Khim Chye Gary Ong

Behavior of Prestressed Concrete Self-stabilizing Floating Fuel Storage Tanks

Prestressed concrete (PC) cylindrical tanks are used in industrial applications as liquid containing facilities, and are commonly constructed as base-supported structures with their associated foundations poured in place. In land-space constrained countries, however, it becomes viable to construct such facilities on sea as floating structures. This study deals with the design of an innovative self-stabilizing floating fuel storage tank. For this new type of fuel storage facility, the self-weight of the tank and the in-fill fuel are automatically balanced by the buoyancy force, and there is no need for vertical supporting foundations. Furthermore, the hydrostatic pressures on the tank wall due to outside sea water and in-fill fuel balance each other to a great extent, leading to significant reduction in material consumption and construction costs. Due to the absence of specific guidelines and engineering practices, it remains unknown whether PC floating self-stabilizing fuel storage tanks are applicable in the offshore environment. In this study, a comprehensive stability analysis was first carried out to determine the geometrical dimensions for tanks of different capacities varying from 5,000 m3 to 15,000 m3 in order to meet the operational requirements. Finite element (FE) models were then developed to assess the structural performance of a selected tank of 12,500 m3 capacity when subjected to self-weight and hydrostatic pressure. Based on the analytical results, potential technical challenges were identified and design recommendations were further provided.