Risk Analysis of Port Facilities

During recent earthquakes, seaports have demonstrated that they can be highly vulnerable to seismic motion and associated ground failures. Poor seismic performance of seaports has resulted in billions of dollars of losses. Seaports are critical nodes in regional transportation networks and have an important impact on the economy of the area. Thus, the need for risk analysis of port facilities is clear. In this paper a general port seismic risk model is developed that provides information on potential direct and indirect economic losses from potential failure of facilities and operations at a port. The model is composed of two independent sub-models: the vulnerability model and the port operations model. The vulnerability model combines seismic hazard analysis with fragility analysis to the individual port components to produce a set of post-event damage states for port components, corresponding repair times and direct repair costs. The main component of the port operations model is a discrete-event simulation that estimates ship waiting times and the number of diverted ships. The operational output data from this model are used to estimate the expected loss of revenue due to downtime (direct loss). The results on direct repair costs and operational losses provide decision-makers with tools that can be used in the development of seismic risk mitigation strategies. Users may adjust the post-event input data set using expert opinion to further take advantage of the model’s power and flexibility. For example, decision-makers can compare different reconstruction and repair plans. The intent of the methodology is to help decision-makers take the necessary steps to prevent disasters such as the one experienced in the Port of Kobe in the1995 Kobe, Japan earthquake.