近断层竖向地震动对摩擦摆隔震矮塔斜拉桥地震反应的影响  

Effect of near-fault vertical ground motion on extradosed cable-stayed bridge isolated with FPS

作　　者：石岩[1] 范向鑫 刘云帅[1] 郑国足[1] 罗程凯 Shi Yan;Fan Xiang-xin;Liu Yun-shuai;Zheng Guo-zu;Luo Cheng-kai(School of Civil Engineering,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050

出　　处：《工程抗震与加固改造》2022年第3期121-129,共9页Earthquake Resistant Engineering and Retrofitting

基　　金：国家自然科学基金项目(51908265)。

摘　　要：近断层竖向地震动会放大桥梁地震反应,威胁桥梁地震安全。为研究近断层竖向地震动对摩擦摆隔震桥梁地震反应的影响,以一座三跨矮塔斜拉桥为研究对象,基于OpenSees建立了全桥动力分析模型,选择40组具有速度脉冲效应的三向地震动记录,通过调整输入竖向加速度峰值与水平加速度峰值的比值(V/H),研究了竖向地震动对摩擦摆隔震矮塔斜拉桥地震反应的影响,分析了摩擦摆支座位移、塔底截面曲率、墩底弯矩以及主梁与挡块、主梁与桥台的碰撞效应等,并研究了竖向地震动对桥梁关键构件轴力的影响。结果表明:竖向地震动作用显著放大了支座、桥塔等关键构件的轴力,支座水平位移、塔底截面曲率、墩底弯矩以及主梁与挡块、主梁与桥台的碰撞力明显增大,且随着V/H的增大而增大。The near-fault vertical ground motion will amplify the seismic response and threaten the seismic safety of bridges. In order to study the effect of near-fault vertical ground motion on the friction pendulum isolation bridge, a three-span extradosed cable-stayed bridge is taken as the research object, and its dynamic analysis model is established by OpenSees. Selecting 40 groups of three-dimensional near-fault ground motion records as input, the effect of near-fault vertical ground motion on the seismic response of cable-stayed bridge is studied by changing the ratio of the vertical PGA to the horizontal PGA(V/H). The displacement of friction pendulum system(FPS), the curvature of bottom bridge tower, the moment of pier and the impact effect between the beam and the shear key and between the beam and the abutment are analyzed. The effect of near-fault vertical ground motion on the axial force of key members is also analyzed. The results show that the near-fault vertical ground motion has a significant effect on the axial force of key members such as bearing and tower. The displacement of the bearing, the curvature of bottom bridge tower, and the moment of the pier are obviously enlarged, as well as the impact between the beam and the shear key, and between the beam and the abutment are obviously increased when the near-fault vertical ground motion is considered. With the increase of V/H, all of them show an increasing trend.

关 键 词：桥梁工程 矮塔斜拉桥 摩擦摆支座 近断层竖向地震动 地震反应 

分 类 号：U448.27[建筑科学—桥梁与隧道工程]