Seismic Vulnerability Analysis Of Railway Continuous Girder Bridge With Steel Bar Damper-movable Support

With the development of seismic design of bridges in China,seismic isolation technology were widely used in railway bridges.Many engineering examples also proved the damping effect of seismic isolation technology on bridge structures.Among them,the steel bar damper based on the design idea of "bearing function separation"were widely used in railway bridges due to its clear energy dissipation mechanism,superior damping performance,convenient installation and replacement.Domestic scholars studied the mechanical properties,design method,working principle,seismic isolation effect and seismic vulnerability of the steel bar damper.However,there were few studies on the application of the steel bar damper in railway continuous girder bridges,and there was nearly no research on the seismic vulnerability of steel bar damper-movable support continuous girder bridges.Therefore,it is necessary to study the seismic vulnerability of the steel bar damper-movable support continuous beam bridge.In this paper,a(40+56+40)m railway continuous girder bridge is regarded as the research object,and the seismic damping effect and seismic vulnerability of the railway continuous girder bridge with steel bar damper-movable support are analyzed.The main research work of this paper is as follows:(1)Simplified calculation method for seismic force of steel bar damper-movable support railway continuous girder bridgeThe mechanical properties and working principle of the steel bar damper are simply introduced,and the simplified calculation method of the seismic force of the steel bar damper continuous girder bridge is presented.In addition,the nonlinear time-history analysis of the steel bar damper-movable support continuous girder bridge is carried out by the finite element software OpenSees.Comparing 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 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 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 earthquake.(3)Analysis of factors affecting seismic vulnerability of continuous railway girder bridge with steel bar damper-movable supportBased on the seismic vulnerability analysis of inconsistent pier height and the consistent pier height bridge model,the influence of pier height on the seismic vulnerability of the steel bar damper-movable supporting continuous girder bridge members and systems are studied.The seismic vulnerability of bridge models considering pounding and non-consideration conditions are compared and analyzed,and the influence of pounding on the seismic vulnerability of the steel bar damper-movable supporting continuous girder bridge members and systems are studied.