考虑土-结构相互作用的空间网格结构地震响应分析

Seismic response analysis of space frame structure considering soil-structure interaction

阐述了人工黏弹性边界的机理及实现地震动输入的方法,采用MATLAB软件编制了等效节点荷载计算程序。通过算例分析将理论解与数值解进行对比,验证了程序的正确性。利用ABAQUS软件建立了位于典型软土场地的正放四角锥网架土-结构相互作用体系数值仿真模型,分析了考虑土-结构相互作用后对结构动力特性的影响,并且对土-结构相互作用体系进行了动力时程分析,得到了网架结构的加速度响应、相对位移和杆件内力的分布规律,并与刚性地基假定下结构的响应进行了对比和分析。结果表明,考虑土-结构相互作用后分析所得结构峰值加速度、相对位移和杆件内力等性能指标均有显著增大。不考虑土-结构相互作用可能会低估软土场地上的空间网格结构的地震响应。进行软土场地上空间网格结构工程抗震分析时应考虑土-结构相互作用对结构地震响应的影响。

The mechanism of viscoelastic artificial boundary and the method of seismic motion input were stated in this paper. Using the MATLAB,the program for calculating equivalent nodal force is given. A case study of comparison between theoretical results and numerical solution is presented,which has verified the correctness of the program. A numerical simulation model of soil-structure interaction system for square pyramid space grids is built on the typical soft ground in the platform of ABAQUS software,analyzes the effects of soil-structure interaction on dynamic characteristics. And the incremental dynamic analysis is performed based on soil-structure interaction system. The acceleration response,vertical relative displacement and distribution of internal force of square pyramid space grids were obtained,comparing and analyzing the result of dynamic response under the assumption of rigid ground. It is found that when we take into consideration of soil-structure interaction the structure of performance indicators,for instance,acceleration response,vertical relative displacement and internal force will be increased significantly. The seismic response of the structure built on the soft ground is likely to be under estimated if the effect of soil-structure interaction is not considered. So it should be considering the influence of soil-structure interactionin seismic response analysis when the structure is built on the soft ground.