Bending tests of large diameter fabricated steel cylinders

Abstract

Columns, stacks, conveyor galleries, and other similar civil engineering structures are often constructed in the form of an unstiffened tube or as a discretely stiffened tube that behaves in an essentially unstiffened manner. Tubes of this type are used extensively in the materials-handling operations of industrial plants. These are fabricated circular steel cylinders, typically 2.4-4 m in diameter, with radius-to-thickness ratios in the range of 150–400. They support and enclose conveyor systems, and they customarily span distances up to about 50 m. The task of the designer is similar to that faced with plate girders: the bending capacity, shear capacity, and the combined effects of shear and bending all must be examined. The results of a test program established to examine the flexural strength of large diameter fabricated steel tubes is reported herein. Although the number of tests is not great, the program is distinguished by the fact that the tests were done using relatively large specimens made in a way similar to that which would be employed in full-size tubes. These tests are believed to represent the best information currently available, and the results should be useful to both designers and other researchers who are approaching the problem using analytical tools. Key words: buckling, conveyors, pipes, steel, structural engineering, tubes.