The Bending Moment Capacity of Flexural Members with Interaction of Local and Lateral-Torsional Buckling

This paper describes the moment capacity of flexural members based on FE and test results of H- section beams. Flexural members with large width-to-thickness ratios in the flanges or the web may undergo local buckling before lateral-torsional buckling. The local buckling has a negative effect on the lateral-torsional strength of flexural members. Simple bending moment capacity formulas for flexural members were proposed to account for interaction between local buckling and lateral- torsional buckling. The proposed moment formulas for the direct strength method (DSM) use the empirical strength formula and the gross section modulus. The ultimate flexural strengths predicted by the proposed formulas were compared with the AISC (2005) and Eurocode3 (2003). The comparison showed that the moment formulas proposed can predict conservatively the bending moment capacity of H-section flexural members with buckling interaction.