Residual strength of steel beam columns under elevated temperature

• Published in: Journal of constructional steel research 2019-04, Vol.155, p.176-191
• Main Author: Al-Thairy, Haitham
• Format: Article
• Language: English
• Subjects: Beam-column; Elevated temperature; Eurocode 3; Resistance; Steel sections
• ISSN: 0143-974X; 1873-5983
• DOI: 10.1016/j.jcsr.2018.12.016

Owing to its thermal conductivity property, the strength of structural steel is highly susceptible to elevated temperature. When steel is used in main load-bearing members in buildings that are vulnerable to fire, great attention should be paid to the effect of the elevated temperature on the residual strength of those members. Hence, the design criteria of such members must incorporate temperature in their requirements. Current standards and codes of practice for steel structures have attempted to address the elevated temperature in their design procedures. However, the design procedures suggested by these standards and codes still lack accuracy and rationality compared to experimental results, especially at high values of elevated temperature. The main objective of the present study is to suggest a new and accurate analytical method to reasonably predict the residual axial and lateral strength of steel beam columns when subjected to elevated temperature. The suggested method uses a newly derived moment-curvature equation of steel beam columns at elevated temperature. The effect of elevated temperature on the material and mechanical characteristics of the steel was accounted for by utilizing reduction factors suggested by Eurocode 3 (EC3). Validation of the suggested method against experimental and numerical simulation results has demonstrated that the developed method can reasonably predict the residual axial and lateral resistance of steel beam-columns at high values of elevated temperature. The suggested method has many significant applications in the design of steel members at elevated temperature induced by fire. •An analytical method to predict the residual resistance of steel beam-columns at elevated temperature has been presented.•A new moment-curvature equation of axially compressed steel sections at elevated temperature was derived.•The suggested method was validated against the experimental and numerical results.•Validation results have indicated the reliability of the proposed method.