Abstract

This research introduces a novel and dynamic mathematical modeling methodology of infrastructure interdependency which has been examined through two case studies. The urban infrastructure interdependency was illustrated with a case example of California electricity outage in 2001. The developed Petri-Net model captured the interdependencies among the infrastructures in the network of a power plant, oil refinery, natural gas plant, fuel transporting pipes and tanks, water supplying pipes, and telecom. Extended Petri-Net and Markov Chain have been applied to the part of the network to assess the safety of the infrastructures. The developed modeling tools have been used to demonstrate the floodplain infrastructure interdependency with a case study of Canyon Ferry reservoir area having the infrastructures network of a water storage multi-purpose concrete gravity dam, penstock, power plant, transformer substation, intake pipes and pumping station, irrigation systems, municipal water supplying systems, and telecom. Additionally, gravity dam vulnerability assessment with empirical and analytical fragility curves and flood frequency analysis have been integrated with the extended Petri-Net analysis. The obtained results are reasonable showing that the more interdependent infrastructures present in the network, the more vulnerable they are. Also, higher degree of interdependency results in intense coupling leading towards higher vulnerability. Overall, this research contributes to the emergency management planning for safety assessment of the critical infrastructures.