A Qualitative-Risk-Based Model to Assess Group Decisions for Planning the Maintenance-Renewal Works of Water Pipelines with Unreliable Operational Data

Maintenance-Renewal Works (MRWs) are among the most complicated planning operations of water companies and usually involve a group of experts. However, experts are often hesitant in their decision making as they often need to rely on unreliable quantitative operational data, which prompts doubts about the effectiveness of their decisions. This problem can be addressed by using linguistic (qualitative) values instead of imprecise numerical data. Hence, this study develops a qualitative-risk-based model to plan the MRW of six Iranian networks comprising pipes with unreliable operational data. The study also investigates the effectiveness of group decisions on planning pipe MRW. The results indicate that planning with imprecise numerical operational data can be improved by using a qualitative-risk-based model. Additionally, it is found that group decisions do not significantly change the pipe priorities, although they have a decisive effect on determining the pipe maintenance-renewal strategies. Furthermore, increasing the number of criteria is found to lead to more accurate results within the developed model, although increasing the number of decision-makers has no decisive effect on the results.