Experiments on the Buckling of Thin-walled Model Silo Structures

Many experiments have been conducted to determine the distribution of pressures and frictional drags on silo walls. Based on this information, both design calculations and failures in service indicate that buckling under vertical compressive stresses is usually the critical consideration for thin walled steel silos. Existing knowledge of the buckling strength of empty cylindrical shells is extensive, and the effects of internal pressurisation are also quite well known. However, little is known about buckling failures in which the wall stresses are directly induced by stored solids, or about the increases in buckling strength which derive from the stiffness of a stored granular solid in contact with the silo wall. This paper describes experiments on model silos in which the wall stresses and the consequent buckling failure were caused solely by a stored granular solid. These experiments were designed to explore the buckling strength and behaviour of thin-walled, flat-bottomed silos on initial filling and during discharge. Both concentric and eccentric discharge conditions are described. Buckling failures with both stable and unstable characteristics are noted. Finally, conclusions are drawn for the structural design of bins.