Cylindrical Shell Roofs With Draped Prestressing

An analysis of circular cylindrical shells prestressed within the curved surface and supported on diaphragms at the shell ends is presented. The prestressing loads from the anchorages, cable curvature and friction are arranged as symmetrical or antisymmetrical actions along a number of shell generators. Satisfactory convergence of a Levy type solution to the Donald-Karman-Jenkins cylindrical shell equation is found. The theoretical solutions are compared with experimental results obtained from a small scale aluminum model of intermediate length. Deflections and strains at a number of places were measured when the model was prestressed with a variety of draped and straight cables. The test results, which were repeatable and reliable, were generally within a few per cent of the theoretical values. Transverse stresses, found to be of the same order as the longitudinal stresses, frequently changed sign across the shell and altered considerably with changes of cable position.