大跨度斜拉桥摩擦摆式支座减震性能分析

Analysis of Damping Performance of Frictional Pendulum Bearings in Long-Span Cable-Stayed Bridge

为选用合适的摩擦摆支座设置方案,以改善地震作用下大跨度斜拉桥下部结构的受力性能,以安庆-九江高铁鳊鱼洲长江大桥主航道桥为背景,利用有限元软件建立全桥模型,比较不同摩擦摆支座设置方案下桥梁下部结构的地震反应。结果表明:在地震作用下,不设置摩擦摆支座时,承台底轴力及墩梁之间相对横向位移不满足减震要求;仅边墩设置摩擦摆支座墩梁之间相对横向位移不满足设计要求;边墩及辅助墩均设置摩擦摆支座后,下部结构最不利轴力显著提高,墩梁之间相对横向位移响应明显下降,安全系数大幅提高,均能满足结构减震要求。鳊鱼洲长江大桥主航道桥最终采用边墩及辅助墩均设置摩擦摆支座方案。

To improve the load bearing capacity of superstructure of long-span cable-stayed bridge under the action of earthquakes by selecting proper installation scheme for frictional pendulum bearings,the main navigational channel bridge of Bianyuzhou Changjiang River Bridge on Anqing-Jiujiang High-speed Railway was taken as the background project.The full-scale model of the bridge was built by finite element software to compare the seismic response of superstructure under different frictional pendulum bearing layouts.The results show that the axial force in the base of pile cap and relative transverse displacement between the pier and girder could not meet the seismic protection requirements,when there were no frictional pendulum bearings.When the frictional pendulum bearings were installed on the side piers,the relative transverse displacement between pier and girder could not meet the design requirements.When the frictional pendulum bearings were installed on both side and auxiliary piers,the most unfavorable axial force in the substructure was significantly improved,the relative transverse displacement between pier and girder was obviously reduced,and the safety coefficient was greatly enlarged,which all met the seismic mitigation requirements of the structure.As a result,the frictional pendulum bearings in the main navigational channel bridge of Bianyuzhou Changjiang River Bridge were installed on the side and auxiliary piers.