支撑布置对火灾下钢框架结构抗连续性倒塌性能影响研究  

Influence of Bracing Systems on the Fire Resistance of Steel Frames against Progressive Collapse

作　　者：姜健[1] 李国强[2] 

机构地区：[1]同济大学土木工程学院,上海200092 [2]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《防灾减灾工程学报》2016年第3期394-398,共5页Journal of Disaster Prevention and Mitigation Engineering

基　　金：国家自然科学基金重大国际合作项目(51120185001);国家自然科学基金青年基金项目(51408418)资助

摘　　要：研究了支撑布置对火灾下钢框架结构抗连续性倒塌性能的影响。考虑水平和竖向两种支撑布置形式,前者沿水平向布置在结构顶部,后者布置在结构各楼层,分别考虑其布置在结构边缘或者内部的情况。应用OpenSees软件对某7跨8层平面钢框架结构模型进行了数值分析。结果表明,火灾下结构倒塌始于受火柱的屈曲,该局部破坏向周边传播,导致整体结构下沉式倒塌或侧向倾覆式倒塌。竖向支撑可有效抑制结构的侧向倒塌,但容易导致底层柱的依次屈曲,不建议单独使用;通过将竖向支撑布置在结构内部,可有效阻止破坏向周边结构传播;水平支撑通过平均分配各柱轴压力,有效抑制周边柱的压曲,但容易造成结构局部或是整体侧向倒塌;同时应用两种支撑可有效提高结构抗倒塌性能。This paper studies the fire-induced progressive collapse. effect of bracing layout on the Two types of bracing systems resistance of steel frames against （horizontal and vertical） are considered. The horizontal bracings are arranged horizontally on the top of the frame and the vertical ones are placed along the height either on the edge or in the interior. A 7 span-8storey plane steel frame is numerically modeled in the^finite element software OpenSees. The results show that the progressive collapse of structures in fire is triggered by the buckling of heated columns. In general, its collapse mechanism is either in the form of global downward or a global lateral collapse. Vertical bracings can effectively resist the lateral drift of frames but may lead to successive failure of columns which should be prevented. An interior arrangement of vertical bracings can prevent the spread of the local failure to surrounding structures. Hat bracings can avoid the sequential buckling of columns by uniformly distributing the loads on all the columns, but are prone to cause local or global lateral collapse. Therefore, a combined bracing system is recommended.

关 键 词：支撑布置 水平支撑 竖向支撑 火灾 钢框架结构 连续性倒塌 

分 类 号：TU311[建筑科学—结构工程] O322[理学—一般力学与力学基础]