Seismic Performance Analysis Of "Integrated Station-bridge" High-speed Railway Station Structure

The structural system and overall seismic performance of high-speed railway station play an important role in the whole railway transportation process.Among them,the"integrated station-bridge"structural system,with its advantages of large space,less land occupation and diversified functions,has become the first choice of structural design of large-scale hub type stations in China.The high-speed railway station structure has the characteristics of large span,dense frequency spectrum and complex dynamic characteristics,which is quite different from the traditional structure.At present,the research on the seismic design of high-speed railway station structure and its failure mode under earthquake action is not mature at home and abroad.Taking a high-speed railway station as the engineering background,this paper establishes a three-dimensional finite element model of the structure,and evaluates its seismic performance systematically,which provides an important reference for seismic design and analysis of such"integrated station-bridge"high-speed railway station in the future.(1)Firstly,define the structural system,main components and load conditions of the high-speed railway station structure.Based on this,establish the three-dimensional finite element model of the high-speed railway station structure.Carry out the modal analysis,the response spectrum analysis of the elastic stage and the static elastoplastic analysis of the whole structure under the action of frequent and rare earthquakes,and obtain the dynamic characteristics,the distribution of stiffness and mass,seismic performance.The results show that,the dynamic characteristics are different from the traditional structure,the vibration mode of the structure is complex,the periodic interval of the high-order vibration mode is becoming shorter,the frequency spectrum is very intensive,the dynamic characteristics are complex,the difference between the upper stiffness and the lower stiffness is great,the lower structure with large stiffness can be used as the embedded layer of the upper structure.The seismic performance of the structure under frequent and rare earthquakes is good,and the mode distribution loading mode is more suitable for the static elastic-plastic analysis of the vertical irregular structure of high-speed railway station.(2)Select Ten seismic waves to carry out the incremental dynamic analysis(IDA)of the whole structure model,The IDA curve and performance point value drawn by each of these 10 seismic waves through continuous amplitude modulation are obtained,the seismic intensity index IM is transformed,and the IDA curve drawn under different seismic intensity indexes is compared to determine which is more suitable for the seismic intensity index which is more suitable for the incremental dynamic analysis of the high-speed railway station structure is found.The results show that,the multi record IDA curve cluster can reflect the possible response of the structure under the action of different ground motion intensity levels,Compare the PGA with S_a(T,5%)as the calculation result of the seismic intensity index,it can be seen that the incremental dynamic analysis of the large-scale complex traffic hub structure with the ground peak acceleration PGA as the seismic intensity index is more accurate.(3)Based on the calculated results of incremental dynamic analysis,the seismic vulnerability of the whole structure is analyzed,and the seismic performance of the structure is evaluated.The results show that,after the structure enters the plastic stage,its ductility performance plays a better role in the seismic resistance of the structure.When the maximum inter story displacement angle is taken as the performance value standard,the probability of the structure reaching the immediate use limit state in case of frequent earthquake is 0,which meets the requirements of"small earthquake is not bad".The probability of the structure reaching the immediate use limit state and life safety limit state under the action of fortification earthquake is very small,which will not endanger life in this case,and meet the requirements of"medium earthquake repairable".In case of rare earthquake,the probability of the structure reaching the collapse prevention limit state is 0.It can meet the requirement of"no collapse under strong earthquake",which fully shows that the seismic performance of the structure in this paper is good.(4)A modified interface connection method based on displacement coordination and equal work is proposed and applied to the multi-scale analysis of the high-speed railway station structure.The results show that the multi-scale analysis method can well analyze the seismic response and dynamic characteristics of high-speed railway station structure,and has good accuracy and calculation efficiency.There are 55 pictures,15 tables and 114 references in this paper.