Abstract：Numerous offshore bridges are located in the complex environment with the non-uniform spatial distribution of chloride ions. During the service life, the non-uniform chloride-induced corrosion often leads to the performance degradation of material and structure as well as the reduction in the seismic resistance of the bridge to earthquake. In order to investigate the variation of seismic damage risk of bridges subject to the non-uniform chloride-induced corrosion, the probability distribution type and statistical characteristics of different environmental parameters and corrosion parameters are determined, and the degradation laws of reinforcement and concrete are established combine the Duracrete model, the previous test results, the diffusion law of chloride ions and the corrosion mechanism of reinforcement. According to the analysis theory of seismic fragility, the evaluation process of the time-dependent seismic fragility of bridges subject to non-uniform chloride-induced corrosion is established. Then, a multi-span girder bridge is taken as an example, the variation characteristics of seismic capability of degenerated bridges are analyzed and the time-dependent seismic damages of various components are investigated. The results show that the flexural capacity and curvature ductility of the cross-section of the piers degrade obviously due to corrosion of the chloride ion, and the degradation of curvatureductility is more significant than that of the flexural capacity. Non-uniform chloride-induced corrosion may change the damage distribution of the pier, and the vulnerable position of the pier may be shifted from the top and the bottom of the piers to the position at low water level. With the increase of service time, the damage probability of the pier maybe increased obviously, and the damage probabilities of the bearing, shear keys and the abutment may be decreased slightly.
