带深桩基础高层建筑结构的地震反应分析通常按刚性地基假定选择地震动输入,其合理性一直受到工程界关注。本文探讨了此类结构考虑桩-土-结构相互作用的整体有限元分析的地震激励施加、单元网格划分、积分步长确定、边界处理等问题,通过整体有限元分析模型和常规分析模型的算例分析对比,探讨了常规地震动输入方法的合理程度。结果表明,常规输入法总体偏于安全,是基本可行的,但可能低估结构底部几层的地震反应,应引起注意。
The ground motion excitation for the analysis of tall buildings with deep pile foundation is usually determined on the basis of the rigid ground assumption. Its rationality has attracted engineers' attention. Several problems in finite element analysis of pile-soil-structure system, such as simulation of ground motion excitation, meshing element, determination of integral interval, simulation of border, etc. , are discussed in this paper. The conventional method to select ground motion excitation is evaluated by comparing the responses of the pile-soil-structure system with the responses of conventional model. The results show that the conventional method is feasible in most cases but may underestimate the seismic responses in bottom floors.