Degree
Doctor of Philosophy (PhD)
Department
Department of Civil and Environmental Engineering
Document Type
Dissertation
Abstract
This research addressed the performance of aboveground storage tanks (ASTs) and connected pipelines during floods. ASTs, integral to the oil and gas industry, store hazardous materials like crude oil and chemicals. Positioned near coastal regions, especially the hurricane-prone Gulf Coast, these areas are vulnerable to natural hazards such as floods and hurricanes. This vulnerability can lead to potential environmental and economic disasters, as seen with past hurricanes.
The primary objectives were to investigate AST bottom plate failure mechanisms under flood conditions, assess material failure in tank shells and bottom plates using finite element models, examine the behavior of connected pipelines, and evaluate the likelihood of failure among different AST components. The study also analyzed the impact of waterborne debris on ASTs during floods.
Using analytical formulations and finite element simulations, this dissertation evaluated stresses and deflections on AST bottom plates due to flood-induced uplift pressures. Fragility models developed with logistic regression provided a probabilistic assessment of material yielding and rupture in AST components.
Key findings indicated that bottom plate failure began at lower inundation depths for larger diameter tanks, especially unanchored ones, suggesting that the current API 650 guideline for a minimum bottom plate thickness of 6.5 mm might be inadequate in high inundation areas. Proper anchoring reduced flotation probability but did not prevent bottom plate failure, leading to potential hazardous material spillage.
Finite element analysis revealed that pipelines connected to ASTs are critical failure points during floods, with higher stresses in pipe connections than in tank shells. Using higher yield strength materials for pipes did not significantly change failure patterns. The study also examined debris impacts, finding that common debris such as wood logs and steel pipes did not cause significant stress, and the stresses were well below the yield strength of the tank materials.
This dissertation concludes with a call for revised API guidelines, particularly regarding bottom plate thickness and tank-pipe connection design. Future research should focus on accurate modeling of pipe connections and debris impact analysis to develop robust design guidelines that enhance AST flood performance and safety.
Date
7-12-2024
Recommended Citation
Mia, Md Manik, "Performance Assessment of Aboveground Storage Tanks during Flood Events" (2024). LSU Doctoral Dissertations. 6532.
https://repository.lsu.edu/gradschool_dissertations/6532
Committee Chair
Sabarethinam Kameshwar
DOI
https://doi.org/10.31390/gradschool_dissertations.6532