Study On Key Parameters Of Seismic Vulnerability And Risk Analysis Of High-Speed Railway Bridge-Track Structure

Intensity measure(IM),damage measure(DM)and seismic hazard model in seismic vulnerability and risk analysis are some of the key parameters that affect the evaluation of seismic performance of structures.However,the current seismic performance evaluation of girder bridges,which occupies the largest proportion in high-speed railway network,has the limitation of following the research results of highway girder bridges,which not only leads to the evaluation results of emphasizing"bridge structure"and neglecting"track structure",but also the credibility of the evaluation results is questionable.Therefore,based on the characteristics of high-speed railway bridge and track structures,it is of great significance to realize the goal of more effective and reliable evaluation of the seismic performance of bridge-track structure.In light of this,based on the high-speed railway simply supported girder bridge,continuous girder bridge and simply supported+continuous girder bridge of high-speed railway with ballastless track slab II,this dissertation aims to seek the IM and DM applicable to high-speed railway bridge-track structure,screen important model uncertainty parameters to be considered in seismic vulnerability analysis,and propose an seismic hazard model to improve the accuracy of seismic risk analysis.The major research contents are as follows:(1)Establish the finite element model(FEM)of bridge-track structure verified by shaking table test.Using Open SEES platform,a refined FEM of high-speed railway bridge-track structure is established,and the accuracy and rationality of the FEM is verified by comparing with the measured dynamic characteristics and dynamic response of the scaled high-speed railway girder bridge in the shaking table test.(2)Propose a new IM based on multi-order spectral acceleration.According to the dynamic characteristics of high-speed railway bridge-track structure,a new IM,namely S _a*,calculated by taking the spectral acceleration of the dominant mode as the base and the proportion of mass participation coefficient as the index,is proposed.Compared with other 17 IMs,the superiority of S _a*is tested from the feasibility,efficiency,sufficiency and hazard computability.(3)Propose the component DM conforming to the characteristics of bridge-track structure.The pier drift ratio is proposed as the DM of high-speed railway piers,which is quantified by the method of statistics of pier test results.The sliding layer,CA layer and rail transverse deformation are proposed as the DM of track components,which are quantified by establishing the relationship between rail deformation and running indexes.(4)Carry out the seismic vulnerability analysis based on the uncertainty of model parameters.The fractional factorial design and variance analysis method are used to screen out the important model uncertainty parameters of high-speed railway bridge-track structure,and the impact of model parameter uncertainty on the probabilistic seismic demand model and seismic vulnerability is analyzed.(5)Carry out seismic risk analysis based on improved seismic hazard model.An improved seismic risk model,which is superior to the classical power law model,namely the quadratic polynomial model,is proposed,and a semi-analytical solution based on the improved model is derived to solve the response demand and seismic risk probability.After the verification of numerical integration,the proposed semi-analytical solution is used to carry out the seismic risk analysis of high-speed railway bridge-track structure.