Structural reliability analysis based on vulnerability function

Abstract This paper proposes a structural reliability analysis methodology based on vulnerability functions, taking into account the uncertainties in seismic excitation and structural seismic response parameters. A probabilistic seismic demand model, following a β -distribution, is introduced to investigate the correlations between seismic response parameters under the same seismic event. The fragility function is constructed by combining the log-normal distribution with correlation coefficients to calculate the probability of structural failure. The fragility curve is fitted using the probability distribution function of the log-normal distribution and compared with the fragility results obtained from traditional fragility functions. A two-span continuous reinforced concrete highway bridge is used as a case study for seismic fragility analysis. The results indicate that when the structure is subjected to seismic intensities exceeding 9 degrees, the correlation becomes significant, which is beneficial for pre-earthquake disaster prediction and structural reliability evaluation.