非规则梁桥横桥向地震碰撞反应分析

Analysis on pounding effect of irregular girder bridges under transverse earthquake

针对连续梁桥在横桥向地震作用下梁体与抗震挡之间的碰撞现象,建立了考虑支座非线性和墩柱弹塑性的碰撞模型。在此基础上,应用非线性时程方法分析了横桥向地震作用下非规则梁桥梁体与抗震挡之间的碰撞对结构横桥向地震反应的影响,探讨了减轻碰撞和限制相对位移的措施和方法。研究结果表明:梁体与抗震挡块间的碰撞不仅产生很大的撞击力,还会导致桥墩的地震需求增大,对结构抗震不利。通过在抗震挡内侧安装橡胶缓冲垫,可以极大地减小梁体与抗震挡之间的碰撞力,同时减小矮墩区桥墩的墩顶横向位移和墩底塑性转角,不显著增加高墩区桥墩的墩顶位移和墩底塑性转角。

For continuous girder bridges,based on the pounding phenomenon between girder and retainers under transverse earthquakes,a simplified model that considers the nonlinear behaviors of bearings and the elasto-plastic behaviors of piers was developed to study the effects of pounding.By use of the model,the pounding effects of irregular girder bridges were studied by nonlinear time history analysis method.The measures to mitigate pounding and limit relative displacement were discussed.The results show that pounding can lead to strong pounding force and amplify the responses of piers.Installation of rubber shock absorbing devices inside retainers significantly reduces impact force between girder and retainers,and also reduces displacement at the top and plastic rotation at the bottom of dwarf piers,however those of tall piers are amplified observably.