超长联大跨连续梁桥摩擦摆支座隔震研究

SEISMIC ISOLATION OF LONG SPAN AND SUPER LONG UNIT CONTINUOUS BEAM BRIDGE WITH FRICTION PENDULUM BEARINGS

基于某长周期超长联大跨度预应力混凝土连续梁桥梁,开展了摩擦摆支座的隔震研究。建立全桥有限元计算模型,采用双线性滞回模型模拟摩擦摆支座,输入50年超越概率2%的3条安评地震波进行了非线性时程反应分析及抗震性能验算。该联桥的分析表明,当摩擦摆支座的曲率半径为5m、滑动摩擦系数为0.03时,隔震后桥墩及桩基础的均处于弹性工作状态;支座顺、横桥向的最大水平滑动位移分别为207mm、198mm,在可按受的范围之内。超长联大跨连续梁桥有其自身的结构及受力特点,采用摩擦摆支座隔震时能显著地提高其抗震性能。

Isolation using friction pendulum bearings is utilized in a long span and super-long unit prestressed concrete continuous girder bridge with a long period. A finite element model of the full bridge is established, and a bilinear hysteretic model is used to simulate the friction pendulum bearings. A nonlinear time history response analysis is carried out by inputting three safety evaluation seismic motions with 50-year 2% exceedance probability and seismic performance as verification. The results show that when the friction pendulum bearings have a curvature radius of 5m and a coefficient of sliding friction of 0.03, the piers and its pile foundations behave elastically. The maximum displacements of the bearing are 207 mm and 198 mm in the horizontal and transverse directions, respectively. The displacements can easily be accommodated by the gap. Long span and super-long unit continuous beam bridges with long period have their own structural features; friction pendulum bearings can effectively improve their seismic performance.