Probabilistic Life Cycle Simulation Model of the Performance of Asbestos Cement Water Mains

摘要

Many municipalities in developed countries are being confronted with aging networks of water mains which are experiencing increasing numbers of breaks/service interruptions, and therefore consideration must be given to the question of," if and when", these water mains should be rehabilitated or replaced. This paper presents the results of a project initiated in 2006 wherein a Probabilistic Life Cycle Simulation Model of the Performance of Asbestos Cement Water Mains in the Whitmore Park - Hillsdale Subdivision in Regina was developed. This original simulation model used the historic break experience combined with forecasted break rates as input and developed estimates of the number of breaks, the costs of repairing breaks plus the cost of replacing mains for the next 100+ years, for varying levels of service, as measured by the total number of breaks/service interruption prior to replacement. The results of this original modeling and analysis resulted in the identification of ways work - methods could be changed thereby reducing the number of subsequent breaks. In addition this early analysis indicated that breaks where highly concentrated as opposed to being uniformly distributed across the network. An upgrade to the model in 2011 enables the evaluation of the effect of improved work - methods as well as the implementation of a strategy wherein only short sections of water mains are replaced, as opposed to whole sections, when breaks have occurred in highly concentrated sections or "hot spots" in water mains.