This paper presents a numerical study on the cumulative plastic deformation capacity determined by local buckling of cold-formed circular tubular beam-columns subjected cyclic loading. The parameters are diameter-thickness ratio, axial force ratio, and slenderness ratio, the main amplitude of rotation angle which is expected to be occurred to the strong earthquake motion is 0.03rad. The equations that can evaluate the cumulative plastic deformation capacity are proposed, these equations are compared with the results of experiments.
