Experimental investigation of geometrical and physical behaviors of thin-walled steel tanks subjected to local support settlement

Abstract Thin-walled steel storage tanks are generally located in coastal areas and therefore are prone to settlement. In investigating the effect of possible settlement types, the effect of local settlement is impressive due to its destructive impacts on the performance and stability of tanks. Hence, the need for laboratory studies to investigate the behavior of thin-walled tanks against this phenomenon becomes clear in advance. Many variables can be evaluated in the study of the effect of local settlement on the behavior of tanks. In this study, the variables of height-to-radius ratio ( L / R ) and settlement-range-to-tank-circumference ratio ( S ) were considered. The effect of top stiffening ring on tank’s behavior was also investigated. A total of 12 unstiffened and stiffened specimens with L / R = 1.0 and 1.5 as well as S = 0.05, 0.08, and 0.13 were tested in this experimental endeavor. All specimens had a radius-to-thickness ratio ( R / t ) of 500. This study shows that increasing of the L / R ratio improves the stiffness, strength, and toughness performances of the tank, while increasing of the S ratio results in the reduction of the aforementioned parameters. The presence of the top stiffening ring plays an important role in controlling the radial displacement and preventing the ellipse of the upper edge of the tank. Accordingly, it is demonstrated that tanks with the top stiffening ring have higher stiffness, strength, and toughness performances compared to the unstiffened tanks.