钢桁架屋盖结构抗火设计实用方法  

Fire Safety Design Approach for Steel Roof Trusses Exposed to Localized Fire

作　　者：林苏敏 杜咏[1] 蒋云[1] 付建新[1] 

机构地区：[1]南京工业大学土木工程学院,南京211816

出　　处：《建筑钢结构进展》2015年第3期57-64,共8页Progress in Steel Building Structures

基　　金：国家自然科学基金(51378259)

摘　　要：钢桁架结构作为大空间建筑屋盖结构常用的形式之一,其火灾下的承载能力对于保证大空间建筑屋盖结构在规定耐火极限内的安全性至关重要。采用有限元数值分析方法和结构力学理论分析,对桁架屋盖在多参数影响下的抗火性能进行了研究,发现平面外支座约束条件、火源位置及结构荷载比是影响钢桁架结构抗火承载力的关键因素;桁架屋盖体系中的支撑构件在火灾下失效会使桁架平面外支座约束方式产生变化,从而影响上弦杆件平面外抗火承载力;基于整体结构受火性能,提出了钢桁架屋盖抗火设计实用方法,该方法有助于明确临界温度法或承载力法中相关参量的取值,为基于计算评价桁架屋盖结构在大空间建筑火灾下的抗火性能提供科学的依据。Steel truss has been widely applied in large span buildings. Fire resistance is very important to ensure the safety for the roof structure under ultimate fire limit state. In this paper,a series of steel roof truss models are established by using ANSYS software,and the behavior of truss exposed to localized fire is studied. Then the key factors influencing fire resistance of steel roof truss are identified through parametric studies. The theoretical and numerical studies indicate the out-of-plane constraint condition, fire location and loading ratio are the key factors influencing fire resistance of steel roof trusses. At last, design approach is proposed for fire safety of roof truss. This study helps to determine values from the relevant parameters using critical temperature method or loading-bearing capacity method, and it also provides a useful reference for evaluating the performance of roof truss under localized fire.

关 键 词：钢桁架屋盖结构 大空间建筑火灾 抗火设计 临界温度 抗火承载力 

分 类 号：TU391[建筑科学—结构工程] TU352.5