Interaction Equations for Biaxially Loaded Sections

A simple method for obtaining the exact interaction relationships of doubly symmetric sections under combined axial force and biaxial bending moments is presented. Simple expressions for approximating the interaction curves of wide-flange sections are proposed, and the associated plastic deformations are calculated. For illustration, interaction curves for a wide-flange section, a box section and a circular section are developed using the method. Simple analytical expressions to approximate the interaction relations of wide-flange sections are proposed, and the associated plastic deformations are calculated.