Post elastic-plastic lateral-torsional buckling behavior and strength of H-shaped steel beam-columns permitted to sway

An analytical method to evaluate the post elastic-plastic lateral-torsional buckling behavior of H-shaped beam-columns permitted to sway under axial force and horizontal load is presented and it is ascertained that those analytical results show good agreement with the experimental results. Using the present method, a parametric study is carried out to investigate the effect of variations of parameters which affect the lateral-torsional buckling behavior, on the post lateral-torsional buckling strengths of H-shaped beam-columns permitted to sway. Summarizing the results of analysis, it is concluded ; (1) For the beam-columns of H-shaped cross section in the medium-width flange series under high axial force ratio, the maximum strengths are remarkably changed by the variations of residual stresses and initial croockednesses. (2) For, the beam-columns of H-shaped cross section in the medium-width flange series under low axial force ratio or in the wide-width flange series, each variation of residual stress and initial croockedness has an almost independent effect on reduction of those maximum strengths, and those degrees are pronounced with the increase in the slenderness ratio., (3) Design formula given in design Standard for Steel Structures of Architectural Institute of Japan can evaluate the proper strengths of beam-columns