基于临界温度法的钢桁架结构抗火设计与分析

Fire resistant design and analysis of steel truss based on limiting temperature method

介绍了以临界温度法进行钢桁架结构抗火设计的方法与过程,提出根据资料选用或根据构件荷载比计算临界温度的两种做法,在利用对称羽流公式求解火灾温度场的基础上,给出了钢结构温度的确定方法,并提出结构抗火设计的五种防护方案。最后,对某会展建筑的屋盖钢桁架进行了抗火分析,通过分析提出应对钢桁架在二层楼面标高以上12m以下的部位喷涂膨胀型防火涂料进行局部防火保护。

This paper studies how to carry on the fire resistant design of steel truss using limiting temperature method, It in troduces two ways of calculating limiting temperature. One is to select limiting temperature through data and experience. The other is to use the toad ratio of component to calculate limiting temperature. In this article, symmetrical plume formulas are selected to calculate fire temperature field, the method of calculating the temperature of steel structure is proposed, and five solutions to fire resistant design were put forward. Finally, fire resistance analysis of a Convention Center＇s roof steel truss is carried out. According to the analysis results, the author suggests to spray expansible fire-retardant coating in the position below 12 m of steel truss.