火灾非均匀温度场中正放四角锥网架结构的临界温度

Critical temperature of regular pyramidic space truss in non-uniform fire temperature field

为了保障大尺度空间建筑网架屋盖结构在火灾下的结构安全性,采用非线性有限元计算方法,按设计的结构方案对不同火灾场景下的正放四角锥网架结构进行结构全过程反应分析,得到反应结构抗火性能的临界温度.对临界温度进行参数分析,结果表明,温度场非均匀系数和结构荷载比是影响结构临界温度的关键参数.用最小二乘法对临界温度随关键参数变化的曲线进行拟合,得到正放四角锥网架结构临界温度的实用计算公式.通过算例比较表明,实用计算式可简便并偏于安全地计算正放四角锥网架结构的临界温度.

To ensure fire safety design for grid roof structures of large space buildings, the whole process response of regular pyramidic space truss is analyzed by nonlinear infinite element method to calculate different structural schemes. A series of critical temperatures are used to evaluate the fire performance for regular pyramidic space trusses on non-uniform fire temperature fields. The parameters for determining the critical temperatures, structure loading ratio and the coefficient for describing the non-uniform fire temperature field were considered as the key parameters. Fitting the relation of the critical temperature with key parameters by least square method, the practical equation for determining the critical temperature of regular pyramidic space trusses can be obtained. The calculated example shows that the practical equation can calculate the critical temperature for regular pyramidic space trusses.