A component-based approach in assessing sewer manholes

Abstract

Infrastructure asset management domain has an extensive advancement in condition assessment and rehabilitation decision models. However, most of the focus is devoted to pipelines, giving little attention toward manholes. Recent studies revealed that more than three-million manholes in the United States (U.S.) have structural deficiencies. Defective manholes are a main source of the inflow/infiltration and contribute up to 50% of the collection system’s input to treatment plants. As a result, it is of great importance to assess them on a regular-basis to avoid any operational and structural failure. The main objective of this study is to develop a condition assessment model for sewer manholes. The model divides the manhole into several components and filters the possible observed distress in each element. Later, the study determines the relative importance weight of each component using the analytic network process (ANP) decision-making method. Moreover, the condition of the manhole is computed by aggregating the condition of each component with its corresponding weight. As a result, the proposed assessment model will enable decision-makers to have a final index suggesting the overall condition of the manhole and a backward analysis to check the condition of each component. Thus, better decisions are made pertinent to maintenance, rehabilitation, and replacement actions.