火灾下大跨度弦支穹顶结构的性能分析

摘要

基于实用大空间火灾空气升温经验公式及预应力钢结构材料高温力学模型,采用考虑时间积分效应的非线性有限元数值分析法,建立了用于大跨度弦支穹顶结构抗火性能分析的数值模型.通过对大跨度弦支穹项结构的抗火分析,研究结构的温度场分布、位移和应力特征以及支座约束条件对结构抗火的影响.分析结果表明:在火灾作用下,大跨度弦支穹顶结构具有较好的抗火性能,结构的抗火薄弱区域位于上层网壳的中心区域；火灾下引起弦支穹顶结构产生较大变形的主要原因是环向约束作用、材料升温膨胀以及结构刚度的降低.%Based on the large space air temperature formula and mechanical properties of steel cable under high temperature, and using nonlinear finite element numerical analysis method considering the time integral effect, numerical model for the fire resistance analysis of beam string structure was built. Through the fire resistance analysis of suspen-dome structure, the tem-340perature field distribution, displacement and stress together with the influence of bearings constraint conditions to the structure fire resistance were studied. The results showed that's suspen-dome structure has better fire resistance performance; the weak area of the structure is al the central; main reason of large deformation is the circumferentially restrained condition material expansion with temperature and reduce of stiffness.