SRB与LRB隔震连续梁桥地震响应对比研究

A Comparative Study on Seismic Response of Isolated Continuous Girder Bridges with SRB and LRB

为研究SRB与LRB隔震连续梁桥地震响应的差别,根据G-C模型模拟SMA丝的热力学本构关系,采用Bouc-Wen模型模拟LRB力-位移的滞回非线性特性,通过对结构的离散建立了全桥有限元计算模型,分别编制了求解SRB和LRB隔震结构非线性运动方程的时程分析程序.利用自编程序并结合算例对不同地震激励下的非隔震、SRB和LRB隔震模型进行了时程对比分析.分析结果表明:在非低频脉冲波激励下,采用SRB与LRB隔震,梁体位移虽被放大但均在限值范围内,其它关键部位的地震响应均明显降低;在低频脉冲波激励下,SRB的隔震效果同样显著,但LRB隔震桥梁的地震响应比隔震前有明显放大,梁体位移超出了限值范围.

To investigate the difference on isolated continuous girder bridges with SRB（SMA rubber bearings） and LRB（lead rubber bearings）,the G-C model was adopted to simulate the thermodynamic equation constitutive relation of SMA（shape memory alloy） fiber,and Bouc-Wen restoring force model was used to simulate the LRB nonlinear hysteretic characteristics.FEM computation model of the entire bridge was established by the way of making the structure discrete.Further,the time history analysis program was prepared to solve the nonlinear motion equation of the isolated structure with SRB and LRB.The comparative analysis of time history was implemented for no-isolated,SRB and LRB isolated bridges under different kinds of seismic excitations by using the prepared program.The results indicate that,under non-low frequency pulse seismic excitations,the beam displacement is amplified by SRB and LRB isolation,but the maximum beam displacement is still within the range of standard and the seismic response of other key positions is decreased obviously.For the low frequency pulse seismic excitations,the isolating rate of SRB is still good,while the response of isolated bridges with LRB is much bigger than that of the non-isolated bridges,and its beam displacement might exceed the range of standard.