ABSTRACT
Large diameter fabricated steel cylinders are often used as conveyor galleries, stacks or masts, or as members in offshore structures. As an illustration of proportions, cylinders used for conveyor galleries typically have diameters of 2.5-4.0 m and radius to thickness ratios, R/t , of 100-400. Spans can reach 60 m. As such, these members act as beams in flexure and they may also be subjected to axial forces. The cylinders are fabricated by cold-rolling steel plates to form short cans. The cans are then joined together by circumferential girth welds to produce long spans. Circumferential (or, ring) stiffeners at intervals of 0.5-2.0 times the diameter are almost always present to help maintain the circular shape of the tube. Longitudinal stiffeners may be used as well. If they are present, they will be welded to the cylinder surface, thereby improving the behavior under axial compression or beam bending. For cases where flexure predominates, it is usual to attach the longitudinal stiffeners over only part of the tube.
