Investigation of shear resistance of steel bridge girders by load testing and monitoring of load response data under highway traffic conditions

Abstract

A recent strength evaluation of the Hogg’s Hollow Bridge on Highway 401 in Ontario revealed a significant deficiency in the shear resistance of the existing girders at support locations. This was attributed to the absence of transverse stiffeners at the extreme ends of the girders. However, none of the bridge girders showed any signs of distress. The Ontario Ministry of Transportation recently conducted a field study to investigate this shear issue in greater detail. To that end, a test program was devised to (a) monitor the real stresses in the end panels of two selected girders in the Hogg’s Hollow Bridge when subjected to (i) a test truck with known axle loads and (ii) normal highway traffic loading, and (b) calibrate the observed stresses against theoretically expected responses in the girders and calculate the live load capacity factor using the shear data derived from the field measurements.