Research On Seismic Damage Assessment Theory And Prediction Method Of Railway Pier Considering Cumulative Effect

The performance-based seismic design requires that the structure can meet the performance goal of multi-level fortification.According to this idea,China’s seismic code also puts forward the threelevel fortification principle of "No damage in small earthquake,repairable in medium earthquake and no collapse in large earthquake".In the actual seismic design of railway bridges,the code lacks guiding analysis methods and reference indexes.This may lead to the distortion of seismic damage evaluation results.At present,many scholars have studied the quantitative theory and prediction method of seismic damage based on the failure form of bridges.Existing studies mainly focus on common highway piers and building columns.However,Railway Piers have the characteristics of low axial compression ratio,shear span ratio and reinforcement ratio.TThe research on the damage prediction is of great value to meet the actual needs of Sichuan Tibet railway before and after the earthquake.This paper focus on the two core issues of "railway pier seismic damage assessment theory" and "railway pier seismic damage prediction method" :(1)Based on 16 groups of pier test data in PEER test database,this paper combs the structural failure process,clarifies the characteristics of failure modes,and summarizes four main influencing factors and three secondary influencing factors of seismic performance of Railway Piers combined with theoretical analysis.At the same time,based on 16 groups of test data,the parametric finite element model is established by using Open Sees and Abaqus.(2)By combing and summarizing 466 groups of parametric finite element analysis results,the effects of different structural parameters on structural ductility,energy consumption and β Based on the influence of combination coefficient,the calculation formula of Park ang seismic damage index of railway rectangular pier is deduced through nonlinear regression analysis,the critical value of damage state is defined,and the mapping relationship between damage degree and repairability is constructed;(3)Based on the modified Park ang damage index,the seismic time history calculation results of1000 groups of simplified dynamic models are analyzed,and the neural network prediction model of probabilistic seismic demand analysis parameters is constructed to realize the rapid prediction of damage probability and repairability based on pier structural parameters.(4)According to the above research results,taking a three span steel-concrete hybrid beam bridge as an actual engineering case,verify the universality of seismic damage assessment theory and damage prediction model,and summarize the seismic design method of railway bridge considering cumulative effect,so as to provide theoretical basis for engineering design.