Considering Time-Varying Factors and Social Vulnerabilities in Performance-Based Assessment of Coastal Communities Exposed to Hurricanes

Abstract

Climate change, population dynamics, the aging of built infrastructure, and their growing complexity have gradually increased the vulnerability of coastal communities around the world. Among the many critical coastal infrastructures, the residential coastal building stock has exhibited significant vulnerabilities in past storm and hurricane events. Beyond the initial impact of these hurricane events on the built environment, coastal communities struggle to recover even years after landfall. Moreover, the initial shock as well as the recovery phase do not evenly affect all sectors of the population and frequently uncover social vulnerabilities and inequalities in the preparedness, response, and recovery from disasters. This study explores and expands a performance-based coastal engineering (PBCE) framework that allows for consideration of time-varying aspects of the hazard, depreciation, and aging or deterioration of coastal structures and infrastructure systems by applying it to evaluate the future performance and recovery of a portfolio of residential structures subjected to surge and wave loads. Using the residential building stock of Galveston, Texas as a case study, a Bayesian network framework is leveraged to evaluate the uncertain damage and subsequent recovery of the portfolio for the years 2030 and 2050, and correlations with representative social vulnerability factors are drawn. The correlation analysis between immediate damage and social vulnerability factors, as well as between the recovery index and social vulnerability factors up to six years following the storm landfall, is pursued to expose potential disparities in the impact of the storm to different sectors of the community in the short- and long-term. Results show that changing climate conditions exacerbate the probability of failure of the building stock and associated housing recovery. Also, the correlations in the short- and long-terms show that the elderly and women might be most at risk in future hurricane events. The incorporation of multi-structure systems and time-varying factors in the performance assessment framework is of great importance to inform resilience and adaptation engineering models, in particular, when the effects of chronic hazards, a growing population, and increases in asset values are expected to grow in the future. The methodology and case study also provide useful tools to inform planning and decision-making, resilience assessment, and facilitate recovery efforts in coastal settings while accounting for the impact of the hazard on vulnerable populations.