Optimal Design and Analysis of Spatial Grid Structures with Large Column Spacing Based on Fiber Model

In recent years,according to the rapid development in civil aviation industry,there is a new development chance for its spatial grid structures with large column spacing.In this paper,the lateral resistant system of a factory building with large column spacing is optimally designed for its structure.Three structure schemes of the lateral resistant system is determined preliminarily,in which the structure is without braces,with steel braces or with energy dissipation braces between columns respectively. After the above work,the three-dimensional finite element models of these three schemes are established,and the elastic time-history analysis is done under frequent earthquake,then the concrete design parameters of the steel braces and the energy dissipation braces are confirmed through repeated optimization calculation.Finally,the elasto-plastic performance of the three schemes is analyzed under rare earthquake,and the collapse mechanisms are studied.The analysis results indicate that: fiber model can be used for the elasto-plastic time-history analysis;compared with the story drift of the scheme without braces between columns,the story drifts of the scheme with steel braces and the scheme with energy dissipation braces between columns are decreased by 32% and 64% respectively under frequent earthquake,and the data are 12% and 46% under rare earthquake;and obviously the collapse resistant capacity of the latter two schemes are much better.The study of this paper can provide an important reference for design and analysis of the spatial grid structures with large column spacing.