Research On Dynamic Characteristics And Seismic Respomse Study Of Extradosed Cable-stayed Bridge Based On Cable Damage

As an important part of the transportation network,bridges play a very important role in economic and social development.However,due to geographical reasons,earthquakes occur frequently in China,which makes the Bridges in China subjected to serious safety threats.Earthquakes can easily damage Bridges,or even destroy them completely,paralyze traffic and cause incalculable damage to the country and society.The low pylon cable-stayed bridge,as a relatively novel composite system bridge,have been widely used and developed at home and abroad for their advantages of wide application range,economical appearance,and convenient construction since their appearance.With the development of design and construction of cable-stayed bridges with low towers,the related researches on their dynamic characteristics and seismic response are also improving,but the research on cable-stayed bridges with low towers when the cables are damaged is still lacking.This paper takes the main bridge of the Beijing-Hangzhou Canal Bridge as the research object,and establishes a full-bridge finite element model of a low-tower cable-stayed bridge with a tower-girder consolidation system,analyzes its dynamic characteristics and seismic response,and selects appropriate variables in the process.To simulate the damage of cables,the effects of broken cables and different degrees of damage of cables on the natural vibration frequency and seismic response analysis results of cable-stayed bridges with short towers are studied.The main contents are as follows:(1)This paper briefly describes the development history and characteristics oflow pylon cable-stayed bridge,as well as the bridge dynamic and seismic analysismethods,and explains the calculation principle and relevant calculation formulas.According to the characteristics of the project and relevant design requirements,the full bridge finite element models of low pylon cable-stayed bridge under cable damage andcable damage are established respectively.(2)The natural vibration characteristics of the established model are analyzed,and the natural vibration period and mode shape characteristics of the low pylon cable-stayed bridge with a tower-girder consolidation system are summarized,the effect of cable damage on the natural vibration frequency of low pylon cable-stayed bridges is obtained(3)On the basis of studying the natural vibration characteristics,the seismic response spectrum analysis is carried out for the low pylon cable-stayed bridge under the condition of non-destructive and damaged cables,and the influence of the damage of the cables on the dynamic response of the structure is studied.(4)Input the seismic wave parameters that conform to the site parameters of the bridge site,select the appropriate actual seismic waves,conduct time-history analysis on the structure,and study the influence of the cable damage on the results of the seismic time-history analysis of the structure.Design for reference.