iRe-CoDeS: A framework for demand/supply-based resilience assessment of interdependent civil infrastructure systems

Tools for measuring the resilience of infrastructure systems are necessary for engineering the increase in the resilience of communities to natural hazards. Such tools can also inform early and effective disaster risk mitigation actions that lead to rapid post-disaster recovery of the built environment, providing the foundation for a swift restoration of economic and social activities in the affected communities. We present iRe-CoDeS, a framework that measures the resilience of infrastructure systems by dynamically simulating their post-disaster changes in the ability to supply resources to users as well as the change in users demands during the post-disaster recovery period. The iRe-CoDeS framework builds on top of well-established regional hazard and risk assessment tools and extends them by simulating the post-disaster recovery of the built environment and its interdependent infrastructure systems. The interdependencies among different systems are captured at the component level. Apart from providing resource supply, each component of an infrastructure system can have a demand for resources provided by other systems (e.g., a cellular tower providing communication services requires electric power). The iRe-CoDeS framework simulates the flow of resources among components at every time step of the recovery simulation and constrains the component’s ability to supply resources based on its demand fulfillment. Lack of Resilience (LoR) of an infrastructure system is used as its resilience metric: it represents the unmet demand of the community for a resource that the considered infrastructure system is providing. Such a resilience metric is particularly suited for assessing the impact of component interdependencies on community resilience and evaluating community resilience goals. The application of the iRe-CoDeS framework will be briefly illustrated in a case study that addresses the recovery of housing in North-East San Francisco after a hypothetical earthquake. Our recent work on applying the iRe-CoDeS framework for measuring and operationalizing seismic resilience in Switzerland will also be presented.