PROBABILISTIC DAMAGE-BASED SEISMIC DEMANDS ANALYSIS OF REINFORCED CONCRETE BRIDGE

Due to Wenchuan earthquake, many bridges have been damaged severely Most of them are needed to be retrofitted or rebuilt The revised damage index is proposed which is associated closely with the residual seismic capacity. To make retrofit decision for many damage bridges, multi-criteria comprehensive damage evaluation system is modified with considering economic-social facts and the engineering circumstances in the affected regions of Wenchuan earthquake. Based on three springs model, the hysteretic model coupled strength and stiffness deterioration with damage energy is refined. Chosen PGA as IM, the attenuation relationship between revised damage index and PGA can be regressed with nonlinear time-history analysis results by IDA. Combined probabilistic capacity analysis, probabilistic capacity analysis with probabilistic hazard analysis, the seismic risk assessment was built on the fragility curves. With the risk assessment the reasonable retrofitting decision for severe damage bridges in Wenchuan earthquake was made.