A bridge is composed of two trusses whose configuration is shown in Figure P12.38.

The trusses are loaded at their top chord panel points by the reactions from a stringer and floor beam system that supports a roadway slab. Draw the influence lines for forces in bars \(F E\) and \(C E\). Assume that vehicles move along the center of the roadway so one-half the load is carried by each truss. If a fully loaded motorized ore carrier with a total weight of \(70 \mathrm{kN}\) crosses the bridge, determine the maximum live load forces in bars \(F E\) and \(C E\). Assume the truck can move in either direction. Consider the possibility of both tension and compression force in each bar.

Transcribed Image Text:

30 KN 30 kN 10 KN 1-2m-l-3m- B F 6 @ 3m= 18 m E D 4 m