Experimental and Numerical Response of a 1915 Riveted Through-Girder Bridge

Chester County Bridge #21, a 16.5-m (54-ft), single-span, riveted, through-girder bridge located in upper Oxford Township, Pennsylvania, was field tested to determine the response to controlled loading. The bridge was instrumented with strain and displacement transducers to monitor response at critical locations as a single-axle truck of known weight was driven across the structure at crawl and posted speeds. Strains generated in the girders and in transverse floor beams supporting the deck were measured along with girder midspan vertical deflections. Information produced from the tests was used to ( a) assess the level of composite action and load distribution in the structure and ( b) determine if certain members are reaching critical stress levels and to determine the load rating. In addition, analytical models were developed both to predict the response and to evaluate the level of calibration required to establish a model that accurately reflected measured response.