近远场地震作用下基于摩擦摆支座的高速铁路连续梁桥减隔震研究

Research on Seismic Mitigation and Isolation of Continuous Beam Bridge for High Speed Railway Based on Friction Pendulum Bearing under Near-and-Far Field Ground Motions

以1座跨径布置为(60+100+60)m高速铁路预应力混凝土连续梁为研究对象,采用SAP2000软件建立基于CRTSⅡ型板式无砟轨道系统的线桥一体化模型,运用非线性时程分析法,考虑近远场地震动,进行基于摩擦摆支座的高速铁路连续梁桥减隔震研究。结果表明:对于中小跨径高速铁路连续梁桥,在远场地震动下,主墩支座采用摩擦摆支座,联间墩支座采用普通盆式支座,可实现与全桥采用摩擦摆支座相当的减隔震效果;在近场地震动下,采用摩擦摆支座应用于主墩,普通盆式支座配合减震榫应用于联间墩,在避免邻梁碰撞的同时也可达到预期的减隔震效果;轨道约束系统对墩梁相对位移的限制及联间墩支座承担梁体质量较小是造成应用于联间墩的摩擦摆支座减隔震效果不佳的主要原因。

A prestressed concrete continuous beam with the span arrangement of(60+100+60)m for high speed railway was taken as the research object.The integrated model of track and bridge based on CRTS Ⅱ slab ballastless track system was set up by SAP2000 software.The seismic mitigation and isolation of continuous beam bridge for high speed railway based on friction pendulum bearing were studied by using nonlinear time history analysis method and considering near-and-far field ground motions.Results show that,for continuous beam bridges with small and medium spans of high speed railway under far-field ground motions,the main pier bearings adopt friction pendulum bearings and the joint pier bearings adopt ordinary pot bearings,which can achieve the same vibration reduction and isolation effects as the full bridge with friction pendulum bearings.Under near-field ground motions,the main pier bearings adopt the friction pendulum bearings and the joint pier bearings adopt the ordinary pot bearings and vibration absorbers,which can avoid the collision between adjacent beams and at the same time achieve the expected seismic mitigation and isolation effects.The main reasons for the poor seismic mitigation and isolation effects of the friction pendulum bearings applied to the joint pier are the limitation of the rail constraint system to the pier-beam relative displacement and the smaller mass of the beam body of the joint pier bearing.