Seismic Evaluation of a Long Span Bridge by Modal Testing

This paper descibes the results of experimental and analytical vibration studies on the Queensborough Bridge over the Fraser River in Vancouver, one of the densely populated areas of significant seismic hazard in Canada. To evaluate the bridge’s dynamic response, ambient vibration measurements were conducted to determine the hmdamental mode shapes and frequencies. The vertical and torsional modes of the Main Structure were used to veri@ the result.9 from a linear elastic free vibration analysis.