Buckling Strength of T-Section Ringbeams in Steel Silos

Abstract

This chapter presents a simple approximate method for assessing the out-of-plane buckling strength of T-section transition ringbeams in elevated steel silos and tanks. A typical elevated steel silo consists of a cylindrical vessel above a conical hopper, which is then supported on a skirt or a number of columns. The point of intersection of the cylinder and hopper is called the transition. A T-section ringbeam, consisting of an annular plate and a vertical edge stiffener, is often provided at the transition to resist a large circumferential compressive force in the transition junction. The equivalent circumferential compressive force needs to be related to the circumferential compressive stress at the ringbeam inner edge in assessing the elastic buckling strength of the ringbeam. Elastic buckling only governs the strength of junctions with a slender ringbeam or with a high-yield stress, while the plastic collapse strength generally overestimates the ultimate strength, as plastic buckling is likely to precede plastic collapse. For most transition ringbeams, failure is by plastic buckling. The division between elastic buckling and plastic buckling is based on the strength behavior, so the elastic buckling region covers purely elastic buckling failures as well as nearly elastic buckling failures occurring after limited yielding.