Behaviour of cold-formed high-strength steel tubular columns at elevated temperatures

In this study, the behaviour and resistances of cold-formed high-strength steel (CFHSS) square and rectangular hollow section (SHS and RHS) columns at elevated temperatures up to 1000°C were numerically investigated. A finite element model was developed and developed finite element model was validated with available test results of CFHSS SHS and RHS columns in terms of ultimate capacities, failure modes and load-deflection curves. After validation, a parametric study was performed by utilising stress-strain relationships of CFHSS at elevated temperatures developed based on prior research. A total of 280 CFHSS tubular columns of steel grade S700 were studied, covering a wide range of cross-sectional classes and member slenderness ratios. The applicability of current column design provisions in Eurocode 3 and AISI S100 Specification to the studied tubular columns at elevated temperatures was evaluated. Overall, it is shown that the codified design provisions may be used for the resistance predictions of the CFHSS tubular columns at elevated temperatures, while further improvement in terms of accuracy and consistency remains possible.