Stability of tapered and stepped steel columns with initial imperfections

The elastic stability of eccentrically loaded steel columns with tapered and stepped cross-section and initial imperfection is studied herein. The stability problem is formulated in a manner covering most cases met in design applications. The formulation presented herewith is based on the exact solution of the governing equation for buckling of columns with variable cross-section. A parabolic shape is assumed for the initial imperfection according to EC3 provisions. A plasticity criterion is applied to determine material failure in the buckled configuration. Nonlinear finite element analyses are performed to verify the analytical results. The findings presented in this study can be used for the design of such type of imperfect steel columns.