Effects of bearing damage upon seismic behaviors of a multi-span girder bridge

The effect of possible bearing damage during seismic excitations is investigated through examining the dynamic behavior of a multi-span simply supported bridge. Proper analytical models are developed, which can simulate the realistic seismic behavior of the bridge before and after the bearing damage. The damaged bearings are modeled as sliding elements with the appropriate friction between the superstructure and the top of the pier. Various values of the friction coefficients are examined to verify the effect of damaged bearings under the wide range of peak ground accelerations. It is found that the global seismic behaviors of the bridge are significantly influenced by the occurrence of bearing damage. It should be noticed that the most possible location of unseating failure of superstructures differs from that in the bridge model without consideration of the bearing damage. It can be concluded that bearing damage may play the major role in the unseating failure of a bridge system. The damage of bearings should be included to achieve more rational seismic safety evaluation.