Inelastic H-Columns Under Biaxial Bending

A numerical procedure is presented for determining the displacements of an isolated H-column loaded eccentrically with respect to both principal axes of the end cross sections. The procedure is an indirect incremental-load analysis in which the strain history is considered. With this procedure the column behavior may be studied as the load is increased from zero to the ultimate carrying capacity of the member and for unloading accompanied by increasing displacements. The procedure is applicable to initially straight and untwisted columns made from an elastic-perfectly plastic material. Torsional warping of the end cross sections may be either permitted or prevented. The eccentricities of loading must be alike at both ends of the member. Residual thermal strains are accounted for in the analysis. Based on limited numerical studies it appears that warping restraint at the end cross sections increases the ultimate carrying capacity. The results also show that residual thermal strains present prior to loading have a significant influence on the deformational response and strength of columns under biaxial bending.