Decision framework for maintenance activities in water pipelines: repair or replace? : A literature review and a decision framework proposal

Sammanfattning: The research provides a tool for decision making concerning maintenance activities in water pipelines. The thesis aims to bring attention to the fact that use of modern and faster non-destructive technologies can improve conventional maintenance strategies as long as the results can be interpreted. More precisely, this thesis aims to propose a framework to help decision makers understand the results from a potential new technology and make the most appropriate decision in order to achieve preventive maintenance. This can improve water losses reduction. Considering the complexity of the deterioration process of urban pipelines, the lack of framework to interpret results of condition assessment, and the fact that decision makers should deal with uncertainty, Belief Function Theory arise as an applicable method to determine which maintenance activity should be carried out: repair or replace. As a result, a decision framework was proposed to choose the most appropriate maintenance activity based on current pipeline condition and expert knowledge. Since this thesis is a basis for future research, Fitness for Service approach was also included in the proposed framework. Its possible application was illustrated with the evaluation of three cases.  The presented tool illustrated the first steps of developing a framework for a practical decision-making. This framework, which is aimed to be employed in maintenance strategies of water pipelines, ensures a proper implementation of the results of condition assessment. This was exemplified by analyzing three case studies which illustrate the framework’s application in water pipelines maintenance activities. Despite its simplicity, the result showed that the proposed framework could facilitate decision-making process in maintenance activities by having a graphical representation.