Study On The Seismic Behavior Of Railway Gravity Piers

In China gravity concrete piers with low reinforcement are widely used in railway bridges,and their reinforcement ratio is usually less than 0.5%.At present,there is a lack of systematic seismic performance study on railway gravity piers at home and abroad.There is also no relevant provisions about the piers with the reinforcement ratio which is less than0.5% of the current Code for seismic design of railway engineering.Therefore,the study on seismic performance of railway gravity pier with low reinforcement characteristics has important engineering application significance and theoretical research value.This paper is based on the national natural science foundation of China(51768036).Based on the method of combing model test with theoretical analysis,the seismic performance of railway gravity pier is studied in this paper.The main works are as follows:(1)On the basis of reading a lot of literature,this paper analyses the characteristics of seismic damage of railway gravity piers,summarizes about the current situation of experimental research on seismic performance of reinforced concrete piers at home and abroad,and points out the shortcomings of seismic design of railway gravity piers at present.(2)Based on the similarity theory,two railway gravity rectangular piers with longitudinal reinforcement ratios of 0.3% and 0.5% were designed and made by using the railway gravity piers in the eight-degree fortified area as the prototype.The shaking table test of two models under unidirectional horizontal earthquake is carried out respectively,the acceleration response,displacement response and pier bottom strain response of the two pier models with different longitudinal reinforcement ratios are obtained,and the influence of longitudinal reinforcement ratio on the seismic response of piers is analyzed.(3)By using finite element software ABAQUS to establish the finite element calculation and analyse models of shaking table test piers.The dynamic elastic-plastic time history analysis of the two models under unidirectional horizontal earthquake is carried out.The finite element calculation results are compared with the test results,and the correctness of the selected finite element calculation model is verified.(4)Considering the longitudinal reinforcement ratio,stirrup ratio,pier height and concentrated mass at the top of the pier,the finite element models of railway gravity pier under different structural parameters were established.The dynamic elastic-plastic time history analysis of the model was carried out by using ABAQUS,and the effects of these four parameters on acceleration response,relative displacement response,equivalent plastic strain and energy response of the pier top of railway gravity bridge pier were compared.(5)Dynamic elastic-plastic time history analysis of 24 pier finite element models based on different structural parameters was carried out by using ABAQUS.Based on theequivalent plastic strain value of pier model and the ratio of plastic dissipation energy to seismic input energy,the seismic design suggestions for railway gravity piers are put forward.