Structural Optimization of the Self-Supporting Dome Roof of a Large Oil Tank

Abstract

Self-supporting dome roofs are a widely adopted solution for the roof structure of welded oil storage tanks. These structures, consisting of an arrangement of steel girders and plates, are capable of resisting various external actions, in addition to their own weight, relying solely on perimeter support. The diverse range of structural configurations available for this type of roof structure has made it a frequent subject of structural optimization research. This paper focuses on optimizing the 50-meter- diameter, 17.5-meter-high, self-supporting dome roof of an industrial oil tank. The optimization parameters include the plate thickness, the stiffness of the roof-to-shell junction ring, and the dome radius. A numerical model with quadratic Lagrangian MITC shell elements in COMSOL Multiphysics is used. The static response of the structure is analyzed under two critical load combinations, including live loads, gas pressures, and wind action in accordance with API-650 standard. Performance is assessed based on critical linear buckling load factors, while attempting to minimize the structure's total weight. The study concludes by identifying an optimal configuration that balances weight efficiency with safety margins, providing valuable insights into the design of large-span, self-supporting dome roofs.