Structural responses of restrained steel columns at elevated temperatures. Part 1: Experiments
Structural responses of restrained steel columns at elevated temperatures. Part 1: Experiments
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DOI：
10.1016/j.engstruct.2006.12.005
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发表时间：
2007-08
影响因子：
5.5
通讯作者：
K. Tan;W. Toh;Zhan Huang;Guan-Hwee Phng
中科院分区：
文献类型：
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作者：
K. Tan;W. Toh;Zhan Huang;Guan-Hwee Phng
本文概述了在不同轴向约束比下确定无保护钢柱破坏时间的试验研究方案。采用轴向约束法模拟火灾中相邻冷构件对钢框架结构的热约束效应。所有柱的有效长度为1.74 m，根据其小轴长细比分别为45、55、81和97分为4组。柱被轴向加载并暴露在单调增加的加热条件下。通过专门设计的设备测量了柱的弯曲度和载荷偏心等初始缺陷。试验结果表明，轴向约束和初始缺陷显著降低了轴向加载钢柱的破坏次数。相比之下，轴承摩擦大大延缓了柱的破坏时间。这些影响表现为在柱试件两端的弯曲弹簧。此外，还采用了一种简单而可靠的朗肯方法来计算柱的失效次数。朗肯的预测与实验结果吻合得很好。
This paper outlines a research program on an experimental investigation to determine the failure time of unprotected steel columns subjected to various axial restraint ratios. Axial restraints were applied to simulate the thermal restraint effects due to adjacent cooler parts of a steel framed structure in fire. All columns had an effective length of 1.74 m, and were divided into 4 groups according to their minor-axis slenderness ratios of 45, 55, 81 and 97, respectively. The columns were axially loaded and exposed to a monotonically increasing heating condition. Initial imperfections such as column crookedness and load eccentricity were measured by a specially designed facility. The test results show that axial restraints, as well as initial imperfections, significantly reduce the failure times of axially-loaded steel columns. By contrast, bearing friction substantially retards column failure times. These effects are represented by flexural springs at both ends of a column specimen. Besides, a simple but reliable Rankine approach is used to compute the column failure times. The Rankine predictions agree well with experimental results.