Earthquake risk to civil infrastructure systems

This dissertation makes three major contributions to the development of a new method to describe the earthquake risk to civil infrastructure systems in terms of societal (household) impact. The overall method is the focus of an interdisciplinary research project funded by the National Science Foundation, Critical, Resilient Infrastructure Systems, and Processes (CRISP) program. The contributions of this dissertation specifically are summarized as follows. First, we developed the Multihazard Optimization-Based Probabilistic Scenario (multihazard OPS) method and applied it to Los Angeles. To present a computationally efficient set of multihazard scenarios including the effects of three different co-occur hazards (e.g., ground motion, liquefaction and surface fault rupture), we applied mixed-integer linear programming from the Extended OPS-based method and extended the objective function for multiple hazards. The application to Los Angeles shows that while more scenarios are necessary for the multihazard analysis to obtain similarly small errors as for an analysis of ground motion alone, errors small enough for practical reasons may still be achieved with only a few hundred multihazard scenarios.Second, we developed a computationally efficient set of probabilistic earthquake damage scenarios for the Los Angeles water transmission system. We applied a damage model for the water pipeline system assuming different design levels (given specific system objectives) of the components to estimate the damages due to the final reduced set of multihazard scenarios achieved by the first contribution. In addition, applying a mixed-integer nonlinear program ensured us that the method is computationally efficient enough to be implemented to a real network for many risk management strategies. The application to the Los Angeles water transmission system demonstrates how a set of probabilistic earthquake damage scenarios can support the design and analysis of spatially distributed infrastructure systems to achieve a specific system performance. These damage scenarios can assist in making informed component replacement decisions because they indicate the damage state of each network component under different resistance levels.Third, household adaptations to and impacts of electric power and water supply outages were examined. We deployed a web-based survey for the Texas 2021 winter storm and built statistical models to investigate the effects of household and event attributes, household risk experience and perception, and social connectedness on household impact and adaptation adoption. The results from this study were compared to findings from Los Angeles (both revealed and stated preferences) studies to explore the patterns and generalizability of the results. The findings revealed a similar frequency of implemented adaptations to those in Los Angeles, but predictors of adaption and the household impact that were somewhat different. These findings provide insight to comprehend the degree of societal impact and adaptation adoption due to service interruptions, which facilitates efficient emergency management.