机场航站楼屋顶钢结构防火性能化分析

Performance-based fire resistance on airport terminal steel roof

为了得到某机场航站楼屋顶钢结构的抗火性能,利用火灾动力学、传热学和有限元分析相结合的方法,通过火灾危险性分析,按照可信最不利原则设定机场航站楼结构火灾场景;运用火灾动力学软件FDS和传热学公式得到火灾影响区域构件温升曲线,建立结构有限元模型,并结合结构荷载条件和温升曲线计算出结构在设定火灾场景下的力学性能.结果表明:部分结构构件在火灾下内力增加很多,甚至接近构件在火灾温度下的设计强度,但结构整体竖向位移相对于整体跨度较小,整体结构仍然处于安全状态.为了整体安全,利用结构自身强度来进行有效的抗火设计,通过加强空间结构的整体性和超静定次数可以有效提高结构的抗火性能.

Fire dynamics,heat transfer and finite element analysis method were used to obtain the fire resist-ance of airport terminal steel structure.First,the credible and most dangerous fire scenarios of airport terminal roof were adopt.Then,the fire dynamics software FDS and the heat transfer formula were used to get the tem-perature rise curves in the fire affected region.Finally,the model of the structure was set up by finite element method,the load conditions and temperature rise curves were combined to calculate the mechanical properties of the structure.The resulit shows that the internal force of some members in the structure are increased and e-ven close to the design strength,but the vertical displacement of the structure is relatively small to the overall span of the structure,the structure is still in safe condition.From the perspective of overall security,it is effi-cient to carry out the fire-resistant design of structure by its own strength,and to improve the fire-resistant properties of the structure by strengthening the integrity and increasing the number of statically indeterminate.