Collaborative Research: Numerical and Probabilistic Modeling of Aboveground Storage Tanks Subjected to Multi-Hazard Storm Events

University Of Texas At Austin, Austin TX

Investigators

Abstract

Aboveground storage tanks (ASTs) used to store hazardous materials, such as crude oil, can suffer major damage in severe storms resulting in spills with catastrophic social, environmental, and economic consequences. Failure of these structures has been attributed to flotation, buckling, or damage from debris. Despite significant evidence of tank vulnerability and consequences of failure, understanding of the mechanisms leading to AST failure under multiple storm-induced hazards (e.g., surge, wave, wind) is limited. This research will address such gaps by providing numerical models that are capable of capturing the complex fluid-structure interaction (FSI) and nonlinear system behavior exhibited by ASTs under multi-hazard loads. Furthermore, probabilistic models of tank performance in severe storms will be developed, filling a major gap in risk assessment of this critical industrial and energy infrastructure. The advanced computational resources and collaboration and analysis tools of the National Science Foundation-supported Natural Hazards Engineering Research Infrastructure (NHERI) cyberinfrastructure, DesignSafe-CI.org, will be utilized and enhanced in this effort. Through this research, open source codes and probabilistic tools will be provided to better understand the public's risk of being exposed to hazardous spills with far reaching environmental and social impacts. To support risk reduction efforts, viable strategies to avoid such spills are investigated and disseminated to relevant stakeholders in addition to the scientific community. Along with the contribution of open source computer models to the natural hazards engineering community, this project will provide training materials and demonstration applications of DesignSafe-CI functionalities that can be used for education and community outreach on cyberinfrastructure-enabled research. This project will harness the synergies of a multi-disciplinary team spanning computational sciences and structural engineering to provide robust numerical models of AST response under multi-flow conditions and to subsequently derive the first models of AST fragility under multiple storm-induced hazards. The project's research and educational objectives include: 1) advanced numerical modeling of FSI with emphasis on surge, wave, and wind impacts on ASTs; 2) derivation of multi-hazard flotation and buckling fragility models for ASTs in the presence of local and global imperfections; 3) case study analysis of a portfolio of tanks with the developed numerical and probabilistic models and dissemination of lessons learned; and 4) development of learning modules on cyberinfrastructure-enabled multi-disciplinary teaming for the natural hazards engineering community. To meet these objectives, open source, multi-physics software will be developed to capture complicated multi-phase flow scenarios and also allow for streamlined analysis of regional storm simulations with localized FSI response modeling. Numerical simulation with the resulting codes will provide new insight into the response of ASTs subjected to surge, wave, and wind and enable sensitivity and fragility analysis for flotation and buckling failure modes across a range of uncertain hazard and structural parameters. Given the computational complexity of simulating associated AST behavior, statistical surrogate models will be derived based on the numerical FSI simulations. This strategy is expected to render efficient limit state analysis for fragility modeling of ASTs feasible for the first time under surge, wave, and wind and address a major gap in risk assessment of ASTs. The resulting parameterized formulations will be amenable to sensitivity analyses and ready application to a portfolio of tank infrastructure, which will be tested through a case study in the Houston, Texas region.