Research On Seismic Responses And Seismic Fragility Analysis Of Continuous Welded Rails On Simply-Supported Bridge

With the rapid development of high-speed railway in our country,the application of continuous welded rails on simply-supported bridge is more and more widely used in railway construction.Recent years,earthquakes occur frequently,the Wenchuan Earthquake and Yushu Earthquake have caused great damage to local traffic lifeline.Therefore,the engineering seismic research on continuous welded rails is becoming the urgent affairs.On the basis of both domestic and international studies,this paper studies the seismic response and seismic fragility analysis of continuous welded rails on the simply-supported bridge.The main research works are as follows:1?Establish a ballastless track-bridge system coupling analysis model of 5 × 32 m concrete simply-supported bridge.Establish the track structures such as U-shaped abutment,WJ-7 fastening,concrete-asphalt mortar,cam basement accurately.Consider quality and stiffness distribution in detail.Ensure the correctness of the analysis model.2?Analyze the dynamic response of the Rail-Bridge-Pier analysis model of high speed railway concrete simply-supported bridge by time-historic analytical method.Tianjin Ninghe wave(north-south direction),Taft earthquake wave and artificial seismic wave are selected as input seismic waves.The seismic wave input location are the roadbed,abutment and pier.Analyze the seismic response of the model.At the same time,the natural frequency characteristics of the model are analyzed.Analyze the weak parts of the structure.Then,Analyze the displacement of rail,the displacement of pier top,the deformation of the track plate and the deformation of the cam basement respectively.3?Compare the relationship between the force and the displacement curve of the rail's buckling instability under the restraint of the fastening and without the restraint of the fastening.Analyze the effect of fastening restraint on the instability of rail.Make Eigenvalue buckling analysis on the track structures.0.02 times of the first order buckling mode is input into the track structure as initial imperfection.The nonlinear buckling analysis of the orbital structure is performed.Analyze rail,buckle deformation and instability.Carry on reversal load pattern analysis to the track structure.The hysteresis characteristics and dissipation capacity were analyzed.The damage criterion of the track structure is proposed.The Skeleton curve of the track structure is reached.The results provide the basis for model simplification.4?On the basis of the displacement of pier top and the hysteresis characteristics,Establish the resilience simplified model.The elastic-plastic parameters of the model are simplified repeatedly.Carry on reversal load pattern analysis and time-historic analysis to the simplified model.Make the result of analysis consist with the previous analysis.Produce seismic waves by our team's artificial seismic wave program.Put these earthquake waves to the simplified model.Conduct Seismic Fragility Analysis by the skeleton curve of the track structure as mentioned above.