火灾下蜂窝钢梁腹板屈曲性能研究  

Investigation on Web-Post Buckling Behavior of Cellular Steel Beams in a Fire

作　　者：李鹤[1,2] 王旭东[2,3] 张露露[2] 刘梅[2] LI He WANG Xudong ZHANG Lulu LIUMei(Shandong Provincial Architectural Design Institute, Jinan 250001, China School of Civil Engineering, Shandong University, Jinan 250061, China Ploy（Qingdao）Holdings Co. ,Ltd. , Qingdao 266000, China)

机构地区：[1]山东省建筑设计研究院,济南250001 [2]山东大学土建与水利学院,济南250061 [3]保利(青岛)实业有限公司,山东青岛266000

出　　处：《建筑钢结构进展》2016年第6期42-51,共10页Progress in Steel Building Structures

摘　　要：通过有限元方法研究火灾下无防火保护蜂窝钢梁孔间腹板屈曲性能及屈曲温度。首先采用有限元传热分析,获得标准火灾下无防火保护蜂窝梁不同受火时刻的三维有限元温度分析结果,然后采用有限元受力分析确定三维有限元温度分析结果下蜂窝梁孔间腹板的受力性能和屈曲温度。传热分布结果表明,开孔后增加了孔洞周边厚度方向上腹板与空气间的热量交换,使得腹板升温速率明显大于翼缘。火灾下结构受力分析结果表明,由于钢材的力学性能随温度升高而降低,而且中心腹板升温速率快使蜂窝梁更易发生孔间腹板屈曲破坏。蜂窝梁的屈曲温度随孔间距及腹板厚度的增大而增大。通过对采用三维有限元温度分布与均匀温度分布的蜂窝梁进行对比分析,结果表明,由于不均匀温度分布使得沿腹板高度产生附加热应力,从而使得孔间腹板屈曲变形增大。Web-post buckling behavior and the critical temperatures of cellular steel beams at elevated temperatures in a fire are investigated using validated finite element models.The true temperature distribution of the cellular steel beam is obtained through the thermal analysis firstly.Then the structural behavior and buckling temperature of the web-post are investigated under the true temperature distribution.Temperature distribution shows that the existence of openings leads to higher temperatures in web than those in flange.Structural analysis shows the cellular steel beam is more vulnerable to web-post buckling due to the degradation of steel mechanical property and the higher elevation rate of the central web.Buckling temperature of the cellular steel beam increases with the increase in the opening distance and the web thickness.Results show that additional thermal stress is induced into the web due to non-uniform temperature distribution along the section height which increases the buckling deformation of the web.

关 键 词：蜂窝钢梁 无防火保护 孔间腹板屈曲 屈曲温度 不均匀温度分布 

分 类 号：TU352.5[建筑科学—结构工程]