| Lifeline systems comprise the network infrastructure of urban centers. Because of their vulnerability to natural hazards such as earthquakes and extreme wind events, efforts in the civil engineering research community have and will continue to be focused on the evaluation of their performance.; This investigation examines empirical data for an electric utility distribution system following four winter storms and one earthquake of moment magnitude 6.8. New performance measures for the distribution system are defined; more standard measures are significantly modified and enhanced. Not only are empirical data of this type rare as most investigations rely on a combination of simulation and expert opinion, they also include behavior information under more than one natural hazard. A thorough examination of these unique data resulted in the development of a toolbox with three primary tools. These tools relate and compare various performance measures, allow for site-specific prediction of system behavior for future events, and allow for comparison of performance under different hazards. The results of the investigation are provided in a format amenable to both structural engineering concerns and those of emergency management personnel, public policy analysts and urban planners. In this manner, the investigation represents a significant contribution to the hazard mitigation knowledge base. |
