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Full text of "Annual report of the City Engineer"

City Document, — No, - 14. 



CITY OF BOSTON 




a^ me c(^?nAumen/d o/ me 

CITY ENGINEER. 



CITY ENGINEER. 



1870. 



City Document. — No. ■ 14. 



CITY OF BOSTON 




ANNUAL REPORa 



CITY ENGINEER. 



1870. 



CITY OF BOSTON. 



Office op City Engineer, City Hall, 

Boston, January 10, 1870. 
To the Honorable City Council : 

In compliance with the sixth section of the ordinance relating 
to the City Engineer's Department, I have the honor to present 
the following report, viz : 

The ordinance above alluded to was passed October 12, 
1868, and differs from the previous one mainly by effecting a 
complete separation of the Departments of Engineering and 
Surveying, which were partially distinct before, and under the 
control of two heads or officers. Each department is now dis- 
tinct and independent, with well defined duties. 

The change had become not only mutually desirable to the 
officers in charge of said departments, but imperatively neces- 
sary to the thorough efficiency of each organization, owing to 
the enormous increase of work called for by the numerous and 
extensive schemes of public improvements already initiated, and 
those in contemplation. 

Although the ordinance went into effect upon- its passage, 
and the City Engineer and City Surveyor each assumed charge 
and control of their special business as defined by the ordi- 
nance, yet it was found impracticable to immediately reorganize 
the working force so as to assign to each department the assis- 
tants required, and, as the Auditor decided that the appropria- 
tions could not well be divided, it was thought best to continue 
the old system of using the same force of assistants and em- 
ployes in common until the close of the financial year 1868-9. 

New rooms were assigned to this department, which were 



4 City Document. — No. 14. 

furnished and occupied in February, and a division of the plans, 
note-books, furniture, etc., was then made. The experience of 
the few months that had intervened since the passage of the 
ordinance, proved that it would have been impossible to have 
maintained the old system much longer; that the combined force 
of the two departments had already become inadequate, and 
that besides the additional room required, a reorganization and 
enlargement of the corps of assistants was imperatively neces- 
sary. The work of organizing a force for this department, and 
getting fairly at work under the new system, interfered for a 
while with the work of the department ; but, by the middle of 
March, the new office was pretty well equipped, and, so far as 
this department is concerned, I am satisfied the change has 
worked well. 

The following is a statement of the expenses of the City 
Engineer's Department, as paid from the appropriation for the 
department : 



Amount of appropriation . 


. 


$12,000 00 


Salary of City Engineer, and amounts 






paid assistants, draughtsmen, rod- 






men, etc 


$6,206 77 




Instruments and repairs of same . 


485 99 




Drawing paper and materials . 


366 35 




Stationery, note-books, etc. . 


390 23 




Travelling expenses 


214 82 




Cloth and labor mounting and bind- 






ing plans 


109 69 




Incidental expenses, tools, stakes. 






postage and revenue stamps, and 






expenses of committee 


617 61 




Books and picture-frames 


151 85 


$8,543 31 




• • 


Unexpended balance 


$3,456 69 



Eeport op City Engineer. 5 

The following: statement shows the amounts paid since Jan- 
uary I, 1869, for engineering, from special appropriations: 

WATER WORKS. 

Chestnut Hill Reservoir : pay rolls 

and incidentals . . . $4,805 03 

Roxbury extension (Wards 13, 14 

and 15) : pay rolls and incidentals 1,448 89 

Deer Island water-pipe : pay rolls 

and incidentals . . . 143 18 

$G,397 10 



PAVING DEPARTMENT. 

Atlantic avenue : pay rolls and inci- 
dentals $434 24 

Broadway extension : pay rolls and 

incidentals, etc 1,176 79 



$1,611 03 



CHURCH STREET DISTRICT. 

Pay rolls and travelling expenses . . . $565 50 



Total from special appropriations . . . $8,573 63 



The number of persons employed and paid from the de 
partment appropriation was, on the 1st of May (includ 
ing the City Engineer) 

The present number is ..... , 

The Chestnut Hill Reservoir party numbers 



10 

14 

5 



The following statement exhibits the operations of the de- 
partment during the past year : 



WATER WORKS. 



Several designs for a stand-pipe for the Roxbury high service 
were prepared, and detailed drawings and specifications made 



6 City Document. — No. 14. 

for the plan finally adopted. Plans and specifications have also 
been made of the pumping engine house, and numerous draw- 
ings of special castings for the extension of the works in the 
Highland District. 

Two large plans of Roxbury, comprising also portions of the 
city proper and South Boston, have been made, upon which are 
shown the water pipes, hydrants, and gates as already laid in 
the said portions of the city proper and South Boston, and the 
connection between the same and the newly laid pipes, etc., in 
Roxbury. These plans show the sizes and location of all the 
mains and distributing pipes laid, and the location of all hy- 
drants and gates established up to January 1, 1870. Two 
other large plans of the Highland District have also been 
made : one showing the location of all houses whose door-sills 
are more than eighty feet above " tide marsh level," with the 
actual height of said sills ; and the other showing the elevations 
and depressions of all the streets, and the exact height in 
figures above " tide marsh level " of all points in the streets 
where a change of grade occurs. These plans were prepared 
in order to determine the line of separation between the high 
and low service, the boundaries and extent of the high service 
districts, the location of blow-offs and air-cocks, and also to 
show at a glance the exact pressure to which the pipes will be 
subjected at any given point, whether in the high or low service 
system of distribution. A description of the high service dis- 
tricts, as determined by the aid of these plans, will be found in 
my report to the Cochituate Water Board, which is embodied 
in the last annual report of that Board. 

A copy has been made of the map of Dorchester, which was 
compiled for the commissioners on annexation, by T. W. Davis, 
Esq., City Surveyor. Upon this map will be shown the loca- 
tion of all buildings, the elevation of all door-sills above a plane 
of eighty feet above " tide marsh level," the heights of the sum- 
mits of all hills, the elevations and depressions of the streets, 



Report of City Engineer. 7 

and a proposed system of water-pipes, hydrants and gates for 
the distribution of the water. A party is now engaged upon 
the field work, and rapid progress is being made. 

A compiled map has also been prepared on a scale of 500 feet 
to an inch, showing Boston and its environs south of Charles 
River, and as far west as Watertown village. Upon this map it 
is designed to delineate such general topographical features as 
will be of service in planning the future extensions of our water 
supply and distribution. It will also be of service as a map of 
reference in the discussion of tlie question of public parks, and 
the further extension of our corporate limits. 

Three plans of East Boston have been made, showing the 
sizes and location of the water-pipes laid, and the position of 
hydrants and gates established. One of these plans was made 
for the use of the Mystic Water Board, of Charlcstown, one for 
the Superintendent of the eastern division, B. W. W., and one 
for office reference, and upon which to delineate future addi- 
tions. 

A copy of the plan of South Boston, made under the direction 
of the commissioners appointed to define the bounds of the 
streets, has been prepared for the use of the Water Depart- 
ment, upon which to show the water-pipes, gates, etc. 

A plan, on a scale of three hundred feet to tlie inch, has been 
made, showing tlie proposed extension of Swett street, across the 
South Bay to the junction of Dorchester and Federal streets, 
and also the route for a new main water-pipe to South Boston, 
from the junction of Dudley and Hampden streets, via Magazine 
street, the aforesaid extension of Swett street, Dorchester, Tele- 
graph and Thomas streets, to the reservoir on Telegraph Hill. 
This plan was designed to show the general features of the pro- 
jects. Surveys have been commenced, and are now in progress, 
to enable the construction of a plan upon a larger scale and 
exhibiting more details. 

Surveys iiave been made and a plan and profile prepared of 



8 City Document. — No. 14. 

the route for a pipe from East Boston to Deer Island, including 
soundings of the Cliannel or " Gut," between Point Shirley and 
the island. This survey was made by order of the President 
of the Water Board, after the appropriation had been passed by 
the City Council. The low grade of a portion of the highway 
in the town of Winthrop, necessitating the laying of a portion 
of the pipe below tide water, unless the town will fill up or alter 
the location, and the question of the necessity of laying a larger 
size of pipe than was estimated for, over a portion of the route, 
has delayed action. These questions will undoubtedly be set- 
tled soon, so that the work may be commenced in the early 
spring. 

Surveys have been made, and a plan nearly completed, which 
will show the proposed limit of the Beacon Hill high service, 
the number of houses, hotels, etc., within the district, and the 
elevations of their door-sills and cisterns above " tide marsh 
level." Observations by means of pressure gauges will deter- 
mine the line of division between the high and low service. A 
variety of calculations have also been made, bearing upon the 
best mode of supplying this elevated district as thoroughly and 
efficiently as it is proposed to do the Roxbury high districts, and 
a report now in progress will soon be laid before the Cochituate 
Water Board. 

Plans have been made of various alterations in the brickwork 
of the effluent gate house at the Chestnut Hill Reservoir, and of 
the iron railing, stairs and galleries in said gate house, and the 
gate chamber connected therewith. 

Finished drawings have also been made, and others are in 
progress, which will show all the structures connected with the 
reservoir, just as they had been actually built. The work 
upon these finished drawings is kept as reserve work, to be done 
in leisure time, when current work is not pressing. A very 
considerable amount of time was consumed in preparing the 
estimates and statements called for by the Water Board last 



Report of City Engineer. 9 

spring in connection with tlie request then made for an addi- 
tional appropriation for completing the reservoir. These esti 
mates and statements may be found in City Document No. 59, 
1869. 

Very few clianges have been made or required in the work 
at this reservoir during the year, aside from those previously 
alluded to at t!ie effluent gate house. It was found necessary to 
strengthen the retaining wall which supports the filling of a 
portion of the driveway, and a plan prepared by Mr. Wight- 
man, the Resident Engineer, was approved, which accomplishes 
the object by building a supplementary wall, connected by stone 
piers with the old one, and forming a terrace along the entire 
front. 

The plans for the gate chambers at Brookline, for inclosing the 
gates, rendered necessary by the joining of the 48-inch main 
from the Chestnut Hill Reservoir with the three mains which 
now supply the city, were also prepared by the Resident En- 
gineer. 

"With the exception of the slight changes above referred to, 
the general plans of the work were well matured early in the 
year, and the work of executing the same and completing the 
reservoir was in that state of forwardness or maturity that it 
needed only the well-known executive ability of the Superinten- 
dent and Resident Engineer to push the work as rapidly as pos- 
sible towards its final completion, and the result shows that 
they have done their duty. 

The report from this department to the Water Board in May 
next, will present in* detail the progress of operations on this 
work as well as of the extension of the works in Roxbury and 
Dorchester and the general condition of the whole. 

ATLANTIC AVENUE. 

Soundings were made at the beginning of the year on the 
easterly line of Atlantic avenue, where it crosses the several 

2 



10 City Document. — No. 14. 

docks, and levels taken of the whole line, from which profiles 
were made showing the elevations of the existing piers and 
wharves above mean low water, the depths of water at low tide, 
and the depth of mud or other material overlaying the hard 
bottom in the several docks ; also, the proposed grade of the 
avenue as recommended by the Superintendent of Streets, which 
grade was fixed at an elevation of sixteen feet above mean low 
water for the whole line from Commercial street to the north- 
erly side of India wharf; thence rising at the rate of about .j^^^^ 
of a foot in one hundred feet to meet the grade of Broad street 
as previously fixed. 

The depth of water below mean low tide and of the mud, was 
found to vary very materially in the difierent docks, and the 
hard bottom appeared to be of the same character as the mate- 
rial of Fort Hill, a mixture of clay and gravel, very hard and 
compact, and what is commonly called " hardpan." 

The first plan proposed for a sea-wall contemplated the exca- 
vation of all the mud and objectionable material for a space of 
about twenty-five feet in width at the bottom of the trench under 
the whole line of wall, and of building the wall solid from this 
foundation, without using piles, to the grade of the street. 
This plan would have called for a wall whose average height 
would have been thirty feet, fourteen feet of which would have 
to be laid under water, below the level of low tide, whose 
width at the base would be seventeen feet, at low water thir- 
teen feet, and at the top three feet, the rear of the wall to be 
heavily ballasted. This plan, although the most substantial, was 
also the most costly, and was deemed too expensive. 

Another was proposed, the wall resting upon a foundation of 
piles cut off at a level of one foot below mean low water, and 
placed three feet apart on centres longitudinally, and two feet 
transversely of the wall. The principal objection to building 
a wall designed to support a heavy earth filling, as in this case, 
upon a pile foundation, where the mud is soft and of considerable 



Report op City Engineer. 11 

depth, is that the mud being soft and yielding, affords very lit- 
tle lateral support to the piles, and the weight of the filling ia 
the rear presses upon the mud as upon au elastic cushion, which, 
moving laterally, tends to crowd the piles outward, and over- 
turn the wall. To avoid this objection it was proposed to 
excavate a trench as in the first instance, removing all the soft 
and yielding material, and to replace it with good clean gravel 
in part, and in part with broken stone ; thus the piles would be 
surrounded with a firm, unyielding material that would hold 
them in place, and the danger to the wall from the spreading of 
the mud would be avoided. This plan was deemed amply 
secure, and as its cost per running foot was estimated at about 
fifty dollars less than the first, it was approved and specifica- 
tions were drawn. 

A practical difficulty, however, made it necessary to slightly 
modify the plan of the wall, to change its location, placing it 
twenty feet back from the line of the street, and to build a plat- 
form sidewalk resting upon oak piles outside of it. This change 
was rendered necessary from the fact that the plan of con- 
struction of the wall as approved, required that a portion of 
the trench to be excavated as described above, and afterwards 
filled with stone ballast, was necessarily in front of the wall, 
and being outside the limits of the street, upon private ground, 
the city would be a trespasser unless the consent of the owners 
could be obtained. Efforts to procure this consent were unsuc- 
cessful, and hence the adoption of the modified plan. Proposals, 
however, were invited and received upon both plans, and the 
contract, which was awarded to Boynton Brothers, was so 
drawn that either plan could be executed in part or the whole, 
as the Committee on Paving should direct. Both of the plans 
and the specifications were approved by a majority of the Har- 
bor Commissioners, and copies of all plans referred to in the 
specifications were made and deposited in said commissioners* 
office. 

The contract was awarded to Boynton Brothers, and was 



12 City Document. — No. 14. 

duly executed on the 4th of March, 1869. The contractors 
were to commence work on or before the 10th of March, and 
complete the whole on or before the tenth day of October. 
They were to receive for so much of the wall as should be built 
according to ^^ Plan No. 1" (the second above described), 
$92.50 per lineal foot; for so much as should be built accord- 
ing to " Plan No. 2 " (with platform sidewalk, but not including 
the same), $91.82 per lineal foot; for all sluices which might be 
found necessary, built according to the plan, $11.17 per lineal 
foot; and for the platform sidewalk, $25 per lineal foot; all the 
work to be done to the approval of the Committee on Paving 
and the Superintendent of Streets, or some person appointed 
by them to superintend the work. A superintendent, Mr. 
Leighton, was appointed by the Committee on Paving, and the 
work was promptly commenced under his direction and super- 
vision, and would probably have been completed at or near the 
appointed time, but for changes in the plan of construction which 
the contractors were ordered to make by the superintendent in 
charge of the work. 

These changes had been discussed by the superintendent 
and myself, and I had given a conditional verbal assent, subject, 
however, to the approval of the Committee on Paving. 

The superintendent, understanding or claiming that he was 
authorized by the chairman of the committee to make the 
change, if I approved of it, and being ignorant of the fact that 
such change required the approval of the Harbor Commis- 
sioners, directed the contractors so to alter the plan of construc- 
tion of a certain portion of the wall as to omit the dredging, 
where the mud was only seven or eight feet deep, and substitute 
small stone chips or ballast for the gravel filling between the 
piles and in the rear of the wall up to the level of the tops of 
the piles. 

Acting upon the orders of the superintendent, the contractors 
proceeded to drive the piles for the foundation of the wall in 



Report op City Engineer. 13 

the dock between T and Commercial wharves, — omitting the 
preliminary dredging, — and had made considerable progress, 
when the fact was reported to the Committee on Paving by the 
Harbor Commissioners, accompanied by a statement that the 
change which was being made would result in a saving to 
the contractor of over forty dollars per running foot of wall. 
The work upon this section was at once stopped by order of 
the Committee, the Harbor Commissioners positively refusing to 
sanction the change, and the Committee on Paving disclaiming 
the authority of the superintendent in ordering it ; while the 
contractors, insisting that they had acted in good faith in com- 
plying with the orders of the superintendent, whom they re- 
garded as the authorized agent of the committee, declined to 
undo the work already done, and proceed according to the 
specifications, without due compensation. 

A modified plan was proposed by the Harbor Commissioners 
which they deemed an equivalent to the original, and by which 
the work already done might be saved ; but this plan was pro- 
nounced impracticable by the superintendent, and the contract- 
ors refused to accept it as an equivalent for the original. 

Several conferences were held between the committee, the 
Superintendent of Streets, the City Engineer, the superintendents 
(Mr. Leighton and T. W. Pratt) and the contractors, and it was 
finally decided that the City Engineer and Mr. Pratt should con- 
fer with the Harbor Commissioners, and, if possible, devise a 
plan which should meet their approval, and that in devising such 
plan the engineers need not consider the question of equiva 
lency at all. Plans were accordingly made and submitted to the 
commissioners, which met their approval and that of their en- 
gineers. The plans were then laid before the contractors, who 
expressed their willingness to execute them, but demanded an 
additional sum per running foot. 

The question of what should be equitably paid the contract- 
ors, in addition to the original price, was referred by the com- 



14 City Document. — No. 14. 

mittee to the City Engineer and T. Willis Pratt, who, after 
several fruitless conferences with the contractors, reported the 
additional amount that should be paid for the section between T 
and Commercial wharves at nine dollars and forty-one cents per 
lineal foot, and for a short piece between T and Long wharves, 
four dollars and twenty-two cents per lineal foot. 

These prices were finally accepted by the contractors, and a 
new contract made in October, under which the work is now 
progressing and by the terms of which the whole work is to be 
completed on or before May 1, 1870. 

It should be explained in this connection that the statement, 
above referred to in the communication of the Harbor Com- 
missioners, that the change ordered by the superintendent would 
result in a saving to the contractors of over forty dollars per 
running foot, was undoubtedly made under a misapprehension of 
facts both as to quantities of material and the prices ; for I 
found, by careful estimates, that tlie actual difference in cost to 
the contractors would be inside oi fifty cents in their favor, 
while the contractors claimed that the balance would be on the 
other side. In fact, such a misapprehension is evident when it 
is shown that the entire cost of dredging and gravel filling in 
this particular dock would not have exceeded five dollars per 
running foot, and if all the broken stone required had been 
omitted, the cost of that would have been only nine dollars per 
running foot. 

In my judgment, the modified plan of construction as ordered 
by the superintendent would, in that particular dock, have been 
equally as secure as the original, and would have expedited the 
work very materially. But as the Harbor Commissioners 
thought differently, and had absolute legal power in the prem- 
ises, the work was necessarily delayed in this locality for several 
months, and was finally resumed at an additional cost of over 
nine dollars per running foot. 

The work is now progressing favorably, and is in that state of 



Report op City Engineer. 15 

forwardness that there is every prospect of its completion at 
the appointed time. 

FORT HILL. 

The final grading and paving of Oliver street was completed 
in August, and in the fall the work of excavating the main body 
of the hill was commenced on the easterly side at the level of 
Purchase street, under a contract for filling Atlantic avenue, 
made with B. N. Farren, Esq., on the 27th of October, 1869. 
All material removed is measured in the bank, and monthly 
estimates of the amount so taken are made by this department 
and certified to by the City Engineer. 

CHURCH STREET DISTRICT. 

In tlie early part of the year the final estimates were made 
of the amount of gravel removed from the bank at Readville, 
and deposited in this district. Since then the necessary sur- 
veys, levels and estimates have been made to determine the 
amount of gravel removed from the banks at Monterey and Mt. 
Hope, and used for filling on this territory. The amount of 
filling from other sources has also been determined and certi- 
fied to. 

BROADWAY EXTENSION. 

A general plan for the bridges and necessary structures re- 
quired for the extension of Broadway at " the high grade " was 
prepared under my direction in 1867. This was designed more 
especially to illustrate the main features of the " high grade " 
project, and, at the same time, afford the necessary basis for the 
preliminary estimates of cost. 

The necessary orders for the extension at the " high grade " 
were passed by the City Council in the latter part of April, by 
which the Committee on Paving were authorized to make all 
contracts for the execution of the work. 

The work of preparing detailed plans and specifications of 



16 City Document. — No. 14. 

the bridges and piers was commenced on the following week by 
Mr. Clemens Herschell, C. E., well known as the designer of 
the Columbus avenue bridge over the Boston and Albany Rail- 
road, the Albany street bridge over the same railroad, and of 
the Public Garden bridge. He had been engaged by the Com- 
mittee on Paving to do the work under the direction of this 
department, the expense to be charged to the appropriation for 
the extension. 

Before much progress had been made by Mr. Herschell, plans 
and specifications were presented to the committee by the Mose- 
ley Iron Bridge Works Co., with which the committee were so 
well pleased, that the same were referred to me for my opinion 
as to style and strength. Although confined at home by ill 
health, I examined the plans and specifications as requested, 
calculated the strains of the various parts, and noted my objec- 
tions. Subsequently, the plans were returned to me with addi- 
tional details, and the specifications in a new draft for re-exam- 
ination. I suggested some further slight changes that would 
be necessary before I could give my approval; these were 
promptly made by the Bridge Co., and my approval was given 
to the committee on the 24th of May. Mr. Herschell's designs 
and specifications not being ready at this time, and the com- 
mittee not feeling satisfied with the progress made, accepted the 
Bridge Co.'s plans, and at once advertised for proposals, to be 
received until June 7th, for building the bridges, etc., according 
thereto. The contract was awarded to the Moseley Iron Bridge 
Co., and the necessary agreements were prepared, dated June 
12, 1869. 

The plans and specifications, though approved and adopted 
by the committee, had yet to receive the sanction and approval of 
the Harbor Commissioners before the work could begin; for, 
by the terms of the act of the Legislature, authorizing the exten- 
sion of Broadway and the building of a bridge over Fort Point 
Channel, the work must be done under their supervision and 



Report op City Engineer. 17 

direction. The plans were retained for a considerable time, 
and were tliorouglily and critically examined by their engineers, 
and several changes were prescribed, some of which, in my 
judgment, were judicious, and some not ; but nearly all were of 
a nature to increase the cost of the work quite materially. By 
the terms of the contract, the entire work embraced in the speci- 
fication is to be done to the satisfaction of the City Engineer, 
the Committee on Paving, the Superintendent of Streets, and 
the superintendent in charge of the work on the part of the 
city, for the sum of $331,708.76. 

As this is one of the most important structures of the bridge 
kind ever erected in the city, a description of it may be of in- 
terest, and not out of place in this report. 

The structures embraced in the contract with the Moseley Iron 
Bridge Co. include everything except paving, between the east- 
erly side of Foundry street in South Boston and the north- 
westerly side of Lehigh street in Boston proper, a distance of 
1,117 feet. 

Beginning at tlie easterly side of Foundry street, the first 
structure is an iron bridge over said street of a clear span of 
fifty-six feet, and at an elevation of twelve feet in the clear 
above the same. This structure is to rest upon a substantial 
stone abutment built by the city on the easterly side of the 
street, and upon wrought-iron columns built by the contractor 
on the westerly side. 

The bridge is a modification of the style known as the " Bow- 
string Girder," and consists of two main wrought-iron arches 
springing from shoes or sockets at the ends, which rest upon the 
abutment or pier, the ends being tied together by a horizontal 
tie, or what is usually called the lower chord. This lower 
chord and the floor beams or cross-girders of the roadway and 
sidewalk are suspended from the arches by vertical suspension 
bars. Besides the arches, a supplementary horizontal boom or 
upper chord of wrought-iron is provided and attached to the 
3 



18 City Document. — No. 14. 

arches at the crown, adding greatly to its strength, and, by 
means of the vertical and diagonal bars connecting said chord 
with the arches, forming a spandril-bracing, the stablility of the 
arch, nndcr a travelling load, is greatly increased. The height 
of tlie arches in this span is five and one-half feet from the 
lower chord to the upper chord at the centre. 

Each arch and the attached upper chord combined is to have 
a sectional area of twenty-six square inches, and each lower 
chord at its centre a sectional area of twenty-six square inches, 
exclusive of rivet holes. The vertical suspension bars to be of 
bar-iron, three inches by f -inch, and to be placed two feet apart, 
and the diagonal or lattice bars to be two inches by l-inch, 
the intersections of these bars to be covered with ornamental 
castings. Stays or bracings, of 3-inch T iron, are to be placed 
eight feet apart to give lateral stiffness to the arches. The 
floor-beams or cross-girders are to consist of double 9-inch 
wrought-iron I beams, brought into compressive strain by ten- 
sion rods of two inches diameter, attached to the I beams be- 
neath the main arches, and strained over struts of cast-iron. 
These beams project beyond the arches to form a support for 
the sidewalks and are placed four feet apart. Upon these iron 
floor-beams or cross-girders are to be laid, for the roadway, 
cast-iron plates four feet square and ^-inch thick, ribbed twice 
across the surface by ribs three inches by |-inch at the mid- 
dle, and tapering toward the edges. This completes the road- 
way ready to receive the wooden pavement, which is to be 
furnished by the city. 

The sidewalks of this bridge and throughout all the struc- 
tures hereinafter described, are to be floored with yellow pine 
three inches thick. The railing for the sidewalks is to be uni- 
form throughout the whole length of the several structures, and 
is to consist of an upper rail of double 21 inch I iron, middle 
and lower rails of double 2-inch I iron, with vertical rods |-inch 
diameter, placed six inches apart on centres and diagonal rods 



Report op City Engineer. 19 

J-inch diameter, — the intersections to be covered with orna- 
mental castings. Stays or bracings of 3-inch T iron will be in- 
troduced wherever required to give lateral stiffness. 

The next structure extends from the last described, to a point 
on the easterly side of the Old Colony and Newport railroad 
tracks, a distance of about four hundred and forty feet. In 
this structure the street is supported upon wrought-iron columns 
set in rows of three, crosswise the street, twenty feet apart; 
the rows being eleven feet apart, lengthwise the street. The 
roadway being forty feet wide, and the middle column of each 
row being placed in the centre, the two outer ones come diretly 
under the sidewalk curb, and the sidewalks — each ten feet 
wide — are supported upon wrought-iron brackets attached to 
the outer columns. These columns are twelve inches in diam- 
eter and ^-inch thick, of the Phoenix Company's make, and 
are each supported by three piles cut off two and one half feet 
below mean high water, and capped with stone to a point four 
feet below the surface of the ground. That portion of the 
column which comes below the surface of the ground (four feet 
deep) is enclosed in boxing two feet square, and the space be- 
tween the boxing and the column is filled with concrete com- 
posed of broken stone or gravel, and hydraulic cement. 

The columns themselves are also filled solid with concrete, 
and are then capped with a cast-iron cap, so formed on its 
upper side as to receive and hold in position the transverse 
girders, which are 12-inch wrought iron I beams. These I 
beams project beyond the outer columns, and rest upon the 
brackets before described, forming the support for the sidewallc. 
Upon these 12-inch I beams, longitudinal beams of heavy 6-incIi 
I iron are placed under the roadway, and are four feet apart 
from centre to centre. Upon these rest the cast-iron plates 
four feet square, similar to those above described. 

The last or westerly row of columns, near the Old Colony 
and Newport Railroad, supporting the structure just described, 



20 City Document. — No. 14. 

differs from the others inasmuch as it forms a pier upon 
which is to rest the southerly end of the long span bridge here- 
inafter described. The number of columns in this pier is the 
same (three) ; but the two outer ones are to be twenty-four inches 
in diameter, and y^g-inch thick, and the middle one twelve 
inches by one-quarter, like the others. These columns are to 
be connected at the tops by a pedestal constructed of 15-inch 
wrought-iron I beams, securely fastened. This pedestal forms 
the southerly bridge seat for the next structure, which is a 
bridge of one hundred feet span, extending from the last de- 
scribed pier, over the tracks of the Old Colony and Newport 
Railroad, at an elevation of fourteen feet in the clear above 
said tracks, to a pier in Fort Point Channel situated about 
eighty feet southeastwardly from the centre of said channel. 

This pier is to consist of five cast-iron screw-piles, of twenty- 
four inches internal diameter and one and a quarter inches 
thick, so placed that two of them cotne directly under the ends 
of the adjoining arches on each side of the roadway, and one 
under the centre of the roadway. 

These screw-piles are coated with a coal-pitch varnish, which 
has been in successful use for several years in protecting water- 
pipes from corrosion. The sections are joined by bolting the 
projecting flanches firmly together. They are to be screwed 
into the clay bottom until a firm and substantial bearing is ob- 
tained, and then the soft material is to be removed fiom the 
interior, and the pile filled with hydraulic concrete and capped. 

Upon these piles, and connecting them at the tops, is to be a 
pedestal of wrought-iron I beams, fifteen inches high and f- 
inch thick at stem, securely fastened to the piles, and widened, 
if necessary to receive the ends of the bridges properly, by 
brackets. Diagonal tie-bars four inches by ^inch will connect 
the outer piles with the middle one. 

The bridge of one hundred feet span, which rests upon the 
piers above described, is of the same style as the one above 



Report op City Engineer. 21 

described over Foundry street, differing only in dimensions and 
proportions, and in the style of flooring. 

The main girders or arches in this bridge are to be ten feet 
high from lower to upper chord, and are each to have a sec- 
tional area of fifty-six square inches for the arch and upper 
chord combined, and fifty-four square inches for the lower 
chord. The suspension-bars, lattice-bars, and ornamental cast- 
ings, and also the floor-beams or cross-girders are to be pre- 
cisely the same as in the Foundry street bridge ; but, instead of 
cast-iron plates, the flooring will be of wood, consisting of 8-inch 
by 4-inch Burnettized spruce timbers fitted between the iron 
floor beams, flush with their tops, and placed three feet apart on 
centres, to which is spiked an under flooring of 3- inch Burnet- 
tized spruce plank, upon which an upper flooring of 3-inch white 
oak plank is laid at right angles therewith, and spiked thereto. 

The pivot drawbridge and pier are the next structures in 
order, and are located nearly in the centre of the channel. The 
openings for the passage of vessels are about forty-four feet 
each, and the whole length of the bridge is one hundred and 
sixty feet, and rests upon a central and two end-piers. The 
southerly end-pier has just been described; the northerly pier 
is of precisely the same description. The central pier upon 
"which the bridge turns is composed of cast-iron screw-piles of 
the same dimensions as those already described. Sixteen of 
these piles are placed in the circumference of a circle of about 
forty feet diameter, being about eight feet apart, and three are 
to be set at the centre in a line with the current of the stream. 
Each of the outer piles is to be connected with the central ones 
at the top, and also at a level of eight feet below the tops of the 
piles by radial 6-inch wrought-iroa I beams, firmly bolted to 
clasp-rings encircling each pile. 

Similar I beams will also connect the outer piles with each 
other at the same levels, and diagonal rods crossing each 



22 City Document. — No. 14. 

other will connect the top of each outer pile with the lower 
clasp-rings of the adjoining piles. Upon the caps of the 
outer piles is to be a pedestal of 15-inch wrought-iron I 
beams, curved to form a true circle and securely fastened to the 
piles; and, to the top flanch of this beam, a steel-headed track- 
rail, weighing not less than iifty-seven pounds per yard, is to be 
bolted. Upon this track-rail rest the wheels which support the 
turntable. These wheels are to be of cast-iron, chilled, sixteen 
inches in diameter, with a face or bearing surface six inches 
broad and truly coned to the radius of the circle. They will 
be placed about four feet apart. Radial rods, two inches in 
diameter, pass through the centre of each wheel, connecting it 
with a central hub eighteen inches in diameter. The outer enda 
of these radial rods project and pass through a curved wrought- 
iron band, four inches by J-inch, which extends entirely around 
the circle just outside the wheels and keeps them always at 
equal distances apart and insures a uniform motion. A 6-inch 
wrought-iron pivot passes through the aforesaid hub at the cen- 
tre, and extends downward through the cap of the centre pile, 
and three feet into tlie concrete filling ; it also extends upwards 
and passes through a heavy cast-iron disc-plate five feet square, 
and one and one-half inches thick. Fastened to this central disc 
are to be radial 7-inch wrought-iron I beams, connecting it with 
a ring composed of 15-inch wrought-iron I beams, to the under 
side of which is bolted a steel-headed rail similar to the one 
above described. This ring is an exact counterpart of the cir- 
cular pedestal before described, only it is inverted and the 
track-rail rests upon the tops of the wheels. Circumscribing 
this upper ring is to be a square frame of 7-inch wrought-iron 
I beams, firmly secured thereto at the points of contact, and 
also by means of the same sized beams at the angles. This 
square frame, with the upper ring, radial beams and central 
disc, all securely fastened together as described, form the turn- 
table upon which rests the bridge. The towers, to the tops of 



Report op City Engineer. 23 

r 

which are attached the cables or suspension rods that sustain a 
portion of the weight of the bridge when swung open, are placed 
directly over the ring which forms part of the turntable, and 
exactly midway of the bridge longitudinally. These towers are 
to be thirty-seven feet high, five feet by one and a quarter feet at 
the base, and twelve inches square at the top. The corner posts 
are to be 5-inch angle iron, connected either by plate iron or by 
lattice bars. The towers are tied together and braced, across 
the roadway, by three wrought-iron tubes or beams, of trian- 
gular section, five-sixteenths inch thick and of nine-inch faces 
attached at different levels, and connected together by vertical 
struts of 6-inch I beams. In the bays thus formed are to be 
diagonal rods, meeting in a ring at the centre, formed of bar 
iron three inches by three-fourths inch. The cables or suspen- 
sion rods, which transmit a portion of the weight of the bridge 
to the towers, are three in number for each tower; the longest 
one being two inches in diameter, the middle one, one and 
three-fourths inches, and the shortest one, one and a half inches. 

The construction of the bridge itself is the same as already 
described in the case of the one hundred fieet span, except that 
the spans being only about eighty feet, the crods-section of the 
arches and chords is correspondingly reduced. The arches are 
to be of the same height (ten feet). 

Within the space formed by the circle of screw-piles, and 
resting upon the lower set of radial beams, is to be a floor of 
3-inch yellow pine, — the space to be enclosed and partitioned 
ofi' to form apartments for an engine-room and a dwelling for 
the draw tender; or iu lieu thereof, a suitable building is to be 
erected on the fender pier. 

Two caloric engines, of not less than three-horse power and 
all necessary gearing for moving the bridge, to be furnished. 
Also, a wrought-iron stairway, with steps of yellow pine, will 
be built from the level of the roadway to the fender pier. 

The fender-pier is to be two hundred and sixty feet long and 



24 City Document. — No. 14. 

sixty feet wide, and is to entirely enclose the draw-pier 
witliout being" connected with it, thus preventing any shock 
caused by passing vessels from being communicated to the draw- 
pier. In construction, this fender-pier is quite a novelty, and 
rather expensive as an experiment. It consists of three parallel 
rows of tongued and grooved sheet-piling of 6-inch spruce or 
pine, placed twenty-nine feet six inches apart from centre to 
centre of each row — the rows being in the direction of the 
thread of the current. Each row to be capped longitudinally 
with a cap twelve inches square tenoned to the piles every five 
feet, or oftener, if necessary. Cross timbers twelve inches 
square and thirty-two feet long, lapping each other at the centre, 
are to be bolted to the longitudinal caps and to each other at 
the lap joint. These cross timbers are to be placed six feet 
apart from centre to centre, and covered with a flooring of 3- 
inch spruce or pine plank. Suitable belaying-posts are to be 
bolted to the longitudinal caps, floor-timbers and sheet-piling, 
and longitudinal oak ribbons three inches thick are to be 
fastened to the channel side of the sheet-piling between low 
water and the top of the pier. Fender-guards of oak piles or 
sheet-piling are also to be built to protect the end piers of the 
drawbridge, and to extend out from said piers to meet the 
fender-guards which extend from the shore parallel with, and 
eighteen feet outside of, the bridge. 

From the pier at the northerly end of the drawbridge is to 
be another bridge of one hundred feet span, precisely similar 
to the one of the same span already described. But the pier 
upon which its northerly end rests is composed of five screw- 
piles arranged like those already described. 

From this last mentioned pier to Lehigh street, a distance 
of about two hundred feet, the structure rests upon wrought- 
iron columns, and is identical in every respect with that on the 
South Boston side already described. 

The bridge over Lehigh street completes the list. It is of a 



Report op City Engineer. 25 

clear span of fifty feet, of the same style of construction as tho 
one over Foundry street, is to be twelve feet in the clear above 
Lehigh street, and its northerly end is to rest upon stone abut- 
ments, built by the city. 

Before work was commenced by the contractor, borings 
■were made at various points on the entire line of the extension. 
Eight borings were made on the South Boston side, which 
showed that the surface of the clay bed underlying the mud was 
about level with mean low water at Federal street, and thence 
sloped downwards to the lowest point, which was on the easterly 
side of Fort Point Channel, near tlie tracks of the 0. C. & N". R. 
R. At this point the surface of the clay was twenty-four feet 
below mean low water, in the centre of the channel it was eigh- 
teen feet below mean low water, on the westerly side eight feet, 
and thence to Lehigh street, it varied from eight to ten feet. 
Two of the borings were sunk into the clay with a view of de- 
termining its thickness and consistency at various depths. One 
of these borings was made at the point where the clay bed was 
most depressed. The total depth of this boring was ninety-five 
feet from the surface of the ground, and the clay was penetrated 
to a depth of fifty-five feet and was found to be of the very 
finest quality, entirely free from stones, gravel or sand, and, in 
point of consistency, appeared to be firmer and tougher near 
the surface, than at a greater depth. The other deep boring 
was made in the channel near the centre, and was carried down 
to the rock, a depth of one hundred and eight feet below mean 
low water, and through ninety feet of clay. The character of 
the clay was much the same as in the last boring, and, so far as 
the stability of the structures which are to rest on it are con- 
cerned, it was evident that nothing would be gained by penetrat- 
ing the clay more than eight or ten feet. In view of the clay 
being softer than was anticipated, I suggested the addition of a 
broad exterior flanch to the screw piles at a point eight or ten 
feet above the screw-blade to form a bearing shoulder on the 
4 



26 CiiY Document. — No. 14. 

surface of the clay when the piles were screwed into place. The 
suggestion was approved and is being carried out. 

PROGRESS or THE WORK. 

The construction of the fender-pier in the centre of the chan- 
nel has been a very slow and difficult job, as might have been 
expected. It is, however, nearly completed. The screw-piles 
for the draw-pier are all in position and ready to be sunk. The 
iron columns on the South Boston side are nearly all set, and 
some of the 12-inch iron floor-beams are in position. On the 
Boston side, the pile foundations for the iron columns are all 
driven. Most of the iron-work and lumber is on hand and ready 
to set up as soon as the sub-structures are ready. The amount 
paid to date is $174,388. 

The Resident Superintendent of this work, on the part of the 
City, is T. Willis Pratt, Esq. 

ABUTMENTS AND RETAINING WALLS FOR [BROADWAY EX- 
TENSION. 

These comprise two abutments — one on the easterly side of 
Foundry street, and one on the northwesterly side of Lehigh 
street — and retaining walls on each side of the street from 
said abutments, to Federal street on the South Boston side, 
and to Albany street on the Boston side. 

The abutments and retaining walls to rest on piles, cut off at 
a level of seven and one-half feet above mean low water. The 
abutments to be of such height as to permit the bridges above 
described to rest thereon, at an elevation of twelve feet in the 
clear above the roadways, and to be built of Quincy or Rock- 
port granite, cut to dimensions, with rough-hammered beds, 
builds and vertical joints. The retaining walls to be coursed 
rubble masonry, laid in cement mortar, and suitably bonded, 
the top surface to be built on an incline corresponding with the 
grade of the street. 



Report of City Engineer. 27 

Proposals were duly iuvited, and the contract was made with 
Messrs. Clapp & Ballou, in August, to furnish all materials 
and do all the work on or before October 1st, at the following 
rates for the various kinds of work,-viz : 

For excavation, per cubic yard $0.85 

For filling " " 1.00 

For furnishing and putting ia ballast, per cubic yard, . 1.50 

For furnishing and driving all piles, per pile . . 3.90 
For furnishing and laying in cement all rubble masonry, 

per cubic yard ....... 8.81 

For furnishing and laying in cement all dimensioned 

stone, per cubic yard 21.35 

The work on the South Boston side has been completed. On 
the Boston side the retaining walls are finished and a portion 
of the abutment. The whole work will be finished, probably in 
February. 

The amount paid contractors to date, as per my estimates, is 
$45,512.42. 

BRIDGES. 

• The duties of the City Engineer in respect to this class of 
structures remain the same under the present ordinance as 
under the preceding one. 

The following is a list of the bridges which the city has to 
maintain in whole or in part : — 

1st. bridges over tide-waters, riters and creeks. 

* Albany street bridge, — over the Roxbury Canal. 

* Dover street bridge, — across entrance to South Bay. 

* Broadway bridge, — over Fort Point Channel (now building). 

* Federal street bridge, — over Fort Point Channel. 

* Mt. Washington avenue bridge, — over Fort Point Channel. 

* Meridian street bridge, — over Chelsea Creek. 



28 City Document. — No. 14. 

* Chelsea street bridge, — over Chelsea Creek. 
Winthrop bridge, — from Breed's Island to Winthrop. 

* Ncponset bridge, — over Ncponset River. 

* Granite bridge, — over Neponset River. 

Milton bridge, — over Neponset River, at Lower Mills. 
Mattapan bridge, — over Neponset River, at Upper Mills. 

* Commercial street bridge, — over Creek at Commercial Point, 
Dorchester. 

Mill Dam bridge, — over sluices connecting the " Fall Basin " 
with Charles River. 

Longwood avenue bridge, — over Longwood Creek and Brook- 
line Branch Railroad. 

2d. bridges over RAILROADS AND HIGHWAYS. 

Albany street bridge, — over Boston and Albany Railroad. 

Tremont street bridge, — (water pipes) Boston and Albany 
Railroad. 

Ferdinand street bridge, — over Boston and Albany Railroad. 

Berkeley street bridge, — over Boston and Albany Railroad. 

Columbus avenue bridge, — over Boston and Albany Railroad. 

Dartmouth street bridge, — over Boston and Albany and Boston 
and Providence Railroads, at junction. 

Berkeley street bridge, — over Boston and Providence Railroad. 

Dorchester street bridge, — over Old Colony and Newport Rail- 
road. 

Broadway bridge, — one over Lehigh street ; one over Foundry 
street (now building). 
All the bridges marked with an asterisk in the first list, and 

the Chelsea Point or Winthrop bridge are, or will be, when 

completed, in the charge of superintendents under the direction 

of the Committee on Bridges. 

All the others, except the Tremont street water-pipe bridge, 

* Bridges provided with draws or openings for the passage of vessels. 



Report of City Engineer. 29 

which is in the charge of the Water Board, are in the charge of 
the Superintendent of Streets, under the direction of the Com- 
mittee on Paving. 

ALBANY STREET BRIDGE (OVER ROXBURY CANAL). 

This bridge is a new one, and was completed and opened to 
travel early in the year. 

Plans and specifications were made last year by this depart- 
ment, and a contract made with Joseph Ross, Esq., of Ipswich, 
to build the structure for the sum of $7,450. It is provided 
with a draw, of the kind known as a Counter-balanced Turn- 
Table Draw. It has a roadway of thirty feet, a single sidewalk 
of six feet on the westerly side ] and the opening for vessels is 
thirty-four feet. Changes in construction, authorized by the 
committee, increased the cost to $7,965.58. The estimated 
cost was $8,000. 

There has been expended in repairs on the bridge, replank- 
ing, etc., $594.80. 

The amount of travel over this bridge is very great, and con, 
stantly increasing, and it seems highly improbable that the in- 
significant requirements of navigation in this canal will much 
longer make this bridge a necessity, and it will give way to 
solid filling, and the full width of the street made available. 

DOVER STREET BRIDGE. 

A thorough examination of the draw of this bridge was made 
last summer, and a report of its condition, accompanied with a 
plan and specifications of changes and repairs, -which I deemed 
necessary, was submitted to the Committee on Bridges, with the 
recommendation that this bridge and the Mount Washington 
avenue bridge should be put in thorough repair at once, so that, 
upon the completion of Broadway, three good avenues would be 
available while the necessary work contemplated on the Federal 
street bridge should be in progress. That report is, 1 presume, 



30 City Document. — No. 14. 

on the files of the Committee on Bridges, and its recommenda- 
tions should be carried out without delay. 

An examination of other parts of this structure will be made 
at an early day. 

The repairs on this bridge during the year cost $834.14. 

FEDERAL STREET BRIDGE. 

The city of Boston was authorized to widen this bridge to a 
width of seventy feet, by an act of the Legislature, approved 
April 24, 1869. 

Estimates were made of the cost of this widening, exclusive 
of the drawbridge, which amounted to $19,000.00. 

It was, however, subsequently deemed that such a widening, 
leaving the drawbridge in its present narrow and contracted 
condition, would be poor economy and of little public advantage. 
The opinions of the Committees on Streets, Paving and Bridges, 
favored the making of the drawbridge of the full width of 
seventy feet, with the roadway clear and unobstructed by any 
middle truss, and this department was called upon to devise a 
plan for the draw, which would fulfil these conditions, without 
materially altering the present bridge beyond what would be 
necessary to provide room for the enlarged draw. Accordingly 
levels were taken, and measurements made to determine the 
amount of available room beneath the roadway for depth of 
girders, wheels, etc., without raising the grade of the street ; 
and also to locate the present piling to see how much would be 
available for the new structure, and the additional amount that 
would be required. Progress upon this work was necessarily 
interrupted by the current demands upon the department from 
work already in progress, and was suspended entirely for a 
season, while the surveys, plans and specifications for the Dart- 
mouth street bridge were being prepared. 

The problem presented by the requirements of tiie committees 
was more difl&cult of solution than at first appeared. It was 



Report of City Engineer. 31 

not simply to decide upon the best style of draw, but upon the 
best style that could be fitted to the place, and at the same time 
satisfy the requirements of the committee and the demands of a 
judicious economy. If an entirely new structure were to be 
built and no restrictions as to grade, it need not require a very 
long time to perfect designs and specifications ; although, in that 
case, there would be room for considerable debate as to which 
of the various styles of drawbridges now in use would be best 
adapted to the unusual width of roadway demanded in this case, 
and the oblique angle which the opening for the passage of ves- 
sels makes with the axis of the bridge. If the bridge could be 
placed at a proper elevation, there would be no question but 
that permanent foundations and a substantial iron structure 
would be the most suitable, and, in the end, most economical. 
But, with all our present bridges, the grade is so low that the 
tracks and running gear have to be placed below extreme high 
water mark, and no little trouble and inconvenience ensues. 
The superintendents have complained of the low grade of the 
draw-piers, and the necessarily contracted space beneath the 
bridges into which the machinery is crowded. Of course, the 
greatly enlarged dimensions of the drawbridge in the present 
case called for additional depth or space between the surface of 
the roadway and the top of the draw-pier, which could only be 
obtained by raising the grade of the roadway or still further de- 
pressing the draw-pier. 

Under these circumstances, I felt that the expense of perma- 
nent foundations and an iron superstructure, as an adjunct of 
the present patched-up bridge and at its present grade, would 
be quite unwarrantable. 

Accordingly, designs were prepared of several styles of 
draws, to be built of wood, which, it was thought, would outlast 
the present wooden structure. At this stage the policy of the 
Harbor Commissioners, as announced in the case of the Broad- 
way bridge, rendered it certain that additional requirements 



32 Cixr Document. — No. 14. 

would be made in this case, and that, besides the widening of 
the roadway of the bridge, the span would also have to be in- 
creased so as to make the opening for the passage of vessels 
forty-four feet in the clear. It therefore became necessary to 
make a new series of calculations of strains to determine the 
new proportions and dimensions of parts, and to reconstruct the 
designs. The designs, which have been made, include several 
styles of draw, or modifications of styles already in use, such as 
the " Counter-balanced Turn-table '' ; a " Centre Pivot," without 
turn-table, — the draw travelling upon attached wheels — a 
"Side Pivot," with wheels attached, and a" Slide " or " Rolling 
Draw," like the present. The " Centre Pivot " design would 
require a middle truss, and would probably be the least expen- 
sive, although no definite estimates have been made. 

After the Broadway bridge contract was made, and it became 
certain that within a year this addidional avenue to South Bos- 
ton would be opened, the necessity for pressing this work be- 
came less urgent, and a majority of the Bridge Committee 
favored its postponement until the completion of Broadway. For 
this reason, and on account of the demands of other work, very 
little has since been done on the work by this department, ex- 
cept preparing a plan exhibiting the present pile foundations, 
with the proposed additions, to present to the Harbor Commis- 
sioners for their opinions and views ; for it would be useless to 
spend further time upon the details of any plan unless the com- 
missioners will approve of the necessary foundations. Some addi- 
tional drawings have, however, been recently made to illustrate 
the application of a plan proposed by a Mr. Rich, of South Boston, 
to this particular locality. The general features of this plan 
were exhibited in a model, and, as applied to this locality, may be 
thus described : — The present draw is to remain just as it is, and 
a turnout bridge, wide enough for two lines of vehicles to pass 
each otlier, is to bo built in an easterly direction alongside the 
present pathway of the vessels approaching the draw, for a dis- 



Report of City Engineer. 33 

tance of about two hundred feet, or far enough to permit a ves- 
sel to lay between the present draw and the easterly end of the 
" turnout," where another draw is to be built, connecting with a 
similar turnout on the opposite side of the shipway. At the en- 
trance to the turnouts, gates are so arranged that when the 
present draw is open for the passage of vessels, its guard gate 
is closed and the turnout gate is open. By this plan it is 
claimed there will be no detention of travel, as only one draw 
will be open at a time. The idea is not a new one by any 
means, although the particular mode of its application is novel. 
In this instance, it involves the building of about five hundred 
feet of bridge, including an extra draw. It could be applied to 
this bridge in connection with the proposed widening, without 
any interruption to the travel ; and it is claimed that the com- 
bined cost of widening the present bridge to seventy feet, exclu- 
sive of the draw, and building the " Turnout bridge " and draw, 
will be from ten to twelve thousand dollars cheaper than the 
proposed plan of widening the present bridge, including the 
draw ; and that the '' Turnout " plan will better accommodate 
public travel. 

The various plans will soon be laid before the Committee on 
Bridges. 

The cost of repairs on this bridge during the past year was 
$1,512.10. 

MOUNT WASHINGTON AVENUE BRIDGE. 

This bridge was examined early in the season, and found in 
a most wretched condition throughout. 

The wooden trusses of the drawbridge were in an unsafe 
condition, the chords being badly decayed, and in one place the 
lower chord was rotted entirely through. The stringers and 
timbers which form the sidewalk bulkhead were very rotten, 
and the flooring of the bridge in bad condition. In short, the 
whole bridge is in such condition as to require almost an entire 



34 City Document. — No. 14. 

renewal above the caps of the piles, or at least, above the 
stringers. At that time it was thought that the widening of the 
Federal street bridge must be taken hold of, and, as both could 
not go on together, this was repaired as well as possible, and 
the trusses strengthened so as to make it last until another year. 
When it became apparent that the work on. Federal street 
bridge would be postponed until the completion of Broadway, 
I again called the attention of the committee to this bridge, in 
the report above alluded to, in connection with the Dover street 
bridge. No action, however, appears to have been taken. I 
consider this bridge in a very bad condition, and should be 
attended to at once. 

The amount expended for repairs on this bridge during the 
year was $2,486.52. 

MERIDIAN STREET BRIDGE. 

This bridge, exclusive of the draw, is in very good condition. 
The draw itself, as to soundness and stability, is in good condi- 
tion ; but it does not work as easily as it should. The track 
was levelled up, new white oak bearing-plank put in, and 
wrought-iron plates interposed between the track-rail and the 
oak bearing-plank, in 1868; but owing to the work not having 
been properly done, or for some other reason, it did not entirely 
remedy the evil. The draw is a cumbrous, unwieldy affair, 
and its foundations not the best, and it would undoubtedly have 
been better policy to have built it anew, upon more substantial 
foundations, at the time the bridge was rebuilt, in 1866. A 
smaller and lighter draw would answer every purpose in this 
locality. 

The repairs on this bridge during the year have cost $842.58. 

CHELSEA STREET BRIDGE. 

This bridge was partially renewed in 1868. At that time 
plans and specifications were prepared by this department for 



Report op City Engineer. 35 

rebuilding the entire structure, whicli I deemed the wisest 
course. The committee, however, thought differently, so the 
specifications were redrawn to cover the building of a new 
draw and certain prescribed repairs, and a contract made with 
Joseph Ross for doing the work for tiie sum of $6,150. It was 
found, however, upon removing the earth covering of the bridge, 
that the entire flooring was so much decayed as to be unsafe. 
A new flooring was accordingly ordered by the committee, 
which was put in by Mr. Ross. The total cost was $9,146.35. 
The bridge is now in very good condition. The repairs 
during the year amounted to $42. 

WINTHROP BRIDGE (BREED'S ISLAND TO WINTHROP). 
Tills bridge has no draw, and the travel over it is very light . 
The bulkhead stringers need renewal in some places, and an ex- 
amination of the flooring, which will be made in the spring, will 
undoubtedly discover many defects now concealed by the earth 
covering. 

NEPONSET BRIDGE (OVER NEPONSET RIVER). 
This Bridge was formerly a toll-bridge belonging to the Turn- 
pike Corporation, and since it was made free has been maintained 
jointly by the towns of Dorchester and Quincy. Its condition 
is reported good by the authorities of Dorchester ; but an exam- 
ination will soon be made and its condition reported to the 
Committee on Bridges. 

GRANITE BRIDGE (OVER NEPONSET RIVER). 
This bridge is " Granite " only in name, which is derived from 
the street of which it forms a part. It is a pile structure, pro- 
vided with a drawbridge of the old style known as tlie " Leaf- 
Draw." It is in very fair condition; but will require some 
repairs on the planking of the roadway. The city maintains 
the bridge to the centre of the draw. 



36 City Document. — No. 14. 

MILTON BRIDGE (OVER NEPONSET RIVER AT LOWER MILLS). 
This is a substantial stone bridge, in good condition, with 
new railings ; but is rather too narrow, and a widening to cor- 
respond with the width of roadway on the Milton side would 
be a great improvement. It is maintained jointly by the city 
and the town of Milton. 

MATTAPAN BRIDGE (OVER NEPONSET RIVER). 
This bridge is a light iron structure, recently erected and in 
good condition. The web of the main girders is very thin, and 
lower chord too light for the standard of burden usually re- 
quired in our city bridges. It is maintained jointly by the city 
and the town of Milton. 

COMMERCIAL STREET BRIDGE (OVER CREEK AT COMMER- 
CIAL POINT). 

This is a pile structure, provided with a " Leaf-Draw." The 
draw, draw-pier, and northerly end of the bridge are in good 
order. The southerly end of the bridge is quite "shaky," — 
the bulkhead stringers are rotten, and the piling needs renewal. 
The flooring is covered with earth, and is probably more or less 
decayed, and should be examined soon. 

MILL-DAM BRIDGE (OVER SLUICES). 

These sluices or water-ways through the Mill-dam were origi- 
nally provided with tide-gates, which permitted the water to 
flow into the " full basin," so-called, duriug flood-tide, but closed 
at the ebb and shut the water in. After the abandonment of 
the tide-mills, caused by the filling of the " empty basin," these 
gates were removed and the tide now ebbs and flows through the 
sluices. They are openings or water-ways, six in number, about 
twenty feet wide, and separated from each other by stone piers 
about five feet thick, built up to within four feet of the roadway. 
The sluices are then covered with round logs laid close together, 



Report op City Engineer. 37 

the ends resting on these piers, and upon the logs is the earth 
covering of the roadway. These logs are more or less rotten 
and insecure, and the question has arisen — " With what shall 
they be replaced ? " 

These sluices will have to remain open for many years, cer- 
tainly as long as this basin remains unfilled; for into this basin 
flows all the drainage of " Stony " and " Muddy " brooks, and 
until the basin is filled and very large covered canals provided 
for conveying this drainage to tide water in Charles River, the 
maintenance of these sluices will be a necessity. 

Plans have been prepared, by request of the Paving Depart- 
ment, for covering these sluices in a safer and more substantial 
manner, with either a wooden or iron structure, whichever shall 
be decided most suitable under all the circumstances. Specifi- 
cations will be drawn as soon as the committee determine which 
plan to adopt. 

LONGWOOD AVENUE BRIDGE. 

This bridge crosses " Muddy Brook " (the centre of which 
forms the boundary line between Boston and Brookline), the 
adjacent marsh flats and the Brookline Branch Railroad. It is 
a trestle-work structure, resting on oak piles, has a plank road- 
way, and a sidewalk, on the southerly side only, and is not a 
suitable structure for the locality. The abutments are poorly 
built, and in bad condition. The care and maintenance of the 
structure belongs to Boston and Brookline jointly. By orders 
from the Paving Department, — to prepare plans and specifica- 
tions for a suitable structure, with proper abutments, — consid- 
erable work has been done in making surveys, levels and 
soundings, and preparing the necessary plans. The plans in 
detail will soon be ready to submit to the Committee on Paving, 
and the Selectmen of Brookline. 

ALBANY STREET BRIDGE (OVER BOSTON & ALBANY R. R.) 

This bridge was built in 1867-8, by JklcKay and Aldus, from 
designs by Clemens Herschell, C. E. The entire cost of the 



38 City Document. — No. 14. 

bridge, abutments, and rctainiug walls, was $65,973.22. The 
structure is in good order. 

HARRISON AVENUE AND WASHINGTON STREET BRIDGES. 

These bridges are maintained by tlie Boston and Albany 
Railroad Co. ; but by an agreement with the city, by which the 
corporation was permitted to raise these bridges, the plans of 
reconstruction were to be approved by the City Engineer. Ac- 
cordingly plans for new iron bridges, designed by E. S. Phil- 
brick, C. E., were submitted to me, and carefully examined in 
all respects as to their strength and stability, and approved. 
The Harrison avenue bridge has since been buiit, and is a first- 
class specimen of iron work. The Washington street bridge 
will probably be built this season, in connection with the raising 
of the Suffolk Street District. 

FERDINAND STREET BRIDGE (OVER BOSTON & ALBANY R. R.) 

This bridge lias been lowered during the year, by permission 
of the Boston and Albany Railroad Corporation, improving very 
materially the grades of the adjacent streets. It is in good 
condition. 

BERKELEY STREET BRIDGE (OVER BOSTON & ALBANY R. R.). 

This bridge was built for the Boston Water Power Company 
by the " Moscley Iron Bridge Works." It is probably as good 
a bridge as could have been built for the money it cost ; but it 
is a lighter and cheaper structure than I should have recom- 
mended. It has, however, been quite well tested during the 
past year while Treraont street was closed, and a recent exam- 
ination disclosed no perceptible deflection or permanent set to 
the girders as compared wiih an examination made last spring. 

The present mode of planking the roadway on a dead level, 
is objectionable, as there is no provision for shedding the rain- 
fall. A substantial Burnettized bottom flooring should be laid 



Report op City Engineer. 39 

and covered with asplialtum concrete so as to give a longitu- 
dinal crown to the roadway, and upon this a pavement of 
•wooden blocks should be laid. The iron work should be 
thoroughly painted. 

BERKELEY STREET BRIDGE (OVER BOSTON & PROVIDENCE 

R. R.). 

This structure was built by the Boston & Providence Rail- 
road Company, and was accepted as a part of Berkeley street 
last year. The roadway and sidewalks are supported upon 
very heavy cast-iron columns, placed in rows crosswise the 
street, the rows being about twenty feet apart. The columns 
rest upon a pile foundation, capped with granite blocks. Upon 
these columns heavy wrought-iron Phoenix I beams or girders 
are laid crosswise the roadway, and upon these, similar longi- 
tudinal floor-beams are placed about four feet apart. The floor- 
ing, as originally built, consisted of spruce plank laid flatwise 
and fitted between the floor-beams, re&ting on the lower flanch. 
The space above the plank was filled with gravel to the level 
of the tops of the floor-beams, and directly upon the gravel was 
placed the wooden block pavement. As might have been ex- 
pected, the gravel covering rotted the plank; a portion of the 
wooden blocks also rotted at the bottom and settled unevenly, 
causing the surface of the roadway to present a very rough ap- 
pearance. Under these circumstances it is not surprising that 
the heavy travel of last summer broke through the planking and 
revealed its rotten condition. 

This department was immediately called upon to prepare 
plans for re-covering the bridge, and the following general plan 
was proposed. To strip the bridge to the iron work, then to 
fit between the longitudinal iron girders 4-inch spruce plank 
floor-beams, set edgewise, and resting upon the lower flanch of 
the girders ; these planks to be placed three feet apart from 
centre to centre and to be of gi-aduatcd widths, — from twelve 



40 City Document. — No. 14. 

to eight inches, — the widest being placed in the centre of the 
roadway and thence diminishing in width to the gutters, forming 
a lateral crown to tlic roadway. Upon these plank floor-beams 
a flooring of 4-inch spruce planij, planed to an even thickness, to 
be laid diagonally of the roadway and thoroughly spiked. The 
Nicholson block pavement to be laid on this flooring. The curb 
or wheel-guard to be of cast-iron. The sidewalk to be replanked 
with 3-inch plank laid close and covered with asphaltum con- 
crete. 

The lumber was to be one-half Burnettized and one-half cre- 
osoted, to test its relative merits. The proposed plan as above 
described was carried out. 

Upon uncovering the bridge it was discovered that some of 
the iron columns had either settled or were not properly levelled 
when set, and that it would be necessary to level up the whole 
structure. The Providence Railroad Company desired that the 
whole bridge should be raised a foot, and ofi"ered to bear the 
expense of raising, and as this operation would enable us to re- 
adjust the columns at their proper relative height it was decided 
to raise the whole bridge an average height of twelve inches. 
The execution of the entire work was intrusted to Joseph Ross, 
Esq., and it was promptly and successfully accomplished. 

The bridge, with all its travel, was lifted bodily by screws 
attached to each column. Every column had marked upon it 
the exact height it was to be raised, and a granite leveller was 
provided for each column, whose thickness corresponded with 
the mark upon the column. Tiie work was all done without 
any interruption to the public travel. 

The cost of the work was $16,124.18. 

COLUMBUS AVENUE BRIDGE (OVER BOSTON & ALBANY R. R.). 
This bridge was built in 1865 from designs by Clemens 
Herschell, Civil Engineer for the Boston Water Power Com- 
pany. It is a wrought-iron lattice bridge of very good design 



Report of City Engineer. 41 

as to strength and stiffness ; but not a remarkably good speci- 
men of workmanship. By the laying out of Columbus avenue, 
June 24, 1869, the care and maintenance of this bridge and 
abutments was assumed by the city. Its condition is fair, but 
similar measures to those proposed for the Berkeley street 
bridge should be taken here to crown the surface of the road- 
way so as to shed the rainfall. 

DAKTMOUTH STREET BRIDGE (OVER B. & A. AND B. & P. R. R.). 

This department was called upon to furnish plans and esti- 
mates for a bridge over the Boston and Albany and the Boston 
and Providence Railroads, at their junction. Approximate 
estimates were furnished of the cost of a substantial iron 
bridge, with suitable abutments and piers, and some progress 
made in the preparation of drawings in detail ; but it was de- 
cided that there was not ample time to prepare, decide upon 
and execute plans for such a structure in season for the " Peace 
Jubilee " ; and it was also thought that a well-built wooden 
structure would answer all the public requirements for ten or 
fifteen years, and could be built for less than half the money. 
Accordingly, plans and specifications were at once prepared for 
a wooden trussed bridge. 

The abutments and intermediate piers consist of oak piling 
and heavy trestle-work. The two main trusses, which are built 
continuous over the piers, are respectively two hundred and 
twenty and one hundred and ninety-eight feet long, and of the 
style known as the " Pratt Truss." The lower chord is formed 
of four pieces each six by twenty-four inches ; the upper chord 
has four pieces, each six by ten inches ; the posts or struts are 
each six by twenty-four inches, except over bearings, where they 
are twelve by twenty-four inches. All counter-rods are single 
and one and one quarter inches in diameter, and the others are 
in sets of two and three, and vary from one and thi-ee-fourths 
G 



42 City Document. — No. 14. 

inches diameter at the bearings to one inch at the centre of the 
spans. 

The sidewalk trusses rest on the same piers as the main 
trusses ; but as the piers are necessarily at an angle oblique to 
the axis of the bridge, the lengths of tlie spans vary. They are 
continuous over piers. 

The lower chords consist of three pieces: the centre one, 
six by twelve inches ; the two outer ones, four by twelve inches. 
The upper chord has three pieces : the middle one, six by eight 
inches, and the outside ones, three by eight inches ; the struts 
over bearings are eight by twelve inches, and the intermediates, 
four by twelve inches. 

The counter rods are single and one inch in diameter ; all 
the others are double and one inch diameter at the centre of 
spans, and increase one-eighth of an inch for each bay to the 
bearings. 

The trusses are eight feet in height from outside to out- 
side. 

The floor-timbers are four by fourteen inches, placed two in 
each bay or panel ; every other one is double and trussed with a 
truss-rod one and one-fourth inch diameter, the struts being 
continuous twelve by twelve inch timbers running the whole 
length of the bridge. 

The roadway floor is double, the lower one being of 4-inch 
spruce, and the upper one 2-inch white oak, laid crosswise the 
bridge. 

The sidewalk floor is of two thicknesses of 2-inch spruce 
plank. 

The trusses are covered with a wooden coping, and all the 
woodwork and ironwork exposed, was painted three coats and 
Banded. 

All the woodwork was creosoted or Burnettized. 

Proposals were invited, and the contract awarded to Joseph 
OSS, of Ipswich. 



1 



■ Report of City Engineer. 43 

Although not entirely completed by Jubilee week, yet the 
roadway was finished and the bridge pretty severely tested by 
the moving crowds. 

The bridge is a first-class piece of work, and as substantial 
as could be made of wood. The cost was $26,780. 

DORCHESTER STREET BRIDGE (OVER OLD COLONY AND NEW- 
PORT R. R.). 

The bridge over the Old Colony and Newport Railroad at 
this place was originally built, and has since been maintained, 
by the Railroad Company. In order to complete the widening 
of the street it was necessary to enlarge this bridge, extend the 
abutments, and build new retaining walls. So far as the alter- 
ation of the bridge and abutments were concerned, the city was 
powerless to act without the consent of the Railroad Company. 
Therefore an agreement was concluded between said company 
and the city, by which the city was to do all the work required, 
and assume the care and maintenance of the bridge and abut- 
ments ever after, the Railroad Company paying four-fifths of 
the cost. 

Plans and specifications were prepared, for all the work 
required, last March. Proposals were invited, and contracts 
awarded, to the Atlantic Works for building the bridge ; and to 
Messrs. Clapp and Ballon for the masonry, grading and filling. 

The old bridge was a wooden one, and could not be econom- 
ically widened, and a structure, mainly of iron, was recom- 
mended. The width of 'the street, as widened, is fifty feet, and 
the clear span of the bridge twenty-seven feet. The bridge 
consists of seven parallel wrought-iron plate-girders, thirty feet 
in length, twenty-two inches high in the centre, and seventeen 
inches high at the ends, placed eight feet six inches apart from 
centre to centre, under the roadway, and eight feet under the 
sidewalks, — all tied together at the bottoms with two-inch 
angle iron Oak stringers of 4-inch plank are placed edge- 



44 City Document. — No. 14. 

wise on the lower flanches of the girders, and bolted to the 
webs. Upon these stringers floor-timbers of four by twelve 
inch creosoted spruce are placed at right angles with the girders, 
and three feet apart from centre to centre. An under flooring 
of 4-inch creosoted spruce plank is laid upon these floor-tim- 
bers, the top surface being just flush with the tops of the 
girders, and over this an upper floor of 3-inch white oak plank 
is laid at right angles, or crosswise the roadway. The outer 
roadway girders support a cast-iron wheel-guard or curb, pro- 
vided with flanches and sockets on its sidewalk face for 
receiving one end of each of the sidewalk floor-timbers, — the 
other end resting upon an angle-iron flanch, riveted to the web 
of the sidewalk girder. The sidewalk floor is of 2-inch spruce 
plank. 

The railing is composed of cast-iron posts riveted to the 
sidewalk girders, and horizontal rails of wrought-iron pipe 
fitted to posts by a right and left screw. 

Beneath the sidewalk, and not connected with the bridge, are 
a pair of wrought-iron plate girders, sixteen inches deep and 
twenty inches apart, with cast-iron cradles fitted between and 
bolted to the web-plates, to support a 12-inch water pipe. All 
the work under both contracts has been done, and the cost of 
the bridge work was $3,000, and of the mason work, grading 
and filling, $8,250. 

D STKEET EXTENSION BRIDGE — ABUTMENTS AND WALLS. 

Estimates for the Committee on Laying out and Widening 
Streets have been made of the probable cost of an iron bridge, 
the necessary abutments and retaining walls, that would be 
required if the extension of D street, from its present terminus 
to Federal street, were made at the high grade, crossing the 
Old Colony and Newport Railroad fourteen feet in the clear 
above the tracks. 



Report op City Engineer. 45 

shawmut avenue extension and indiana place 

WALLS, &c. 

Surveys, levels and soundings have been made, and plans 
partly finished for the structures that would be required by the 
extension of Shawmut avenue over the Boston and Albany 
Railroad, the raising of the grade of Indiana place and of 
Castle street. Preliminary estimates have been made for the 
Committee on the Suffolk Street District, of the cost of these 
structures. 

Respectfully submitted. 

N. HENRY CRAFTS, 

City Engineer. 



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