近断层地震作用下软限位对层间隔震结构动力响应影响分析

结构隔震对远场地震动有较好的减震作用,但遭遇含长周期大脉冲的近断层地震动,隔震支座易产生较大水平位移,导致支座损坏甚至上部结构倾覆失稳,须对隔震支座进行软限位保护。对隔震层软限位的层间隔震结构振动台模型试验进行数值模拟,验证数值模拟精度;进而建立原型结构数值分析模型,进行了285种工况数值模拟计算,对非限位和限位工况下隔震层和主体结构的动力响应进行对比分析,结果表明,隔震层软限位可以限制隔震层变形,但对主体结构地震响应有增大影响;通过对限位设计参数优选,可将主体结构响应控制在不发生损伤或轻微损伤范围内;给出了软限位设计参数对层间隔震结构动力响应的影响规律,提出通过隔震限位结构损伤分析进行限位刚度优选的方法。

Effects of soft limit on dynamic response of layered isolation structure under near-fault ground motion

Structural isolation has a better seismic reduction effect under far field earthquake. But under the action of near-fault ground motion with long-period and large pulses, isolation supports are easy to produce larger horizontal displacements causing support damage, and even upper structure’s overturning or losing stability. It is necessary to protect isolation supports using soft limit. Here, finite element software was used to simulate shaking table model tests of layered isolation structures with soft limit of seismic isolation layer to verify the accuracy of numerical simulation and establish the numerical analysis model of the original structure. Then, numerical simulation computations were performed under 285 operational conditions. The contrastive analysis was made for dynamic responses of isolation layer and the main body structure under limited and unlimited operational conditions. The results showed that the soft limit of isolation layer can restrict deformation of isolation layer, but it can make the seismic response of the main body structure increase;through optimizing design parameters of the limit, the response of the main body structure can be controlled within the range of no damage or slight damage;the influence law of soft limit’s design parameters on dynamic responses of layered isolation structures is derived, the method to optimize limit’s stiffness through damage analysis of layered isolation structures with soft limit is proposed.