Study on buckling and critical temperatures of H-section steel columns under fire considering dynamic effect

In this paper, the buckling and critical temperatures of H-section steel columns under fire were studied by parametric analysis. The finite element model of the steel column was verified by test data in literatures. The considered parameters include rotational restraint stiffness ratio (βR), axial restraint stiffness ratio (βl), and load ratio (ρN). Besides, the buckling and critical temperatures of steel columns under static analysis and explicit dynamic analysis were compared. It was found that the buckling temperatures obtained by these two analysis methods were almost the same, while the critical temperatures obtained by static analysis were slightly less than that obtained by explicit dynamic analysis, and the difference was within 30 ℃. The results of parametric analysis show that the buckling and critical temperatures increased with the increase of βR, and βR had greater influence on the critical temperature. In addition, with the increase of βl and ρN, the buckling and critical temperatures of the steel columns both decreased significantly. Finally, the buckling and critical temperatures obtained from the parametric analysis were compared with the existing calculation formulas. Results show that predictions of the existing formulas generally agree well with the analysis results.