Seismic fragility analysis of the time-varying system of a bridge with a Gaussian process model
Chloride ion erosion in bridges in long-term service leads to the degradation of material properties and affects the seismic performance of bridge structures.Accurately evaluating the seismic performance of bridges in service can effectively guarantee and improve the safety of bridge structures.Therefore,seismic fragility analysis considering a time-varying effect is essen-tial.In this study,the time-varying seismic fragility analysis of bridges was carried out.The deg-radation of material properties caused by chloride ion erosion on the seismic performance of the bridge was considered.Given that seismic fragility analysis involves comprehensive dynamic time-history analysis,the calculation efficiency is low.Thus,the Gaussian process model was used to replace the time-consuming dynamic time-history analysis to improve the efficiency of the analy-sis.The degradation law of the pier material properties under the action of chloride ion erosion was explored in a three-span continuous beam bridge.Then,the degradation time-varying curves of the longitudinal reinforcement,stirrup,protective layer concrete,and core concrete were es-tablished.Based on the Gaussian process and probabilistic seismic demand models,the fragility curves and surfaces of bridge systems with different service years were established.Results show that(1)the strength of the reinforced concrete materials of piers is substantially reduced by chlo-ride ion erosion,and(2)chloride ion erosion obviously increases the seismic fragility of the bridge with high-level damage,and the structure is more prone to high-level damage.
chloride ion erosionbridge structureseismic fragilitytime-varying effectGaussian process model
万方数据
维普
