To develop a hysteresis model for a H-shaped steel beam under cyclic loading, it is necessary to obtain a high-precision load-deformation curve over a wide deformation range under monotonic loading. The purpose of this study is to develop elastic-plastic models of load-deformation relations for H-shaped steel beams under monotonic loading that consider coupling of local and lateral buckling. The finite element method is employed to investigate such coupling for large deformations. In addition, the effect of the steel yield ratio on beam behavior is clarified, and formulae for the maximum strength and the deformation capacity are determined. Based on the results, a model of load-deformation relations are formulated that were functions of the width-to-thickness ratio, the slenderness ratio for lateral torsional buckling, and the yield ratio for the steel.
