Buckling assessment of cylindrical steel tanks with top stiffening ring under wind loading

Abstract

A stiffening ring is commonly used at the top of the tank wall to increase its strength against external pressure instability. Traditional design treatments generally consider cylindrical storage tanks under uniform external pressure for sizing of the top ring. However, cylindrical steel tanks under non-uniform wind loading have rather different and complex buckling behaviour from those of tanks subjected to uniform external wind loading. In this study, the buckling resistance of the cylindrical steel storage tanks with top stiffening ring under wind loading is investigated using finite element analyses. The changes in the buckling capacity are studied in light of the proposed stiffness ratio for a particular harmonic of wind loading. The results revealed that the changes in the buckling capacity are closely related to the shell-top ring stiffness ratio. Furthermore, a generalized solution that shows buckling pressure ratio (q(cr,w)/q(cr,D)) is then developed.