轴向约束对钢结构柱抗火性能的影响  

Effect of Axial Restraint on Fire Resistance Performance of Steel Column

作　　者：计琳[1] 赵均海[1] 翟越[1] 李新忠[1] 

机构地区：[1]长安大学建筑工程学院,陕西西安710061

出　　处：《建筑科学与工程学报》2006年第4期64-69,共6页Journal of Architecture and Civil Engineering

基　　金：教育部高等学校博士学科点专项科研基金项目(20040710001);陕西省自然科学基础研究计划项目(2003E215)

摘　　要：采用大型商用有限元软件MSC MARC Mentat研究了钢结构柱所受轴向约束的刚度对抗火性能的影响,对无保护层钢结构柱的抗火性能进行有限元分析,分析结果与试验结果吻合较好。结果表明:在室温情况下,轴向约束有利于提高钢结构柱的极限承载力,但在高温情况下,约束刚度的增大对钢结构柱的抗火承载力却具有负面影响,轴向约束的提高降低了高温下钢结构柱的极限承载力,并降低了钢结构柱的极限温度承载力;在温度达到450°C之前,由于钢材的弹性模量改变与构件的热膨胀,导致构件的承载力降低,温度超过450°C之后,弹性模量与屈服强度的折减及构件的热膨胀所导致的约束反力共同作用,使得构件更早失效。Authors investigated the axial restraint on fire resistance of unprotected steel column with commercial finite element method （FEM） software MSC MARC Mentat. The effect of axial restraint stiffness on fire resistance of steel column was analyzed. The FEM analysis results were fairly close to test results. The results show that although raising axial restraint stiffness can benefit bearing capacity of steel column in ambient temperature condition; in fire condition, fire resistance of steel column decreases as restraint stiffness increases. Under the fire condition, the reduction of elastic modulus and thermal expansion of column result in the decrease of bearing capacity before the temperature arrives at 450 ℃; after temperature exceeds 450 ℃, the yield strength of steel begins to decrease and the high temperature leads to high reaction of axial restraint, finally, it leads to the column collapse in fire.

关 键 词：钢结构 抗火性能 轴向约束 有限元方法 

分 类 号：TU392.1[建筑科学—结构工程]