Assessing Infrastructure Vulnerability to Sudden Events

Over the past twenty years, numerous infrastructure management systems have been developed to address gradual failure modes. Unfortunately the management of sudden failure modes within large infrastructure systems (principally: natural hazard induced failures) have not been systematically addressed. This is particularly an issue within liberalized public-private partnerships where the management of and liability for natural hazard vulnerabilities evolves in time. This paper details a methodology for determining an infrastructure system’s vulnerability to sudden events which 1) assesses a component’s failure potential by superimposing natural hazard and infrastructure network data and applying simple standardized structural failure models and 2) quantifies the cost of a system’s post-failure consequences by calculating the infrastructure system demand redistribution costs. The set of potential failure links are then prioritized as a function of their respective vulnerabilities – their failure potential multiplied by the associated consequences. Through applying this methodology within a public-private partnership, the public entity can assess and prioritize the infrastructure objects with respect to their vulnerabilities and can thus require the private entity to reduce infrastructure vulnerability, where warranted, by implementing specific mitigation activities or to operate the system within maximum acceptable vulnerability levels. The private entity can likewise quantify and appropriately price their liability to natural hazards. The example herein presented is the application of this methodology to assess a transportation infrastructure network’s vulnerability to avalanche hazards.