis, Ind. ; Washington, D. C;
Dayton, Ohio; South Bend, Ind.; Philadelphia, and Spokane.
The first two bridges over Fall Creek, at Indianapolis, dif-
fering only in their width, were erected in 1899 and 1900. The
Illinois Street bridge is 60 feet wide, while the Meridian Street
bridge is 10 feet wider. Each has three spans of 74 feet be-
tween 8-foot piers, and the exposed surface of spandrel and
Saclional Side Elevation.
'.' . ^" -^ \
mr -
Porr Plan.-
Fig. 307.
piers is faced with limestone. The railings are stone, but all
other parts, including the arch soffits, are gravel concrete.
The roadway of the Meridian Street bridge is paved with as-
phalt, but the other bridge has creosoted yellow pine blocks,
and both of them have cement sidewalks. Other Indianapolis
bridges are at Northwestern Avenue, Morris Street, Cruft
Street and East Washington Street. The Northwestern Ave-
nue bridge is similar to that at Illinois Street, with three spans
of 74 feet. Above the piers circular pilasters are carried up to
support retreats in the balustrade, which is very ornamental.
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The Morris Street bridge, over White river, has five concrete
steel Melan arches 90 to 110 feet long, with stone facing on
parts exposed to view. Crossing from Green Island to the
American side of the Niagara river, over the main channel,
is a three-span concrete arch bridge faced with stone (Fig.
307). It was designed by the engineers of the Indianapolis
bridges. It crosses the rapids where the water has a velocity
of 24 miles per hour, and just below the bridge is the Amer-
ican Falls of Niagara. The body of the masonry is concrete
reinforced on the Melan system, and for arches of so flat a
rise the design is very artistic. The stone arch rings and fac-
ing with belt course of different material, and a smoother
coping, together with the rounded pilasters at the piers, all
unite to produce a pleasing effect.
The Interlachen bridge, Minneapolis, erected (1900) for the
Board of Park Commissioners, spans two lines of electric car
tracks and carries a roadway, with a foot path on one side and
a bicycle track on the other. The face of the arch ring, the
skew back and copings, are Kettle river sandstone, but all
other facing is blue limestone, while the body of the arch is
concrete steel construction on the Melan system. The city of
South Bend has reinforced concrete bridges at Colfax and
Jefferson Avenues, the first being a single span, while the
Jefferson Avenue bridge (Fig. 310), over the St. Joseph
river, has four elliptical arches of 110 feet each. Few con-
crete bridges in America show more artistic treatment. The
pier ends have elaborate detail and are carried up to support
retreats in the sidewalk. A moulded cornice relieved with
dentils is mounted with a heavy ornamental railing. At the
ends are steps leading down from the bridge to the water.
Concrete has been used in this bridge true to its own nature
and not worked to imitate stone, a plan that is commendable
when well executed. Sixth Street bridge at Des Moines
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(1901) is one of the finest in America, for the elliptical arches
are well proportioned, and the combination of vitrified bricic
face with concrete trimmings makes it unique. A bridge tit
Gary, Ind., shows some possibilities in concrete for single
spans. The face of arch and spandrels are panelled and the
wings are curved to facilitate approach. At either end of the
arch are pilasters extending up to the cornice and forming
in the balustrade pedestals for future lamp standards.
453. The Boulder faced bridge over Rock Creek, in the
National Park, Washington (1901), is a segmental concrete
arch of rustic design made to conform with the surround-
ings. The body of the arch is concrete reinforced on the
Melan system with steel, and the soffit is darkened with lamp
black to harmonize with the facing. The boulders of the
arch ring extend down several inches below the soffit and
partly obscure it. The bridge is located in a very beautiful
part of the valley and is much admired. The concrete arch on
Ross Drive over Rock Creek (1907), with a span of 100 feet,
was built when the monumental solid concrete bridge at
Connecticut Avenue was nearing completion. Other boulder
faced bridges are at Hyde Park on the Vanderbilt estate, At-
lantic Highlands, and one with rustic parapet in Marion Coun-
ty, Indiana. The last bridge is on an ordinary country road
and is a type quite suitable for wooded parks or rural dis-
tricts.
454. Two bridges over the Passaic river at Paterson and
Clifton, N. J (1902), contain some unusual features, being
proportioned to resist water pressure when submerged. The
eleven reinforcing ribs are continuous over the piers and are
securely anchored into the abutments, resulting in combined
arch and cantilever action. Each rib consists of four old track
rails, two in each chord, riveted together with plates between
them, and the chords are united with web members. The
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Arch Street bridge at Paterson has three spans of 58 feet
with a 2^-foot rise and 50-foot road 170 feet long between
abutment faces. The rings are cinder concrete, 20 inches
thick at crown and 50 inches at the springs. It cost $38,000,
but' was seriously damaged in 1902. The Passaic river bridge
at Clifton, N. J. (1902), with five spans of 60 feet, is similar
to the last. Reinforcing ribs on both bridges are spliced at
the points of contra flexure, and piers and abutments are
faced with stone. The last bridge was submerged about two
feet in the freshets of 1903.
455. Four large bridges with seven spans in each bridge
were erected 1902-1905 at Waterloo, Iowa; Plainwell, Mich.;
Peru, Ind., and Kankakee, 111., the cost per square foot of
floor surface being nearly the same in all cases, about $2.00
per square foot. The Kankakee bridge is a subsequent work
of the engineers of the Topeka bridge, and the floor is made
on a vertical curve. The Wayne Street bridge at Peru, Ind.,
(Fig. 309), was built in six months, June to December, 1905.
The center one of the seven spans is 100 feet, and others
95, 85 and 75 feet, respectively, towards the ends. The clear-
ance above low water is 24 feet, and the thickness of arch ring
varies from 21 to 25 inches at the crown. Piers 6 feet thick
at springs stand on bed rock. The arch rise varies in differ-
ent spans from 13 to l5 feet, and the bridge contains 5,200 cubic
yards of concrete and 50 tons of steel reinforcement. In
January, 1907, it was severely tested when the water in the
Wabash river rose to within five feet of the soffits, and the
approaches at both ends were submerged 2 feet, but the bridge
sustained no injury. Two other large bridges of 1904 and
1906, with five spans in each, are at Grand Rapids, Mich., and
New Goshen, Ohio, the lengths being almost identical. The
Grand Rapids bridge is a typical example of the best American
practice in slab arches. The center span is 87 feet, the two
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adjoining ones 83 feet, and the two end spans 79 feet each.
It was designed by Wm. F. Tubesing, for L. W. Anderson,
city engineer.
456. The City of Dayton, Ohio, erected three fine concrete
bridges over the Great Miami river in 1902-6 at Main, Third
and Washington streets, with seven spans in each bridge. Ow-
ing to a bend in the river above Main street the water in flood
season rises 20 feet above low water level, and the banks are
therefore confined by levees above and below the bridge. High
water line is now a foot above the arch springs at Main street,
with the street graded 2^% on one side of the bridge and
Bj4% on the other side. To increase the arch rise would have
resulted in a steeper street grade, which was not desirable.
Piers were made thin to avoid obstructing the already crowded
channel. The center span is 86 feet, the two adjoining ones
83 feet, the next two 76 feet, and the end ones 69 feet. The
bridge (Fig. 311) contains 150 tons of steel in the nineteen
lines of reinforcing ribs, and 11,400 cubic yards of concrete.
The distance from the upper surface of the brick pavement
to the arch crown is only 13 inches, and the track rails are
therefore very close to the masonry. The rise of the arches
is such that the horizontal thrust on the piers is the same on
both sides. The second concrete bridge over the Miami river
at Dayton was at Third street, and the third one was at Wash-
ington street (Fig. 312). The last replaced an old iron bow-
string bridge that was too light for the heavy car travel. All
the Dayton concrete bridges are on the Melan system from
plans by The Concrete Steel Engineering Company of New
York. Wm. Menser, engineer.
457. Long concrete street viaducts over railroad yards
have been erected at Jacksonville, Fla. (1903) ; Atlanta, Ga. ;
Knoxville, Tenn., and Winnipeg, Manitoba. The Jackson-
ville viaduct has sidewalk brackets projecting 3 feet 9 inches
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BRIDGE ENGINEERING.
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from the spandrels, and the arch rings are reinforced with
twenty lines of Thacher bars 15 inches apart, and eight Melan
frames 30 inches apart under the spandrels and car tracks.
The Nelson Street viaduct at Atlanta, Ga., has ten spans of 20
to 75 feet, and a total length of 480 feet. The Knoxville via-
duct is 767 feet long in thirteen spans, with overhanging side-
walks. Designs for a proposed concrete viaduct about 3,000
feet long, were made in 1907 by the writer to cross the railroad
yards at Ogden, Utah, but steel and wood construction were found
to be less expensive.
458. Many concrete park bridges began to appear in
American cities soon after 1900, most of them being notable
^sr^
FIgr. 313.
more for their artistic design than for their large proportions.*
It frequently happens that a combination of steel and masonry
in the same structure is offensive to the artistic taste, but in
the park bridge at Madison, N. J. (Fig. 313), a pleasing effect
has been produced. The bridge spans two lines of railway and
has an opening of 50 feet, and the floor is 10 feet wide with
stone and concrete steps at each end. The central arch girder
is steel with a projecting fascia at the lower flange, represent-
ing a thin arch surmounted with a plate iron railing. The pro-
jecting fascia on the lower external face of the girders is 9
♦American Park Bridfifes. H. G. Tyrrell, In American Architect. 1901.
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428 BRIDGE ENGINEERING.
inches wide at the crown, increasing to 24 inches at the
springs. Each of the girders is capped with an ornamental
cast iron coping, and the piers are surmounted with electric
lamps. The whole bridge is surrounded with shrubs and flowers
and altogether presents an artistic appearance. H. G. Tyrrell,
engineer. (The Engineer, London, and Engineering News,
1900.)
A foot bridge at Columbia Park, Lafayette, Ind., has a 40-
foot span and an under clearance of 8 feet. The crown thick-
ness is only 9 inches, and beneath the water are tension rods
embedded in concrete resisting the arch thrust. The Como
Park foot bridge at St. Paul, Minn., built in 1903, for the
Twin City Rapid Transit Company, carries traffic entering
Como Park over the tracks of the street railway company.
As large numbers of passengers leave the cars at the bridge,
it was desirable that the structure should have a neat ap-
pearance. In order to avoid form marks on the exposed sur-
face, the boards were covered with metal lath and neatly plas-
tered with a fine coat before placing the concrete. The length
between centers of abutment piers is 83 feet and the total
width of arch is 17 feet, while the openings over spandrels and
abutments are 12 feet long, and skew back piers 2 feet thick.
The arch is reinforced with five Melan ribs in the concrete.
459. The overhead railroad bridge at the entrance to
Forest Park, St. Louis, shows the architectural treatment of
a horizontal girder. The relative grade levels of street and
railroad prevented the use of an arch and an ornamental
through plate girder bridge was used instead. The exposed
fascia over the roadway is a concrete parapet concealing the
steel girder behind it. The clear opening for the street is
70 feet, and the whole bridge in 1904 cost $25,000. This is the
principal entrance to Forest Park and it adjoins a fine resi-
dential section of St. Louis. Other park features in the im-
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mediate vicinity display the highest art of the landscape gar-
dener and architect, and any structure lacking in artistic treat-
ment would mar the surroundings. The curving wing walls
i
terminating in circular columns, add greatly to the general
effect. The Yellowstone Park concrete arch (Fig. 315) crosses
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BRIDGE ENGINEERING.
the Yellowstone river just above the Upper Falls, over the
rapids. Bridges adjoining water falls are usually placed below
the falls, that passengers over the bridge may enjoy the view,
but at Yellowstone the upper location was selected to avoid
any obstruction of the view by the bridge itself. The roaa-
way has a camber of 2J^ feet and at the center is 43 feet
F\g. 315.
above the water. A bridge in Branch Brook Park, at Newark,
N. J., carries Park Avenue over a waterway, walk and drive.
It contains 6,200 cubic yards of concrete and 124 tons of steel,
costing, without pavements, $84,000. Construction occupied
five months, from August, 1904, to January, 1905, work being
under the direction of the Park Commissioners of Essex Coun-
ty, New Jersey. A. M. Reynolds, engineer. Several fine park
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431
bridges are located in and about New York, one at Newell
Avenue in the Botanical Gardens being faced with granite.
The outlines of the bridge with the different kinds of surface
finish and its setting in the foliage produce a satisfactory ef-
fect.
At the little town of Venice, in Lower California, laid out
with canals in imitation of Venice, Italy, are a number of in-
teresting concrete bridges of curious design. The town is a
watering place for travelers wishing to escape the severe cli-
Fig. 316.
mate of northern latitudes. There are streets of tents and
thatched cottages, with many features for the amusement and
entertainment of visitors. In a district where novelties abound
and where entertainment is a principal object, there is perhaps
reason for the unusual decorations, which were doubtless sug-
gested by the proximity. to the sea coast. The arch faces are
decorated with festoons of flowers and on the balustrades are
huge and horrible images of sea monsters. An ornamental
foot bridge in Lake Park, Milwaukee, near the pavilion, crosses
a gorge 50 feet deep, and is much seen especially in the sum-
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432 BRIDGE ENGINEERING.
mer time (Fig. 316). The structural features consist of two
reinforced concrete ribs 12 inches wide and 54 inches deep,
with an inner flange on the lower side of the arch ribs.
These ribs are 12 feet apart in the clear, and they support
spandrel walls which carry the 6-inch reinforced concrete floor
slab. Cross walls and struts 12 feet apart longitudinally con-
nect the arch ribs, and between them is a double system of
steel angle bracing, the ends of the angles being securely fas-
tened in the concrete. Spandrel walls are 12 inches thick with
expansion joints at each end adjoining the abutments. The
arch ribs and abutments are a monolith and the floor is cam-
bered 8 inches longitudinally for drainage. The abutment side
walls are connected with cross walls which support a floor slab
similar to that on the bridge. R. E. Newton, engineer.
460. Ribbed arches were not used to any great extent in
America previous to the erection of the one in Lake Park,
just described, but in the next few years others appeared at
La Salle, Playa del Rey, Sandy Hill, Belvidere, Spokane,
Washington, Denver, Jamestown, Wakeman and St. Paul.
The bridge over a lagoon at Playa del Rey, a suburb of Los
Angeles, is exceedingly light for so long a span. The Sandy
Hill bridge (Fig. 317), over the Hudson, one of Mr. Burr's
designs, has a long series of spans between piers 6 feet thick,
the distance between abutments being 984 feet, and the ex-
treme length 1,026 feet. The clear width between railings for
carriages, electric railway and sidewalks is 32 feet Beneath the
bridge the river is rapid and shallow, and a few hundred feet
below the site is a natural falls 60 feet high. A century ago
an old toll bridge crossed the river just below the new site,
but it was destroyed in 1832 and a new bridge was immediately
begun, but never completed. The spandrels, pier faces, cop-
ings and railings are molded concrete blocks bonded into the
masonry. The arch ribs are 32x14 inches at the crown, in-
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433
creasing to 32x27 inches at the springs, supporting 12-inch
spandrel walls which carry the 8-inch floor slabs and asphalt
pavement. A temporary wood bridge was used during con-
struction.
The method of building the ribs for the new Elgin-
Belvidere Electric Railway bridge was somewhat similar to
*a?V— -*^'
Pcvt Section orr Pier.
FIfir. 317.
that proposed by Thomas Telford about 1824 for erecting a
500-foot cast iron arch over Menai Straits, a modification of
which was used on the Eads bridge at St. Louis. Concrete
steel forms for the two arch ribs were supported by guy ropes
from temporary towers on the piers and abutments. The
ribs are 9 feet apart on center, 24 inches thick and 32 inches
deep at the crown, increasing to 60 inches at the springs, not
including the thickness of the forms, which have 3-inch sides
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BRIDGE ENGINEERING.
and 4-inch bottoms. The ribs are braced together with eight
cross walls in each span, 21 inches thick between the ribs and
12 inches thick above. Between the piers are similar ones,
which, together with 12-inch spandrel walls, support the 6-
inch floor slab and track ballast. The forms for each rib are
divided into seventeen voussoirs about 6 feet long, weighing
1,500 to 2,200 pounds each. They are dowelled together and
were placed with a wood traveler on a temporary wood bridge,
though a cable way might have been more convenient. A two-
span ribbed arch was also built by Mr. Strauss at Howard
Street, Spokane (Fig. 318), with six ribs and open spandrels.
The plan shows brick paving between the car tracks and as-
Fig. 318.
phalt at the sides, on a floor slab supported by 12-inch cross
walls about 10 feet apart through the central portion, and on
spandrel columns and floor beams near the ends.
The Jamestown bridge, built in 1907 by the United States
Government to connect the outer ends of two piers, is of
reinforced concrete for pedestrian travel only, the ascent of
the roadway being made by a series of steps and landings.
Two reinforced concrete ribs carry the roadway on four longi-
tudinal walls. Abutments are cored out, and each one rests
on 26 plumb and 126 batter piles. The Boulevard bridge at
St. Paul, with a central span of 110 feet has three reinforced
concrete ribs with open cross spandrels and a floor width of
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40 feet. At each end are approach spans, making the bridge
222 feet long. The Wakeman, Ohio, bridge over the Ver-
million river (1908) is a ribbed arch and a cantilever with
brackets 37 feet long at each end. It has two three-hinged arch
ribs with open spandrels and a floor slab supported on beams
and columns, the whole being proportioned for 18-ton wagons
or rollers. Wilbur J. Watson, engineer.
461. The first concrete cantilever bridge in the United
States was at Marion, Iowa (1905), for the Marion Street Rail-
way Company. It has three 60-foot spans with two longitud-
inal ribs 12 inches wide supported on concrete columns, and
a floor slab on transverse beams. The bridge has very lijfht
abutments in comparison with an arch, and a proportionately
less cost. The two-span arch over Charley Creek at Wabgsh,
Ind. (1905), was designed with cantilever spandrel walls. In
1906 the Belvidere bridge, previously described, was erected by
cantilever methods, and in 1907 a two-ribbed highway bridge
was placed across the Rhone at Pyrimont, with a cantilever
arm at one end. The Wakeman bridge followed in 1908, and
in the same year a three-span concrete cantilever bridge for
the Newcastle and Toledo Electric Railway, with center and
end spans of 60 and 20 feet, respectively. The bridge is 16
feet wide, with side girders 26 inches wide and 7 feet deep,
with a 20-inch floor slab, the appearance being that of a half-
through girder bridge. An enclosed or tubular concrete foot
bridge of four spans was erected in 1909 s^t Southbridge, Mass.,
the clear width and height being 10 and 8 feet, respectively.
It carries pipes over the river to a manufactory.
462. Three large bridges of unusual interest are those at
Emerichsville, Ind. (1905), Cedar Rapids, Iowa (1906), and
Waterville, Ohio (1908). The Emerichsville bridge, over the
Whitewater river, has an entrance archway over the road at
the park end, and the arches are ornamented on the face and
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436 BRIDGE ENGINEERING.
spandrels with panelled work, with elaborate moldings above
the piers. The adjoining boulevards and landscape gardening
tend to make it attractive.
The Cedar Rapids bridge, in two sections with four spans
in each, is divided in the middle by an island in the Cedar river.
All spans are 75 feet long, with 7-foot rise, and piers are 7J4
feet thick at the springs. Arches are three-centered, 16 inches
thick at the crown and 36 inches at the skewbacks, and are
reinforced with lattice frames 3 feet apart. It was under con-
struction from April, 1906, to January, 1906. The Maumee
river bridge at Waterville, Ohio, has twelve spans of 75 to
90 feet, with a 25-foot rise. The total length is 1,200 feet,
and the 16-foot deck is 45 feet above low water. It carries a
single track of the Lima and Toledo Traction Company over
the Maumee river fifteen miles southwest of Toledo and con-
tains 9,200 cubic yards of concrete and 100 tons of steel. (Fig.
326.) It is the work of Mr. Daniel B. Luten, designer and
builder of many fine concrete bridges throughout America.
463. Reinforced concrete bridges diflFer so greatly from
those of solid masonry that a great variety of patents have
been secured on special types and features, and on different
kinds of reinforcing bars and frames. Many of these patents
are owned by a few companies making a specialty of con-
crete bridge construction, and the patented features include
cored abutments, double arches, pavement ties, hinges, un-
symmetrical end spans over sloping ground, portal features,
T-shaped arches, trussed slabs and collapsible centers. An
8-inch curved slab with 28-inch rise was used on a 40-foot
span near Albany, Ind. (1905), the slab being trussed with
ribs 4 feet apart. Double arch rings one above the other with
earth filling between them, were used (1905) on a bridge near
Muncie, Ind., the rings being united at intervals of about 8
feet with web ties. The object in the special form was to
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eliminate inefficient material near the neutral axis of the arch
section. The Kissinger bridge (1907), southeast of Wabash,
Ind., has a concrete arch rib 8 feet wide with a single central
spandrel wall on which a flat floor slab 16 feet wide is sup-
ported and balanced.
Fig, 819.
464. The longest reinforced concrete arch completed, not
including those which are proportioned like solid masonry
arches, is the Stein-Teufen bridge (Fig. 819), Switzerland
(1909), with a central span of 259 feet. The main piers are re-
inforced to resist unbalanced thrusts from the adjoining arches.
The main arch rings are 21J4 feet wide and 4 feet thick at
Tig. 820.
the crown, reinforced with IJ^-inch round bars 10 to 18
inches apart. The bridge has a Telford pavement, and side-
walks 2 feet wide on concrete slabs supported on stringers and
spandrel columns. The concrete balustrade has openings 3 feet
wide, guarded with embedded bars. A longer span of 285 feet
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BRIDGE ENGINEERING.
is projected to carry the New York State barge canal over a
gorge near Medina, N. Y. (Fig. 320.) Previous to making
designs for this bridge, elaborate experiments on arches were
undertaken at Albany, May, 1910, under the direction of the
state engineer, the model arches having 8-foot spans and
crown thickness of 2 inches. But the longest masonry arch
of any kind, either stone or concrete, is now (1910) under con-
struction to cross the Tiber river at Rome with a single span
of 328 feet. It will be 65J4 feet wide and is estimated to cost
$250,000. The next longest span is the Plauen arch in Ger-
many, with a span of 295 feet. It is appropriate that Rome,
where some of the first arch bridges appeared, should also have
tz7*^'^^^'^X!^ci
Fig. 321.
the longest modern span. The longest series of reinforced
concrete arches are the bridges at Sandy Hill, 1,025 feet;
Waterville, 1,200 feet; Glendoin, 1,019 feet; Austin, 1,000 feet*
Boston, 1,740 feet, and Galveston, 2,455 feet.
465. The Galveston bridge (Fig. 321), with a long series
of arches somewhat similar to those at Key West, crosses the
bay from the city to the mainland. In addition to the twenty-
eight spans of 70 feet, there is also a rolling lift bascule with
100-foot clear opening. The viaduct, 2,466 feet long, is only
a part of the whole causeway over two miles in length, the re-
maining portion being embankment faced with a slab of con-
crete. Provision is made for three lines of railway on one
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440 BRIDGE ENGINEERING.
side, and a 19-foot highway on the other side, the whole width
being 66 feet. The deck is 16J4 feet above low water, which
has average depth of 6 feet. Other notable bridges of 1910
are at Toulouse, Constantine, Kansas City, Dallas, and Wes-
ton. The bridge at Toulouse over the Garonne river, is 730
feet long and consists of two separate bridges side by side,
with five pairs of elliptical arches, the largest or center pair
having an opening of 150 feet. Each arch of the pair is 10
feet wide and they are separated by an interval of 33 feet,
which is spanned by a floor framing in reinforced concrete,
the total width of deck being 70 feet. The masonry arch at
Constantine, Algeria, is 330 feet above the Rummel River and
is one of the highest of its kind. It is 1475 feet long, and
contains twenty-seven arches of unequal length, the largest
being 280 feet. The twin arch rings are 13 feet apart as in
the Luxemburg bridge, and they are connected at the crown
by a plate of reinforced concrete. The Kansas City concrete
bridge, with a length of 2500 feet, has a series of arches from
50 to 200 feet, each having four concrete ribs, supporting a
40-foot roadway and two 10-foot walks.* One of the longest
concrete bridges is now (1911) under construction between
Dallas, Texas, and the suburb of Oak Cliff. It is 5106 feet
long and crosses a shallow valley which, though usually dry,
is occasionally flooded from the Trinity river. The bridge
contains fifty-one arches with a clear span of 71}4 feet, in
addition to the river span and end trestle approaches. The
arches are reinforced curved slabs 395^ feet wide, varying in
thickness from 16 inches at the crown to 36 inches at the
springs, and the open spandrels support a 56-foot deck.
Every fifth pier is thicker than the rest and is proportioned
as an abutment. Its total cost will be about $570,000, or
*It is not far from the old railroad bridge built under the direction of Mr. Octave
Chanute. who was one of the foremost bridffe and railroad engineers of America.
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$2.10 per square foot. The longest concrete arch in Canada
is the Wadsworth bridge over the Humber at Weston, On-
tario, with a span of 118J4 feet. It was completed in 1910,
and replaced an old timber bridge built about thirty-five years
ago by William Tyrrell, of Weston, who for twenty-five years
was Reeve of the Township of York, and Warden of York
County, and under whose direction this and many other
bridges in the district were built.
466. Other fine bridges in America are at Pittsburg, Bos-
ton, Los Angeles and Milwaukee. The Meadow Street bridge
(Fig. 322) at Pittsburg, 60 feet wide, is one of the best and the
largest one of the kind in that district. The center opening
is 209 feet, and at each side are three approach spans, making
a symmetrical arrangement. In the center span are three re-
inforced concrete arch ribs whose curve approaches a para-
bola, the ribs being connected by struts at the panels, and the
deck supported on spandrel beams ancT columns 15 feet apart.
It is the work of Mr. Willis Whited, and cost $65,000. The
new Charles river bridge at Boston, Mass., for the Boston Ele-
vated Railway Company, will contain nine river spans of 98
to 122 feet, with lift spans at each end, the total length of
bridge being 1,740 feet. The deck is 31 feet wide inside of
parapets, with accommodation for two lines of track and a 4-
foot walk at each side. In each span are two reinforced con-
crete arch ribs 29 feet apart on center, with end hinges, and
under each rail is a line of steel beams. The spandrel faces
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BRIDGE ENGINEERING.
are enclosed with 8-inch curtain walls. Two fine bridges have
recently been completed at Seventh Street and Main Street,
Los Angeles, each having three spans and widths of about 70
feet. The Seventh Street bridge has 80-foot elliptical slab
arches with spandrel face walls and earth filling. Arch rings
have a thickness at the crown of 18 inches under the roadway,
and 24 inches under the two lines of car tracks. Piers and
abutments are hollow, the piers being 8 feet thick at the
Figr. 824.
springs. The total cost was $105,000. Main Street bridge
contains most of the best features of economical design, use-
less material being eliminated as far as possible. Piers and
abutments are hollow, and the deck is supported by spandrel
beams and columns on eight lines of three-hinged reinforced
arch ribs. Both these bridges are the design of Mr. H. G.
Parker. A fine example 6f ribbed arch design was submitted
in 1908 for the Grand Avenue viaduct in Milwaukee, which has
lately been completed on another plan.
Other small American bridges are at Riverside Drive,
Derby and Mishawaka. The Derby bridge (Fig. 323) has a
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REINFORCED CONCRETE BRIDGES.
443
panelled balustrade of unusual design — heavy and substantial
— giving a feeling of security over dangerous or rapid water.
A much lighter one is used on the Mishawaka bridge, which
has a metal balustrade between concrete pedestals above the
piers. The two-span bridge at Reno (Fig. 324), has elliptical
arches, and a foot bridge with solid curving balustrade is illus-
trated in Fig. 325, while Fig. 326 is made without any balus-
Fig. 325.
trade. The Market bridge at Monterey, Mexico (Fig. 327), is
enclosed somewhat similar to Pont Vecchio and the Rialto.
467. Bridges of the most economical design and least cost
are those at Stockbridge, Forest Park, Oconomowoc, Water-
loo, Plainwell, Kankakee, Greensburg, Peru, and Sandy Hill,
with costs of $1.44 to $2.15 per square foot of roadway sur-
face.
468. Failures have occasionally occurred, and expensive
lessons have thereby been learned. Complete or partial fail-
ures happened to bridges at Peoria, Edinburg, Mamaroneck,
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444
BRIDGE ENGINEERING.
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REINFORCED CONCRETE BRIDGES.
445
and Pasadena. The highway bridge over Flat Rock river
near Edinburg, Ind., which failed February 28, 1910, had been
in use for eight months. Of the three spans the center one
had an opening of 90 feet, and the side ones 75 feet each. A
bridge at Mamaroneck, N. Y., with five small spans of about
Half.SW««ClvvaTion.
\<— VO' >^ liStalh.S'H^'-
85 5i
Lil L
A
Half PJan .
Fig. 327.
Half Swtton Half Sutton
at Plw. at Crown.
20 feet each, partially failed in 1904. All of these failed be-
cause of scour at the foundations. The Pasadena bridge, de-
signed by Michael De. Palo, and built by Carl Leonard of
Los Angeles, was examined in 1907 by the writer, after
its partial failure, and a report made on repairing it. The
side girders were badly cracked and sagged from their orig-
inal position, and the center span was blocked up on timber
work. After much delay the timber tower was replaced with
an additional concrete pier, holes being cut through the floor
for its connection. Cracks were enlarged and refilled solid
with concrete (Fig. 328).
469. The design of highway bridges in the State of Illinois
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446
BRIDGE ENGINEERING.
has lately been placed under the supervision of the State High-
way Commission, thus bringing them under government super-
vision, as has been done in some foreign countries. It has
become a duty of this Commission to undertake the engineer-
ing work for highway bridges, and to prepare surveys with
complete designs, estimates, plans and specifications. These
are supplied to municipalities in the state, free of charger No-
tices are also sent to construction companies, and instructions
given to municipal officers in reference to awarding contracts.
Fig. 328.
The movement is somewhat similar to that adopted by the
French government in the middle of the eighteenth century,
when a Department of Bridges and Highways was established
under the direction of Perronet, or to the later movement in
Great Britain, when more than twelve hundred bridges were
erected throughout the islands under the direction of Thomas
Telford.
470. The general tendency in the construction of concrete
railroad bridges has been towards the use of solid arch rings
proportioned like masonry arches, reinforcement being intro-
duced not to resist tension, but rather to unite the materials
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REINFORCED CONCRETE BRIDGES.
447
into a solid monolith. As weight and mass are essential to
security under heavy moving loads, the preference in railroad
bridges has been for either solid spandrel filling, or open
spandrels with 4 to 5 feet of earth and ballast beneath the
track. The tendency in highway bridges, reinforced to resist
bending stresses from moving loads, has been to proportion
arch rings so that line of pressure will lie within the middle
third for uniform loading. For highway bridges, open span-
drels with projecting sidewalks are preferred to solid span-
drel filling, and ribbed arches, sometimes with cantilever ends*
are proving more economical than arches with solid slabs.
Wide structures with slab arch rings are now generally made
with double rings 10 to 15 feet apart, the space between them
at the deck being bridged with the regular floor construction
of beams and slabs.
PONS FABRICIUS
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ERRATA
Page 22. Caption * *Ponte Rotto* * should read * *Pons Fabricius. ' '
Page 43. Lines (2-3-4) and (6-7) should be reversed.
Page 118. Paragraph 157, omit line 3.
Pages 102, 178, etc., word Morrison should read Morison.
Page 425. Line 29, word **Menser" should read **Mueser."
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INDEX
Engineers, Architects and Builders.
Adair, Sir Shafto, 408
Adams, J. W., 94, 100, 143
Aelius Scaurus, 29
Aemilius Lepidus, 27
Agrippa, 112-114
Alexander the Great, 16, 36, 104
Allah- Verdi-Kahn, 70, 71
Ancus Martius, 26
Anderson, L. W., 149, 425
Anderson, James, 208, 275
Antoniiis Pius, 26
Antonio da Ponte, 63
ApoUodorus, 35
Appius Claudius, 113
Arnodin, M. R, 236
Arrol, Sir William, 182, 292, 306,
308
Augustus, Emperor, 29, 33, 34, 40,
113, 114
Augustus II., 49
Avana, Antonio, 117
Baker, Sir Benjamin, 87, 162, 260,
266, 359
Baker, William, 174
Baker, G. T., 282
Baldwin, Elector, 50
Balet, J. W., 247
Baratiere, Nicolo, 46
Barlow, W. H., 183
Barlow, P. W., 228, 229
Barnabo, Viscounti, 47
Barry, Sir J. W.. 292
Bates, David S., 90
Bates, Onward, 110, 264
Bazalgette, Sir J., 87, 213
Becker, M., 312
Bell & Miller. 312
Bender, Oiarles, 376
Bernard, Abbot, 55
Bicheroux, F., 335
Bidder, G. P., 195
Bigot, Stanlislan, 218
Blackmore, John, 147
Blake, Mr., 172
Blazer, Mr., 172
Bludgett, Mr., 128
Blyth & Westland, 89
Bodin, Paul, 360
Bogue, V. G., 355
Boiler, A. P., 103, 191, 269, 287
Boiler & Hodge, 361, 293
Bollman, Wendell, 169, 370
Bonzano, Adolphus, 238, 275
Boomer. L. B.. 169
Bouch, Sir Thomas, 182, 237, 372,
375. 383
Bouscaren, G., 178, 180, 379, 380
Bowman, A. L.. 286
Boyd, Mr., 200
Bradley. D. E., 286
Brady, F., 174
Brassey, Thomas, 76
Breithaupt, W. H., 343
Brothers of the Bridge, 39, 40, 42,
43, 53
Brown, Sir Samuel, 208, 209, 214,
224
Brown, Moses, 107
Brown, William, 95
Brown, Glenn, 149
Brunei, Sir Marc I., 84, 89, 1587166,
197
Brunei, I. K., 84, 172, 408
Brunless, Sir James, 299
Bruyere, M., 309
Buchanan, W. O., 226
Buck, L. L., 102, 224, 248, 254, 274,
325, 343, 254, 274
Buck. R. S.. 248
Buckholz, C. W., 94
Bull, William, 139
Burdon, Rowland, 154
t449)
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INDEX
Burr, Theodore, 96, 126, 129, 133,
140
Burr, William H., 102, 181, 417
Bum, James, 129
Bush, W. E.. 405
Bush, Lincoln, 403
Caius Flavius, 28
Califfe, M., 309
Caligula, 34, 36, 105, 114
Canfield, A., 165, 260
Canfield, E., 387
Carl, Peter, 65
Carroll, Howard, 173
Casey, E. P., 404
Cerceau, Androuet, 60
Chaley, M., 215, 216
Chanute, Octave, 440
Charlemagne, 50
Charles IV., 50
Charles, Theodore, 78
Cheever, A. S., 96
Cheyne, Bishop, 55
Choate, Col., 90
Clark, T, C, 238, 243, 376, 397
Clark, W. T., 213, 220
Clark, Adam, 220
Clark Edwin, 196
Clark, Reeves & Co., 178, 336, 381
Claudius, 114
Qement IX., 31
Clement VII., 31
Cobham, Baron dc, 56
Colechurch, Peter of, 41, 53
Collyer, G., 230
Coolidge, W. C, 169
Cooper, R. E., 317
Cooper, Theodore, 178
Cort. 164
Corthel, E. L., 185
Cox, Eugene L., 125
Croyland, Abbot, 52
Cruttwell, E., 87
Cubitt, Sir J., 162, 167
Cubitt, Sir William, 160
Cyrus, 21, 104
Czekelius, Aurel, 251, 284
Daimio, 69
Darby, Abraham, 151
Darius Hystaspes, 104
Darius, 21, 104
Davis, G. J., 149
Diodorus, Siculus, 18
Dixon, J., 383
Doane, W. A., 181, 329, 367
Dodd, George, 86
Doran, F. O., 321
Douglas, W. J., 355, 404
Douglas, Benjamin, 266
Dredge, James, 216, 229
Dufour, Col., 209
Duggan, G. H., 266, 290, 329
Dumbcll, Mr., 207, 252
Dum, Mr., 175
Eads. James B., 233, 313
Edwards, William, 68
Ellet, Charles, 215, 222, 223, 226, 231
Emmery, M., 139
Ende, Max, 317, 336
Estone & Greiner, 43
Etzel & Riggenbach, 309
Eyton, H. M., 408
Fairbairn, William, 159, 162, 165. 195
Fidler, T. Qaxton, 299
Fink, Albert, 169, 176, 370
Finley, James, 204, 206. 210
Fitzgerald, Mr., 91, 120
Fitzmaurice, M., 359
Flachat & Petiet, 218
Flad, Henry, 313
Fotius, 49
Fowler. C E., 244, 344, 386
Fowler, Sir John, 161, 200, 260, 310
Fox, Sir Charles, 310
Fra Giocondi, 46
Franciscan Friars, 68, 117
Gabriel, M., 61
Gaddi, 46
Galbraith, John, 301
Galeas, Viscounti, 47
Gamochot, M., 160
(450)
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INDEX
Gauthey, M., 44, 117
Gayler, Carl, 243
George of Antioch, 47
Gerber, Herr, 261
Gcrwig, Herr, 310
Girourard, Sir Percival, 358
Godfrey, M. J., 110
Golboume, M., 210
Graham, J. M., 242
Graves, Rufus, 129
Green, John & Benjamin, 142
Griffith, Thomas, 227, 234
Grimm, C. R., 335, 387
Grubermann, John & Ulrich, 124,
125, 128
Hadrian, 24, 31, 32, 35
Hains, P. C, 241
Hale, Enoch, 126, 127
Handy, R A., 94
Harbach, Frederick, 166
Harding, George, 270, 324
Harrison, T., 84, 88, 183, 366, 377,
383
Harrison, C. A., 328
Harrison, T. E., 84, 88, «9
Harrison, C. A., 183, 366, 377, 383
Harrison, Joseph, 160
Hartwich, Herr, 310, 311, 314
Haupt, Herman, 141, 166, 367
Haven, Thomas, 213
Hawgood, Henry, 398
Hawksha-w, Sir J., 174, 229
Hay, P. S., 393
Hemberle, Edward, 169, 235
Herbertson, John, 157
Hermann, Herr, 311
*Herodotus, 18, 104, 105
Hildenbrand, William, 231, 239, 247,
324
Hilton, Charles, 178
Hilgard, K. G., 322
Hobson, G. A., 358
Hodges, James, 199
Hodgkinson, Eaton, 159, 163, 195
♦Homer, 21, 104
Horton, H. E, 282
Howe, William, 141
Hupeau, M., 73
Huss, Ludwig, 80
Hutton, William R., 102, 324
Isembert, 41, 54
Jackson, William, 357
Jarvis, Sir Humphrey, 68, 87
Jervis, John B., 119
Jones, Inigo, 66
Jordan, James, 204, 309
Julius Frontinus, 112
Justinian, 58, 116
Julius III., 28
Keifer, Samuel, 223, 233
Kellar, George, 96
Keller, Herr, 172
Kennard, T. W., 174, 372
King, John, 66, 123
Kneas, Strickland, 161
Koepcke, G., 243
Krell, H.. 79
Krohn, R., 351
Kubler, Herr, 247, 251
Kuhn, Herr, 226
Labelye, Mr., 67, 123
Lacer, 34
Lamande, M., 74
Landor, E. J., 333
Langer, Joseph, 262
Lasterria, Aurelio, 284
Latrobe, Benjamin H., 94, 140, 375
Latrobe, C. H., 378
Laub, Herman, 247, 291
Lauter, Herr, 320
Laurie, James, 174
Leather, George, 156
Le Blanc, M., 218
Lees, Richard, 208
Leibold, C. H., 81
Leonardo di Vinci, 121
Leslie, Sir Bradford, 271, 336
Liddell & Gordon, 371
Lindenthal, Gustav, 180, 239, 256,
254, 264. 362
Linville, J. H.. 173, 176, 180
(451)
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INDEX
Linz, Herr, 148
Long, Stephen H., 138
Lowthorp, F. C, 169, 372
*Lucarus, 104
Lucius, Albert, 355
Lucius Fabricius, 29
Luten, Daniel B., 436
MacDonald, Charles, 238, 262
MacLeod, J. W., 273
Malberg, Herr, 217
Mallory, C. S., 292
Mandrocles, 104
Mansard, M., 60, 61
Marburg, E., 343
Marie, M., 60
Martin, George, 160
Mathieu, M., 374
Mausel de Maya, 118
McAlpine, W. J., 100, 119, 239, 267
McCallum, D. C, 142
Meigs, M. C, 91, 120, 160
Melan, M., 409
Merritt, William, 222
Mertens, H. E., 286
Michael Angelo, 64
Milholland, James, 195
Milne, Robert, 84, 85
Milne, William C, 155
Milroy, John, 141
Ming, Emp., 202
Mitchel, W. M., 267
Moehring, B., 351
Modjeski, Ralph, 295
Monier, Jean, 408, 409
Montfort, Simon, 56
Moors, 37, 39, 48, 396
Morison, George S., 102, 178, 180,
184, 279, 380, 389
Morton, John, 56
Mott, Basil, 359
Mueser, William, 425
Moulton, S., 166
Moulton, Mace, 269
Murphy, J. W\, 166, 169, 173
Nagy, M., 251
Neri di Fiorvante, 46
Nichols, O. F., 254
Nicholson, Peter, 129, 312
Nimmo, Alexander, 87
Nitocris, 18
Noble, Alfred, 266, 295
Nordling, M., 378
Olmstead, F. L., 99
Ordish, Rowland, 229, 230, 242, 337
Osbom, R. B., 157, 165
Osborn, Frank, 386
Oudry,, M., 309
Page, Thomas, 159, 228, 310
Paine, Thomas, 136, 152, 153, 272
Palladio, 63, 121, 128
Palmer, Timothy, 126, 128, 130, 206,
272, 285
Parker, H. G., 442
Parker, C. H., 262
Parsons, W. B., 336
Pelz, Paul, 241, 320
Perronet, Jean R., 61, 73, 446
Peterson, P. A., 330
Peto, Brassey & Betts, 199 '
Philbrick, E. S., 199
Picard, M., 77 '
Pitot, M., 118
Pitron, M.. 61
Planchet, M., 76
♦Plutarch. 26
Polonceau, M., 157
Pope, Thomas, 135, 259
Porter, J. M., 131, 285
Post, S. S., 175
Pratt, Caleb, 142, 169
Pritchard, Mr., 152
Pyrrhus of Epirus, 105
Quimby, H. H., 402
Quintius Martius, 113
Rainey, Thomas. 238
Rastrick & Hazeldean, 163
Raymer, A. R., 307
Redpath & Brown, 208
Rendel, Sir Arthur 214, 388
(452)
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INDEX
Rennie, George, 84, 87
Rennie, Sir John, 84, 87, 359
Resal, M., 282
Reynolds, A. M., 430
Riddle, William P., 126
Rider, Mr., 166
Rieppel, A., 248, 307, 337
Ritchie, J., 286
Ritter, Joseph, 123, 261
Robinson, Moncure, 141
Roebling, John A., 219, 223, 228, 231,
263. 303
Roebling, Washington, 237
Romano, 61
Ross, A. M., 199
Rust, H. B., 101, 334
Sanders, Avery, 131
Sanne, Oscar, 100, 328
Saraceus, 48
Scala. 46
Schaub, J. W., 341, 346
Schell, F. R., 288
Schinkel, Herr, 78
Schneider, C C, 180, 266, 324, 367,
392
Schneider & Frintzen, 352
Schnirch, Herr, 214, 218, 234, 299
Schwitzer, J. E., 394
Schwedler, Herr, 220
Seckel, William, 148
Sedley, A. J., 261
Seguin Brothers, 209, 217
Semiramis, 18
Semple, George, 87
Serrell, Edward, 223, 224, 227, 377
Sewell, J. S., 264
Sewell, Samuel, 125
Sextus. 112
Seymour, Silas, 366, 370
Seyrig, M., 315, 319
Shah Abbas. 70
Shanley, Walter, 286
Shaw, E. S., 269, 287, 288, 299
Shunk, F. R., 357
Sixtus IV., 32, 48
Smart, George, 165
Smeaton, John, 68, 84
Smedley, Samuel, 179
Smith, Fred H., 375
Smith, Charles S., 95, 178, 263, 376
Smith, Jas. F., 365
Smith, Messrs., 208
Smirke, Sir Robert, 90
Snowden, J., 157
Spengler, Herr, 125
St. Benezet, 41, 54
Stebbings, W. L., 281
Steiner, Charles, 243, 335
Stephenson, George, 84, 88, 151, 214,
225, 370
Stephenson, Robert, 84, 139, 154, 159,
197, 260, 312
Stewart, George, 108
Stone, A. B., 169
Strauss, J. B., 434
Strobel, C. L., 293
Symonds, T. W., 241, 320
Szlapka, H., 286
Talbot, A. N., 413
Tarquin, 25
Tarquinius, 36
Tembleque, 68, 117
Templeton, John, 127, 206
Telford. Thomas, 84, 89, 118, 151,
153, 155, 158, 211, 252, 313, 446
Thacher, Edwin, 409, 413
Thomson, T. K, 181, 254, 286, 329
Thompson, A., 195
Theodelapius, 44
Thayer, Russell, 102
Tomlinson, Joseph, 266
Torrey, A., 266
Town, Ithiel, 137
Trajan,' 34, 115, 118
Trautwine, John C, 225
Tredgold, Mr., 149
Trowbridge, W. P.. 238, 262
Trubshaw, James, 88
Trucks, Mr., 134
Trumbull, Earl, 165
(453)
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INDEX
Tyrrell, William. 146, 441
Tyrrell, H. G., 191, 249, 360
Vallency, Col., 87
Van Diesen, G., 175
Vanvitelli, 118
♦Vasari, 64
Vautelct, H. E., 330
Vescovali, 83
Vicat, M., 284
Von Emperger, Herr, 409, 411
Von Mites, Herr, 213
Von Ruppert, Carl, 175
Waddell, J. A. L., 274
Walker & Kimball, 99
Walker, James, 359
Walton, F. T. C, 183
Watson, Wilbur J., 435
Webster, George S., 40'"
Webster, J. J., 332
Welsh, J., 286
Wendelstadt, Herr., 211
Wentworth, C. C, 247
Wemwag, Lewis, 126, 135
Wheelwright, E. M., 103, 357
Whipple, Squire, 165, 166
Whited, Willis, 344, 357, 441
White & Hazard, 205
Whistler, Col., 144, 174
Whitton, Mr., 200
Wild, Charles, 167
Wilke, R., 79
Wilson, Thomas, 154
Wilson Bros., 269
Witmer, A., 90
Wood. E. M., 359
Wood, J. T., 332
Woodhousen, H., 386
Worthington, Charles, 291, 362
Wright, Abraham, 226
Wright, C. H., 286
Wunsch, R., 408
♦Xenophon, 104
Xerxes, 21, 104, 105
♦Early Historians.
(454)
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GENERAL INDEX
Aar River, 50, 171, 309, 316, 339, 378
Aberdeen Bridges, 163
Aberfeldy Bridge, 66
Abydos Bridge, 104
Academy of Science, 153
Acambarro Bridge, 68
Adabazar, Asia Minor, 58
Adda River, 46, 83, 327
Adana Bridge, 49, 58
Adige River, 46, 320
Admiral Bridge, 47
Adriatic Gulf, 105
Aelius, Pons, 26, 31
Aemilia, Road, 24
Aesculapius, 30
Aemilius, Pons, 26, 27, 29
Agassiz Bridge, 97
Agrippa, Pons, 32; Gardens of, 31
Aire River, 156, 163, 196
Aix Aqueduct, 75, 119
Albano Bridge, 82
Albany, N. Y., Bridge, 326
Albany Ind., 436, 437
Alaska Bridge, 326
Albemarle Sound, 369
Albert Bridge, Glasgow, 129, 312
Albert Bridge, England, 160
Albert Bridge, England, 229
Albert Bridge, Dresden, 82
Albi Bridges, 43, 77, 242
Alcantara, Lisbon, 62. 117
Alcantara, Toledo, 25, 34, 38
Albula River, 80
Alconeter Bridge, 37
Aleppo Bridge, 49
Alexander III. Bridge, 163, 346
Alexandria Bridge, 48
Algoma Central Ry. Bridge, 368,
389
Allah-Verdi-Kahn Bridge, 70, 71
Allegheny River, 219, 228, 234, 239,
290, 291
Allentown Bridge, 207
Allier River, 43, 61, 236
Alma Bridge, 346
Almazar Bridge, 37
Alsientina Aqueduct, 114
Altier River, 76
Alvord Lakelet Bridge, 412
Amalfi, Italy, Bridge, 396
American Bridges, 68; Bridge
Builders, 126; Scientific Building
in Wood, 127; Railways, 72;
Stone Ry. Bridges, 95; Bridge
Co., 189; Stone Bridges, 72, 90;
Patents, 165, 166
Amoskeag River, 126
Amou-Daris, 188
Amsterdam, Holland, Bridge, 79
Anacosta Bridge, 355
Andernach Bridge, 33
Anker Viaduct, 89
Andover Bridge, 126, 127
Angarten Bridge, 234
Angelroda Viaduct, 374, 375
Angerman River, 284
Anglers Bridge, 214, 224
Anio River, 36, 113
Anio Novus Aqueduct, 114
Anio Vetus Aqueduct, 113
Antioch Aqueduct, 116, 407;
Bridges, 25, 38, 49
Antonius, Pons, 32
Aosta Bridge, 33
Appia Aqueduct, 113
Appian Way, 24
Aqueduct Bridges, 112
Aqueducts, in North America, 117;
Concrete, 407; Croton, 91; Wash-
ington, 90; Rochester, 91; Rome,
29; Masonry, 75. In England,
118. In France, 75.
Aranyos River, 148
Arc River, 75, 119
Arch: Slab Construction, 22; Metal,
in America, 320; Triangular,
(455)
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Google
GENERAL INDEX
Bridge, 52; Method of Tying,
319; First Application in Bridges,
28; Conoidal, 74, 87; Bridge —
Oblique, 73; Ancient, in Britain,
52; Natural, 17; Ancient, Timber,
36; Combination Truss, 127; Ogi-
val, 70; Flat Vaulted, 61; Ellipti-
cal, 60, 73; Roman or Triumphal,
25, 42 49; Pointed, 41; Brick,. 19;
False, 17, 21, 24; True, 17, 24;
Masonry, 19; Ribbed, 432
Arcole, Pont d', 309, 310
Arricia Viaduct, 82
Areley Bridge, 161
Arequipa, Peru, Bridge, 69, 376
Armeria Riv^r, 259
Arno River, 46, 63, 82
Arran Bridge, 68, 87
Ashtabula Bridge, 180
Asia Minor, Bridges, 18, 49, 58
Aspen Bridge, 229
Aspendon Bridge, 49
Assenheim Viaduct, 374, 375
Assopos Viaduct, 359
Assos Bridge, 20
Assyrian and Persian Bridges, 104
Assyria Bridge, 18
Atcheson Bridge, 177
Athbara Bridge, Egypt, 188
Atlanta, Ga., Viaduct, 425
Atlantic Highlands Bridge, 421
Attica, 24
Auckland Bridge, 370, 402, 404, 405,
406
Aude River, 43
Audubon Bridge, 97
Augustus, Emperor, 29, 33, 34, 113,
114
Augustus II., 49
Augusta Bridge, 17
"Auld Brig o' Ayr," 55
Aulne Viaduct, 76
Aurelia, Road, 24
Aurelius, Pons, 32
Austerlitz Bridge, 74, 163, 347, 364
Austin Bridge, 438
Australia, Bridges, 183
Austria, Bridges, 81; Mediaeval, 49
Auteuil, Viaduct, 75
Avignon Bridge, 40, 54
Avon River, 90, 229
Ayr River, 55, 90
Azores Bridge, 20
Babylon Bridges, 17, 104
Baden Bridges, 79, 125
Baiae Bridge, 34, 106
Balgownie Bridge, 55
Balloch Ferry Bridge, 216
Ballochmyle Bridge, 90
Baltimore Bridges, 138, 320, 325
Bamberg Bridge, 131, 214
Bangor Bridge, 211
Barbaruh Bridge, 70
Barentin Viaduct, 75
Barnes Bridge, 163
Bascule Span, 213, 220
Basket Ferry, 223
Basle Bridge, 317
Battle River, 393
Bavaria, Bridges, 49, 401, 406
Bear River, 392
Beaumont Bridge, 216
Beaver, Pa., Bridge, 201, 306
Beaver River, 201
Bedford, England, Bridge, 317
Belgium Bridges, 78, 79
Beirut Bridge, 49
Belah Viaduct, 372, 395
Bellaire Bridge, 247, 286
Bellefontaine Bridge, 184
Bellegrade-Chizery Bridge, 77
Belleview Park, Detroit, Bridges,
100
Bellevue Bridge, 97
Bellevue Trestle, 368
Belle Isle Park, Detroit. Bridges,
100, 328
Bellon Viaduct, 378
Bellows Falls Bridges, 96, 127, 354,
364
Belvidere Bridge, 432, 433
Belly River, 393
Benares Bridge, 183
Benwood Bridge, 181
(456)
Digitized by
Google
GENERAL INDEX
Bentlcyville Bridge, 336
Bent Bracing, First Use of, 370
Berlin Bridges, 65, 66, 78, 316, 332,
349
Berne Bridges, 50, 171, 315, 316, 339
Berwick Bridge, 89, 90, 209» 214. 224
Bessemer Process, 171
Bethlehem Bridge, 134
Bettws-y-Coed Bridge, 67, 155
Beveriy Bridge, 125
Bieda Bridge, 24
Big Creek Bridge, 332, 400
Big Four Railway Bridge, 96, 400
Big Muddy River, 398
Birmingham Canal Bridge, 156
Birmingham, Ohio, Bridge, 353
Bishop, Auckland, Bridge, 56
Bismark, Dak., Bridge, 180
Blaauw Krantz Viaduct, 317
Black River, 334
Blackfriars Bridge, 72, 85, 162, 174,
358, 359
Blackweirs Island Bridge, 237, 238,
243, 262, 270, 376
Blois Bridge, 61
Bloomfield, Ind., Viaduct, 391
"Blue Wonder" Bridge, 244
Boberthal Viaduct, 79, 80
Bogota Bridges, 69
Bohemia, Bridges, 50
Bollatfall Bridge, 311
Bommel Bridge, 171
Bonn Bridges, 33, 248, 349, 363
Boone, Iowa, Viaduct, 368, 388, 395
Boonville Bridge, 175
Borcea River, 277
Bordeaux Bridge, 74, 336
Borghetto Bridge, 33
Borrodale Bridge, 397
Borsig Bridge, 252
Bosphorus Bridge, 104, 175, 313
Boston, Lincolnshire, 84, 156
Boston, Mass., Bridge, 69, 97, 123,
125, 138, 244, 411, 438
Boucheries, Pont des, 65
Boulder Bridge, 421
Boulevard Bridge, St. Paul, 434
Bourgas Aqueduct, 38, 116, 407
Bow, England, 53
Boylston Bridge, 97
Boyne River, 171, 260
Branch Brook Park, Newark, 430
Brandywine Creek, 136, 205
Brazil Bridge, 283, 314
Brazos River, 234
Brechin Bridge, 56
Brenta River, 122, 123
Brick Viaducts in England, 89
Bridesburg Bridge, 136
Bridge of Sighs, Venice, 62, 63
Bridge-building, Roman, 23; in
Italy, 62; in Great Britain, 106;
in France, 59
Bridges and Roads, Dept., 61, 73,
446
Bridge Commission, 84, 445, 446
Bridgeport, Ohio, 201
Bridle Path Bridge, 97
Brighton Pier, 209, 214, 224
Brighton, Mass., 123
Brioude Bridge, 43
Bristol Bridge, 163, 229
British Bridges, Med., 51; Ren., 66;
Mod., 83
British Columbia Bridges, 320
Brittania Bridges, 84, 158, 197, 200,
211, 221
Broadway, St. Paul, Bridge, 272
Bronze Bridges, 57
Brooklyn-Brighton Viaduct, 332
Brookline Bridge, 97
Brooklyn Bridge, 237, 252, 254
Broomielaw Bridge, Glasgow, 89
Brookside Park Bridge, Cleveland,
400
Brotherton Tubular Bridge, 196, 197
Broughton Bridge, 214
Brownsville, Pa., Bridge, 205
Brunot's Island Bridge, 181
Brunswick Bridge, 95
Buckeye Viaduct, 370, 371
Budapest Bridge, 109, 220, 251, 269,
2H:\, 290, 292, 314, 416
Buffalo Canal Bridge, 336
(457)
Digitized by
Google
GENERAL INDEX
Buffalo, N. Y., Park Bridges, 320,
325
Bulkley River Bridge, 258
Buildwas Bridge, 153
Bulloch Penn., Viaduct, 375
Burmah Railway Co., 388
Burr Truss, 96
Burr Type, 133
Burton Bridge, 55
Busseau Viaduct, 374
Busetti Viaduct, 76
Bushnell Park Bridge, 96
Butterfly Iron Co., 155
Cabin John Bridge, 90, 120
Cachoeira Bridge, 283
Cables — Method of Making, 214
Cable Bracing — First Use of. 271
Caesar's Bridge, 32, 121, 365
Cahors Bridge, 42
Cairo Railway Bridge, 180
Caissons, Early Use of, 36
Calah Bridge, 16
Calci Bridge, 46
Calcutta Bridges, 109, 261, 336
Calder & Hibble Nav. Bridge, 139
California Exposition Bridge, 412
Callao, Peru, 69, 274
Callowhill St. Bridge, 135, 179
Cam River, 155
Cambridge, Mass., Bridge, 126, 138,
357
Cambridge, England, Bridge, 155
Cambridge, Ohio, Bridge, 137
Campagna Bridge, 114
Campus Martius, 37
Canadian Bridge Co., 394
Canadian Pacific Ry. Bridges, 194
Canals: Medina, N. Y., 438; An-
cient, 19, 25, 57, 58; at Osaka, 58;
in Great Britain, 84; Durance-
Marseilles, 75
Canada, Bridges, 187, 194, 198, 199,
245
Cannon Street Bridge, London, 174
Canso, Straits of, 307
Cantilever Bridges, 257; Ancient,
57; Primitive, 257; of Great
Height, 302; First Railyray, 263;
Span — Largest in America, 305;
Wood, 123; First Concrete in
United States, 435; Largest Pro-
posed, 308
Cape Colony Viaduct, 317
Caperton Bridge, 249
Capadarso Bridge, 63
Capua Bridge, 82
Cap Rouge Viaduct, 393
Caravan Bridge, 18
Carazoa Bridge, 110
Carcasonne Bridge, 43
Carey St., Baltimore, Trestle, 370
Carlisle Bridge, 90
Carlsburg Bridge, 340
Carnarvonshire, Wales, Bridge, 210
Carquinez, Cal., Cable Span, 256
Carrollton Viaduct, 93
Carrick-a-Rede Bridge, 203
Carrousel, Pont du, 157
Carter Co., Ky., Bridge, 203
Carthage Aqueduct, 115, 407
Cartlane Crags Bridge, 87
Cascade Glen Viaduct, 143
Cassia Road, 24
Castelleneta Viaduct, 374
Castellane Bridge, 43
Cast Iron Bridges, 151, 152; for
Menai Straits, 210; Cast and
Wrought Iron Truss, 165; Larg-
est in America, 161; Experiments
in Cast and Wrought Iron, 158;
Cast and Wrought Iron Girders,
157; Floor Plates, 157; One of
First Suspension Bridges, 217
Catwater River, 52
Cauca River, 245
Caucasus Bridge, 203
Cayuga Lake Bridge, 12&
Cazerta Aqueduct Bridge, 118
Cedar Ave., Baltimore, Bridge, 325
Cedar Rapids, Iowa, Bridge, 415,
436
Cement, Used by Romans, 25
Central Bridge, Cincinnati, 279
Cephisus River, 24
(458)
Digitized by
Google
GENERAL INDEX
Ceredo Bridge, 181
Cerct Bridges, 40, 42
Ceriog River Aqueduct, 118
Cerveyrette Gorge Bridge, 327
Cernavoda Bridge, 267, 277
Cestius, Pons, 26, 27, 30
Cestius Gallus Bridge, 32
Ceylon Bridge, 148, 360
Chalonnes Bridge, 76
Champlain Bridge, 412
Change Creek Bridge, 368
Change, Pont au, 60, 75
Channelsea Bridge, 53
Characteristics of Mediaeval
Bridges, 39
Charente River, 41
Charing Cross Bridges, 174, 220,
221, 220
Charles River, Boston, Bridges, 91,
125, 126, 138, 357, 441
Charlesgate Bridge, 97
Charlestown Bridge, Boston, 125
Charleston, W. Va., 226, 239
Charley Creek Bridge, 435
Chateau Neuf Bridge, 40
Chatellerault Bridge, 417
Chatsworth Bridge, 89
Chaudiere Suspension Bridge, 225
Chaumont Viaduct, 76
Chausi, China, Bridge, 106
Chaves Bridge, 37
Cheat River Viaduct, 370
Chelsea Bridge, 228, 229, 310
Chemong Lake Bridge, 108
Chenonceaux Bridge, 59
Chepstow Bridge, 162, 169
Chester, England, Bridge, 88, 157
Chestnut St., Philadelphia, Bridge,
161
Chiffa Bridge, 162
Chicago, 111., Bridges, 100, 244, 411,
444
Chicago, Milwaukee & St. Paul Ry.
Bridges, 110
Chicago & Northwestern Ry.
Bridges, 388
Chili Bridges, 68
China, Bridges, 106; Sea, 57; Med.,
10; Pontoon, 22; Mod., 353.
Chirk Aqueduct, 118
Choate Bridge, 90
Chuka Castle Bridge, 203
Cilicia Bridge, 58
Cincinnati, Ohio, Bridges, 176, 180,
181, 228, 231, 336, 411
Cinq Mars Bridge, 75
Circus Maxiraus, 25; of Nero, 31
Cismore Bridge, 122
Civita Castellan e, Italy, 82
Clain River, 204
Claix Bridges, 60
Clark Park, Detroit, Bridges, 100
Clark's Ferry Bridge, 144
Clark Run Viaduct, 376
Clarion Bridge, 190
Claudius Aqueduct, 114
Cleveland, Ohio, Bridges, 384, 386,
401, 402, 406
Clifton, N. J., Bridge, 421
Clifton, England, Bridge, 221, 229
Clifton- Niagara Bridge, 233
Clinton, Iowa, Bridge, 272
Cloaca Maxima, 25
Clyde River, 56, 89, 129, 135, 139,
312
Coalbrookdale Bridge, 52, 53, 151,
309
Coatsville Bridge, 95
Coblenz Bridge, 33, 50, 110, 311, 314
Coburg Bridge, 150
Coepenick Bridge, 82
Cognet Bridge, 60
Colico & Soudrio Ry., 83
Colfax Ave., South Bend, Bridge,
419
Colfax, Cal., Viaduct, 392
Cologne Bridges, 310, 107, 171, 220,
248
Colombo, Ceylon, 110
Colombia, South America, 69, 245,
283
Colon, Bogota, Bridge, 69
Colorado River, 273
Colossus Bridge, 135, 136, 219
(459
Digitized by
Google
GENERAL INDEX
Columbia River, 190; Park, 428
Columbia Bridge, 133, 139
Colima, Mexico, Bridge, 259
Commentry-Gannat Ry., 377
Commerce, Bridge of, 357
Commission on Bridges, Great
Britain, 84; Illinois, 445
Como Park Bridge, 428
Computation of Stresses, 166
Comun Bridge, 69
Concord, Wash., 288
Concorde, Pont de la, 73
Concrete: Filling, 77; Lining, 114;
Use of, 25, 29; Bridges in Amer-
ica, 72; Monolithic, 77; First Can-
tilever, 435; Railway Bridges,
446; Solid, Bridges, 396; Arch,
First American Hinged, 452
Concrete Steel Engineering Co.,
425
Congleton Viaduct, 89, 90
Connecticut Ave., Washington,
Bridge, 343, 404, 421
Connecticut River, 96, 102, 127, 128,
131, 142, 176, 223, 287, 354
Connel's Ferry Bridge, 292
Conneswingo Bridge, 136
Constance-Baden Bridge, 310, 311
Constance, Lake, 247
Constantine, Algeria, Bridges, 161,
440
Conway River, 66, 155; Bridge, 84,
158, 211
Coppel Viaduct, 79
Cora Bridge, 24
Cordova Bridge, 48
Cork, Ireland, Bridge, 87
Cormery Bridge, 216
Cornwall Bridge, 187, 289
Cornhouse Bridge, 316
Costa Rica Bridges, 326, 353, 364
Covington-Cincinnati Bridge, 250
Craigellachie Bridge, 153, 156
Credits, Preface
Crescent, N. Y., Aqueduct, 119
Cresheim Creek Bridge, 100
Creuse Viaduct, 374, 378
Croton Aqueduct, 91, 118
Croton Lake, N. Y., Bridge, 295,
297
Crou River, 309
Crueize River Viaduct, 76
Cruft St. Bridge, Indianapolis, 418
Crum Elbow Creek Bridge, 413
Crumlin, So. Wales, Viaduct, 371,
372, 383, 395
Cubzac Bridge, 217, 218
Cuence Bridge, 37
Cuernavaca, Mex., Bridge, 68, 117
Cumberland, Md., Bridge, 140, 205,
379
Curvo, Ponte, 63
Customs, Ancient Bridge Building,
51, 81, 271
Cuyahoga River, 384
Cyssylte Aqueduct, 118, 155
Dacia, Bridge, 116
Daff Viaduct, 374
Dallas, Tex., Viaduct, 440
Dalton Viaduct, 89, 90
Damascus, Bridge, 35, 83
Damascus & Mecca Ry. Viaduct,
83
Damietta Branch Bridge, 196, 197,
199
Danube Canal, 213, 229, 314, 317
Danube River, 35, 40, 49, 104, 107,
109, 148, 178, 220, 277, 283, 292, 339
Danville, 111., Bridge, 271, 400
Dartmoor Bridge, 51
Darzeeling, India, 258
Data for Bridges, 73, 77, 111, 136,
194, 363, 395
Daumur Bridge, 305
Davenport Bridge, 190
Davis Ave., Allegheny City, Bridge,
281
Dayton, Ohio, Bridges, 425; Wash-
ington St., 418; Third St., 418;
Main St., 418
Dean Bridge, Edinburg, 87
Dearness River, 366
Dee Viaduct, 88; River, 56, 90. 155,
157
(460)
Digitized by
Google
GENERAL INDEX
Dee Aqueduct, 155
Deer Island Bridge, 127, 206
Delaware River, 120, 126, 131, 146,
187, 225, 285
Denver, Colo., Bridge, 432
Department of Bridges and Roads,
61, 446
Derby, Conn., 442
Design of Bridges by Companies,
178; Artistic Design, 385
Des Moines River, 388, 419
Des Plaines River, 245
Destruction of Bridges, 26, 32, 33,
35, 40, 47, 49, 54, 66, 125, 140
Detroit Ave. Bridge, Cleveland, 402
Detroit Park Bridges, 328; Bridge,
100, 269, 286
Deutz Bridge, 172
Devil's Bridges, 44, 82
Devil's Pool, Philadelphia, 100
Dinan, Scotland, Viaduct, 76
Dirschau Bridge, 171
Dixville, Ky., Bridge, 263
Diz River, 21
Dizful Bridge, 21
Dneiper River, 183, 224
Doktare Pol. Bridge, 58
Dolhain Viaduct, 79
Dominion Bridge Co., 290
Don River, 55, 129, 146
Donora Bridge, 190
Dorchester Bridge, 66
Dordogne River, 217, 218
Doubs River, 77
Doux River, 59
Douro River, 218, 315, 319
Dowery Dell Viaduct, 383
Drac River, 60
Dredging Machine, 61
Dresden Bridges, 49, 243, 337
Drin River, 37
Drogheda Viaduct, 171, 260
Dryburg Abbey Bridge, 208
Dublin Bridges, 68
Dubuque Bridges, 176, 190
Dundee Bridge, 182
Dunlap Creek, Pa., Bridge, }57
Durance River, 43, 61; Canal, 75,
119
Durham Bridge, 214, 224, 226
Dusseldorf Bridge, 348, 351, 363
Dussern Bridge, 310
Eauplet Bridge, 141
Eads Bridge, St. Louis, 158, 163
East Berlin Bridge, 201
East Dart River, 51
Eastern Bengal Ry., 208
East Liverpool, Ohio, Bridge, 247
East River, 237, 252, 287, 361, 362
Easton Bridges, 126, 131, 249, 285
East Washington St., Indianapolis,
418
Ebbw Valley Viaduct, 371
Echo Bridge, 91, 120
Economical Designs for Bridges,
443
Economical Types of Suspension
Bridges, 242
Ecuador Bridge, 69
Eddy Patent Suspension, 242
Eden River Bridge, 90
Eden Park, Cincinnati, 411
Edinburg, Ind., Bridge, 443
Edinburg, Scotland, 88, 357
Edmondson Ave., Baltimore, 404
Egypt, 15, 16, 18, 188, 306
Ehrenbreitstein Bridge 110
Eighteenth St., St. Louis, 267
Elastic Method, First Use in Amer
ica, 409
Elbe River, 49, 179, 337, 351
Elbe-Trave Canal, 247, 326, 349
Eleusis, 24
El Ghajar Bridge, 71
Elizabeth Bridge, 251, 324
Elizabethtown Bridge, 189, 191
El Kantara, 161
Elk River, 226, 239, 302
Ellesmere Canal, H8
El Rodeo Viaduct, 392
Elsterthal Viaduct, 79
Ely Bridge, 163
Emerichsville, Ind., 435
(461)
Digitized by
Google
GENERAL INDEX
Ems River, 298
Engineering — Early, 29, 35
Engineering — Oriental, 66
Engineering — School, 61
English Channel Bridge, 286
England, Early Bridges in, 51, 72
English Engineers, 84
Erection Methods, 338, 341; Canti-
lever Erection, 260, 433; Cable-
way Erection, 393
Erdre River, 315
Erie Railway, 94, 365, 380
Erie Canal, 165, 320
Erivan Bridge, 58
Esk River, 56
Essex Bridge, 68, 87
Esscx-Merrimac Bridge, 126, 127
Etchin, Japan, 257
Euboea Bridge, 19
Euphrates River, 16, 17, 18, 104, 106
Euripus River, 19
European Wood Bridges, 123
Euxine Sea, Pontoon Bridge, 105
Evora Bridge, 37
Executioner's Bridge, 65
Experiments in Concrete, 409; On
Strength of Wrought Iron, 159,
196; On Strength of Cast Iron,
158
Exporting Bridges: Suspensions,
245; Structural Work, 188
Fabricius, Pons, 26, 29, 37, 407, 447
Fades Viaduct, 392, 394, 395
Failure of Bridges: Concrete, 443;
Suspensions, 224, 235, 239, 214,
217; Cantilevers, 300
Fairmount, W. Va., Bridge, 291
Fairmount, Pa., Bridges, 135, 205,
218, 343
Fall Creek, Ithaca, 344
Fall Creek, Indianapolis, 418
Falls of Schuylkill, 179
Fechew, 57
Fegana River, 82
Feldkirch Bridge, 49
Felice, Ponte, 34
Fenway Bridge, 97
Ferdinand Bridge, Graz, 315
Ferrato, Ponte, 32
Fink Truss, 169
Finnan Valley, Scotland, Viaduct,
399
Fishing Creek Viaduct, 379
Fitchburg Ry. Viaduct, 96
Fives-Lille System, 234
Flamingos Valley, 20
Flaminian Way, 24, 29
Flat Rock River, 443
Fleischbrucke, 65
Florence Bridges, 46, 62, 63
Florida East Coast Ry., 398
Floating Piers, 107
Floating Bridges, 106, 107
Flying Bridge, 57
Flying Lever Bridge, 259
Fokien, China, 67
Forbes St., Pittsburg, 344
Forest Hills, Boston, 97, 99
Forest Park, St. Louis, 413, 428
Forth Bridge, Scotland, 56, 88, 208,
237, 275
Fort Miller Bridge, 127, 130
Fort Dodge Viaduct, 389
Fort Snellinj? Bridge, 264, 357, 401,
405
Forsmo Bridge, 267, 284
Fosse River, 209
Fountainebleau Valley, 77
Fractus, Pons, 32
Frankford, N. Y., Bridge, 165
Frankfort, Germany, 50, 173, 225,
234, 298, 299, 315
Frankfort, Ky., 226
Franklin Bridge, 413
Franklin, Pa., Bridge, 235
Franzens Bridge, Vienna, 317
Franz-Joseph Bridge, 230, 283, 290
Frazer River Bridge, B. C, 266, 330
Frederick Bridge, 277
Freiderichsbrucke, Berlin, 78
French Bridges. Statistics of, 77;
Mediaeval, 40; Renaissance, 59;
Modern, 73
French Congo Bridge, 252
(462)
Digitized by
Google
GENERAL INDEX
French River, 194
Freysingen bridge, 131
Fribourg Bridge, 215, 374, 395
Fricdalhausen Bridge, 82
Fuentecen Bridge, 78
Gabii Bridge, 32
Gainsborough Ry. Co., 200
Gatacia Bridge, 80
Galawater Bridge, 207
Galton Bridge, 156, 163
Galveston Bridge, 186, 438
Ganges River, 105, 183, 271
Garabit Bridge, 315, 318, 319, 364,
392
Gard, Pont du, 24, 38, 114, 119, 407,
417
Garden River, 407
Gardner, N. Y., Bridge, 201
Garfield Park Bridge, 100, 245
Garibaldi Bridge, 32, 326
Garonne River, 59, 74, 336, 440
Gary, Ind., Bridge, 421
Gateshead Bridge, 167
Gauley River, 227
Gaunless River, 165, 369
Gave River, 43
Geneva Bridge, 209
Genessee River, 119, 325, 365
Genoa Y Bridge, 416
Georgetown Bridge 126
German Bridges. Mediaeval 49;
Renaissance 65
Germantown Bridge, 401
Gerrard's Hostel Bridge, 155
Ghizeh, 18, 19
Gignac Bridge, 74
Girard Ave. Bridge, 179
Girder Spans. Longest Simple
Plate, 201
Girder Bridges. Tubular and Plate,
195; Longest Through Plate, 201;
First Wrought Iron, 195; Riveted
Lattice, 173
Glasgow Bridges, 56, 85, 89, 129,
135, 139, 195
Glasgow, Dakota, Bridge, 180
Glendoin Bridge, 438
Glenury, Scotland, Bridge, 143
Gliscard Type, 252
Golden Gate Park Bridges, 245, 408
Godavari River, 188
Goeltzschthal Viaduct, 79
Goose Creek, 136
Gorlitz Viaduct, 79
Gorz, Austria, 81
Gotteron Bridge, 218
Gouritz, Cape Colony, Bridge, 266
Grafton Bridge, 405
Grand Ave., St. Louis, Bridge, 243
Grand River, Ohio, 403
Grand River, Mich., 94, 148, 333,
358
Grand Ave. Viaduct, Milwaukee,
442
Grand Rapids, Mich., Bridges, 148,
423
Grand Tower, 111., 398
Grand Trunk Ry.. 373, 393
Grand Maitre Aqueduct, 77, 396
Granite Blocks and Slabs, Use of,
35, 47, 52, 57
Grant Memorial Bridge, 241, 320
Grasshopper Creek Trestle, 387
Gratianus, Pons, 30
Great Bridge, Boston, 69, 123
Great Miami River, 189, 425
Great Northern Ry., 167
Great Salt Lake Trestle, 369
Great Western Ry., England, 367,
371, 85
Greece, Bridges, 19, 24, 110, 116, 359
Greenville, Me., Bridges, 394
Greensburg Bridge, 204, 443
Green Island Bridge, 419
Grenoble Bridge, 60
Grey^s Point Bridge, 295
Grosshesselote Bridge, 172
Grosvenor Bridge, 88
Gruenwald, Munich, 399, 406
Grunenthal Bridge, 331, 364
Guadalaviar River, 77
Guadalquiver River, 48, 77
Guadalupe Aqueduct, 117
Guadiana River, 37
(463)
Digitized by
Google
GENERAL INDEX
Guarino, 245
Gutach Bridge, 79
Guatemala Ry., 392
Guillotiers Bridge, 42
Guls Bridge, 315
Gunpowder Creek, 136
Gwynns River, 404
11 St., Washington, Bridge, 193
Habra Bridge, 162
Haddlesley Bridge, 163"
Haight St. Bridge, 412
Hainsburg, N. Y., Bridge, 403
Halle Bridge, 81
Hamarth Bridge, 49
Hamburg Bridges, 82, 138, 177
Hameln Bridge, 217, 298
Hamilton, Ont., Bridge, 336
Hamilton Co., N. Y., Bridge, 292
Hamilton, Ohio, 189
Hammersmith Bridge, 213
Hannibal, Bridge of, 82
Hannibal, Mo., 177
Hanover, Timber Arch, 128
Harburg Bridge, 351, 319
Harlem River Bridges, 90 141, 239,
269, 397, 361
Harper's Ferry Bridge, 109, 136,
169
Harrington Viaduct, 90
Harrisburg Bridges, 127, 140
Hartford, Conn., Bridges, 96, 102,
150
Hassan Bey Bridge, 71
Hassfurt Bridge, 261
Hastingsport, 307
Hastings, Minn., Bridge, 185, 239
Havre de Grace Bridge, 143
Haverhill, N. H., Bridge, 126, 128
Hawk St., Albany, Viaduct, 326, 345
Hawksbury River, 183
Heidelberg Bridge, 78, 315
Hellespont Bridge, 104
Hell Gate Bridge, 287, 362
Henderson Bridge, 181
Hertford Bridge, 108
Hessich Bridge, 217
High Bridge, 91, 118
High Force Bridge, 204
Highland Park Bridge, 290
Hindustan Bridge, 203
Hoelzbach River, 305
Hohenschwangen Bridge, 311
Holland Bridges, 61, 65, 178
Holt's Rock Bridge, 128
Holy Cross Bridge, 49
Homersfield Bridge, 408
Honda, Colombia, Bridge, 283
Hoogly Bridges, 109, 271, 337
Horse Shoe Run Viaduct, 379
Housatonic River, 411
Houses and Shops on Bridges, 34,
43, 46, 51, 71. 443
Howe Truss, 141
Hubbard, Ohio, Bridge, 201
Hudson River, 129, 130, 134, 233,
254. 259, 308, 361, 362, 405
Humber River, 373, 440
Hungary Bridges, 35, 283, 284
Hungerford Bridge, 220, 229
Hunslet Bridge, 156
Hutcheson Bridge, 312
Hyde Park Bridge, 413, 421
111 River, 49
Iller River, 401
Illinois Central Ry., 398
Illinois St. Bridge, Indianapolis, 418
Imera River, 63
Imnau Bridge, 397
India, Bridges, 71, 183
Indre River, 216
Indus River, 110, 271, 305
Inn River, 171
Interlachen Bridge, 419
Inverkip Bridge, 374
Inverness Bridge, 236
Inzighofen Bridge, 397
Ipswich Bridge, 408
Ireland, Bridges, 68, 87, 125
Iron Bridges in America, 165; Via-
ducts for B. & O. Ry., 166;
Bridges, First, 164; Early Iron
Suspension Bridges, 204; Earliest
Iron Bridges in Europe, 152;
First Iron Girders in America,
(464)
Digitized by
Google
GENERAL INDEX
165; First Railway Bridges of
Iron, 166; First Iron Trestle, 369
Iron Gate, 35
Tsar River, 79, 131, 172, 399
I sere River, 43
Island Park, Pa., Bridge, 207
Isle of Bourbon Bridges, 221
Isle of St. Louis, 160
Isle of Honda, Bridge, 69
Ispahan Bridges, 70
Isonzo River Viaduct, 81
Italy, Bridges, 24, 62, 116
Italian Bridges, Mediaeval, 44;
Renaissance, 62; Modern, 82
Ivry, Pont, 139
Iwakuni, Japan, Bridge, 69, 121
Jacksonville Viaduct, 425
Jacob's Creek Bridge, 204
Jamaica Rys., 397
Jamaica Viaducts, 397
Jamestown Exposition Bridge, 434
James River, 141
Janiculensis, Pons, 26, 32, 48
Japan, Med., 56; Metal Bridges, 164
Jaremcze Viaduct, 79, 80
Java, Bamboo Bridge, 148
Jaxtfeld Bridge, 312
Jefferson Ave., South Bend, Bridge,
452
Jekaterinoslaid, 183
Jena Bridge, 74, 346
Jones Falls Bridge, 136
Jordan Creek Viaduct, 372
Jordan River, 71
Jordan River, Utah, 138
Jour, Pont du, 75
Jubilee Bridge, India, 271
Julia Aqueduct, 113
Julius Caesar's Bridge, 32
Jutland Bridge, 307
Kaiser Wilhelm Bridge, 315, 337
Kaisersteg Bridge, 290
Kanday, Ceylon, Bridge, 148
Kandel River, 123
Kankakee Bridge, 423
Kansas City Bridges, 176, 184, 241,
440
Karlsbrucke, 50
Karun River, 21
Kelso Bridge, 84, 85, 208
Kempton Bridges, 401, 406
Kenawha River, 273
Kennebeck River, 145, 251
Kerventhal Bridge, 81
Kentucky River, 225, 228, 263, 273
Kent, England, Bridge, 307
Key West Viaduct, 398
Khartoum Bridge, 192
Khorsabad Bridge, 16
Khushalgarh Bridges, 110, 305
Kieif Bridge, 224
Kiel Bridge, 138, 172
Killarney Bridge, 87
King's River, 242
King's Meadow Bridge, 207
King St. Bridge, Toronto, 146
Kintai River, 69, 121
Kinzig River, 171
Kinzua Viaduct, 381, 387, 395
Kirchen Bridge, 202
Kirchenfeld Bridge, 316
Kirchheim, 396
Kishangauga Bridge, 203
Kisilousou River, 58
Kissinger Bridge, 437
Knoxville Viaduct, 386, 425
Konigstein Viaduct, 79, 80
Korea Bridge, 188
Kornhaus Bridge, 316, 339
Kosen Bridge, 50
Krast Nemoust Bridge, 58
Kremlin Bridge, 362
Kreuznach Bridge, 51; Illustrated,
364
Kuilenburg Bridge, 175
Laasan, Silesia, Bridge, 153
La Bouble Viaduct, 377, 395
La Cere Viaduct. 374, 375, 378
Lachine Bridge, 265
Lademburg Bridge, 79, 82
La Fayette, Ind., Park Bridge, 428
Laffranyi River, 57
Lahn Bridge, 82
Laibach River, 416
(465)
Digitized by
Google
GENERAL INDEX
Lake Forest, 111., Bridge, 333
Lake Park, Milwaukee, Bridges,
100, 328, 431
Lake Constance Ry., 247
Lake Shore Ry., 178
Lake St., Minneapolis, Bridge, 322
Lake Shore & Mich. So. Ry., 94, 96,
342, 397
Lambeth Bridge, 228
Lamothe Bridge, 236
Lancaster, Pa., 90
Landsberg Bridge, 125
Langenargen Bridge, 247
Lansing, Mich., Bridge, 333, 358
Lapideus, Pons, 28
Larimer Ave., Pittsburg, Bridge,
404
La Rochelle Bridge, 54
Lary Bridge, 163
La Salle Bridge, 432
Las Vegas Viaduct, 392
Latina Road, 24
Lattice Trusses, 167
Lautrach Bridge, 403
Lea River, 53, 87, 195
Leavenworth Bridge, 175
Leek River, 175
Leeds & Liverpool Canal, 195
Leeds Bridge, 84, 156
Lehigh River, 173, 206, 249, 245
Leithbridge Viaduct, 319, 393, 395
Lendal Bridge, 163
Lenticular Trusses, 172
Levensau Bridge, 331, 332, 364
Leverett Pond. Bridge, 97
Lewiston Bridge, 224, 248, 288
Liege Bridge, 327, 358
Liflfy River, 87
Lima & Croya Ry., 378
Limmat River, 125
Limerick Bridge, 87
Limoges Bridge, 61
Lincoln Park, Chicago, Bridge, 280
Lisson Grove Bridge, 153
Lisbon Aqueduct, 62, 117
Little Conemaugh River, 95
Liverpool Bridge, 332
Livettan Bridge, 65
Llangallen, 89, 90, 155
Llanrwst Bridge, 66
Loa, Bolivia, Viaduct, 384, 395
Loban Viaduct, 79
Loch Lomond Bridge, 216
Loch Etive Bridge, 292
Lock Joseph, 141
Lockport, N. Y., Bridge, 320
Lockwood Viaduct, 89, 90
Log Arch, Wash., 149
Lohse Type, 177
Loing River, 76, 396
Loire River, 61, 73, 75, 216
Loop Canal, 328
Lombards Bridge, 82
London Bridge, 41, 53, 66, 72, 84,
86, 155, 229
Londonderry Bridge, 125
Long Bridge, 134, 140, 320
Long Key Viaduct, 398
Long Lake Bridge, 292
Long Type, 144
Longest Span in America, 354;
Fixed-end Arch in Europe, 338;
Railway Masonry Arch, 80;
Highway Draw Span, 185; Bridge
in Britain, 55; Highway Bridge
in America, 185; Simple Truss
Span, 191; Plate Girder Bridge
in America, 201; Arch in Europe,
349
Loraine St., Cleveland, Viaduct, 386
Lorois Bridge, 244
Lorient Bridge, 218
Los Angeles Viaduct, 385, 442; Park
Bridge, 148
Loschwitz Bridge, 243
Lot River, 42, 62
Louisville Bridge, 176, 180, 181, 267
Louvre Bridge, 156
Lowell, Mass, Bridge, 251
Loyong Bridge, 57
Lubeck Bridge, 247, 349
Lucca Bridge, 44
Lucerne Bridge, 148
Lndwigshafen Bridge, 174
(466)
Digitized by
Google
GENERAL INDEX
Luiz I. Bridge, 319, 351, 363
Lupo, Pont, 113
Luxemburg Bridge, 80, 91
Lutzon Bridge, 317
Lynn, Mass., Bridge, 107
Lyon Brook, Viaduct, 375, 387
Lyons, France, Bridges, 40, 42, 115,
236
Lyons, N. Y., Aqueduct, 201
Lysedalen Viaduct, 380
Maas River, 61
Maastricht Bridge, 61
Madison Park Bridge, 427
Madrid Bridge, 77
Magdeburg Bridge, 82, 351, 364
Magdalena River, 283
Magnesia Bridge, 25
Mahoning River, 344
Maidenhead Viaduct, 89
Main St., Lockport, Bridge, 320
Main St., Los Angeles, Bridge, 441
Main St., Minneapolis, Bridge, 321
Main St., Dayton, Ohio, Bridge, 418
Main River, 50, 234, 261, 299
Mainz Bridge, 319, 351, 352
Makatote Bridge, 392, 393, 395
Maiden Bridge, 125
Malberg Bridge, 217
Malleco, Chili, Bridge, 384, 395
Mamaroneck Bridge, 444
Mampimi, Mex., Bridge, 245
Manawater, N. Z., Bridge, 369
Manayunk, Pa., Bridge, 94, 165
Mancanares River, 77
Manchester, N. H., 126
Manhattan Bridge, 254
Mannheim Bridge, 174, 217, 269, 277,
404
Manoquay Bridge, 135
Mans Bridge, 416
Mapocho River, 68
Marble, Use of, 34, 44, 67, 63, 65
Marent Gulch Trestle, 367, 383, 395
Margaret Bridge, 314
Margherita Bridge, 83
Marie, Pont, 60
Marietta Bridge, 293
Marion, Iowa, 435
Marion Co., Ind., Bridge, 421
Market St. Bridge, Philadelphia,
130, 161, 225, 272
Market Bridge, Monterey, 443
Marne River, 73, 162
Martian Aqueduct, 113
Martorell Bridge, 25, 37
Maryborough Bridge, 413, 415
Marschall Bridge, Berlin, 317
Marvejois Viaduct, 76
Masnedo & Falster Bridge, 192
Massachusetts Ave. Bridge, Wash-
ington, 343
Mason City and Ft. Dodge, 388
Mattabessett River, 201
Mattig River, 298
Mauch Chunk Bridge, 173, 245
Maumee River, 436
Maupas Bridge, 40
Maxau Bridge, 109
Mayence Bridge, 36, 116, 173, 320
McGregor Ry. Bridge, 110
McKees Viaduct, 380
McKeesport Bridge, 291
McKenzie River, 150
McKinley Bridge, 191
Meadow St. Bridge, Pittsburg, 441
Mechanicsville Bridge, 397
Mediaeval Bridges, 40; Spanish, 48;
Austrian and German, 49; British,
51
Mediaeval and Modern Pontoon
Bridges, 107
Medway River, 55, 160
Melan System, 409
Meles River, 18
Mellingen Bridge, 127
Memorial Bridges, 74, 96, 241, 320,
405
Memphis Bridge, 267, 279
Menai Bridges, 84, 151, 155, 197, 210,
Mendota Ravine, 149
225, 241, 313
Menominee River, 353
Merida, Spain, Bridge, 37
(467)
Digitized by
Google
GENERAL INDEX
Meridian St. Bridge, Indianapolis,
418
Merrimac River, 127, 206, 213, 251
Mersey River, 174, 207, 332, 386
Messenia Bridge, 20
Metaxidi Bridge, 20
Metz Aqueduct, 38, 115
Metza River, 63
Meuse River, 65, 163, 357
Mexico Bridges, 68, 117
Mezzo, Pont di, 65
Mianeh Bridge, 70
Michael Bridge, 316
Middletown, Conn., Bridge, 177,
185, 223
Midi, Pont du, 326
Midland Ry., 90
Midlothian Bridge, 84
Military Pontoons, 106
Mill St., Watertown, Bridge, 236
Mill Creek Park Bridge, 244
Mill Dam Bridge, 138
Mill River, 137
Miltenburg Bridge, 397
Milvian Bridge, 24, 26, 29
Milwaukee Bridges, 100, 328, 431
Mina River, 162
Mingo Junction Bridge, 293
Minneapolis Bridges, 95. 148, 227,
234, 295, 320, 322, 364, 419
Mirabeau Cantilever, 282
Mishawaka Bridge, 442, 443
Mississippi River Bridges, 95, 110,
149, 176, 185, 190, 227, 233, 239,
279, 295, 312, 321, 384, 405
Missoula, Mont., Bridge, 367
Missouri River, 175, 177, 180, 185
Mittweida Valley, 385
Mobridge, 190
Modern Stone Bridges, 72
Moerdyck Bridge, 178
Mohawk River, 119, 133
Mojave River, 242
Moldau River, 50, 65, 218, 230, 385
Moline Bridge, 295
Molle, Ponte, 29
Molln Bridge, 349
Monaster Bridge, 37
Monk Bridge, 156
Monongahela River, 169, 190, 219
Monoquay Bridge, 137
Montford Bridge, 84
Montlouis Bridge, 75
Montmorency Falls Bridge, 224
Montpelier Aqueduct, 118
Montreal Bridges, 84, 187, 199, 247,
269, 286, 335
Montreal River, 389
Montrose Bridge, 214, 224
Moodna Creek, 391
Mopsuesta Bridge, 58
Morand Bridge, 326
Moret Viaduct, 75
Morgan town Bridge, 227
Morris St., Indianapolis, Bridge,
418
Morlaix Bridge, 76
Moscow Bridge, 362
Moselle River, 50, 62, 315, 351
Mossa Bridge, 48
Mostar Bridge, 36
Moulins Bridge, 61
Mountain Creek, 367
Mousewater River, 88
Movable Bridges, Preface
Msta River, 145
Muhlendamm Bridge, 332
Muhlenthor Bridge, 247
Muhlheim Bridge, 217, 218, 311
Multiple Web System, 165
Muncie, Ind., Bridge, 436
Mungsten Bridge, 315, 337, 363
Munich Bridge, 79, 399
Municipal Bridge, 191
Municipal Art Commission, 361, 405
Munster Bridge, 63
Murphy-Whipple Truss, 166
Muscatine, Iowa, 272
Musselburg Bridge, 84
A^ytilene Aqueduct, 115
Mycenae Bridge, 21
Nami-Ti Gorge, 360
Nantes Bridge, 315
Naples Bridge, 34
(468)
Digitized by
Google
GENERAL INDEX
Narni Bridge, 33
Narrowsburg Bridge, 146
Narses, 36, 44
Nashammony Creek, 135, 136
Nashua Bridge, 141
National Bridge & Iron Works, 262
Navante River, 63
Navier Principle, 210
Nebraska City, 110, 184
Neckar River, 78, 82, 217, 312, 315,
404
Nepean River, 200
Neptune Bridge, 97
Nera River, 33
Neronianus, Pons, 31
Ness River, 236
Neuf, Pont, 59, 361
Neuilly Bridge, 73
Neuvial Viaduct, 378
Neva River, 126, 159
Nevers Bridge, 163
New River, 249
Newark Dyke Bridge, 166, 171
Newark, N. J., Bridge, 430
New Baltimore Bridge, 188
Newbridge, 67
New Brunswick Trestles, 393
Newburyport Bridge, 141, 206, 213
Newcastle Bridge, 55, 142, 159, 167,
235
Newell Ave. Bridge, New York
City, 431
New Found Creek, 368
New Goshen, Ind., Bridge, 423
New Galloway Bridge, 84
New Haven Bridge, 320, 325
New Hope Bridge, 135, 136
New Orleans Bridge, 301
Newport Bridge, 201, 279
Newton, Mass., Bridge, 91, 120
Newton-Stewart Bridge, 84
New Zealand Bridges, 369, 393, 403,
404
New York City, 91, 100, 118, 252,
305, 320, 336, 353, 411
Niagara Canyon, 368
Niagara-Clifton Bridge, 233, 341,
363
Niagara River, 222, 223, 224, 227,
248, 325, 340, 363, 419
Niagara Falls Canal, 336
Nicholas Bridge, 224
Nidda Viaduct, 375
Nikko Bridge, 57, 257
Nile River, 19, 192, 196, 306
Nimes Bridge, 38, 42, 114, 407
Nine Mile Run Viaduct, 344
Nineveh Bridge, 16
Nions Bridge, 41
Nippur Bridge, 16
Noce Schlucht (Gorge), 327
Nogent Bridge, 73
Nona, Ponte di, 32
North Harvard St. Bridge, 69, 123
North River, 233, 336
Northampton Bridge, 207
North Ravine, Milwaukee, 328
North Sea, Baltic Canal, 331
Northfield Bridge, 287, 288, 334
North Umpqua River, 279
North Walpole Bridge, 354
N. W. Ave., Indianapolis, Bridge,
418
Norwich Bridge, 55
Norway Viaducts 380
Notre Dame Bridge, 43
Noya River, 37
Nova Scotia Bridge, 307
Nuovo, Ponte, 63
Nuremburg Bridge, 65
Nuttallburg Bridge, 249
Nyne River, 52
Oapaaen River, 242
Oak Cliff Viaduct, 440
Oakland Bridge, 355
Oak Orchard Viaduct, 381
Oak Park Bridge, 245
Oberbaum Bridge, 78
Occidente Bridge, 245
Oconomowoc Bridge, 443
Odda Works Bridge, 242
Offenburg Bridge, 171
Ogden Viaduct, 392, 427
(469)
Digitized by
Google
GENERAL INDEX
Ohio River, 173, 176, 180, 222, 231,
241, 247, 279, 286, 293, 306
Oil City Bridge, 235, 291
Ojuela River, 245
Olloniego Bridge, 37
Olten Bridge, 309
Olter Viaduct, 378
Omaha Bridge, 175, 184
Ona Bridge, 37, 258
Opdal, Norway, Bridge, 258
Oporto Bridge, 218, 315, 318, 357,
363, 364
Ordish-Le Feuvre System, 230, 262
Oregon Bridge, 136, 150
Orense Bridge, 37
Oreto River, 47
Orleans Bridge, 40, 73
Oriental Bridges: Mediaeval, 56;
Renaissance, 69
Orival Bridge, 174
Orizaba, 68, 117
Orthez Bridge, 43
Osaka, Japan, Bridges, 58
Oschulzbach Viaduct, 380
Ostrawitza Bridge, 239
Ottawa River, 225, 289
Ouse River, 66, 89, 90, 142, 163
Oxus River, 105
Paglia, Ponte della, 46, 63
Painsville, Ohio, 94, 403
Paderno Bridge, 327, 364
Pad us River, 204
Palatinus, Pons, 28
Palace Bridge, Berlin, 78
Palermo Bridge, 47
Pamisus Bridge, 20
Panther Hollow, Pittsburg, 333
Panther Creek Viaduct, 385
Park Bridges, 96, 244, 245, 328, 410,
412, 427
Parkersburg Bridge, 176, 273
Paris Aqueduct, 396
Paris Bridges, 43, 59, 60, 73, 157,
216, 282, 326, 34, 47
Paris & Brest Ry., 76; Aire Ry., 309
Pasadena Bridge, 445
Passaic River, 421
Passau Bridge, 171
Passy Viaduct, 297, 347
Patapsco Creek Bridges, 93, 140
Patents for Iron Bridges, 166; for
Reinforced Concrete, 436
Pathhead Bridge, 88
Paterson, N. J., Bridge, 413, 421
Paulding's Ford, 136
Pauli System, 172
Pavia, Italy, Bridge, 47
Pecos River, 272, 274, 384, 385, 392,
395
Pei River, 202
Pendulums on Suspension Bridge
Towers, 221
Pennypack Creek Bridge, 397
Pennsylvania Ry. Co., 95, 133, 144,
397
Penrith Bridge, 200
Peoria Bridge, 443
Peperino, Use of, 25, 28, 30
Percey Bridge, 216
"Permanent Bridge," 126, 130
Peru Bridges. 69. 203. 274. 423
Persian Bridges, 21, 58, 70
Perth Bridge, 55
Peterborough, Ont., Bridge, 108
Petrusse Valley, 80
Philadelphia Bridges, 100, 126, 127,
141, 152, 161, 343, 401, 402, 406
Philadelphia & Reading Ry., 94, 140
Phillipsburg Bridge, 169
Phlius Bridge, 21, 289
Phoenix Bridge Co., 299, 343, 376
Piallee River, 200
Piers, Floating, 104; Ancient, 24;
Mediaeval, 43
Pierre Hollow Bridge, 101
Pietra, Ponte di, Verona, 46
Pimlico Bridge, 228, 310
Pin-connected Truss, First use of,
173
Pine Creek Bridge, 145
Piney Creek Bridge, 401
Pinzano Bridge, 417
Pisa Bridges, 46, 63, 82
Piscataqua River, 128
(470)
Digitized by
Google
GENERAL INDEX
Pittsburg Bridges, 100, 136, 186, 219,
228, 235, 239, 241, 290, 293, 314,
336, 364
Pia Maria Bridge, 315, 318, 364
Pittsfield Bridge, 166
Plainwell Bridge, 423, 443
Plate Girder Bridges, 195
Plattsmouth Bridge. 190
Plauen Bridge, 80, 81, 91, 402
Playa del Rey Bridge, 432
Po River, 82
Pocatello Bridge, 392
Poestum Bridge, 82
Point Bridge, 235, 241, 238
Point Pleasant Bridges, 181, 182,
273, 285
Pompadour Viaduct, 76
Pontchartrain Lake, Trestle, 369
Pontoons, 106
Pontoon Bridges, 36, 104, 21
Pontefeces, 59; Pontifex Maximus,
40
Pont-y-Pridd, 67
Porta del Popolo, 83
Portage Viaduct, 365, 370, 380, 381,
387, 389, 391, 395
Port Deposit Bridge, 137
Port Hope Bridge, 108
Portland Bridge, 403
Portsmouth, N. H., Bridge, 110, 126,
128
Portugal Bridges, 34, 38
Posen Bridge, 263
Patent Post Truss, 175
Potomac River, 90, 102, 109. 134,
205, 215, 222, 241, 320, 355, 367,
417
Poughkeepsie Bridge, 267
Pozillo Viaduct, 82
Pozzuoli, 25, 34
Pozzuolana Cement, 25
Practice in Bridge Design, 192, 193
Prague Bridges, 50, 65, 218, 229, 230
Prairie du Chien Bridge, 110
Pratt Truss, 142, 169
Presburg Bridge, 110
Preservation of Timber Bridges, 131
Probi, Pons, 29
Process for converting Steel, 171
Prospect Park, Brooklyn, Bridge, 397
Providence Bridge, 141
Pruth River, 80
Pulaski, N. Y., Bridge, 320
Puteoli Bridge, 106
Putney Bridge, 66, 87
Pyramids, 19
Pyrimont Bridge, 435
Pyrgos Aqueduct, 117
Quattro-Capi Bridge, 29
Quebec Bridge, 254, 299, 362
Queen's Bridge, Dublin, 68, 87
Queen Carola Bridge, 337
Queensboro Bridge, 238, 303
Querataro Bridge, 117
Quincy Bridge, 176
Quito Bridgfes, 69, 203
Railway Bridges: Suspensions, 224,
228; Inclined Railways, 336; Con-
crete Railway Bridges, 446; Pon-
toons, 110; Trestles, 378
Railroad Building: France, 75; Ger-
many, 79; England, 89, America,
138
Rajahmundry Bridge, 188
Ranee River, 76
Rancidite Viaduct, 76
Rapidan River, 109
Rapallo Viaduct, 376
Rappahannock River, 109
Ratisbon Bridge, 49
Reading, Pa., Bridge, 136
Rebuilding Viaducts, 386; English
Bridges, 357. 358
Redheugh Bridge, 234
Red River, 306
Red Rock Bridge, 273
Regent's Park Bridge, 161
Regnitz River, 65, 131
Reinforced Concrete Bridges, 407;
Largest Arch, 437; Arch Treat-
ment, 412; First Arch, 408; For
Light Weight Bridges, 410; Origin
(471)
Digitized by
Google
GENERAL INDEX
of, 408; Preservation, 415; Rail-
road Bridges, 410
Religious Orders, 39
Retiro River, 314
Reuss River, 148
Rheinhausen Bridge, 314
Rhine River, 32, 50, 107, 109, 121,
124, 171, 298, 310, 314, 320, 349,
365
Rhone River, 42, 214, 244, 326, 435
Rhodesia Railway, 358
Rialto Bridge, 46, 62, 64, 65
Riaza, 78
Ribbed Arches, Use of, 432
Richland Creek Viaduct, 391
Richmond Creek, 397
Richmond, Ind., Bridge, 141, 241, 320,
321, 364
Richmond, Quebec, 188
Richmond, Va., 141
Rider Patents, 166
Riga Bridge, 110
Rimini Bridge, 24, 34, 38
Rio Fiscal, 355
Rio Grande, Costa Rica, 353
Rio della Paglia, 63
Rittenhouse Lane Bridge, loi
Riverside Drive Bridge, 343, 398, 442
Roads, Roman, 23, 24; Improvement
of, 446
Riverside Cemetery Bridge, 332.
Roche-Bernard Bridge, 215, 217
Rochester, Pa., Bridge, 247
Rochester, N. Y., Bridge, 90, 119, 163,
320, 326, 364, 381
Rochester, England, Bridge, 56, 160
Rock Creek, 91, 160, 343, 404, 421
Rock Lane Bridge, 325
Rock Rapids Bridge, 410
Rock River, 102, 295
Rockingham Bridge, 354
Rocky Mountain Viaduct, 391
Rodah Island Bridge, 306
Roesendamms Bridge, 82
Roman Bridges, 23, 24, 32, 162, 396
Roman Republic, 32
Roman Empire, Decline, 31, 44
Roman Builders, 23
Roman Engineering Writings, 112
Rome Bridges, 23, 26, 29, 32, 48, 83,
396, 406, 407
Romney Bridge, 137
Ronda Viaduct, 62
Roquefavour Aqueduct, 75, 119
Roseburgh, Ore., Bridge, 279
Rosedale Viaduct, 381
Ross Drive, Washington, Bridge, 421
Ross River, 66
Rostock, 271
Rotto, Ponte, 27, 241, 407
Rouen Bridge, 107
Roumania Bridges, 277
Royal Alexandra Bridge, 290
Royal Pont, 60
Rugby Viaduct, 90
Ruhr River, 217, 218, 310, 311
Ruhrort Bridge, 298
Ruichenau Bridge, 125
Runcorn Bridge, 174, 207, 252
Running Water Viaduct, 376
Russian Bridges, 188
Saale River, 50
Saintes Bridge, 41, 54
Salamanca Bridge, 37
Salarian Way, 36
Salaro, Ponte, 36
Salcano Bridge, 91. See Isonzo
Salisbury Bridge, 213
Salmon River, 330
Saltash Bridge, 172
San Bartolomeo, Ponti-di, 30
San Francisco Bridge, Bogota, 69
San Francisco, Cal, Bridges, 244,
408, 411, 412
San Pedro, Los Angeles & Salt Lake
RK 397
Sandkrug Bridge, 317
Sandy Hill Bridge, 432, 438
Santa Ana River, 398
Santiago Bridge, 68
Saone River, 215, 217, 236, 297,374
Sarine Valley, 215
Sarthe River, 216
(472)
Digitized by
Google
GENERAL INDEX
Sarthe X Bridge, 416
Saxon-Bavarian Ry., 79
Scarboro Pond Bridge, 97
SchauflFhausen Bridge, 124, 125
Schenectady Bridge, 127, 133
Schenley Park Bridge, 101, 333, 413
Schloss Bridge, 78
Schuylkill River, 130, 135, 152, 173,
179, 205, 218, 343
Schwarzwasser Bridge, 315
Schwaenderholz River, 79
Scotland Bridges, 55, 67, 88, 89,
^ 129. 143. 181, 275
Scotswood Bridge, 147
Scugog Lake, 108
Sebastopol, Boulevard de, 75
Sedley System, 261
Segovia Bridge, 38, 115, 407
Seine River, 59, 60, 73, 139, 141, 157,
218, 245, 282, 297, 309, 326, 346, 361
Selle Viaduct, 76
Sele River, 82
Senator's Bridge, 28
Senerud River, 70
Seraing, Belgium, Bridge, 218
Servians' Pontoon Bridges, 107
Seville Bridge, 110
Seventh St., Los Angeles, 441
Seventh Ave., New York City, 193
Seventh St., Pittsburg, 239
Severn River, 84, 151, 160, 261
Sewer, Ancient Roman, 25
"Shaking Bridge," 66
Shardi Bridge, 203
Sherman Creek, 144, 336
Shocks Mills Bridge, 96
Shogun's Bridge, 57, 257
Shuster Bridge, 21, 70
Sicily Bridge, 63
Sidney Center Viaduct, 376
Siemens-Martin Process, 171
Signa Bridge, 48
Singapore Bridge, 229, 230
Sioulc Viaduct, 378, 394
Sioux City Bridges, 181, 185
Simple Truss Bridges, 164
Sisteron Bridge, 43
Sisto, Ponte, 32, 48
Sister Islands Bridge, 248
Sitter Viaduct, 378
Six Mile Creek, 336
Sixth St. Bridge, Des Moines, 186,
419
Sixth St. Bridge, Pittsburg, 186
Sixteenth St. Bridge, Washington,
401
Skowhegan Bridge, 145
Slab Arches, American Practice, 423
Smithfield St., Pittsburg, Bridge,
180. 219
Smyrna Bridge, 18
Snake River, 288
Snodland Viaduct, 386
Soissons Bridge, 417
Solbergthal Viaduct, 380
Soles Bridge, 80
Solferino, Italy, Bridge, 82
Solid Concrete Bridges, First in
U. S., 396
Solid Lever Bridge Co., 262
Solingen Viaduct, 337
Sommieres Bridge, 43
Song-Ma River, 353
Soochow Bridge, 57
Soluevre Viaduct, 384
South America Bridges, 69, 202, 314
South America, Bridges, 69, 202, 314
South Bend Bridge, 418, 419, 452
Southbridge, Mass., Bridge, 435
South Fork Bridge, 199
South Market St., Youngstown, 344
Southern Pacific Ry., 275
South Ravine, Milwaukee, 328
South Rocky River Viaduct, 386
South Tenth St„ Pittsburg, Bridge,
190
South Twenty-second St., Pittsburg,
Bridge, 334
Southwark Bridge, 156
South Wales Bridge, 371
Spain, Bridges, 34, 37, 39, 48, 115
Spanish Bridges, . Mediaeval, 48 ;
Renaissance, 62; Modem, 77
Sparta Bridge, 20
(473)
Digitized by
Google
GENERAL INDEX
Specifications, Publication of, 336,
418
Spey River, 155
Spokane River, 279, 401, 403, 406,
434, 336, 418
Spoleto Aqueduct, 44, 116, 407,394
Spuyten Duyvil Creek, 406
Spree River, 290, 332, 349, 217
Spreethal Viaduct, 79
Spreuerbrucke, 148
Springfield Bridge, 142
Srinagar Bridge, 71
Stadlau Bridge, 178
Staines Bridge, 163
Starucca Viaduct, 94
State Highway Commission, 445
Steel Trestles, 369; Steel Arches,
363; First Use of Steel in Bridge
Building, 165; First Steel Arch
Bridge in America, 313
Stein-Teufen Bridge, 437
Stephanie Bridge, 271
Steubenville, O., Bridge, 174
Stiffened Suspensions, 220, 299,243
Stirling Bridges, 56, 88
Stockbridge Bridge, 411
Stockport Viaduct, 89
Stockton & Darlington Ry., 369
Stockton Bridge, 221
Stone Arch in England, Largest, 88
Stone Bridges in Germany, Austria,
Switzerland and Belgium, 78
Stone Bridges — Oldest in Britain, 51
Stone Bridges — Modern, 72
Stony Brook Bridge, 97
Stony Brook Glen Viaduct, 391
Stony Creek Bridge, 329, 330
Stow Lake Bridge, 412
Straits Settlements Bridge, 230
Straubing Bridge, 340
Striegauer Wasser Bridge, 153
Stresses, Exact Computation of, 166.
Structural Steel, Strength of, 184
Sturgeon Lake Pontoon, 108
St. Angelo Bridge, 31, 65, 407
" Anthony Falls Bridge, 95
" Bathans Abbey Bridge, 139
St. Benezet Bridge, 41, 54
" Chamas Bridge, 40
" Catharines, 222
" Charles Trestle, 376, 377
" Denis, 163. 309
" Denis Canal, 309, 312
" Esprit Bridge, 41, 42
" Francis River, 188
" Gall Viaduct, 378
" Guistina Arch, 327
" Ilpize Suspension, 236
" John, N. B., Bridge, 224, 266
" Joseph River, 419
" Lawrence River, 187, 196, 199,
247, 264, 286, 289, 335, 362
" Louis Bridges, 185, 191, 233,
243, 260, 312, 320, 364, 413
" Louis Bridge, Paris, 160
" Martin's Bridge, 49
" Maxence Bridge, 73, 74
" Michael Bridge, 60
" Paul Viaduct, 148, 261, 272,384
" Peter's Bridge, 157
" Petersburg Bridge, 110, 159
" Sauveur Bridge, 76
Sublicius, Pons, 26, 121
Sublicio, Ponte, 27
Sukkur Bridge, 271
Sunderland Bridge, 153, 154, 183, 192
Suresne Bridge, 218
Surprise Creek Bridge, 330
Suspension Bridges, 202
Aqueducts: First used, 219; Com-
parison of Suspension Systems,
222; over the Bosphorus, 175;
Introduction in Europe, 209;
Primitive Forms, 202, 203; Old
Paris Bridge, 160; Treatise on,
210; First Railway Suspension
in Europe, 214
Suspended Span : First Cantilever
with, 265
Susquehannah River, 95, 133, 140,
143, 144, 397
Swale River, 158
Sweden Bridges, 284
Swing Pontoons, 110
(474)
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GENERAL INDEX
Swiss Central Railway, 309
Switzerland Bridges, 80, 403, 437
Sydney Harbor Bridge, 252, 307
Syra River, 81
Szegedin Bridge, 309
Taggart Creek, 203
Tagus, River, 34, 49
Tagliamento River, 417
Tamar River, 172
Tanaro River, 48, 298
Tarascon Bridge, 163
Tarente Viaduct, 374
Tarn River, 77
Tarragona Aqueduct, 38, 116
Tauber River, 315
Tauris Bridge, 70
Tech River, 43
Tees River, 157, 204, 214, 226, 261
Tehint-Cliien River, 203
Tempoalo Aqueduct, 68, 117
Temporary Suspension Bridges, 241;
Trestles, 367
Tepula Aqueduct, 113
Terre Haute Bridge, 397
Tess River, 47, 163
Tetes Bridge, 61
Teufen Bridge, 124
Teverone River, 36, 44
Teviot River, 85
Tewksbury Bridge, 153, 155
Thalubergang Viaduct, 375
Thames Rfver, 53, 55, 66, 72, 85,
123, 156, 166, 213, 220, 229, 310,
336, 358, 359
Thebes, 111., Bridge, 267, 293, 295
Theiss River, 284, 309
Thermopylae Bridge, 359
Thirlstone Castle Bridge, 208
Thirsk Bridge, 158
Thomter Viaduct, 380
Thomby Bridge, 157
Three-hinged Arch, Largest in Amer-
ica, 324
Tiber River, 23, 27, 29, 30, 32, 34,
46, 83, 326
Tibet Bridge, 123
Ticino River, 47
Ticonic Bridge, 251
Tigris River, 16, 106
Timber Arches on Stone Piers, 123
Timber Viaducts in England, 142;
Trestle, 365
Tokaj Bridge, 284
Tolbiac St. Bridge, 282
Toledo Bridge, 48, 49
Tolubre River, 40
Tongueland Bridge, 87
Topeka, Kansas, Bridge, 177, 413,
420
Torcello, Bridge, 48
Tottenham Bridge, 195
Toulouse Bridge, 59, 440
Tournai Bridge, 51
Toumelle Bridge, 60
Tournon Bridge, 59
Tours Bridge, 40, 215
Towanda Bridge, 169, 201
Tower Bridge, London, 247, 337
Traffic Bridge, Largest, 253
Transcontinental Ry., 393
Transporter Bridge, 252
Trans-Siberian Ry., 189
Trarbach Bridge, 351
Trastevere Bridge, 32
Travertine, Use of, 25, 28, 30, 32
Tray Run Viaduct, 370, 371
Tremont St. Bridge, 97
Trent River, 55, 167, 200
Trenton Bridge, 95, 127, 129, 130,
141
Trestle Building, New System, 374,
365; Modern, 380
Trestles and Viaducts, 365
Trezzo Bridge, 46
Triangular Bridge, 52
Trilport Bridge, 73
Trinity Bridge, Florence, 62, 88
Trinity River, 440
Triumphal Way, 26, 31, 32
Trocadero, Paris, Bridge, 74
Troy Bridges, 181
Truss, Lenticular, 172; First use,
121; Construction for Timber
(475)
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GENERAL INDEX!
Bridges, 122; First Pin-connected,
169, 173; Patents, 128; Statistics,
184; Simple Truss Bridges, 164,
133, 137, 138, 142; Cast and
Wrought Iron, 166; First Iron,
166; First Form of, 165; Metal
Lattice, 171; Bridges in Europe,
ITl. 172
Truyere River, 318
Tubular and Plate Girder Bridges,
195
Tubular Piers, 174
Tufa, use of, 25, 28, 30, 32
Tunnel, under Thames, 85; Ancient,
17
Tunxdorf Bridge, 298
Turin Bridge, 82
Turkey Bridges, 37
"Twa Brigs o' Ayr," 88
Tweed River, 85, 147, 207, 209
Two Medicine Bridge, 368
Tygart*s River, 291
Tyne River, 55, 88, 147, 159, 167,
234
Types of Trestles, 365
Tyrone Bridge, 273
Ulm Bridge, 406
Union Bridge, 209
Union Bridge Co., 100
Union Pacific Ry., 242
Union Park, Chicago, 408
Utah Bridges, 17, 138
Vaison Bridge, 40
Valence Bridge, 77
Valentre Bridge, 42
Valentinianus, Pons, 32, 48
Valentino, Ponte-di, 83
Valeria, Road, 24
Vanchiglia Bridge, 83
Valley Junction Bridge, 241
Vancouver Bridge, 190
Vanne River, 396
Vaticanus, Pons, 26, 32
Vauriat Viaduct, 394
Vauxhall Bridge, 358
Vecchio, Ponte, 46
Velaine River, 217
Venice Bridges, 46, 62, 63, 65
Venice, Cal., Bridge, 431
Verdun River, 43, 77, 397
Vermilion River, 353, 436
Vemaison Bridge, 244
Verona Bridges, 33, 46, 320, 378
Verrugas Viaduct, 272, 274, 378,
387, 395
Versam Gorge, 337
Vezouillac Bridge, 76
Viaducts, Concrete, 425; List of,
395; European Practice, 374 ; Two
Largest, 388; Stone and Brick
Railway, 75, 89
Viaur Viaduct, 326, 338, 345, 363
Vibel Bridge, 82
Vicenza Bridge, 37
Victor, Cal., Bridge, 242
Victor Emmanuel Bridge, 83
Victoria Bridge, England, 160
Victoria Viaduct, England, 89
Victoria Tubular Bridge, Montreal,
199
Victoria Suspension Bridge, 228
Vienna Bridges, 40, 178, 213, 226,
229, 271, 317, 234
Vienne River, Ancient Bridge, 61
Vieux-Chateau Bridge, 46
Villefranche Bridge, 252, 297
Villeneuve Bridge, 41, 61
Villette Bridge, 312
Vincenza Bridge, 33
Virdoule River, 43
Virgo Aqueduct, 113
Vistula River, 171, 192
Voltumo River, 82
Vulci Bridge, 24
Waal River, 171
Wabash River, 423
Wabash Ry., 293
Wabasha St., St. Paul, 272
Waco Bridge, 234
Wadsworth Bridge, 440
Wakeman Bridge, 435
(476)
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GENERAL INDEX
Walden Bridge, 333
Wales Bridge, 66, 67, 84, 210
Waldi-Tobel Viaduct, 79, 80
Wall of China, 22
Walnut Bridge, 145
Walnut Lane Bridge, 401
Walton Park Bridge, 123
Wandipore, Tibet, Bridge, 123, 257
Wandrahms Bridge, 82
Warfield Viaduct, 89, 90
Warkel Bridge, 35
Wamow Bridge, 271
Warren County, Pa., Bridge, 234
Warren County, Ind., Bridge, 145
Warren Girder, Earliest, 167
Warren Toll Bridge, 138
Warth River, 263
Washington Bridge, N. Y., 100, 239,
324, 364
Washington Aqueduct, 90, 102, 160,
355
Washington, D. C, Bridges, 134,
215, 222, 241, 320, 343, 401, 404,
418, 421, 432
Waterford Bridge, 126, 129
Water of Leith. 84
Waterloo Bridge, 84, 85
Waterloo, la.. Bridge, 423
Watertown, Mass., Bridge, 138
Watertown, Wis., Bridge, 102
Waterville, N. Y., Bridge, 236, 334
Waterville, Me., Bridge, 251
Waterville, O., Bridge, 435. 438
Waudsworth Bridge, 174
Waveney River, 408
Wayne St., Peru, Ind., Bridge, 423
Wear River, 56, 152, 183, 192, 328
Wearmouth Bridge, 137, 153
Weaver River, 110
Webster Ave., Chicago, 150
Weed St., Chicago, 110
Weights of Bridges, 193, 194
Weida Viaduct, 380
Weikersheim Bridge, 315
Welland River, 52
Wellesley Bridge, 87
Wellington Brook, 142
Wemyss Bay Ry., 373
Weser River, 217, 298, 362
West Auckland Bridge, 165, 370
West Boston Bridge, 126
Westerburg Bridge, 305
West Highland Ry., 397
West Indies, Aqueduct, 117
Westminster Bridge, 55, 66, 67, 72,
83, 85, 123, 159, 310
Weston Bridge, 373, 440
West Shore Ry., 201
Western Rys., Paris, 347
Wettstein Bridge, Basle, 317
Wheeling Bridge, 215, 222
Whitby & Loftus Ry., 383 ,
White River, 419
White Pass & Yukon Ry., 345
Whitewater River, 241, 321, 435
Whitadder River, 139
Widest Railway Bridge, 193
Wiedendammer Bridge, Berlin, 298
Wien River, 311
Wiesen Bridge, 79, 80, 403
Wilkesbury Bridge, 136 '
Williamsburg Bridge, 252
Willington Dean Bridge, 142
Wilmington Bridge,' 205
Wilton Bridge, 66, 89
Windsor Bridge, 166
Windsor Locks Bridge, 144, 174
Winnipeg Viaduct, 425
"Winner Bridge," 184
W'inona Bridge, 281'
Wire Suspension, 205, 207
Wissahickon Creek, 94, 100, 401
Witham River, 156
Wittengen Bridge, 125
Wooden Bridges, 121; Railway
Bridges, First in America, 139;
Mediaeval, 44; Red Bridge, 102;
Pile Bridge, Lyons, 326
Worms Bridges, 248, 319, 351, 352
Wood Lattice, 134
Woodsville & Wells Bridge, 131
Writings, Roman Engineering, 112
(477)
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GENERAL INDEX
Wrought Iron, 84, 173; and Steel, Youghiogheny River, 291
Arches, 309; Introduction of ^Youngstown, O., Bridge, 244, 336,
Wrought Iron and Steel, 163 344
Wrsowic Ry.. 262 York River, Me., 125
Wupper River, 337 York, England, 66
Wye River, 162 York, Newcastle & Berwick Ry., 366
Wynch Bridge, 204 Ysoir Bridge, 416
,, ^ . ^ Yunnan Bridges, 202, 360
X Bndges, Mans, France. 416; yunnan Ry., 306
Pans, 361
Y Bridges, Zanesville, O., 315, 415 ; Zambesi River. 358, 364
Budapest, 416; Genoa, 416 Zanesville, O., Bridge, 315
Yellowstone Park Bridge, 429. 430 Zoel-Elbe Bridge. 82
Yenesei River, 189 Zurich Bridge, 125
(478)
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INDEX OF JOURNALISTIC WRITINGS
BY THE AUTHOR
American Export Trade in Structural Steel. I. A., June, '01.
Armories — Steel Framing: for. A. & B. M., October, '01.
Bridsre Office Drafting: Rules. E. N.. March, '05.
Charleston Suspension Bridgre, Failure of. E. N., January, '05.
Coal Hoisting Towers. B. N.. May. '01.
Coal Mine Tipples, E. & M. J., February, '05.
Comparative Cost of Combination and All-Steel Higrhway Bridgres. S. A.,
Augrust, '00; E. N., August, '00; R. R. G., October, '00; S. R. R., '01; Engrin.,
'01; I. & E. E., '01.
Comparative Cost of Wood and All-Steel Factory Buildings. C. E., October,
•04; C. & B., November, '05; R. R. G., October, '04.
Domes, Steel Framing for. A. & B. M., March, '05.
Draw Bridge Gates, Automatic Safety. El. Rev., May, '01; E. N., December,
'00; R. R. G., May, '00; W. B., May, '01; R. & E. R., June, '01; C. E..
May, '01.
Draw Bridge at Portland, Oregon. T. U. E. J., '01.
Easton Suspension Bridge. Engin.. '00; B. N., '00; S. A., Sept., '01; The Eng..
September, '01; M. J. & E., September, '01; C. A., September. *01; F. M.,
November, '02; S. R. R., '01.
Elizabethtown Bridge. C. E., November, '04; C. E., November, '09; W. B.,
August, '10.
Estimating Structural Work. T. U. E. J.. '04-'05; A. & B. M., January, '03.
Foot Bridges. C. & B., '05.
Formulae for Weight of Bridges. E. N., August, '00; S. R. R., December, *00;
Engin., June, '00; C.JE. N.. May, '01; C. E., November, '04; E. C, Sept., *08.
Lift Bridges for Small Water Ways. El. Rev., December, '04.
Madison Park Bridge. The Eng., November, '00; El. Rev., November, '01;
Elec, November, '01; F. M.. January, '02; T. U. E. J., '01; E. N., August, '00.
Market Buildings. A. & B. M., July, '01.
Middletown Bridge. The Eng., March, '01; I. & E. E., April, '01; S. R. R., '01;
R. & E. R., June. '01; Elec, June, '01; El. Rev., April, '01; F. M., August,
•01; El. E., March, '01; R. R. G., December, '01; El. W., February, '01.
Movable Dam at Sault Ste. Marie. E. N., June, '09.
Ornamental Bridges. A. A., August, '01.
Park Bridges. A. A., March. '01.
Shop Cranes. I. A., January, '05.
Shop Drawings for Structural Work, Cost of. I. A., July, '01.
Shipping Directions for Structural Steel. I. A., April, •01.
Steel Buildings for Export. E. N., April, '01.
Storage Pockets. R. R. G., October, *01.
Strengthening Old Bridges. R. R. G., August, '01; S. R. R., April, '05.
Temporary Bridge at Hartford. R. & E. R., August, '01.
Trestle Spans, Economic Length of. R. R. G., December, '04.
Weight of Bridges. E. R., November, '00; C. E. N., May, '01; E. N., December,
'00; S R. R., December, '00; R. R. G., September, '02; Engin., June, '00;
R. & E. R., '01; E. N., May, '00; E. N., April, '01; E. N., June, '01; C. E.,
November. '04; S. R. R., July, '01; Engin., July, '02; R. R. G., February, 05;
E. R., November, '00.
Weight of Steel Roof Trusses. E. N.. June, '00. « , , ,^.
Weight of Trusses and Girders for All Spans and Loads. S. R. R., July, '01;
Engin., July, '02; E. N., May, '00.
Etc., Etc., Etc.
NAMES OF JOURNALS, WITH ABBREVIATIONS
A. A. American Architect.
A. & B. M. Architects and Builders
Magazine.
C. E. N. Canadian Electrical News.
C. E. Canadian Engineer.
C. & B. Carpentry and Building.
The Eng. The Engineer. London.
Engin. Engineering, London.
E. & M. J. Engineering and Mining
Journal.
E. C. Engineering Contracting.
E.N. EnlngeerlngNews.
E. R. Engineering Record.
El. E. Electrical Engineer, Lon-
don.
El. Rev. Electrical Review, Lon-
don.
El. W. Electrical World.
Elec.
Electricity.
F. M.
Feilden's Magazine.
I. & E. E.
Indian and Eastern En-
gineer.
LA.
The Iron Age.
M. J. & E.
Municipal Journal and
Engineer.
R. R. G.
Railroad Gazette.
R. & E. R.
Railway and Engineering
Review.
S. A.
Scientific American.
S. R, R.
Street Railway Review.
T. U. E. J.
Toronto University Engin-
eering Journal.
W. E.
Western Electrician.
W. B.
Ossterr-Wochenschrift. d.
offentl. Baudlenst.
(479)
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BOOKS
BY
HENRY GRATTAN TYRRELL, C. E.
MILL BUILDING CONSTRUCTION
Cloth binding; 6x9 inches. Price $1.00
CONCRETE BRIDGES AND CULVERTS
Flexible leather; 44x6^ inches; 272 pages;
66 illustrations. Price $3.00
HISTORY OF BRIDGE ENGINEERING
Cloth binding; 6x9 inches; 480 pages;
330 illustrations. Price $4.00
MILL BUILDINGS
A Treatise on the Design and Construction of
Mill Buildings and other Industrial Plants
Cloth binding; 6x9 inches; 450 pages;
650 illustrations. Price $4.00
ARTISTIC BRIDGE DESIGN
A Systematic Treatise on the Design of
Modern Bridges according to Aesthetic
Principles
Cloth binding; 6x9 inches; 225 pages; 150 illustrations
READY FOR PRESS
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