Bridges

. Figure 1-44.—Types of bridge spans. Bridges Figure 1-43.—Truss bridge. Figure 1-43 shows the structural framework of a single-span truss bridge. As with all bridges, the floor and traffic loads of the truss bridge are carried by the stringers. In the truss bridge, however, the stringers are supported by transverse beams rather than by the bridge abutments (and intermediate supports when needed). As seen in the figure, these transverse beams are supported by the structural framework of the two trusses. Finally, the entire bridge structure plus any traffic loads are transmitted through the end pedestals and bearing plates to the supporting abutments. As you will note, the nomenclature of the truss members is the same as discussed in the preceding section; however, the Figure 1-45.—A trestle tower. diagonal end members, adjacent to the abutments, are normally called end posts. The truss framework and the manner in which the trusses are used may differ depending upon the design of the truss bridge. Figure 1-44 shows three examples. View A shows a through truss span. In it, the traverse beams are connected to the bottom chord of the trusses, and the top chords are braced by a lateral bracing system under which traffic passes. In the deck truss span, view B, the traverse beams are carried by the top chord 1-22