The Architectural Institute of Japan (AIJ) Recommendations specify requirements for H-shaped steel columns forming plastic hinges. However, the Recommendations contain no rationale for determining an acceptable lateral-torsional buckling slenderness ratio due to the direct quotation of the steel beams’ limitation. A previous study clarified that a beam-column susceptible to lateral-torsional buckling could not be properly evaluated by the requirement. Therefore, in this study, an index considering lateral-torsional buckling is proposed. In addition, a plastic deformation capacity evaluation formula, modified requirements, and strength correlation are proposed based on the proposed index.
