Inelastic Buckling Loads for Nonprismatic Columns

The buckling load or the stability of axially loaded prismatic columns has been well discussed in both the elastic and the inelastic ranges. Nonprismatic or tapered compression members are often used to achieve economy in many practical applications.Therefore, it is necessary to accurately predict their failure loads. In presentday steel buildings, the member with varied web and constant flanges is used more often, the investigation in this study will focus on this type of nonprismatic member The elastic and inelastic buckling capacity or stabilities of nonprismatic columns are discussed herein by using a modified matrix technique, in which the geometric, mate rial nonlinearities and the effect of the residual stress are included. In this study, the nonlinear response of structures is generated by an incremental load approach with a secant type of iteration method at each load level to satisfy the equilibrium equations The stability functions and the discrete element model are employed in the iteration approach to present the geometric and material nonlinearity, respectively.