考虑施工时变效应的大跨空间钢结构合拢方案研究

Study on the closure construction scheme of large-span space steel structures considering time-dependent effect

为减少大跨空间钢结构在施工期间的温度效应,合拢施工的方法逐渐被采用。本文以深圳大运会体育场采用的"折面空间网格结构"为工程背景,依据气象统计资料确定结构合拢施工阶段时的变温度荷载,采用考虑时变效应的施工过程状态非线性分析方法,针对大运会体育场钢结构的四种合拢施工方案进行了全过程模拟分析。对各方案中结构内力和变形的全过程发展进行了比较,结果表明:合拢线的数量对结构的温度效应有较大影响。合拢线由2条增至4条,最大应力和最大位移分别由55MPa和21mm减小至38MPa和17mm,且杆件轴力明显减小;合拢线的位置对结构的温度效应影响较小。不同方向引起的最大温度应力和位移相差分别在5 MPa和1mm以内,其中沿斜向设置合拢线的方案最优。但在实际施工中,沿南北向设置合拢线较为合理。

With the rapid development of large-span space structures,the planar dimension of the structure is increasingly expanded.In order to decrease the temperature effect during construction of structures,the closure construction method has been gradually adopted.In this paper,the ‘folded space grid structure’ adopted in Shenzhen universiade stadium is taken as the engineering background.Based on the time-dependent temperature load obtained by meteorological statistical data,the state-nonlinear construction process analysis method considering the time-dependent effect is adopted to investigate four closure construction schemes of the universiade stadium structure,and the global process development of structural internal forces and deformations of various kinds of schemes are obtained.Results show that the number of closure line has great influence on the structural temperature effect.When the number of closure line increases from 2 to 4,the maximum stress and displacement is reduced from 55MPa,21mm to 38MPa and 17mm,respectively,and the member force decreases distinctly.The closure line location has relatively small effect on the structural temperature.The difference of maximum stress and displacement are 5MPa and 1mm,respectively.The optimum location is oblique direction.