Probabilistic Assessment of Storage Tanks Subjected to Waterborne Debris Impacts during Storm Events

Abstract

Probabilistic models to evaluate the vulnerability of aboveground storage tanks (ASTs) subjected to waterborne debris impacts during storm surge events are currently lacking, despite evidence of debris-induced damage during past severe storms. This paper addresses a gap in understanding the vulnerability of ASTs subjected to waterborne debris, such as shipping containers, by deriving simulation-based fragility models and an associated risk assessment framework for probabilistic performance assessment. First, finite-element models of ASTs and a shipping container are developed to perform debris impact analyses and assess the potential for damage; the shipping container model is also validated against experimental results. Parametrized fragility models are derived using a statistical sampling method, results of debris impact analyses, and logistic regression. Fragility models are derived for two damage mechanisms: inelastic damage of the tank shell and sliding. Next, this study presents a risk assessment framework to evaluate the probability of an AST being impacted by debris and to demonstrate how the derived fragility models can be employed to evaluate and mitigate the vulnerability of ASTs located in industrial areas. The framework is illustrated for a case study storage tank terminal. Insights obtained from the fragility and risk assessments reveal that large ASTs are less vulnerable than are small ASTs to debris impacts, and that neglecting debris impacts for ASTs located near potential debris sources can significantly underestimate the vulnerability of ASTs during storm surge events.