Analysis Of Seismic Response Of High-speed Railway Catenary System

Catenary system is the only part of the railway traction power supply system without standby equipment.Its performance directly influences the current quality of pantograph and the safety of railway operation.Different from the general civil engineering structures,catenary system is a large-span structure connected with cantilever structure and supporting structure.In addition,the contact line and load-bearing rope of suspension structure have initial pretension.In the past earthquakes,the catenary system was prone to damage,which made it difficult for the railway to resume operation in the short term.Currently,the research results of seismic performance of catenary are few at home and abroad.Earthquakes occur frequently in China,so it is urgent to study the seismic response of catenary system in our country.In order to study the high-speed railway catenary system seismic response,three-dimensional finite element model with five posts and six spans is established and calculated,according to the structure characteristics of the catenary system,adopting the geological conditions of the Xianshui River fault zone across the Sichuan Tibet line railway.Firstly,the initial stress and displacement of the contact system in the initial state has been gotten by the nonlinear static analysis.And the dynamic characteristics and mode participation coefficient has been gotten by modal analysis,the latter shows that the natural frequency of catenary system is low and dense,and the contribution of higher modes should not be negligible.Then,the most unfavorable incident angle of seismic motion and vertical earthquake has been obtained by the spectrum analysis.The result shows that the longitudinal input ground motion has the most influence on the catenary system while the vertical earthquake has little influence on the support structure of catenary system.Finally,acceleration time history analysis is used for uniform excitation,and relative displacement method is used for wave travel effect.The influence of traveling wave effect on the seismic response of catenary system is studied by comparing the results of traveling wave with uniform excitation.The conclusions are as follows:(1)Compared with uniform excitation,the seismic responses of the catenary system are obviously amplified by traveling wave effect,especially for the vertical displacement of the contact wires,which is increased 4.87 fold.Different seismic waves make different influence.(2)Under uniform excitation and traveling wave effect,due to the different spectrum characteristics of the input seismic wave and the visual wave speed,the peak of the structure response,the response peak time and the amplification effect are different.(3)The analysis results point out the seismic weaknesses of support structure of the catenary system and provide reference for the catenary system structure aseismic design.