Seismic Vulnerability Analysis Of Railway Continuous Girder Bridge With Steel Bar Damper And Movable Support

With the development of the seismic design of bridges in China,seismic isolation technology has been widely used in railway bridges.Several engineering examples have also demonstrated the damping effect of seismic isolation technology on bridge structures.Among them,steel bar damper based on the design idea of "bearing function separation" has been widely used in railway bridges due to the obvious energy dissipation mechanism,superior damping performance,and convenient installation and replacement.Chinese scientists studied mechanical properties,design method,working principle,seismic isolation effect,and seismic weakness of steel bar damper.However,most of the studies have been done for simply supported bridge girder;therefore,it is necessary to study the seismic performance of the steel bar damper for continuous girder bridge.In my thesis,the continuous girder bridge(40 + 60 + 40)m is viewed as a research object,and the seismic damping effect and seismic weakness of the railway continuous girder bridge are analyzed with the damper and moveable support.The main research work for this thesis is as follows1.Simplified calculation method for seismic force of steel bar damper-moveable support continuous girder bridgeThe mechanical properties and working principle of steel bar damper are simply introduced,and the simplified calculation method for the seismic force of the continuous girder damper for steel bar is presented.In addition,the nonlinear time-history analysis of the steel bar damper-moveable support continuous girder bridge is performed by the finite element software Open Sees.Compared with the simplified calculation results,the accuracy of the simplified calculation method is verified.2.Seismic vulnerability analysis of continuous girder bridge with steel bar damper-movable supportOn the basis of considering the uncertainty of ground motion and structural parameters of the bridge,the sample database of ground motion and bridge for 100 groups of continuous girder bridge with ordinary basin-type supports and continuous girder bridge with steel bar damper-movable supports are established.IDA method is used to analyze the seismic vulnerability of the bridge model to obtain the probabilistic demand model of bridge structure under earthquake action.According to the damage index of each component of the bridge and the earthquake probability demand model,the vulnerability curves of the bridge structure under different damage states are calculated.The results show that the steel bar damper-movable support can greatly reduce the damage probability of each component of the bridge under the action of an earthquake.