The Portland daily press., 1880-12-25
The Brun swick and Topsham Bridge.

The Bruins wick and Topsham Bridge.
Messrs. John F. Anderson and William A.
Goodwin, who, at the request of the Commit
tee on Construction of the bridge over the
Androscoggin river, between Brunswick and
Topsham, examined that structure, have made
the following report:
To e. G. Simpson, Esq, Joseph A. Woodside,
Esq.,, Hon. John L. Swift of Brunswick,
| Col. Wildes P. Walker, Capt. Daniel A.
Committee on Main G0y Street, Bridge 0e Of the
towns of Brunswick and Topsham Me-:
GENTLEMEN
We, the undersigned, having been requested
| by you to examine the iron bridge recently
constructed by the King Iron Bridge and Man.
ufacturing Co., of Cleveland, Ohio, across the
Brunswick and Topsham, and having been
provided with the contract and diagram OF
strains of the longer spans and with working
plans in detail Of the entire structure, have at
| Tended to the duty assigned to us by making the
requisite computations incident thereto, and by
personal examination Of the bridge with
measurement of its more important members
and have the honor to submit the following
! report thereupon:
The contract provides for the furnishing of all
materials and for the construction and completion
| OF an iron bridge at the above named site in ac-
cordance with certain specifications and diagrams
OF strans thereto appended and made part thereof
VI these the principal data are as follows:
,,.. Lbs. per So. Inch.
Ultimate tensile strength of iron, 5O, 900
compressive and shear
u,u,.. ing strength of iron. 10000
working tensile strain. ...... 10000 to II 500
compressive and shearing strain 10000
Static static load ss2 lbs. per nft.of structure
... .. 90 square " s TSsdway
Spans two Of 1 g feet centre of end pins
One OF SO I"
Width of roadway % it. g g "trusses
sidewalk #.
The fulfillment of this contract should ensure a
bridge sufficient for the requirements of traffic in
the vicinity of large manufacturing centres.
we lind that the structure is of an approved de-
sign, IN common use by our prominent bridge build
ing establishments, that the diagram of strains at
tached to the contract is justified by usual methods
OF computation, that the several members of the
bridge are duly proportional to the strain to which
they are severaly subjected and that far as can
be seen in the finished work, the workmanship is
Of the important details of the work, particularly
those in and about the pin connections are now be-
yond the reach of full inspection, all due seems
70 nave been observed in their fitting aud adjust
ment: There is material enough in them, and there
would be no gain in sighting them if one had
50 70 do and further the work has
serving committee and community.
Inc most important factor of the stability of the
structure, the practical strength of the IRON you
nave not submitted to our judgment, as, of course
%aasho. o NO. any one o1so, can know what that
OF safety which is worth anything be determined
without such test
certain designated amount of tension which
every bar has endured within the limit of its elias
ITCHY, and will again endure without injury affords
real factor of safety at least of reasonable CON
ndence and, in our opinion, this fact should be re-
cognlzed in every contract for iron work, and in
every opinion given upon such work, whether spe-
cially asked for or not.
We have learned that a portion of tbe iron of
your bridge has been tested by your order and to
your satisfaction as regards its elasticity, at the
Watertown Arsenal, Mass. If this, or other tests.
nave confirmed the strength of the material, and
i tnis we have no reason to doubt question, you
nave in our opinion structure safe and permanent
IN accordance with the terms of the contract there
ton. - ~ ~ w
You are aware that a few comparatively unim-
p0rtant details of the work remain to be finished
Ihese are in the sidewalk railing at the easterv end
and setting up of part of the upper lateral brac
1pg, winch however are in process of completion.
The last coats of paint also remain to be put on.
Respectfully submitted
JOHN f. ANDERSON, Civil Engineer
VIM. A. GOODWIN.
Brunswick, Dec. a. 1880.