火灾作用下单层球面网壳的非线性有限元分析

基于高大空间建筑火灾作用下的空气升温实用公式,按照欧洲规范规定的火灾高温作用下钢材的材料特性,考虑了温度对钢材特性的影响以及钢材屈服后的强化特征,对一凯维特单层网壳结构在火灾作用下的性能进行了非线性有限元分析,研究其在不同局部火灾作用下的温度场分布和位移特征,以及不同火源影响的最不利位置。结果表明:网壳结构在所有设计火源模型下的极限耐火时间都在20～30min左右;对于结构极限耐火时间,火源位置的影响大于火源面积的影响;结构中心向外延伸的第1环到第3环之间的区域,是结构抗火的薄弱部位。

Nonlinear Finite Element Analysis of Single Layer Reticulated Dome under Fire

Based on the utility of empirical temperature rise formula for large space fire,the nonlinear finite element analysis of the fire-resistant performances of a single layer reticulated dome was carried out with the thermal parameters of the steels specified in the EUROCODE 3,the effect of temperature on steels' properties and the hardening characteristics of steels after yielding were considered.The temperature fields,displacement characteristics and most unfavorable position of the structure under different local fire were studied.Based on the nonlinear finite element analysis,the results show that the ultimate fire-resistant duration are about 20-30 minutes for all designed fire models;the location of the fire has much greater effects on the structure compared with the area of the fire;the range between the first ring and the third ring counted from center of the dome is the most unfavorable position of the single layer reticulated dome under fire.