无梁楼盖地震响应的试验研究与破坏机理分析

Shaking Table Test and Failure Mechanism of Seismic Response for Slab-column Air Defense System

以某典型单层多跨无梁楼盖人防结构为研究对象,根据相似条件设计了场地土和结构模型,分别采用Elcentro波和Kobe波进行水平单向或双向耦合地震动输入,进行两种不同埋深情况下砂土地基中结构地震响应的振动台模型试验研究。给出了结构加速度、应变、位移等动力响应的量测结果,分析了无梁楼盖人防结构地震破坏机理。结果表明:双向耦合输入地震荷载比水平单向输入地震荷载引起的结构动力响应大;浅埋结构与深埋结构相比各种动力响应均明显增大;由于结构中柱相对独立,其动力反应较侧墙强烈;结构中柱上下端、侧墙上下角隅处都是容易遭受地震破坏的部位;竖向地震力对结构的动力响应产生明显影响,其破坏力不容忽视。

A representative slab-column air defense system with multi-spans is selected to be investigated. The model of the ground and the structure are designed according to the similarity relations. The shaking table tests of seismic responses for slab-column air defense system surrounding by sand ground with two different burying depths are carried out by means of one-way ground motion input or coupling ground motion input with Elcentro wave and Kobe wave respectively. The dynamic responses of the acceleration, strain and displacement of the structure are given, and the failure mechanisms of slab-column air defense system subjected to earthquake load are discussed. The test results show that the dynamic responses of underground structures with coupling ground motion input are greater than those with one-way ground motion input. The dynamic responses of underground structures with shallow burying are obviously greater than those with deep burying. The dynamic responses of middle columns are greater than those of the lateral walls due to that the middle columns are independent in the slab-column air defense system. The tops and bottoms of the columns, the corners of the lateral walls are the locations which usually suffered the earthquake damage. The vertical earthquake loads have great effects on the dynamic responses of underground structures and should not be ignored.