Interactive Buckling Behavior and Ultimate Load of I-Section Steel Columns

Abstract

The paper is intended to present a numerical and experimental study on the local-overall interactive buckling behavior and ultimate load of I-section steel columns. The numerical method, named the finite strip plasticity coefficient increment initial stress method, is proposed to trace up the interactive buckling ultimate load-carrying capacity of thin-walled plate structures involved in elastic-plastic and large deflection. The detailed solution procedures based on the amended Newton-Raphson iteration technique are presented. The structure discretization degree is reduced by the finite strip method and the computing quantity of elastic plasticity is significantly decreased by means of the section plasticity coefficient concept. Parameters such as column slenderness, web and flange plate width-thickness ratio, welded residual stress, and load eccentricity are considered in this paper. The experimental results of 11 welded I-section steel columns with relatively large plate width-thickness ratio have been found to agree reasonably with the numerical predictions. The results have shown that the column failure brought about by local buckling, overall buckling, or local-overall interactive buckling, and the local buckling of component plates does not mean a complete loss of the load-carrying capacity of the column at once.