Communities and the economic activity within them rely heavily on critical infrastructure. Utility infrastructure facilities are usually comprised of a range of dissimilar but interconnected components characterised by varying degrees of operational criticality and differing vulnerabilities to earthquake ground motion. The severity of damage to these components in an earthquake has complex implications for facility post-event functionality, repair cost and recovery. This paper describes how an integration of physical component vulnerability, associated component functionality and a system model of the facility have been used to understand the vulnerability, criticality and mitigation opportunities associated with a thermal power station and a major substation.
In this research a review of published component level models has been conducted and the models were adapted using as-built design information and the engagement of industry expertise. The functionality of facility components for a range of damage states have been assessed along with replacement and repair costs utilising the specialist knowledge of asset managers. Finally, the system behavior of the facilities has been analysed using a network model to evaluate facility behaviour and to assess component criticality. These elements have been integrated in a Monte Carlo simulation using an application called SIRA (System for Infrastructure Resilience Analysis) that enables the outcomes of a broad spectrum of events to be assessed and used to develop facility level fragility models.
In this paper the utility of this modelling approach is demonstrated. Comparisons are made with US models in HAZUS that are based on heuristic judgment and the experience in a number of US earthquakes. Finally, the benefits of this approach to assessing the vulnerability of legacy assets and the identification of mitigation opportunities are demonstrated.
