Experimental analysis of cold-formed steel columns with intermediate and edge stiffeners in fire
Experimental analysis of cold-formed steel columns with intermediate and edge stiffeners in fire
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DOI：
10.1016/j.tws.2019.106481
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发表时间：
2020
影响因子：
6.4
通讯作者：
L. Laím;H. Craveiro;Rui Simões;A. Escudeiro;A. Mota
中科院分区：
文献类型：
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作者：
L. Laím;H. Craveiro;Rui Simões;A. Escudeiro;A. Mota
虽然在冷弯薄壁型钢构件中使用纵向加强筋可以提高其在常温下的极限强度，但当冷弯薄壁型钢构件暴露在高温下时，这种加强筋的刚度和钢的强度预计会降低。为此，本文介绍并讨论了带中间加劲肋和边缘加劲肋的冷弯薄壁钢柱在火灾条件下结构反应的试验研究结果，主要用于评估其临界温度、临界时间(抗火)和破坏模式。研究的主要变量包括：(A)截面形状，(B)边界条件，(C)边缘加劲肋配置和(D)周围结构的刚度对此类柱的热伸长的影响。此外，还将欧洲火灾设计预测(EN 1993-1-2：2005)与实验结果进行了比较，以观察其准确性。最后，基于本文的研究成果，采用双边折叠加劲肋的CFS截面明显优于采用单边折叠加劲肋的CFS截面。此外，组合截面的临界温度低于单一截面的临界温度，但耐火时间略高。此外，现有的分析方法已被证明不能预测火灾条件下约束碳纤维柱的复杂屈曲行为。
Although the use of longitudinal stiffeners in cold-formed steel members in compression is known to increase their ultimate strength at ambient temperatures, it is expected that the rigidity of such stiffeners and the strength of steel decreases when the cold-formed steel members are exposed to high temperatures. Therefore, this paper presents and discusses the results of an experimental investigation on the structural response of cold-formed steel columns with intermediate and edge stiffeners under fire conditions for assessing mainly their critical temperatures, critical times (fire resistance) and failure modes. The main variables studied included the: (a) cross-section shape, (b) boundary conditions, (c) edge stiffener configuration and (d) stiffness of the surrounding structure to the thermal elongation of such columns. Additionally, European fire design predictions (EN 1993-1-2:2005) were compared with the experimental results, in order to observe their accuracy. Finally, based on the findings of this research work it is obvious the advantage of using CFS sections with double edge fold stiffeners over the sections with single edge fold stiffeners. Moreover, built-up sections had lower critical temperatures than those for single sections, but with slightly higher fire resistance time. Furthermore, existing analytical methods have been shown to be incapable to predict sufficiently realistic the complex buckling behaviour of restrained CFS columns under fire conditions.