US1252873A - Bridge construction. - Google Patents

Description

W. G. ADAMS.

BRIDGE CONSTRUCTION.

APPLICATION FILED OCT. 26,1916.

magmas Patented Jan. 8,1918.

Znweniar:

WILLIAM; GATEWOOD ADAMS, 0F BOANOK-E, VIRGINIA.

BRIDGE CONSTRUCTION.

Specification of Letters Patent.

Application filed Gctober 26, 1916. Serial No. 127,887.

T 0 all whom it may concern:

Be it, known that: l, W ILLIAM GATEXVOOD ADAMS, a citizen of the United States, and resident of Roanoke, Jirginimliave invented certain new and useful Improvements in Bridge Construction, of which the following is a specification.

My invention is designed for the reinforcing of old bridges to divide up the strain and weight or load by arranging new girders or trusses in juxtaposition with those to be reinforced and having one set of girders o1- trusses carry one part of the load and the other set of girders 0r trusses carry the other part of the load, this being accomplished by supporting the ties or transverse beams or groups of ties or transverse beamsthat would otherwise rest entirely upon the old girders or trusses, some entirely on one pair of girders or trusses, and some on other pair, that is, as having one tic, or group of ties, supported by one pair of deck girders and having no supported connection with the other pair, while the next tie, or group of ties, will be supported from the second pair of girders and having no supported connection to the first pair, and so on.

In the accompanying drawing Figure 1 is a perspective view of a bridge reinforced according to my method, and 111 Fig. 2 I have shown a simple diagram to further illustrate the invention.

In strengthening or reinforcing of bridges, where it may be desirable to place a new girder by the side of an old girder so as to have the new one carry part of the load, such provision is not considered efficient, for the reason that when it would otherwise be advisable to reinforce the girder, it is not possible to so adjust the bearings of the several loads on the two girders, as to enable the designer tov definitely determine what part of the load is being carried by one or the other of the girders, and the custom is, therefore, to

usually remove the old girder and replace it by a new one, simply to increase its capacity to meet the demands of an increased loading.

It is my purpose to distribute the load in such a way as to be able to render mathematically determinate the resulting strains produced in each girder for the loads imposed. and in carrying out my invention in the reinforcement of an old railroad bridge,

asshown in Fig. 1, the girdersu m represent the old structure, while the girders G are,

my improved reinforcement, which, in the present instance, I have shown as interposed between the outer girders suitably braced to each other.

The railway tie A supporting its portion of loads on rails along lines 0 Will be supported upon the inserted girders by means of blocks between the under face of the tie and the upper face of the girders, and these blocks will support the tie in a position above the level of the outer girders. The next tie will be blocked upon the outer girders and will have no supporting connection with the inner girders, and so on, and thus one-half of the load will be sustained by the outer girders and the other half by the inner girders, or any proportion of the load, as, of course, two or more ties may be supported in succession from the outer set of girders and a corresponding number in succession from the inner girders, or a greater number of ties may be supported from one than from the other set, or the left hand outer with the right hand inner girder may act together to support parts of the load while the other two support the remainder.

In Fig. 2 I have shown the invention diagrammatically in connection with a bridge structure, in which deck trusses are utilized to support the transverse beams, and in like manner one beam or group of beams will be supported by the outer trusses and the next beam or group of beams by the inner trusses rhrough suitable blocks, and thus the weight ofthe load adjusted to meet the requirements of the structure, varying, as found best adapted to capacity of trusses, the number and location of beams, that are su Jported by either pair of trusses.

hough the figures indicate only deck structures, it is my intention to apply this reinforcement to through bridges. In which cases, for through girder or truss design, the new and through reinforcing girders, or trusses, will be placed preferably outside of the old and the intermediate or cross beams, carrying the loads to girders, or trusses, will be suspended below the girders or trusses, or will pass through the trusses, provision being made, always, as in cases of deck girders and trusses, for having each cross beam supported only by two of the trusses, whether it be by one old truss and Patented Jan. 8, 1918...

one new truss or by two old trusses or by two new trusses, the words truss or trusses meanin also irder or irders. What I claim is The hereinbefore described method of reinforcing trusses or girders consisting in dividing the reactions of transverse load transmitting beams, or ties, that have been,

10 or would otherwise be borne by the original truss or girder, into separate and distinct groups, and introducing to help bear these reactions, new trusses or girders placed in juxtaposition to the old ones and having the transverse load transmitting beams, or ties, so connected to the individual trusses, or girders, that each group of reactions will be entirely borne by one truss or girder independent of support by any other truss or girder, substantially as described.

In testimony whereof I affix my signature.

' WILLIAM GATEWOOD ADAMS.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

Washington, D. C.

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