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在近断层脉冲型地震动作用下,LRB基础隔震结构可能与周围挡墙或基坑发生潜在的碰撞响应。该文利用改进的Kelvin碰撞分析模型,并假定LRB基础隔震结构的上部结构其层间恢复力模型为经典双线性模型,通过时程分析探讨了碰撞响应对上部结构动力特性的影响,研究发现:碰撞使上部结构的绝对加速度较基础固定时有很大的增加;而且碰撞发生而产生的巨大碰撞力使上部结构底部的层间位移时程曲线呈现出阶梯状并且出现明显的永久残余层间变形,这说明LRB基础隔震结构的上部结构底层较基础固定的上部结构底层有更高的延性需求,否则发生碰撞后容易导致上部结构的整体倒塌;碰撞的发生改变了LRB基础隔震结构的基本变形模态,激发了结构的高阶振形,造成了上部结构的运动不再保持为平动状态。
Under near-fault impulsive ground motions, the LRB base isolation structure may have a potential collision response with the surrounding retaining wall or foundation pit. In this paper, an improved Kelvin collision analysis model is used, and the layer-restoring force model of the superstructure of the LRB base-isolation structure is assumed to be a classical bilinear model. The influence of collision response on the dynamic characteristics of the superstructure is discussed through time-history analysis It is found that the collision accelerates the absolute acceleration of the superstructure more greatly than that of the foundation, and the huge collision force generated by the collision causes the interlayer displacement time history curve at the bottom of the superstructure to show a staircase shape with obvious permanent residual layer The results show that the bottom of the superstructure of LRB base isolation structure has a higher ductility requirement than that of the underlying fixed superstructure, otherwise the collapse of the superstructure may easily lead to the whole collapse of the LRB base isolation structure. The collision changes the structure of the LRB base isolation structure Of the basic deformation mode, exciting the structure of the high-order vibration, resulting in the superstructure of the movement no longer remain in translation state.