高铁简支梁桥横向地震碰撞效应振动台试验研究  

Shaking table tests on transverse pounding effect of high-speed railway simply-supported girder bridges under earthquake excitations

作　　者：孟栋梁 高琼 杨孟刚[1] MENG Dongliang;GAO Qiong;YANG Menggang(School of Civil Engineering,Central South University,Changsha 410075,China)

机构地区：[1]中南大学土木工程学院

出　　处：《振动与冲击》2019年第24期63-73,共11页Journal of Vibration and Shock

基　　金：国家自然科学基金项目(51378504);中南大学中央高校基本科研业务费专项资金项目(2018zzts191)

摘　　要：地震作用下,当桥梁上、下部结构间的横向相对位移超过挡块-梁体或挡块-垫石间的初始间隙时,就会发生碰撞。为研究高铁简支梁桥在地震激励下的横向碰撞效应,以32 m标准跨径简支梁桥为研究对象,按1∶6缩尺比设计并制作了单跨桥梁模型。通过振动台试验研究了地震波频谱特性、地震动峰值加速度(PGA)、挡块-垫石初始间隙等因素对横向地震碰撞效应的影响,并探讨了在挡块与垫石间填充橡胶缓冲垫层的防碰减震效果及橡胶垫层的减震机理。试验结果表明:振动台试验再现了桥梁结构横向地震碰撞过程,在多遇地震作用下,固定支座未发生破坏,挡块与垫石之间没有出现碰撞现象;而在设计地震和罕遇地震激励下,固定支座出现破坏,多数工况发生了碰撞。挡块与垫石之间的碰撞限制了墩梁间横向相对位移的发展,但碰撞会激起结构的高频响应,增大墩底弯矩响应;橡胶缓冲垫层的设置会减小挡块与垫石间的碰撞刚度,降低由地震碰撞所引起的高频响应,从而达到减震的效果。The pounding occurs when the earthquake-induced transverse relative displacement between superstructures and substructures exceeds the initial gap between shear keys and girders or between shear keys and bearing bases.In order to investigate the transverse pounding effect of high-speed railway simply-supported girder bridges under earthquake excitations,taking a 32 m standard-span simply-supported girder bridge as the research object,a single-span bridge model was designed and made with the scale ratio of 1∶6.The influence of the spectral characteristic of the ground motion,peak ground acceleration(PGA),and the initial gap between shear keys and bearing bases on transverse pounding effects was studied through shaking table tests.And the anti-collision effect and isolation mechanism of rubber bumpers were also discussed.The results show that:shaking table tests could reproduce the transverse seismic pounding process of the bridge structure;the fixed bearings were not damaged under the low-level earthquake excitations,and there was no collision phenomenon between the shear keys and the bearing bases;however,the fixed bearings were damaged and most of the test cases collided under the excitations of the design and high-level earthquakes.The pounding between the shear keys and the bearing bases significantly limited the development of the transverse relative displacement between the superstructure and the substructure,but it also aroused high-frequency response of the structure,and hence,amplified the bending moment response at the bottom of the pier.The installation of the rubber bumpers would reduce the pounding stiffness and weaken the high-frequency response of the bridge structure caused by the pounding,thus reduced the seismic responses of the bridge structure.

关 键 词：高速铁路 简支梁桥 地震 横向挡块 碰撞效应 橡胶缓冲垫层 

分 类 号：U422.55[交通运输工程—道路与铁道工程]