热轧槽钢柱在轴向约束下的抗火分析  

Fire resistance analysis of hot-rolled channel column with restraint

作　　者：计琳[1] Tan Kang Hai 赵均海[1] 

机构地区：[1]长安大学建筑工程学院,陕西西安710061 [2]南洋理工大学土木与环境工程学院,新加坡639798

出　　处：《西安建筑科技大学学报（自然科学版）》2007年第1期98-104,共7页Journal of Xi'an University of Architecture & Technology(Natural Science Edition)

基　　金：教育部博士点基金资助项目(20040710001);新加坡教育部科研基金项目(RGM28/03)

摘　　要：基于著名的Rankine公式研究了火灾情况下单轴对称薄壁热轧槽钢柱弯曲扭转屈曲的计算特性,提出了一种用于计算薄壁槽钢柱抗火性能的方法.给出了各种温度状况下,试件的荷载水平与修正长细比的关系曲线、荷载水平与构件扭转变形关系曲线,该方法考虑了端部轴向线弹性约束对柱子受热膨胀的约束作用.采用大型商用有限元软件MSC.MARC Mentat对模型进行非线性有限元分析,详细描述了有限元模拟过程,给出模型网格划分及其失效后的变形图.通过理论及有限元分析,两种方法计算结果吻合较好,得到的荷载温度曲线均表明槽钢柱在温度达到450℃之前,柱的抗火承载力与室温时相比变化不大,而在温度达到450℃之后,柱的极限抗火承载力陡然下降.温度越高,柱子在达到与该温度对应的极限抗火荷载之前的扭转变形越大,并且荷载位移曲线越早趋于平缓.This paper represents the analytical process and manual calculation method of the flexural-torsional buckling behavior of thin-walled structure with monosymmetric cross-section in fire condition. A new design method using Rankine formula considering of restraint to thermal elongation is proposed. The load ratio vs. modified slenderness ratio curves and load ratio vs. rotation deformation curves of column under different elevated temperature condition are obtained. FEM （Finite Element Method） nonlinear analysis is conducted using MSC. MARC Mentat to validate the new proposed method. The analytical results are reasonably accurate as compared to those of FEM analysis. The temperature-load ratio curves show that the fire resistance of channel column is not changed greatly until the temperature exceeds 450℃. Before the column arrives at its capacity corresponding to certain temperature, the higher the temperature, the bigger the torsional deformation, and the earlier the load-deformation curve declines to even.

关 键 词：薄壁钢结构 热轧槽钢柱 轴向约束 弯曲扭转屈曲 抗火 

分 类 号：TU391.1[建筑科学—结构工程]