Experimental Load Rating Study of a Historic Truss Bridge

Abstract

A field test of a complicated statically indeterminate floor system on a historic steel truss bridge has been conducted to obtain a more accurate load rating of the structure than possible using calculated predictions of wheel load distributions. The empirically determined wheel load distributions resulted in the identification of the floor system, particularly the transverse floor beams, as the element governing the load rating of the structure. Favorable lateral distribution of wheel loads among the stringers by a glued laminated treated timber deck was noted. The experimental determination of wheel load distributions has provided an inexpensive means of intelligently allocating limited county resources for the maintenance and rehabilitation of an inventory of aging bridges.