基于摩擦摆支座的连续梁桥抗震性能提升研究

Study on Seismic Performance Improvement of Continuous Girder Bridge Based on Friction Pendulum Bearing

为探究摩擦摆支座对震后预应力混凝土连续梁桥抗震性能提升效果,以实际工程为背景,分别建立了盆式橡胶支座与摩擦摆支座的全桥三维有限元模型,通过模态分析对比了两种支座对桥梁振动周期的影响;通过改变摩擦摆支座的曲率半径和摩擦系数,盆式橡胶支座和摩擦摆支座的组合形式,研究了摩擦摆支座参数、支座组合形式对桥梁地震响应隔震效率的影响。结果表明:采用摩擦摆支座有效延长了混凝土连续梁桥自振周期;支座隔震效率随摩擦系数变化曲线呈Z型,且摩擦系数在0.03~0.07变化时,支座隔震效率变化明显,曲率半径为4 m时该桥支座耗能能力最佳;桥台支座更换为摩擦摆支座更有利于减小桥墩墩底剪力值,特别是仅更换桥台支座的减震效果略低于全部更换,因此建议对同类型预应力混凝土三跨连续梁桥进行隔震设计时,优先考虑更换桥台支座,以实现成本效益与减震效果的良好平衡。

To investigate the effect of friction pendulum bearings on the seismic performance improvement of prestressed concrete continuous girder bridges,two three-dimensional bridge finite element models were established,one with basin rubber bearings and the other with friction pendulum bearing,based on actual engineering data.The influence of the two types of bearings on the bridge's vibration period was compared through modal analysis.Furthermore,the effects of different curvature radii and friction coefficients of friction pendulum bearings,as well as the combination of basin rubber bearings and friction pendulum bearings,on the seismic response isolation efficiency of the bridge were analyzed.The results show that the use of friction pendulum bearings effectively extends the natural vibration period of concrete continuous beam bridges.Moreover,the curve of the bearing isolation efficiency relative to varying friction coefficients exhibits a Z-shaped pattern,with significant changes in isolation efficiency observed when the friction coefficient varies between 0.03 and 0.07.Additionally,when the curvature radius is 4 meters,the energy dissipation capacity of the bridge bearing is optimal.The study also found that merely replacing the abutment bearings with friction pendulum bearings,although slightly less effective in damping compared to replacing all the bearings on the bridge,still significantly reduces the shear force at the base of the bridge piers.Therefore,when designing seismic isolation for similar types of prestressed concrete three-span continuous girder bridges,it is recommended to prioritize replacing the abutment bearings to achieve a good balance between cost-effectiveness and seismic reduction performance.