Columns under Combined Bending and Thrust

Interaction curves relating the axial thrust, applied end bending moment, and slenderness ratio are developed for the ultimate carrying capacity of pinended, wide-flange beam-columns. It is assumed that failure is due to excessive bending in the plane of the applied moments that is further considered to be the plane of the web. The two conditions of loading that are investigated are (1) equal end moments applied such that the resulting deformation is one of single curvature, and (2) end moment applied only at one extremity of the member. The influence of an assumed symmetrical residual stress pattern is considered in the computations, and curves are presented for slenderness ratios up to and including L/r = 120. For ease of design computations, the interaction curves are fitted into approximate equations. Comparisons are made with various column test results.