Analysis On Collision Effect Of Extradosed Cable-stayed Bridge With Wide Box Girder And Single-cable-plane

Extradosed cable-stayed bridge has some characteristics of continuous beam and cable-stayed bridge,which belongs to composite system bridge and has been widely developed in bridge construction.Collision damage is an important cause of bridge damage in earthquake.At present,scholars at home and abroad have done a lot of research on the collision effect of bridge structures,but most of them are medium and small span bridges.Some scholars have also studied the collision effect between main bridge and approach bridge of cable-stayed bridges,while few studies have focused on the collision between wide extradosed cable-stayed bridge and adjacent approach bridges.Therefore,it is necessary to carry out the research on the collision effect of wide extradosed cable-stayed bridge,so as to provide some reference for how to consider the collision problem of extradosed cable-stayed bridge and how to reduce the collision effect in the future seismic design of bridges.In this paper,a wide low-pylon cable-stayed bridge as the research background,the specific research contents are as follows:(1)This paper summarizes the research status of bridge collision,summarizes the influencing factors of collision effect and the measures to reduce collision,and combs the development of extradosed cable-stayed bridge and the research status of collision problem.The simulation method of bridge collision problem and related collision theory are studied.The linear spring model of contact element method is used to simulate the collision effect of extradosed cable-stayed bridge in this paper.(2)According to the characteristics of bridges structure,considering pile-soil interaction,a finite element model is established to calculate the dynamic characteristics of extradosed cable-stayed bridge.Choosing appropriate contact elements and seismic waves,the influence of bilateral and unilateral impact effects on seismic response of bridge structure is studied,and the seismic response of bridge structure under two kinds of collision effects is compared and analyzed by nonlinear time history analysis.(3)The main factors affecting the collision effect between main approach bridges are studied.Taking unilateral impact as an example,the dynamic characteristics of main approach bridges,the gap between expansion joints and the stiffness of collision elements are analyzed.The effects of different parameters on the impact force at expansion joints,the displacement at the end of main approach bridge,the displacement at the top of main tower and the internal force at the bottom of tower,the displacement at the top of fixed pier and the internal force at the bottom of pier are discussed.(4)The measures to reduce the collision effect are studied,the seismic reduction plan of viscous damper is proposed,the reasonable parameters are determined,and the reasonable values of the gap between expansion joints and the internal forces of key sections are analyzed.