SEISMIC PERFORMANCE ANALYSIS OF REINFORCED CONCRETE BRIDGE COLUMN CONSIDERING BOND DETERIORATION CAUSED BY CHLORIDE ION INDUCED CORROSION

The seismic performance of RC structures declines due to the chloride ion induced corrosion in their life cycles. By means of the software OpenSees, numerical models were built to simulate the test results of a full-scale RC bridge column tested on the shake table and some corroded reduced-scale RC columns tested under quasi-static loadings. According to existing investigations on the model of chloride ion induced corrosion, the degradation of the mechanical property of longitudinal reinforcement and bond deterioration were both considered in the numerical models of corroded RC columns. Then fragility analysis was performed based on the probabilistic seismic demand model for three cases of full-scale RC bridge columns, considering different percentage of the corroded mass relative to the initial mass of the longitudinal reinforcement. The results show that:the numerical model established by parallel connecting the zero-length section element to the nonlinear beam-column element can simulate the test results effectively; when the corroded mass of the longitudinal reinforcement is minor, the maximum top displacement of the column is not sensitive to the degradation of the mechanical property of longitudinal reinforcement, but the maximum base shear force and moment decrease obviously; When the damage degree of the column is slight, the corrosion of longitudinal reinforcement affects the structural seismic performance negligibly. When the damage condition becomes severer, the effect of the corrosion of longitudinal reinforcement is more obvious. A minor corrosion of longitudinal reinforcement increases the damage probability observably. The study can provide a reference for the seismic design of reinforced concrete structures when considering the performance degradation in the life cycle.