Quantifying hazard resilience by modeling infrastructure recovery as a resource-constrained project scheduling problem

Reliance on infrastructure by individuals, businesses, and institutions creates additional vulnerabilities to the disruptions posed by natural hazards. In order to assess the impacts of natural hazards on the performance of infrastructure, a framework for quantifying resilience is presented. This framework expands upon prior work in the literature to improve the comparability of the resilience metric by proposing a standardized assessment period. With recovery being a central component of assessing resilience, especially in cases of extreme hazards, we develop a recovery model based upon an application of the resource-constrained project scheduling problem (RCPSP). This recovery model offers the opportunity to assess flood resilience across different events and also, theoretically, between different study areas. The resilience framework and recovery model have been applied in a case study to assess the resilience of building infrastructure to flooding hazards in Alajo, a neighborhood in Accra, Ghana. For the three flood events investigated (5-, 50-, and 500-year return periods) and the chosen standardized assessment period (300 d), the “300 d resilience” successfully shows a meaningful decreasing trend (0.94, 0.82, and 0.69) with increasing hazard magnitude. This information is most valuable for identifying the vulnerabilities of building infrastructure, assessing the impacts resulting in reduced performance, coordinating responses to flooding events, and preparing for the subsequent recovery. This framework expands upon prior work in the literature to improve the comparability of the resilience metric by proposing a standardized assessment period, the “n-time resilience”.