Semester of Graduation
Summer 2024
Degree
Master of Science in Civil Engineering (MSCE)
Department
Civil and Environmental Engineering
Document Type
Thesis
Abstract
The objectives of this research were to: 1) develop an approach to determine the effectiveness of regional storm surge reduction strategies and structural mitigation measures for aboveground storage tanks (ASTs), and 2) study the feasibility of controlled flotation of ASTs during flood and storm surge events. This study provided a comprehensive risk assessment strategy for regional portfolio of tanks, considering all dominant failure modes relevant to future planning initiatives aimed at reducing AST failures. Additionally, this research contributed a new methodology to prevent AST failures during flooding, offering a potential solution to prevent hazardous spills.
Design guidelines such as API 620 and API 650 do not include provisions to prevent AST failures during floods. Past hurricanes, such as Katrina, Rita, Ike, Gustav, and Laura, have caused AST collapses, leading to environmentally destructive spills, and infrastructure damage. Thus, AST failures have catastrophic consequences and cannot be overlooked.
Several studies have developed fragility models for ASTs, but their suitability for different hurricane hazard scenarios is unknown. Additionally, the effectiveness of regional storm surge reduction strategies in improving AST safety is uncertain. Conventional structural mitigation measures, such as anchor chairs, have proven inadequate in preventing bottom plate failures during storm surge events.
A framework was proposed to assess fragility models' suitability and quantify AST failures and their consequences using Monte Carlo simulations. Applying this framework to Cameron, Louisiana, provided key insights: fragility models not accounting for wave loads and dislocation failure are unsuitable for the region; Louisiana's Coastal Master Plan is insufficient to reduce consequences of AST failures; considering bottom plate failure of anchoring tanks as a structural risk mitigation measure would reduce tank failure consequences by 47-72%.
A novel approach of controlled flotation for ASTs was proposed, allowing them to float and prevent bottom plate failure. Feasibility analysis assessed AST stability during flotation, and finite element analysis simulated tethered tank behavior. Findings suggest conventional anchor chair designs are ineffective for controlled flotation. Shifting anchor chairs upward by 0.3m could enable controlled flotation, mitigating bottom plate failure risk. Future research could enhance AST design standards and mitigation strategies in flood-prone areas.
Date
7-11-2024
Recommended Citation
Ghimire, Santosh, "Hurricane Vulnerability of Above Ground Storage Tanks" (2024). LSU Master's Theses. 6016.
https://repository.lsu.edu/gradschool_theses/6016
Committee Chair
Kameshwar, Sabarethinam