Seismic Response Analysis And Antiseismic Performance Of Isolated Continuous Beam Bridges

In recent years,in order to promote the rapid economic development of our country,it is particularly important to build cross-sea bridges in coastal areas.Since the cross-sea bridge is the lifeline project and the important transportation hub between cities,the seismic isolation design of cross-sea bridges can effectively reduce earthquake disasters.In order to study the seismic behavior of isolated continuous beam bridge under earthquake action,based on Dalian Bay cross-sea traffic engineering,this paper aims to make a seismic performance evaluation on the isolated bridge from following four aspects: the parameters of isolation bearing,the damage index of bridge,and the IDA analysis of bridge components,and the vulnerability analysis of the bridge system.The contents of the study are as follows:Firstly,from the angle of bearing rate of energy consumption,the author makes an analysis on parameter optimization on mechanical model of isolation bearing and the relationship between the rate of energy consumption and bearing the earthquake response of the structure,and the laws from the results are summarized accordingly.As the bearing energy consumption rate increases,the earthquake response of the structure tends to decrease.As the flexion weight ratio is in the range of 5%~6%,the energy consumption rate will reach a greater value.Compared with isolated and non-isolated bridge model corresponding,the seismic isolation rate reaches above 60% and the isolation effect is better accordingly.Secondly,taking the sectional curvature of the pier and the shear strain of the bearing as the damage index,the seismic performance targets of the whole bridge are determined as slight damage,moderate damage,severe damage and collapse.Besides,Taking the randomness of the ground motion into the consideration,ten natural ground motion records which were suitable for the engineering site were selected to for incremental dynamic analysis and the failure modes of bridge members were also studied.The results show that the intermediate pier bearings are first destroyed and the bridge piers exhibit better ductility.Thirdly,according to the results of IDA analysis of the bridge model,the probabilistic seismic demand model of bridge pier and isolation bearing is obtained by regression analysis.Additionally,it can be obtained or received the vulnerability curve of bridge member by combining the damage index of bridge pier with isolation bearing.What's more,the damage curve of bridge system is also obtained by using the method of wide limit,and the overall seismic performance of the isolated bridge is also evaluated.The results show that the damage probability of bridge system under earthquake is higher than that of the member.