Abstract
A finite element method based on the modified Hellinger-Reissner's principle is applied to compute the elastic-plastic post-buckling behavior of plate-assembled steel column segments. The effects of both welding residual stresses and initial plate deflections are allowed for in the analysis. Load-shortening curves of uniaxially loaded single plates are shown to be in good agreement with Little's results which are supporsed to be the most reliable solutions. Moment-thrust-curvature (M-P-Φ) curves of locally buckled box column segments are computed and, based on the results, an interaction formula for predicting the ultimate strength of box column segments in combined compression and bending is proposed.
