Dynamic buckling analysis of cylindrical steel water storage tanks subjected to Kobe earthquake loading

Cylindrical steel storage tanks are thin-walled significant engineering structures. This study investigated the buckling conditions of ground-supported cylindrical steel liquid storage tanks according to roof shapes and shell thicknesses. The roof shapes selected were open-top, flat-closed, conical-closed and torispherical-closed-top tanks, and shell thicknesses were 4, 6 and 8 mm. These tanks may be exposed to several types of failure during earthquakes, such as elephant-foot buckling, diamond-shape buckling, overturning and uplift. Great financial loss and environmental damage can also ensue when steel liquid storage tanks are damaged in an earthquake. The seismic analyses were conducted under Kobe earthquake conditions for cylindrical steel tanks with different shell thicknesses and roof types. To investigate dynamic behaviour of the tanks accurately, the hydrodynamic response of each tank was divided into impulsive and convective components. Directional deformation and buckling results are presented for both impulsive and convective masses. As a result, the deformation of the tank is significantly reduced when the top of the tank is in the shape of a torispherical dome. The flat-closed tank has a maximum directional deformation in both impulsive and convective modes. Results also show that when shell thickness was increased, buckling deformation decreased, but different deformation states were observed on the wall and roof components depending on the type of roof.