3-D second-order plastic-hinge analysis accounting for local buckling

In this paper, 3-D second-order plastic-hinge analysis accounting for local buckling is developed. This analysis accounts for material and geometric non-linearities of the structural system and its component members. The problem associated with conventional second-order plastic-hinge analyses, which do not consider the degradation of the flexural strength caused by local buckling, is overcome. Efficient ways of assessing steel frame behavior including gradual yielding associated with residual stresses and flexure, second-order effect, and geometric imperfections are presented. In this study, a model containing the width–thickness ratio is used to account for local buckling. The proposed analysis is verified by the comparison with other analyses and Load Resistance Factor Design results. A case study shows that local buckling is a very crucial element to be considered in second-order plastic-hinge analysis. The proposed analysis is shown to be an efficient, reliable tool ready to be implemented into design practice.