Research On Pounding Analysis Of Seismic Response For Long-span Cable-stayed Bridges And Approach Bridges

Under the seismic response,the cable-stayed bridge and approach bridge is affecting each other and the two structure may happen collision response.The collision increases cable-stayed bridge damage,not only cause the risk of falling beam,but also change the main bridge and approach their respective vibration characteristics and seismic response.So,research on pounding analysis of seismic response for long-span cable-stayed bridges and approach bridges is of important guiding significance to the reality.This paper first reviews the current status of collision studies of bridge structures,and elaborates the collision related theory,followed by a typical large-span public railway dual-use cable-stayed bridge as the engineering background.The main research contents are as follows:(1)Review the literature to understand the development of cable-stayed bridges,t he concept of seismic design,and the development status of the research on the impac t of the main bridges and approach bridges of cable-stayed bridges,including the rese arch status of collision tests,research status of collision models,and status quo of imp act impact parameters.Etc.Secondly,several theoretical foundations for the collision model of the main and approach bridges are introduced in detail,including rigid body collision theory,straight-axis co-axial collision theory and analysis methods based o n the straight-axis coaxial collision theory.(2)Reasonably simulate the main bridge unit,bridge deck unit,bridge tower unit,stay cable unit and pile-soil interaction of steel truss girder.Secondly,based on the d ynamic time history analysis method,the eigenvalue analysis of the cable-stayed brid ge is carried out and the changes are performed.The parameters of the collision unit were used to find out the reasonable stiffness of the collision unit.Secondly,the impa ct response of the cable-stayed bridge dynamic model before and after adding the da mping device was compared and analyzed.The main response included: structural dis placement response,impact force response and partial structural internal force response.The results showed that the damping device was added.Can effectively reduce the seismic response.(3)By changing the initial gap size of the main and approach bridge expansion jo ints in the model,the impact responses of the cable-stayed bridge dynamic model are compared and analyzed,mainly including structural internal force response and struct ural displacement response.The results show that when the expansion joint gap size i s 0.3m,the cable-stayed bridge The seismic performance of the structural system is b etter.Finally,the factors affecting the impact of cable-stayed bridges are discussed,in cluding the main bridge structural system,the different input directions of the seismic waves and the structural cycle ratio changes,and the structural impact responses und er different influencing factors are found out.