【摘要】 为考虑时效及环境因素对隔震支座力学特性的影响,介绍了国外学者和规范提出的支座特性修正系数、调整系数和界限分析方法,结合中国隔震橡胶支座的特点给出了力学特性修正过程.构造了12座具有不同外型特征的连续梁桥作为研究对象,分别采用3种常用的隔震支座(即铅芯橡胶支座、高阻尼橡胶支座和超高阻尼橡胶支座),基于Open Sees地震分析计算平台建立了隔震桥梁的3维动力分析模型,通过大量的非线性动力时程分析考察了时效及环境因素对不同高度桥墩地震反应的影响程度及其在不同外型桥梁中的离散情况,还采用增量动力分析技术研究了不同地震动强度(PGA)的影响.分析结果表明:时效及环境因素对隔震桥梁地震反应的影响较大,尤其是对处于0.2~0.4g加速度峰值下隔震桥梁的较低墩的位移反应;对于采用铅芯、高阻尼和超高阻尼橡胶支座的隔震桥梁,不考虑其影响则可能低估较低墩10%、50%和100%及以上的墩顶位移需求.更多还原

【Abstract】 To count for the effects of aging and environmental conditions on mechanical properties of the bridge bearing,the property modification factors,system property adjustment factors and bounding analysis are proposed by some scholars and guide specifications. Combined with characteristics of the rubber bearing in China,the modification procedure to consider the effect of aging and environmental conditions on mechanical properties of the bearing is suggested.Taking 12 continuous beam bridges with different layout features as examples,three designing schemes for isolated bridges,including bridges isolated with lead rubber bearings( LRBs) high damping rubber bearings( HDRBs),and super high damping rubber bearings( SHDRBs) on all piers and abutments,are proposed. 3-D nonlinear dynamic models of the isolated bridges were developed based on the computational platform Open Sees. The seismic response of isolated bridges under different PGAs of ground motions is analyzed using the technology of incremental dynamic analysis( IDA). The displacement response of varied height piers and its discrete state in different bridges are investigated. The nonlinear time history analysis method is conducted using actual ground motions. The analysis results indicated that the seismic response of isolated bridges is susceptible to influences of aging and environmental conditions,especially for lower piers when the isolated bridges are under the ground motion of PGA from 0. 2g to0. 4g; If the effect of aging and environmental conditions are not considered,the displacement demand of lower piers was underestimated by about 10%,50%,100% and over,when the LRBs,HDRBs,SHDRBs are adopted in the isolated bridges.更多还原