轴向约束高强度Q460钢柱抗火性能试验研究  

Experimental study on fire resistance of axially restrained high strength Q460 steel columns

作　　者：王卫永[1,2] 葛勇[1] 

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400045

出　　处：《建筑结构学报》2015年第8期116-122,共7页Journal of Building Structures

基　　金：国家自然科学基金项目(51008320);重庆市博士后科研项目特别资助项目(渝xm201103007)

摘　　要：为了获得高强度Q460钢柱的抗火性能,对4根轴向约束高强度Q460钢焊接H形截面柱进行了抗火性能试验。试验采用恒载升温模式,升温曲线为ISO 834标准升温曲线,考虑了两种轴向约束刚度和两个级别的荷载比。试验测量了轴向约束高强度Q460钢柱受火过程中的温度、轴向位移和跨中挠曲变形。根据试验结果得到了轴向约束高强度Q460钢柱的屈曲和破坏时的温度。采用轴向约束钢柱的轴力放大系数方法计算了试验构件的破坏温度,并和试验结果进行了对比,同时还对轴向约束高强度Q460钢柱和普通Q235钢柱的抗火性能的差异进行了比较。研究表明:轴向约束刚度和荷载比对高强度Q460钢柱的抗火性能影响较大;相同荷载比下,轴向约束刚度大的高强度Q460钢柱破坏温度低;相同约束刚度下,荷载比大的轴向约束高强度Q460钢柱破坏温度低。采用轴力放大系数方法可以较准确地确定轴向约束高强度Q460钢柱的破坏温度。相同荷载比下,相同约束刚度和几何尺寸的高强Q460钢柱比普通Q235钢柱具有更好的抗火性能。In order to obtain the fire resistance of high strength Q460 steel columns,fire test on four axially restrained H-shaped columns fabricated with high strength Q460 steel was carried out by using a furnace. The temperature of the furnace followed ISO-834 standard curve with the applied load keeping constant. Two kinds of axial restraint stiffness and two load ratios were considered. The temperature distribution,axial displacement and deflection at the mid-section of axially restrained high strength Q460 steel column were recorded in the test. Based on the test results,the buckling and failure temperature of axially restrained high strength Q460 steel column were obtained. The failure temperature of test specimens were calculated by employing the method of amplification factor of axial force in axially restrained steel columns and the calculation results were compared with test results. The fire resistance between high strength Q460 steel columns was also compared with mild Q235 steel columns. The study shows that both the axial restraint ratio and load ratio have great influence on the fire resistance of axially restrained high strength Q460 steel columns. For a similar load ratio,the failure temperature is lower for the axially restrained high strength Q460 steel column with a higher of axial restraint ratio. For a similar axial restraint ratio,the failure temperature is lower for the axially restrained high strength Q460 steel column with a higher of load ratio. The method of amplification factor of axial force in axially restrained steel columns can be used to accurately predict the failure temperature of axial restrained high strength Q460 steel columns. With similar load,axial restraint ratio and dimensions,the fire resistance of axially restrained high strength Q460 steel columns is much better than that of mild Q235 steel columns.

关 键 词：高强Q460钢柱 轴向约束 抗火试验 破坏温度 

分 类 号：TU392[建筑科学—结构工程]