高强度Q460钢柱抗火性能研究  

Study of fire resistance of high strength Q460 steel columns

作　　者：刘兵[1] 王卫永[1,2] 李国强[3] 戴国欣[1,2] 

机构地区：[1]重庆大学土木工程学院,重庆400045 [2]重庆大学山地城镇建设与新技术教育部重点实验室,重庆400030 [3]同济大学土木工程防灾国家重点实验室,上海200092

出　　处：《土木工程学报》2012年第9期19-26,共8页China Civil Engineering Journal

基　　金：国家自然科学基金(51006320);教育部高等学校博士学科点科研基金(20090191120032);重庆市自然科学基金(CSTC;2010BB4224)

摘　　要：采用恒温加载方式和振动法分别对Q460钢材高温下的强度和弹性模量进行试验研究,得到了Q460钢材的力学性能随温度的变化曲线。考虑高强钢Q460高温下力学性能和柱的初始缺陷,对常温下计算钢柱极限承载力的三种方法,即临界应力法、逆算单元长度法(ICSL法)和压杆挠曲线法(CDC法)进行延伸并得到Q460轴心受压柱高温下极限承载力。通过算例对三种方法的计算结果进行比较,并采用有限元分析对极限承载力计算结果进行验证。计算不同荷载比下高强度Q460钢柱的临界温度,将高强Q460钢柱与《建筑钢结构防火设计规范》CECS200:2006中给出的普通钢柱的高温极限承载力和临界温度进行对比。研究表明:高强度Q460钢高温下力学性能与普通钢差别较大,强度和弹性模量随温度升高降低较慢;三种方法计算高温下Q460钢柱极限承载力的结果基本一致并与有限元分析结果吻合较好;普通结构钢柱的稳定系数和临界温度与高强度Q460钢柱有较大差别,《建筑钢结构防火设计规范》CECS200:2006中给出的普通结构钢柱抗火设计结果不适用于高强度Q460钢柱。The strength and elastic modulus of Q460 steel at elevated temperatures were experimentally studied by steady-state test and dynamic method. With consideration of the mechanical properties of Q460 steel at elevated temperatures and initial imperfections, the three methods, namely critical stress method, inverse calculation segment length method （ICSL） and CDC method, to calculate the load bearing capacity of steel columns were extended to obtain the load bearing capacity of Q460 steel columns at elevated temperatures. The results of the three methods were compared and validated by finite element analysis through an example. The critical temperatures of Q460 steel columns at certain load ratio were computed and compared with the results given in the code for fire safety of structures in buildings-CECS200：2006. The study shows that the mechanical properties of Q460 steel are quite different from those of conventional steel, and the strength and elastic modulus decrease slowly with the increase of temperatures. The results from the three methods of calculating the load bearing capacity of Q460 steel columns are similar and agree well with the finite element method, and there is significant difference of critical temperature between Q460 steel and conventional steel columns, and the fire resistance design results given in the code for fire safety of structures in buildings-CECS200 ： 2006 are not applicable to Q460 steel columns.

关 键 词：高强钢 柱 抗火 承载力 有限元 

分 类 号：TU392[建筑科学—结构工程]