.Figure 1-44.—Types of bridge spans.BridgesFigure 1-43.—Truss bridge.Figure 1-43shows the structural framework of asingle-span truss bridge. As with all bridges, the floorand traffic loads of the truss bridge are carried by thestringers. In the truss bridge, however, the stringers aresupported by transverse beams rather than by the bridgeabutments (and intermediate supports when needed). Asseen in the figure, these transverse beams are supportedby the structural framework of the two trusses. Finally,the entire bridge structure plus any traffic loads aretransmitted through the end pedestals and bearingplates to the supporting abutments. As you will note, thenomenclature of the truss members is the same asdiscussed in the preceding section; however, theFigure 1-45.—A trestle tower.diagonal end members, adjacent to the abutments, arenormally called end posts.The truss framework and the manner in which thetrusses are used may differ depending upon the designof the truss bridge. Figure 1-44 shows three examples.View A shows a through truss span. In it, the traversebeams are connected to the bottom chord of the trusses,and the top chords are braced by a lateral bracing systemunder which traffic passes. In the deck truss span, viewB, the traverse beams are carried by the top chord1-22
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