Resistance of Axially Loaded Hot-finished S460 and S690 Steel Square Hollow Stub Columns at Elevated Temperatures

The resistance of axially-loaded hot-finished S460 and S690 steel square hollow stub columns at elevated temperatures was investigated in this study through finite element modelling. Finite element models were developed and validated against test results on hot-finished S460 and S690 steel square hollow stub columns under axial compressive loading. Extensive parametric studies were subsequently carried out to examine the axial compressive resistance of hot-finished S460 and S690 steel square hollow stub columns with a wide range of cross-sectional slenderness and at elevated temperatures up to 700 °C. The results from parametric studies were compared with the strength predictions estimated based on design rules from European and American standards and the direct strength method. The reliability of these design rules for the structures subject to elevated temperatures was also evaluated through the reliability analysis. The comparison between parametric studies results and strength predictions shows that the design rules from European and American standards underestimate the strengths of the stub columns while the direct strength method provides quite accurate strength predictions for stub columns. Modified design rules were also found to provide safe and reliable strength predictions and can be used for structural design.