Cross-section capacity of RHS and SHS at elevated temperatures: Comparison of design methodologies
Cross-section capacity of RHS and SHS at elevated temperatures: Comparison of design methodologies
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DOI：
10.1016/j.istruc.2021.07.072
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发表时间：
2021-08-05
期刊：
影响因子：
4.1
通讯作者：
Boissonnade，Nicolas
中科院分区：
文献类型：
--
作者：
Couto，Carlos;Coderre，Tristan;Boissonnade，Nicolas
本文研究并比较了不同设计方法对受压和主轴弯曲空心截面的精度。为此，开发了基于壳有限元的数值模型，并根据文献中现有的实验结果进行了验证。利用验证的数值模型，对不同截面尺寸、不同荷载条件、不同钢种、不同温度等进行了全面的数值参数研究，得到了一组大型的空心截面耐火极限抗力结果。基于这些结果，对欧洲规范3第1 - 2部分的现有设计规则、AISC 360规范和Couto等人的最新设计建议[1,2]以及适用于火灾的直接强度法进行了评估，以评估其预测截面容量的准确性，包括在高温下抵抗局部屈曲的能力。结果表明，在欧洲规范3和AISC规范中提供的火灾情况的截面分类程序存在不一致性，应在未来进一步调查和修订。为了克服欧洲规范3的限制，建议采用Couto等人[1,2]的设计方法，而不考虑截面分类，对于AISC规范，建议使用基于0.2%证明强度的减小应力，直到开发出更有效的设计方法。
The accuracy of different fire design methodologies for hollow cross-sections subject to compression and major-axis bending is studied and compared in this paper. For that purpose, a numerical model based on shell finite elements is developed and validated against existing experimental results available in the literature. Comprehensive numerical parametric studies are then carried out by means of the validated numerical model, including different cross-section dimensions, loading conditions, steel grades and temperatures, to obtain a large set of results of the ultimate resistance of hollow sections in fire. Based on these results, the existing design rules of the Eurocode 3 Part 1–2, the AISC 360 specification and the recent design proposals of Couto et al. [1,2] and the Direct Strength Method adapted to fire are assessed in terms of their accuracy for predicting the section capacity, including the resistance against local buckling at elevated temperatures. It is demonstrated that the cross-sectional classification procedure for the case of fire, available in the Eurocode 3 and AISC specifications, results in inconsistencies and should be further investigated and revised in the future. To overcome the Eurocode 3 limitations it is proposed that the design methodology of Couto et al. [1,2] is adopted irrespective of the cross-section classification and for the AISC specification it is suggested the use of a reduced stress based on the 0.2% proof strength until more efficient design methods are developed.