考虑动水压力作用隔震桥梁的地震响应分析

Analysis on Seismic Response of Isolated Bridges Under Hydrodynamic Pressure

为了探讨高烈度山区不规则隔震桥梁在动水压力作用下的地震响应,以MORISION方程及其扩展方程为原理计算动水压力,选用铅芯隔震橡胶支座作为隔震支座,利用有限元软件ANSYS对全桥建立简化的力学数值计算模型,并采用非线性时程法进行抗震分析,主要研究了桥墩及铅芯隔震橡胶支座在不同水位处的地震响应。研究结果表明:动水压力作用会使桥墩的地震响应增大,同时也会增大隔震橡胶支座的水平剪力及位移,而隔震橡胶支座利用其耗能的特点则能有效地减小动水压力对桥墩产生的地震响应。因此,对于考虑动水压力作用的不规则深水桥梁,应选取抗剪能力更强、变形能力更大的隔震橡胶支座,以保证良好的隔震效果,提高桥梁结构在地震作用下的整体安全性。

In order to investigate the seismic response of irregular isolated bridges in high earthquake intensity area under hydrodynamic pressure,the hydrodynamic pressure was calculated based on the M ORISION equation and its extended equation.The lead rubber bearing isolator was chosen as the isolation bearing.A simplified mechanical numerical model was established for the whole bridge by using finite element software ANSYS,and seismic analysis was carried out by nonlinear time history method.The seismic responses of pier and lead rubber bearing isolators at different water levels were studied.The results show that the action of hydrodynamic pressure will increase the seismic response of pier and increase the horizontal shear and displacement of lead rubber bearing isolator.Because of the characteristics of energy dissipation,the lead rubber bearing isolator can effectively reduce the seismic response of hydrodynamic pressure to the pier.Therefore,an isolated rubber bearing with better shear resistance and greater deformation capacity should be used for the irregular bridge in deep water considering hydrodynamic pressure to ensure its good isolation effect and improve the safety of the whole bridge structure under earthquake.