R-3 Repository :: Browsing by Author "Bernier, Carl"

Browsing by Author "Bernier, Carl"

Now showing 1 - 7 of 7

Assessing the accessibility of petrochemical facilities during storm surge events
(Elsevier, 2019) Bernier, Carl; Gidaris, Ioannis; Balomenos, Georgios P.; Padgett, Jamie E.
Recent hurricane events have exposed the susceptibility of petrochemical facilities to severe transportation network disruptions due to flooding or storm surge. Network disruptions can result in cascading impacts or amplify the consequences of damage to petrochemical infrastructure due to delayed emergency response and limited access to the site. This study presents a scenario-based framework to assess the accessibility of petrochemical facilities by emergency responders and workers during storm surge events. First, the framework couples storm surge modeling with aboveground storage tank fragility models to determine the locations where natural hazard-triggered technological (NaTech) events could occur. Then, storm surge modeling is coupled with bridge fragility models and geographic system analysis to evaluate the potential for network disruptions such as bridge failures and road inundations. Finally, probabilistic network analyses are performed to evaluate the time-evolving accessibility of NaTech sites to emergency responders and facility workers. As a proof of concept, the framework is applied to a case study area. Results for the case study area demonstrate that the proposed framework is a powerful tool to quantify the accessibility of potential NaTech events, facilitate mitigation and emergency activities, and improve the management of critical resources and personnel during and after a storm.
Buckling of aboveground storage tanks subjected to storm surge and wave loads
(Elsevier, 2019) Bernier, Carl; Padgett, Jamie E.
This study investigates the buckling behavior of aboveground storage tanks (ASTs) subjected to storm surge and wave loads during hurricane events and explores the importance of dynamic effects on the buckling behavior. First, a computational fluid dynamics model is developed to estimate water pressures on ASTs subjected to wave loads. The modeling assumptions of this model are also validated with experimental data. Next, a methodology is presented to perform dynamic buckling analysis of ASTs subjected to surge and wave loads by adapting procedures commonly used for ASTs subjected to wind or seismic loads; the methodology is illustrated with a case study AST located in the Houston Ship Channel. For comparison, static buckling analyses are also performed to determine the significance of dynamic effects. Lastly, design of experiments principles and regression analyses are employed to investigate the effects of varying AST and loading parameters on the buckling behavior and the relative importance of dynamic effects. Results indicate that wave loads can significantly affect the buckling behavior of ASTs subjected to storm surge and need to be considered, while the dynamic effects induced by waves have a negligible influence on the buckling strength of ASTs. Simpler and computationally inexpensive static buckling analysis provides reasonable estimates for ASTs subjected to surge and waves. However, dynamic buckling analysis might still be required if the objective is to assess the post-buckling behavior of ASTs subjected to waves, rather than only to estimate the critical load.
Fragility and Risk Assessment of Aboveground Storage Tanks during Storm Events
(2019-06-10) Bernier, Carl; Padgett, Jamie
Aboveground storage tanks (ASTs) have suffered severe damage during past storm events, resulting in the release of hazardous chemicals in the environment. For instance, more than 30 million liters of oil products were spilled during Hurricane Katrina and Rita in 2005. Despite the evident vulnerability of ASTs, the literature is currently lacking comprehensive studies evaluating the performance of ASTs during multi-hazard storm events. To address this gap, this thesis offers new methods, tools, models, and frameworks to assess the structural behavior and structural vulnerability of ASTs subjected to multi-hazard storm conditions, as well as to support risk assessment and mitigation of ASTs located in coastal regions. First, a series of finite element models are developed to estimate storm loads on ASTs and investigate the structural behavior of ASTs under storm surge, wave, wind, debris impacts, and rainfall loads. Opportunities to reduce the computational complexity and cost of the derived numerical models are also explored using surrogate modeling techniques and assessing the validity of static analyses for dynamic phenomena. A general methodology is then posed to perform fragility assessments of ASTs under concurrent or multi-hazard storm loads using the derived numerical models, a statistical sampling method, and logistic regression. With this methodology, the first comprehensive fragility assessments are performed for (i) ASTs subjected to concurrent surge, wave, and wind loads; (ii) ASTs subjected to waterborne debris impacts; and (iii) floating roof ASTs subjected to rainwater accumulations. This study also proposes frameworks to perform risk assessments of ASTs located in coastal regions. A first framework is developed for large-scale regional assessments of ASTs subjected to surge, wave, and wind loads. As a proof of concept, a scenario-based assessment and, for the first time, a probabilistic risk assessment are performed for a case study region, the Houston Ship Channel. Useful metrics, such as expected spill volumes and annual probabilities of failure, are obtained from the risk assessments. A second risk assessment framework is also developed to estimate the likelihood of debris impacts and damage due to such impacts for small-scale AST terminals located near known debris sources; this framework is illustrated again for a case study terminal along the Houston Ship Channel. Moving from a purely engineering perspective, the results of the risk assessments are also coupled with social vulnerability modeling to explore community impacts. Building from the risk assessment frameworks, an integrated model of built-human-natural systems is also posed to perform a comprehensive assessment of procedural, structural, and protective mitigation strategies. Since no single mitigation strategy appears optimal, a tool is also developed to optimally select and combine mitigation strategies to achieve a given performance target and propose cost-effective solutions, while considering social impacts. Finally, forensic investigations of AST failures during Hurricane Harvey are performed to highlight the viability of the derived fragility models to understand the causes and mechanisms behind AST failures and further evaluate the effectiveness of mitigation strategies. Results obtained throughout this thesis demonstrate that the derived fragility models are efficient tools to perform rapid screening of vulnerable ASTs in industrial regions, and evaluate the viability of mitigation strategies to reduce this vulnerability. Insights obtained from the fragility and risk assessments reveal that neglecting the multi-hazard nature of storms, as existing studies have done, can lead to a significant underestimation of vulnerability and risks. Results of the assessments also indicate that small size ASTs are generally more vulnerable to loads such as wave, wind, debris impacts, and rainfall, and that floating roof ASTs do not appear to be vulnerable during rainfall events unless they are already damaged or their drain system is inefficient. Moreover, results show that simple mitigation strategies such as anchoring ASTs to the ground or filling them with liquid could greatly reduce the likelihood of AST failures and spills during storms. Lastly, this thesis illustrates how using surrogate model and statistical learning techniques can facilitate and reduce the computational complexity of fragility and risk assessments, particularly in multi-hazard settings. Overall, this thesis provides methods, tools, and insights essential to understand, evaluate and mitigate the vulnerability of a key component of energy infrastructure and support stakeholders in doing so. Furthermore, this thesis offers as strong foundation for future vulnerability and risk assessment of other coastal structures and systems.
Fragility and risk assessment of aboveground storage tanks subjected to concurrent surge, wave, and wind loads
(Elsevier, 2019) Bernier, Carl; Padgett, Jamie E.
Comprehensive tools to assess the performance of aboveground storage tanks (ASTs) under multi-hazard storm conditions are currently lacking, despite the severe damage suffered by ASTs in past storms resulting in the release of hazardous substances. This paper presents a rigorous yet efficient methodology to develop fragility models and perform risk assessments of ASTs subjected to combined surge, wave, and wind loads. Parametrized fragility models are derived for buckling and dislocation from the ground. The buckling strength of ASTs is assessed using finite element analysis, while the stability against dislocation is evaluated using analytical limit state functions with surrogate modeling-based load models. Scenario and probabilistic risk assessments are then performed for a case study region by convolving the fragility models with hazard models. Results demonstrate that the derived fragility models are efficient tools to evaluate the performance of ASTs in industrial regions. Insights obtained from the fragility and risk assessments reveal that neglecting the multi-hazard nature of storms, as existing studies have done, can lead to a significant underestimation of vulnerability and risks. This paper also highlights how using surrogate model techniques can facilitate and reduce the computational complexity of fragility and risk assessments, particularly in multi-hazard settings.
Investigation of mitigation strategies to reduce storm surge impacts associated with oil infrastructures
(IASSAR, 2017) Bernier, Carl; Padgett, Jamie E.; Elliott, James R.; Bedient, Philip B.
This paper evaluates different mitigation strategies to reduce the risks posed by aboveground storage tanks and the vulnerability of nearby communities. A framework integrating natural hazard exposure, structural vulnerability, and social vulnerability is proposed to investigate the effects and the viability of different mitigation strategies.
Mitigation Strategies to Protect Petrochemical Infrastructure and Nearby Communities during Storm Surge
(ASCE, 2018) Bernier, Carl; Kameshwar, Sabarethinam; Elliott, James R.; Padgett, Jamie E.; Bedient, Philip B.
This paper explores engineering- and social science-based strategies to mitigate risks posed by aboveground storage tanks (ASTs) during storm events. The Houston Ship Channel (HSC) is used as a case study to illustrate the application of an integrated model of built-human-natural systems and evaluate the viability of alternative risk mitigation strategies for protecting petrochemical infrastructure and nearby communities subjected to storm surge events. First, a model that couples storm surge exposure, fragility modeling, and social vulnerability of communities is used to quantify the effectiveness and economic viability of engineering-based measures to reduce spill risks, such as filling ASTs with liquid, anchoring them to the ground, changing their stiffness, or protecting them with dikes. The results indicate that no single measure is optimal and that combinations of measures could be more suitable. Thus, an optimization approach and a heuristic approach are proposed to select and combine measures considering structural and social vulnerability. Both approaches prove to be effective in reducing storm-induced spills to a given target while minimizing costs; however, they do not improve the resilience of residents in the HSC. Thus, through social science assessment of communities at risk, additional measures are identified, including improved risk communication and evacuation planning, simplified governance structures, moving from equal treatment approaches to equitable treatment approaches, and creating institutions that will empower and benefit local residents. Successful mitigation plans should cut across both engineering and social science approaches.
Simulation of potential formation of atmospheric pollution from aboveground storage tank leakage after severe storms
(Elsevier, 2021) Bi, Shiyang; Kiaghadi, Amin; Schulze, Benjamin C.; Bernier, Carl; Bedient, Philip B.; Padgett, Jamie E.; Rifai, Hanadi; Griffin, Robert J.
Damage by severe storms of infrastructure containing chemicals can cause widespread pollution of the atmosphere and nearby bodies of water. Because atmospheric monitoring equipment is inoperable in the periods after these storms, transport and fate modeling approaches are necessary to estimate the regional atmospheric concentrations of evaporated spill material and secondary pollutants from such events. Hypothetical spills from a single storage tank in Houston were used to evaluate the impact of different meteorological scenarios (Hurricanes Harvey in 2017 and Ike in 2008), leaked materials (oils and organic solvents), background chemical conditions, and cloud conditions on simulated air pollution. Due to differences in evaporation rate, downwind oil plumes are predicted to cover a broader region than organic solvent plumes, which remain concentrated along the path of the prevailing wind. Depending on assumptions regarding evaporation, mixing ratios of spilled material of up to 90 parts per million are predicted. Substantial formation of ozone (up to an enhancement of 130 parts per billion) and secondary organic aerosol (up to an enhancement of 30 μg m−3) could occur in the short-term aftermath of these storms within the downwind solvent plumes, with the magnitude dependent on the solar radiation, type of material, and background pollutant level. This highlights the potential vulnerability of residents and workers in downwind regions to evaporated spill materials and their degradation products.

Browsing by Author "Bernier, Carl"

Results Per Page

Sort Options