In-plane ultimate load-carrying capacity of tapered I columns

Abstract

The buckling of thin-walled steel columns is generally divided into three modes: local buckling, overall buckling, and local–overall interactive buckling. Many previous research works are carried out to investigate the local and overall interactive buckling behavior and ultimate load-carrying capacity of thin-walled columns. However, all of them are focused on the steel prismatic columns with constant sections longitudinally. This chapter presents a study on the local–overall interactive buckling behavior and the ultimate load-carrying capacity of tapered I-section steel columns. Local buckling and postlocal buckling of plate components are considered by using large-deflection elastoplastic shell elements. The behavior of local–overall interactive buckling is investigated in large deformation and elastoplastic range by using shell element provided by ANSYS. Based on the nonlinear finite element (FE) structural analytic method, the effects of parameters on the ultimate load-carrying capacity, including width–thickness ratio of web and flange plates, tapering ratio, and load eccentricity, are considered in the analysis. From the results obtained, it can be concluded that these parameters significantly affect both the buckling failure modes and the ultimate load-carrying capacity of tapered I-section columns. By comparing the results obtained with those of current Chinese code, some valuable conclusions are drawn and some advice is proposed for the design of tapered I-section steel column.