Investigation of verticality criteria on aboveground oil storage tanks

Ensuring the structural integrity of aboveground storage tanks is crucial in the petroleum and chemical industries, where failures can result in severe human, environmental, and economic consequences. Verticality, a key inspection parameter, plays a significant role in tank stability, as excessive deviations can increase stress concentrations and heighten the risk of structural failure. However, limited research has examined the impact of verticality deviations on structural responses under both operational conditions (filled with liquid) and non-operational conditions (empty). To address this gap, this study investigates the effects of verticality deviations on structural performance across varying liquid levels. First, a comparative review of international standards is conducted to assess differences in verticality evaluation criteria. Second, field measurement data are analyzed to classify storage tanks into three deformation patterns based on top shell plate deviations. Third, numerical models incorporating these deformation patterns are developed to evaluate stress distribution and deformation under different liquid levels and planar tilting conditions. The results indicate that increasing tilting severity and liquid levels amplify both stress and deformation, highlighting the importance of considering these factors in structural assessments. The findings offer valuable insights for optimizing inspection practices and enhancing safety while ensuring cost-effective maintenance strategies.