截面温度不均匀受约束钢柱抗火性能试验研究与有限元分析  

Experimental and numerical studies on restrained steel columns with non-uniform temperature distribution across section in fire

作　　者：王培军[1] 王晓[1] 

机构地区：[1]山东大学土建与水利学院,山东济南250061

出　　处：《建筑结构学报》2013年第3期28-34,共7页Journal of Building Structures

基　　金：国家自然科学基金项目(51008181);山东省中青年科学家科研奖励基金项目(BS2011HZ009)

摘　　要：截面温度不均匀钢柱火灾下将发生热弯曲及扭转屈曲破坏,同时对热变形的约束导致钢柱内在升温阶段产生附加压力,在降温阶段出现附加拉力。分别考虑3种约束刚度比和3种截面温度分布形式,进行了9根受约束钢柱的抗火试验,量测了受约束钢柱达到最大轴力时的温度(屈曲温度)、轴力恢复至初始荷载对应的温度(临界温度)及破坏温度,研究其在火灾升温和降温阶段的受力性能、破坏特征。试验结果表明,截面温度不均匀导致钢柱在绕截面对称轴弯曲时同时发生扭转;约束刚度比越大,钢柱的屈曲温度越低,破坏温度与屈曲温度之差越大;截面温差越大,钢柱屈曲温度和破坏温度越高。同时对试验钢柱进行了有限元分析,分析结果与试验结果基本一致,验证了所建立的有限元分析模型的正确性。The non-uniform temperature distribution across the column section causes thermal bowing and flexural- torsional buckling of a steel column in a fire. And the restrained thermal deformation induces an additional compression force in the column during the heating phase and additional tension force during the cooling phase of the fire. Nine steel columns with three axial restraint stiffness ratios and three temperature distribution profiles were tested in fire. Temperatures at which the axial forces in the column reached their maximum values （buckling temperatures） and returned to their initial values （ failure temperatures） were all measured. Behaviors and failure modes of the restrained steel column in fire were also investigated. Experimental results show that the non-uniform temperature distribution causes the torsion of the section when the column bends about the symmetric axis. The column with a higher restraint stiffness ratio buckles at a lower temperature and the temperature difference between the failure and buckling temperatures is greater. The column with a greater temperature gradient has a higher buckling and failure temperatures. The fire tests were simulated through using the finite element software. Simulation results and experimental results agree well with each other, which shows the validation of the proposed numerical model.

关 键 词：约束钢柱 抗火试验 有限元分析 弯扭屈曲 屈曲温度 破坏温度 温度不均匀分布 

分 类 号：TU391[建筑科学—结构工程] TU352.5