Plate buckling strength of steel wide-flange sections at elevated temperatures

Abstract At ambient temperature, estimations of the postbuckling strength of steel plates (web and flanges) in wide-flange beams are based on the assumption that the stress at the edge of the plate equals the yield stress of the material. However, at elevated temperatures material behaves in a nonlinear manner beginning at very small strains. The work presented in this paper has shown that at elevated temperatures the ultimate buckling load occurs when stresses at the plate edge are smaller than the yield stress, which are typically defined at large strains such as at 2%. Hence, the current expressions for plate buckling strength at ambient temperature cannot be directly applied at elevated temperature. By taking into account the nonlinear behavior of steel at elevated temperatures, a new postbuckling strength equation for webs and flanges in wide-flange beams that correlates well with finite-element studies at elevated temperatures is proposed.