超大空间火灾钢构件危险性分析简化方法

Simplified risk assessment method of steel exposed to fire in large spaces

确定350℃为高大空间钢结构耐火的临界安全温度,提出了高大空间钢结构坍塌风险评估方法。基于热平衡方程建立了受火钢构件温升计算方法,方法中包含了火源辐射对钢构件的热作用、烟气辐射对钢构件的热作用以及烟气热对流对钢构件的热作用。分析某钢结构仓库内部发生15 MW火灾时,屋面钢结构的稳定性。结果表明,建筑面积小于6 000 m2且建筑高度小于8m的高大空间钢结构内部发生15 MW火灾时,屋面钢结构存在坍塌风险。

350℃ was taken as the critical temperature for large- space steel structure exposed to fire. Based on the lumped capacity mean, a model for tracing the temperature profile in steel members exposed to fire in large enclosures was proposed. In proposed mod- el, not only the smoke thermal radiation and smoke thermal convec tion were considered, but also the flame thermal radiation effect on the steel members was considered. An example was built to analyze the stability of steel-storehouse in case of 15 MW fire. By analy- zing, we find that there is collapse risk when the building （area less than 6 000 mz and height less than 8 m） occurs 15 MW fire.