ABSTRACT
One of the phenomena influencing the capacity of the structure, or the ultimate state, is local buckling of the frame’s members. This article presents the analyses of the most common setup, the simply supported beam with an I-section, and proposes the equations to estimate the local buckling strength of such beam. The derivation of the solution is based upon the principles of the theory of elastic stability, the shell stability, and the equilibrium of the work done by external forces and the plate’s strain energy. Solutions are proposed for the segments of the beam, depending on the geometrical properties of those, and are later connected into equations considering the coupled interactions between the web and flanges. Finally, the equation allowing for the precise estimation of the strength of the whole beam is proposed.
