A Study On Longitudinal Pounding Effect Of (32+24)m High-speed Railway Simply Supported Girder Bridge Under Strong Earthquakes

There are different dynamic characteristics of the two adjacent bridges of the unequal span high-speed railway simply supported girder bridge,and the collision of girder piers may occur under strong earthquakes because of the different height of the main girder.In this paper,the longitudinal collision model of Bridge is established with the help of OpenSees and Midas/Civil software,and the seismic collision reaction and damping measures between the adjacent beams and the girder piers of the different span high-speed railway simply supported girder bridges under strong earthquakes are studied on the background of the Bridge(2009)4321-IV(32+24)m high-speed rail simple supported girder bridge.The main work is as follows:(1)by consulting a large number of relevant literatures at home and abroad,this paper systematically reviews and summarizes the seismic collision response analysis method,the seismic collision theory of adjacent structures and the measures to reduce collision and drop beam of the simple supported beam bridge.The collision stiffness of adjacent beams and the value of the collision stiffness of girder piers are studied,and the longitudinal collision calculation model of high-speed railway simply supported girder bridges considering the nonlinearity of materials and the nonlinearity of the support is established based on OpenSees.(2)The influence of collision effect on longitudinal seismic response of unequal span high-speed railway simply supported girder bridge is studied by ignoring the collision,considering only the collision of Liang,considering only the collision of Beam piers and considering two kinds of collision four working conditions,and the results show that the collision between the adjacent beams of the unequal span high-speed railway is reduced,The effect of longitudinal displacement of a single main beam may be increased or decreased,the transition pier will be affected by the direct collision force between the main beam and the pier top of the large span,the collision between the girder piers and the collision of the adjacent beams will affect each other,and the collision effect of the girder piers will reduce the collision effect of the adjacent beams.(3)Taking pier height,adjacent beam spacing and pier spacing as variable parameters,the effects of parameters on longi tudinal seismic response of simple supported beam bridges with different spans of high-speed railway are studied.The results show that the relative displacement of pier first decreases and then increases with the increase of pier height,and the force of pier first increases and then decreases with the increase of pier height.The spacing should be slightly larger than the spacing between beams and beams.(4)To study the effect of cable limiter and BRB device on the limit effect of unequal span high-speed railway simply supported girder bridge,and to investigate the relationship between its damping effect and energy consumption,and to give the optimal arrangement of the limit device.The results show that the addition of cable limiter and BRB can effectively reduce the seismic response of the bridge under strong earthquake,and the BRB damping effect with energy dissipation ability is better than that of the cable limiter,and the arrangement mode of the main Liang Chengzhi 22.5° angle is the most advantageous,which can not only guarantee the effective energy consumption,but also not obviously increase the force of the pier.The relative displacement peak of the girder pier is negatively correlated with the BRB hysteresis energy dissipation,the larger the BRB hysteresis energy dissipation,the smaller the relative displacement peak of the girder pier,the lower the relative displacement peak of the girder pier decreases first with the increase of the cross-sectional area of the BRB core section,and increases with the increase of the area of the BRB core section.