Parameters Affecting Distortional Buckling of Tapered Steel Members

Abstract

A finite‐element method of analysis for the elastic distortional buckling of doubly symmetric tapered I‐section beam‐columns has been modified to consider the effects of off‐shear center loading and discrete elastic restraints applied anywhere in the cross section or along the length of the beam‐column. The accuracy of the finite‐element method is demonstrated for prismatic members by a comparison with closed‐form solutions, or numerical solutions for which no closed‐form solution exists. Discrepancies in some other well‐cited formulations are discussed with reference to this model. The method is then used to investigate the significance of distortion in the buckling of I‐section plate girders typical of those comprising fabricated industrial roofs, considering the restraining effects of the purlins and the loading being remote from the shear center.