A second-order inelastic model for steel frames of tapered members with slender web

A concentrated plasticity model is proposed for second-order inelastic analysis of the steel frames of tapered members with a slender web. Such significant effects as residual stresses, initial geometric imperfection, gradual section yielding at the element ends, distributed plasticity within the element and local web buckling are considered in this model. Numerical examples on tapered compact columns, prismatic beam-columns with local buckling, a prismatic frame with local buckling and a tapered frame with local buckling are studied in this paper to verify the accuracy and efficiency of the proposed analytical model. As an application, the column curves of tapered steel columns are obtained with the proposed analytical model, both excluding and including the local buckling effects of slender webs. Some meaningful conclusions are drawn in the end of this paper.