高强冷成型钢开口截面轴压构件的高温后数值仿真与承载力研究  

Numerical Simulation and Load Bearing Capacity Study for High Strength Cold-Formed Steel Open Section Columns After Fire Exposure

作　　者：张佳慧 孙梦茹 ZHANG Jiahui;SUN Mengru(School of Environment and Architecture,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学环境与建筑学院,上海200093

出　　处：《建筑钢结构进展》2021年第9期61-71,90,共12页Progress in Steel Building Structures

基　　金：国家自然科学基金(51508328)。

摘　　要：冷成型钢构件在经历火灾(高温)后,力学性能可能发生衰减,需要关注其承载力的变化并做出准确评估。因此,在现有高强冷成型钢过火后材性与构件测试结果的基础上,通过数值仿真模拟预测构件经历不同温度后的力学行为。通过参数分析,开展开口截面承压构件过火后性能分析,研究高温后的构件长细比、截面形式对承载力和破坏模式的影响,评估常温构件设计方法的适用性。有限元建模和参数分析的结果表明:(1)冷成型钢构件材性的衰减不是影响其过火后性能的唯一因素,在特定温度段须考虑重量折减;(2)高温后长细比与构件破坏模式的关系与常温构件相似;(3)纵向加劲,特别是腹板加劲能够显著改善常温及过火后构件的承载能力;(4)常温构件承载力计算方法(直接强度法)整体上过高地估计了高温后构件的承载力,需引入高温后的构件几何缺陷。There is a loss of mechanical properties for cold-formed steel members after fire exposure.It is important to provide an accurate evaluation for the load bearing capacity of such members.Based on the available results, which were obtained from post-fire mechanical properties coupons and stub columns of high strength cold-formed steel, numerical simulation was used to predict the structural behavior of post-fire compressive members.An extensive investigation was conducted using parametric study on post-fire resistance of open section columns, and to account for the effect of slenderness ratio, section form on the load bearing capacity and failure modes of the post-fire members, and also to access the applicability of the design method.It is shown that:(1) the deterioration of mechanical properties is not the only reason for the decrease of post-fire loading capacity, and the loss of weight should be accounted;(2) the post-fire relationship between slenderness ratio and failure modes is similar to that of room temperature;(3) the longitudinal stiffeners, especially the web stiffeners, can greatly improve the structural behavior of such compressive members;(4) the calculation method of load bearing capacity of members at room temperature(direct strength method) overestimates the load bearing capacity of members after fire exposure, and the geometrical imperfections of members after fire exposure need to be included.

关 键 词：高强冷成型钢 开口截面 高温后 加劲 数值仿真 承载能力 

分 类 号：TU392.1[建筑科学—结构工程]