The history and construction of railroad bridge over the Potomac River at Washington, D.C.

The History and Construction of Baiiroad Bridge
over Potomac River at "tf&shington, D. C.

Summary
This thesis ^hows the evolution of bridge building from 1809,
when the first bridge built on' this site wa3 a simple pile structure.
This bridge soon failed and had to be bought by the Government and rebuilt.
The Government bridge was but little better than the first bridge. The event
of the Civil Tar aaw the crossing of the Potomac Hiver by railroad tracks on
Old Long Bridge. After the *"ar, congress gave the bridge to the railroad
company. The railroad company had to rebuild the bridge a number of times
until the building of the modern steel bridge in 1904. The Old Long Bridge
was one of the last of the era of large wooden bridges. The efficiency of
steel bridges is ahown by the fact that the bridge built in 1904 is still
in use and has not failed since it was opened.

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The old Long Bridge connecting Washington with Virginia, or
rather the series of bridges which rose on the same site are not only of
interest to the historian, but also to the engineer.

Early Bridges
The importance of this site for the location of a "bridge was
recognized soon after location of the capital in the new city of Washington.
In 1808 , after many protests from merchants of Georgetown, Congress granted
a 60 day charter to the Potomac Bridge Company. The bridge was constructed
in 1809 by the 'Vashington Bridge company and soon became the main route of
travel between the North and South* as the Potomac is swift at ordinary
timeB, during freshets and floods especially when there ia ice in the river,
the force against the bridge was great. As the bridge was probably
constructed on pile foundation and offered considerable resistance to
floating ice, ice caused the bridge to act as a dam. As a result the bridge
was damaged to such an extent twenty years later that the bridge company was
financially unable to repair the bridge* July 14, 183*. Congress passed an act
buying the bridge and franchise from the Washington Bridge Company for §20,000.
Examination showed that to repair the old bridge was uneconomical so
Congress appropriated $135,000 to build a new bridge, which was completed in
1835 and formally opened by President Jackson, October 1, 1835.

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It was about a mile long with the draw. The builders of the new bridge had

learned no lee eon from the failure of the old bridge; so the new bridge web

nearly destroyed Babruary 10, 1640. The bridge never had sufficient area

of waterway and every few years it was nearly destroyed or seriously

damaged. This fault was not corrected until the building of the present bridges

many years later.

Civil ffiar Period

At the outbreak of the Civil Tter April, 1861 Long Bridge immediately
became very important. The bridge was one of the main connections between the
ITorth and south. Over this bridge was to pass the supply and the personnel
to carry on the war. As the bridge was the most important entrance into
V/ashington the control of the structure by the Union Army was necessary. 3o
on 23 May 1861 Major Heintzelman crossed over the bridge taking possession of
Alexandria and prepared to defend the south end of the bridge. After the
Battle of Bull Bun defenses were constructed on the wooded ridge at Four
Mile Run to cover the bridge and to destroy it if necessary for the defense
of Wellington.

Long Bridge formed, for land traffic, the main link of communication
with Alexandria and the principal southern routes. It was one mile in length ;
nearly two thirds of which, over the wide shoals of the Potomac, was solid
causeway, and the rest on piles.

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There ware two 1 draws , one near either Bhore. The immense transportation for the
Army over the bridge imposed thr> speedy necessity of an entire rebuilding of
the wooden structure and draws. This was done in the fall of 1861 by the
Quartermaster's Department, Subsequently it 7/ae judged necessary to connect
the railroad route from the Korth with thoee from the South terminating at
Alexandria and in 1864 an entire new railroad bridge was constructed on piles
parallel to the one just described. After reaching the Virginia shore the
latter was prolonged by a causeway over a flat and a marsh until it reached
the more elevated ground at Fort Bunyon.

Use as a Railroad Bridge
On March 3, 1863 Congress authorized the VJashington and Alexandria
Sail road Company to extend its tracks down Maryland Avenue and across the
bridge if it did not interfere with the traffic over the bridge. The
Bailroad Company took advantage of the authority given it by Congress and
the following year completed a bridge 50' below and paralleling the
original structure. The new bridge subdivided the old spans by piles driven
at a distance of about 11 to 18 feet. This was built as a pile trestle
and used for seven years, in doing this the design, of the original bridge
was altered from a truss to pile structure. Great indignation ensued but
nothing was done as the only cure was to built a new bridge and this was
not done until many years later.

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rn 1670 the causeway and the south draw were washed away.

In 1870 Congress authorized Baltimore and Potomac Railroad company
to cross the potomao River on old Long Bridge, and the trestle at that time
becoming useless, was dismantled. The Railroad Company had to keep the
bridge in repair and maintain roadway on one side. When Long Bridge passed
into the hands of the Baltimore and Potomac Railroad Company the bridge
at this time consisted of four wood Howe Truss spans at south end
remainder was a pile trestle, all in poor condition. The railroad company
rebuilt the entire structure in order to pass trains over the bridge. This
consisted of eighteen spans of wood, Eowa Truss type, each 137 feet long,
and two draw spans 136 and 1E3 feet long. Foundations were stone piers on
piles.

At the time of the inception of the project for reclamation of
the Potomac flats (1881), the total length of bridge was 4677 feet. The
bridge consisted of three sections; a wooden bridge 700 feet long resting
on masonary piers across the upper end of the Washington Channel; an
earth fill 1980 feet long between masonary retaining walls across
partially submerged flats; the bridge proper 2000 feet long across the
main channel of the Potomac* The bridge proper consisted of thirteen fixed
spans 135 feet in the clear and a pivot span 182 feet long with two 70 foot
openings, only one however was open to navigation.

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After reclamation of the flats the wooden bridge over the Washington Channel
was replaced by a long fill and a two spau plate. girder. During the great
flood which covered the lower part of the city in February 1881 the bridge
was under the pressure of ice and water. 'Then part of the toridge gave
way the flood subsided. In 1881 the ice banked up at the bridge, the water
level standing 2 feet above the lower chord. The gages above and below
showed plainly the abst motion caused by this condition. In 1889 the water
stood over 2 feet above the lower chord. The reason for these failures
was the same as the reasons for tie previous failures; i.e. the failure to
allow sufficient area for the waterway. In 1884-5 the bridge was again
rebuilt. This bridge was the oldest relic in America of a timber Howe
Truss era.

'ffith the exception of the draw the bridge consisted of three
lines of trusses, the south ones supporting the railroad with timber
arohes. The extreme width out to out of trusses was 40 feet 5 inches, and
roadway 19 feet 2 inches in clear with no sidewalk. The clear distance
between trusses supporting the single track was 13 feet 2 inches. The
masonary piers were of soft sandstone founded on piles with a timber
grillage at low tide level and heavily rlprapped, the riprap reducing the
cross-section of the river by one -third. The axis of piers were not
parallel to the current and the lower chord was 10.3 feet above mean low tide;
also the draw was not placed in proper position for the channel.

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All these things caused the > ridge to be a serious obstruction
to tidal flow, requiring constant dredging in order to maintain a
navigable channel of 20 feet at low tide. The highway and the railroad
ocoupied this same bridge until subsequent to 1901 when, by act of February
11, 1901 Congress passed the following.

"Section 11- That inasmuch as the present Long Bridge iB
inadequate for the accomodation of the largely increased railroad and
vehicular traffic, is in a measure obstruction of navigation and needs to
be reconstructed, the Baltimore and Potomac Bail road Company is hereby
directed and required to remove the present Long Bridge across the Potomac
River and, in accordance with plans approved by the Secretary of ",'ar, to
build on practically the same line a new bridge in lieu thereof, said new
bridge to be for railroad purposes only and to be adapted for two or more
railroad tracks, the Long Bridge to be removed, and the new bridge
constructed within four years from the date of passage of this Act. The
said Baltimore and Potomac Railroad Company shall remove the old Long Bridge
and shall keep in repair said new bridge at its own cost and expense, an
shall maintain an efficient draw in said new bridge* operating same so as
not to unnecessarily impede the free navigation of the Potomac River at
any hour of the day or night, and shall give other railroad companies
the right to pass over said bridge upon such terms as may be agreed upon
between the companies or prescribed by Congress".

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The railroads uBing the bridge abandoned it in July, 1904 and
moved to the new bridge which they had constructed some distance up stream
and in the spring of 190$ the electric railroad transferred their tracks to
the new government bridge nearby. The structure was closed for traffic in
the fall of 1906 and work was started toward its destruction. The
Assistant secretary of 7ar granted a permit to W.H* Johnson Jr., of
Philadelphia to remove the bridge, in accordance with his oontract with the
Pennsylvania Railroad, from which he bought the bridge for $175.

Mr* Johnson was to begin work at once, so as to complete the work
by July 1, 1907. The bridge was to be taken down in sections, piles being
driven under it to support the scaffolding for the work. The work of removal
was to begin at the District end of the bridge and the material to be
removed to the Virginia side. The piers were to be removed by use of
barges*

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The Eew Bridge
To meet the requirements of the Act passed by Congress requiring
the Bailroad Company to "build a new bridge, the Railroad Company in 1902
started surveys, looking toward the construction of a new "bridge acroBS
the Potomac Ttiver. The location finally adopted was approximately
200 feet upstream from the historic "Long Bridge" •

The following is a history of the new bridge and itB construction
from the Pennsylvania Hailroad Company:

"The new "bridge was designed to carry steam operated trains only,
two tracks "being provided, and it consisted of 12 spans, varying in length
from 169 feet to 261 feet, the latter span being the draw which was of the
swing type, operated by steam power, The bridge is 2528 feet in length
between the back walls and the length of the various spans is as follows j
Three spans at 188 feet 6 inches, six spans at 201 feet 3 inches, two spans
at 155 feet 3?r inches and one span at 104 feet. The distance from base of
rail to mean low tide is 24 feet. Construction of the piers and abutments
of this bridge was commenced during the winter of 1902 and the piers were
completed the following fall. The piers and abutments consisted of Ash-
lar granite masonry, backed up with concrete. The masonry portion of the
piers rests on a foundation of concrete from 6 feet to 10 feet in depth,
which in turn is supported by a pile foundation carrying a timber mattress
of 12x12 timbers, laid solid in four courses in opposite directions.

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The center pier, supporting the draw span, however, does not rest on piles,
but was constructed by pneumatic caisson process. The foundation for
this pier was excavated by the pneumatic compressed air method, with workmen
working under air pressure in a large timber caisson, which was built on the
shore, launched and floated to the aits of the pier, and then sunk to the
river bottom by depositing on top of the caisson and within the timber walls,
provided for this purpose, a sufficient weight of concrete to overcome the
bouyanoy of the timber and to sink the cutting edge of the caisson to the
bed of the river. The water was then forced out of the working chamber
at the bottom of the caisson by pumping compressed air in through pipes provided
for the purpose. The workmen then went down into this working chamber and
working under compressed air, maintained at a pressure sufficient to
overcome the weight of the water, which otherwise would have forced its way
into the caisson, proceeded to dig down into the bed of the river, the
excavated materials being hauled up out of the v/orking chamber in large circular
buckets through 35 inch double airlocked tubes, extending from the working
chamber to a point considerably above the surface of the water. After the
river bottom had been excavated down to a very hard and compact gravel
foundation, which process required continuous day and night work for several
months, and during which time concrete was daily deposited on top of the
caisson to force it further down into the bed of the river, the working
chamber was gradually filled up with a rich concrete mixture, the workmen

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being gradually withdrawn from the working chamber as the concrete approached

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the top of the chamber.

The superstructure of this bridge consists, as stated above, of
IE spans of various lengths of double track, through steel pin connected
trusses, all of which, except the draw span and the northernmost fixed
span were taken from another bridge of the Pennsylvania Railroad which in
about 1902 had been replaced by a stone arch. The draw span and the
northernmost truss were fabricated new for this bridge. The bridge was
opened for traffic in 1904."

The bridge is still the main railroad connection between the
Horth and South. The Baltimore and Ohio Railroad Company uses the bridge
to carry its freights trains to the southern rail routes, also the
Pennsylvania Railroad uses the bridge for the same purpose. The
Richmond, Fredicksburg, and Potomac, Southern, Seaboard Airline, Atlantic
Coast line, k or folk and Western, and Chesapeake and Ohio Railroads use the
bridge for their Northern outlet into Washington, thus connecting the
great rail nots of the Horth and South.

Bibliography

A Report of Defenses of "Tashington, to corps of Engineers U.S.A.
by Be r vet kajor General J. G-. Barnard

"ffar Da jartraent, district Engineer's Office. (Offieal files]

Engineering Kews, 1907, Book ill, page # 292.

national Capital's Historic Bridges (Evening otar News writer)
by John C. Procter

Pennsylvania Railroad Company .

Ingineer'a Office through .ir. G. TT. Buzby
superintendent of Police,
Pennsylvania KR.,
Philadelphia, Pa.

This picture shews the two span plate girder over the Washington
Ghanne X .

View of bridge from "ashington shore,

Floor of, bridge from north and
looking south.

Laat pier on northen end from
up stream side.

Fill that replaced part of the old
Long Bridge (1881).

une of the piers showing the pointed
end to releive ice pressure.

Brady Pictures

These photographs were taken during the Civil War by Brady.
(The Picture b ah own here were properly taken after 1863,
and were obtained from the signal Corps U.d.i. )

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