ELASTIC BUCKLING LOAD OF STEEL COLUMN UNDER LONGITUDINAL NON-UNIFORM TEMPERATURE

被引：0
|
作者：
Wang W.-Y. [1 ,2 ]
Yang J.-J. [1 ]
机构：
[1] School of Civil Engineering, Chongqing University, Chongqing
[2] Key Laboratory of New Technology for Construction of Cities in Mountain Area of China Ministry of Education, Chongqing University, Chongqing
来源：
Gongcheng Lixue/Engineering Mechanics | 2024年 / 41卷 / 06期
关键词：
axial restraint; elastic buckling; energy method; fire resistance; non-uniform temperature; steel structure;
D O I：
10.6052/j.issn.1000-4750.2022.05.0497
中图分类号：
学科分类号：
摘要：
In large-scale building fires, due to the rising of hot air, the temperature distribution is usually nonuniform in the longitudinal space around a steel column, and the temperature in its upper zone is much higher than that in its lower zone. This phenomenon is very significant after the flashover condition. It is practical to consider the longitudinally non-uniform temperature for the fire resistance design of steel columns. Besides, advantage can be made of this in a performance-based approach to ascertain the stability of a steel column subjected to prescribed fire size. This paper takes the steel column that has no ending restraint as the research object and assumes that the temperature distribution on the cross-section is uniform. The elastic buckling load of the steel column under the field model fire is derived upon the energy method. Under the condition of the simplified two-zone fire model, the elastic buckling load is derived by the equilibrium differential equation and by the energy method, respectively. The derived results are verified by numerical analysis. It is found that: the error of the exact solution derived upon the equilibrium differential equation is less than 3% compared with the numerical simulation results, while the results derived based on the energy method are significantly larger in some cases. In addition, the results show that: if the longitudinally non-uniform temperature distribution is ignored, the elastic critical load will be seriously underestimated, even reaching about 37%, for a steel column with the same length as the unheated length. Considering the influence of the axial restraint, the calculation method of the buckling load of the steel column with longitudinally non-uniform temperature is proposed. © 2024 Tsinghua University. All rights reserved.
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页码：202 / 211and256
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