Wind-induced response of the flexible floating roofs of large storage tanks considering liquid sloshing

Abstract

Most large storage tanks are built in coastal ports and are prone to strong wind. The deformation and stress fatigue problems of the flexible floating roof of tanks under wind loads are worthy of attention. However, current research and standards mainly focus on seismic excitation, and the effect of wind loads is rarely discussed. Therefore, this paper derives a solution for the response of single-deck floating roofs under wind loads considering the liquid sloshing in storage tanks. The displacement of floating roof and velocity potential of liquid are expressed by modal superposition, and the wind pressure is measured by wind tunnel tests and expanded by Fourier series. The vertical displacement, Von Mises stress and hydrodynamic pressure of the floating roof are calculated for various liquid levels. The difference in response and fatigue damage between single-deck and double-deck floating roofs are discussed and the effect of various size parameters is analyzed. The results show that the response increases significantly with the increase of liquid level. Large Von Mises stresses are generated at the junction between the deck and the pontoon due to the difference in stiffness, which may lead to fatigue failure of the weld. A sufficiently wide pontoon or the choice of a double-deck floating roof can effectively avoid stress concentration. The proposed method can quickly estimate the wind-induced response of floating roofs and is expected to be applied to large-scale parametric design and reliability analysis.