Research on seismic fragility analysis of regular bridges based on response spectrum analysis method

Abstract In this paper, the incremental dynamic analysis (IDA) of a real bridge is carried out by using the nonlinear time-history analysis method and the response spectrum analysis method respectively, and the results of structural response under different earthquake intensity are obtained. Ductility coefficient is used for damage index, and the damage probability of the structure in different damage state is obtained by using logarithmic demand-capacity ratio, and then the seismic fragility curves of the structure are established. To improve the precision of fragility curve of major damage state and failure state by modifying the fitting function is also studied. The results show that the simple linear elastic method is reliable for calculating the seismic response of regular bridges. The seismic response calculated by the response spectrum analysis method could be used as the demand for establishing the fragility curves of regular bridge.