Seismic Vulnerability Analysis Of The High-pier Large-span Continuous Rigid Frame Bridges Considering Pounding Effects Between Adjacent Girders

High-pier large-span continuous rigid frame bridges have been extensively constructed in Western Mountain of China,and the dynamic characteristics of main bridge and approach bridge are quite different.It is prone to collision between girders or between girder and abutment because the dynamic response of main bridge and approach bridge are not synchronous under earthquake.Seismic vulnerability analysis of long-span continuous rigid frame bridges with high piers is very necessary.In this thesis,a long-span continuous rigid frame bridges was taken as an example.Firstly,a nonlinear finite element model of the bridge was established with the help of OpenSees.Then the nonlinear dynamic time-history analysis with artificial seismic waves and natural seismic waves was performed on the nonlinear finite element model.Finally,a large number of natural seismic waves are selected to analyze the vulnerability of both bridge components and system.The main contents of this thesis are as follows:1?This thesis summarized the characteristics of long-span high-pier continuous rigid frame bridge,including the research status of bridge pounding effect and the calculation method of bridge vulnerability.2?OpenSees was used to establish a nonlinear finite element model of long-span highpier continuous rigid frame bridge.This thesis explained the model's material constitutive model and parameter selection,and analyzed moment curvature of bottom of pier section.3?According to the specification and the engineering background,7 natural seismic waves and 7 artificial seismic waves were selected to make dynamic time-history analysis on the bridge structure.The effect of pounding and the gap width on the dynamic response was studied.4?In this thesis,the basic theory of probability seismic demand model was introduced,the seismic damage index was calculated and the uncertain parameters of bridge structure were estimated.Seismic vulnerability analysis of the bridge was calculated by using the Latin hypercube sampling and the cloud method according to the selected 100 natural seismic waves.In addition,the influence of structural parameter uncertainty and pounding effect were studied.5?The basic concept of bridge system reliability was introduced and series model was chosen to analyze the vulnerability of this bridge system.The seismic vulnerability of this bridge calculated by the first-order reliability principle method and the PCM method and then the results were compared with each other to determine the accuracy of the two methods.