Minimum safety liquid levels for cylindrical storage tanks to prevent buckling under fluctuating wind loads

Abstract

Among the diverse Natech scenarios, buckling of storage tanks under extreme winds is of particular concern due to the economical, ecological, and societal consequences the leakage of valuable, flammable, and hazardous substances in the tanks can bring about. Filling storage tanks with water has a stabilizing effect against buckling and has been adopted in practice to preserve the integrity of tanks under extreme wind loads. In previous studies, the description of wind load is mostly limited to rule-of-thumb formulas with empirical parameters, which is insufficient to make credible quantitative decisions in the prevention and preparedness phase of emergency management. In the present study, sophisticated numerical simulations of multiple correlated time histories of fluctuating wind loads and nonlinear finite element analysis allow for a technologically sound methodology for the evaluation of minimum safety liquid levels for storage tanks to prevent buckling under extreme winds. In the case studies, both the proposed methodology and the relevant Eurocode have been applied to assess the minimum safety liquid levels in more than one hundred scenarios of severe winds. It is observed that both approaches agreed that 94 scenarios were safe and 19 were unsafe. However, the remaining 13 scenarios were considered safe by the Eurocode-static-analysis approach while considered unsafe by the proposed approach indicating that the peak velocity pressure formula in Eurocode and static wind buckling analysis adopted in numerous previous studies systematically underestimate the role of fluctuating wind. The proposed methodology may be applied to help make quantitative decisions corresponding to wind disasters.