A model of interdependent infrastructure system resilience

Infrastructure systems of transportation, water supply, telecommunications, power supply, etc. are not isolated but highly interconnected and mutually coupled. Infrastructure interdependences can increase system vulnerability and produce cascading failures at the regional or national scales. Taking the advantage of network theory structure analysis, this paper models a multilayer infrastructure network of street, water supply, power supply and information infrastructure layers. The infrastructure interdependences are detailed using five basic dependence patterns of basic network elements. Definitions of dynamic cascading failures and recovery mechanisms of infrastructure systems are also established. The main focus of the paper is the introduction of a dynamic measure of infrastructure network resilience capable of addressing infrastructure system, as well as network component (layer), interdependences. The measure is based on infrastructure network performance, proactive infrastructure network resistance capacity and reactive infrastructure network recovery capacity. With three resilience features and corresponding network properties, this paper develops the quantitative measure of dynamic space-time resilience and a resilience simulation model for infrastructure networks. The resilience model is applicable to any type of infrastructure and its application can improve the decision-making processes of infrastructure planning, design and maintenance.