连崖结构受力机理及其地震响应分析

Stress mechanism and seismic response analysis of structures resting on cliff

连崖结构是山地建筑结构中的一种﹒本文提出了8种可能的连崖约束方式;推导了连崖结构抗侧移刚度公式,并对影响抗侧移刚度的参数作了详细分析;通过算例进行了连崖框架的地震反应谱分析及弹塑性动力时程分析﹒结果表明:隔震支座可有效减小结构支撑以下楼层层间位移角及层间剪力,小震时其最大降幅分别为13%和14%,同时隔震支撑以上楼层剪力有所增大,但不超过6%;大震时弹塑性层间位移角最大降幅为47%;定向滑动支座对主体结构的侧移刚度影响最小,但不能有效减小结构的位移及剪力;斜坡支座在小震时层间位移及剪力降低率最大,分别为25%和15%,但在大震时,支撑端部出现了严重塑性损伤,导致减震效果不明显;建议连崖结构选择隔震支撑模型。

Structure resting on cliff is a kind of mountain building structure. In this paper, eight possible restraint modes of structure resting on cliff are put forward, the formula of anti-lateral stiffness of cliff structure is derived, the parameters affecting anti-lateral stiffness are analyzed in detail, and the seismic response spectrum analysis and elastic-plastic dynamic time-history analysis of cliff frame are carried out. The results show that the isolation bearing can effectively reduce the inter-story displacement angle and inter-story shear force under the structural bracing, and the maximum reduction is 13% and 14% respectively under small earthquakes. At the same time, the shear force of the floor above the isolation bracing increases, but not more than 6%. The maximum decrease of the elastic-plastic inter-story displacement angle is 47% during a large earthquake, and the directional sliding bearing has the least influence on the lateral stiffness of the main structure, but it can not effectively reduce the displacement and shear force of the structure. The reduction rate of inter-story displacement and inter-story shear force of slope bearing is the largest during small earthquake,which is 25% and 15% respectively, but in large earthquake, serious plastic damage occurs at the end of bracing, and the damping effect is not obvious. It is suggested that the isolation bracing model should be selected for structures resting on cliff.