近断层水平地震激励下巨-子三维隔震结构振动台模型试验

Shaking table test of the 3D isolated mega-sub structure under horizontal near-fault seismic excitation

将三维隔震层从地面标高上移至巨-子结构(巨型框架-子框架结构体系)的各子结构底部,可以解决高层三维隔震结构摇摆反应明显的问题,且整体隔震结构不再受高宽比限值的制约。设计加工了一个3层巨型框架结构模型,底层大空间,上部含有2个次框架。在2个次框架底部与主框架楼板相连部位安装4个三维隔震支座;进行了近断层及远场罕遇水平地震激励下,巨-子抗震结构和巨-子三维隔震结构的地震模拟振动台对比试验和数值分析。结果表明:巨-子三维隔震结构将隔震层上移至次框架底部并未延长结构的基本周期。次框架和主框架的动力响应减震效果显著,近、远场及场地类型对隔震率没有明显影响。由于近断层地震动的脉冲效应及其长周期成分与结构周期更接近,近断层激励下次框架和主框架的动力响应比相同场地的远场地震动大10%~20%,Ⅲ类场地近断层地震激励下的结构响应比Ⅱ类场地大10%~25%。

The three-dimensional isolation layer is moved from the ground to the bottom of the sub-structures in mega-sub structure（megaframe-subframe structure system）,which can solve the problem of the obvious sway reaction of the 3 Dbase isolated high-rise structure,and the structure no longer subjects to the constraint of height-width ratio limitation.A 3-story mega frame structure model is designed and manufactured,it has two sub-structures on the upper structure and a large space at the ground floor.4 3 Disolators were fixed at the connection of the every sub-structure＇s bottom and the floor of mega-structure.The comparison shaking table test and numerical analysis of the seismic mega-sub structure and the 3 Disolated mega-sub structure under rare earthquake excitation of horizontal near-fault and far-fault ground motions were performed.Results indicate that moving the 3 Disolation layer upward does not prolong the structural period.The vibration control effects for the dynamic responses of the mega-structure and the sub-structure are obvious,and they are seldom influenced by the type of the ground motion and site type.Due to the pulse effect and the long-period component of the near-fault ground motions,the dynamic responses of the sub-structure and mega-structure under the near-fault earthquake excitation are 10% ~20% larger than that under the far-fault earthquake excitation of the same site type,responses under the near-fault earthquake excitation of site typeⅢare10%~25%larger than that under the near-fault earthquake excitation of the site typeⅡ.