竖向地震对板式橡胶支座滑移效应的影响

为了探究竖向地震动对板式橡胶支座滑移效应的影响,并讨论现行规范中竖向地震动规定的合理性,利用OpenSEES中平滑动支座单元模拟支座的滑移行为,选取了11条典型地震记录,针对某典型桥例,分别按照不考虑竖向地震、考虑实际竖向地震记录和按细则考虑竖向地震三种模式展开对比研究,并同时分析支座滑移摩阻系数的影响规律.结果表明:竖向地震会大幅增加支座的滑移位移响应,最大位移比可达2.59,且随摩阻系数的增大,竖向地震的影响也越大;竖向地震一般会降低墩柱的变形曲率,尤其是纵桥向曲率,且受摩阻系数取值的影响较大;不考虑竖向地震对求解支座滑移位移是偏不安全的,但对求解墩柱曲率是偏安全的.按照细则的做法,即通过对水平地震进行折减来考虑竖向地震,可以得到较可靠的计算结果.

Effect of Vertical Earthquakes on Sliding Performance of Laminated Rubber Bearings

To study the effect of vertical earthquakes on sliding performance of laminated rubber bearings,and to discuss rationality of vertical earthquake terms in the current specification,a flat slider bearing element of OpenSEES was used to simulate sliding behaviors of bearings.Eleven typical seismic records were selected.For a typical bridge case,a comparison study was carried out for three models which ignored the vertical earthquake,considered the actual vertical earthquake and considered the vertical earthquake according to the current specification,respectively.Meanwhile,the effect of the frictional coefficient of bearings sliding was analyzed.The results show that the vertical earthquake will magnify the slip displacement response of bearings,and the maximum displacement ratio can reach 2.59.With increase of the frictional coefficient,the effect of vertical earthquakes becomes greater.Vertical earthquakes generally reduce the deformation curvature of the pier,especially for the longitudinal bridge curvature,and the deformation curvature are greatly affected by the value of the frictional coefficient.It's not safe to solve the slip displacement of bearings without considering.vertical earthquakes,but it's safe to solve the curvature of the pier.According to the specification,the vertical earthquake can be considered by reducing the horizontal earthquake,and the relatively reliable calculation results can be obtained.