Abstract:With the increase of service time, the durability damage caused by environmental corrosion has a greater influence on the seismic performance of offshore bridges. A pier is the main energy-consuming component of a bridge to resist earthquake. In this study, an offshore rigid bridge pier was taken as an example. Based on the OpenSees platform, seismic waves that meet the site conditions were selected to construct the mainshock-aftershock sequence according to the seismic records. Using the capacity demand ratio method, the seismic vulnerability curves of pier control sections in different service time points under different damage states were drawn, and the influences of chloride ion erosion and mainshock-aftershock sequence on the seismic performance of bridge piers were studied. The results show that the exceeding probability increases with the increase of service time and PGA, but decreases with the increase of damage grade. In the state of slight damage, the mainshock-aftershock sequence has a limited influence on the seismic fragility of the bridge pier. However, under moderate damage, serious damage, and complete collapse, in the same service time, the mainshock-aftershock sequence has a greater influence on the seismic fragility of the bridge pier than the mainshock.
