Ultimate strength of steel outstands in compression

The present study is aimed at developing a rational design formula for predicting the ultimate strength of steel outstands in compression. To this end, an extensive elastoplastic large displacement finite-element method (FEM) analysis is conducted. The outstand is assumed to have initial out-of-flatness as well as residual stresses. Based on the numerical results, a formula is derived as a function of both magnitude of the initial out-of-flatness and residual stress. The formula is then used to predict the ultimate compressive strength of members with II-sections, and comparisons of the predicted ultimate strengths given by the effective width method are made with those of numerical study and tests. It is found that the proposed formula can be used in the prediction of the ultimate strengths of compression members that have steel outstands.