An experimental study of the collapse of horizontal saddle-supported storage vessels

Abstract

The use of plastic analysis in the design of horizontal vessels, used for liquid or gas storage, and supported on twin saddles, allows better utilization of the vessel's material and avoids the problems of categorizing the elastic stresses when designing the component. To understand how the vessel collapses onto the saddle, experiments were conducted on a range of model vessels (40 in all) with different radius-thickness ratios (R/t) and supported on saddles which were either loosely fitted or welded to the vessel. The experimental results show that different collapse mechanisms occurred for loose and welded saddles and also that the modes of failure were dependent upon the value of R/t for the vessel. In general, progressive plastic collapse occurred in those vessels with low values of R/t and elastic-plastic buckling for vessels when higher R/t ratios were employed. This paper presents the detailed experimental results, which are used as the basis of a theoretical design approach; the latter will appear in future papers considering both plastic collapse and buckling failure.