This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1893 Excerpt: ...the vertical members that the load resting on a beam can be transmitted to the abutments, or be made to produce effects at right-angles to its own direction in the flanges; and that the stresses due to loads concentrated at the centre were very different to those arising, both in the vertical web and in the flanges, from the action due to a load distributed in a given manner along the top or the bottom flanges, and that a rolling load would produce effects peculiar to itself. The girder "with diagonally braced webs, or the lattice girder, as it is commonly called, appears to have had its origin in Ireland; at any rate it was in that country that it received its earliest and chief development; but at first, as illustrated by the bridge which used to carry the Dublin and Drogheda Railway over the Grand Canal in Dublin, it was a mere attempt to substitute for plate webs an arrangement of flat bars sloping in opposite directions, placed very close together, and having the oppositely inclined bars connected at their intersections by countersunk rivets. This was naturally a very wasteful arrangement; but soon, in the hands of C. H. Wild, Barton, Bow, and Stoney, the true principles began to assert themselves, and Mr. Barton"s Cusher River bridge, of 70 feet span, on the Great Northern of Ireland Railway, was probably the first example of a lattice girder in which the cross-sections of the members of the webs as well as those of the flanges were correctly proportioned to the stresses imposed by a rolling load. This comparatively small bridge was followed by the Boyne viaduct at Drogheda, which must ever rank as a signal illustration of the successful application of abstract principles to a great work by men who were capable, not only of appreciating them, but of f...