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Water distribution networks (WDNs) are complex interconnected networks that require extensive planning and maintenance to ensure good quality water is delivered to all consumers. The main task of WDNs is to provide consumers with a minimum acceptable level of supply (in terms of pressure, availability, and water quality) at all times under a range of operating conditions. However, the water infrastructure in North America signifies an urgent need of upgrading the aging and deteriorating distribution systems if they are to continue to provide consumers with reliable and safe water supplies. In this context, this research is proposing a new reliability model for assessing the mechanical/structural as well as hydraulic conditions of a WDN to identify failure-prone components and prioritize their renewal. The developed model provides a systematic and practical methodology to calculate the mechanical/structural reliability of the pipe and its accessories (valves, hydrants, and so on) through the consideration of historical failures of components. The research deployed pressure-dependent demand analysis to determine the hydraulic reliability of the network in meeting the pressure requirements and overall hydraulics of the network. The minimum-cut-set theory was implemented in both reliability assessments, and the outputs of the two models were integrated to provide a representative reliability of the network. A sensitivity analysis was followed to study the change in segments' attributes on the mechanical/structural and hydraulic reliabilities. The approach was implemented on the City of London, Canada, network (north and south) to test its applicability. The developed model is expected to assist decision makers in integrating the failure records with the hydraulic simulation to plan for optimum intervention actions. 2022 American Society of Civil Engineers. Scopus

Wastewater treatment plants (WWTPs) are facing significant deterioration due to aging and improper maintenance. Statistics Canada reported that 22% and 14% of the wastewater treatment plants in Alberta and Ontario, respectively, are in poor and very poor conditions. Because of the non-capital and capital improvement requirements for any WWTP, intervention decision-making tools are paramount. The objectives of this research were to develop an integrated condition rating model for the WWTP and an optimized maintenance, rehabilitation, and replacement (MR&R) intervention model. The condition assessment model was applied on case studies and the indices supplied by the operators were used to compare the results of model through the mean absolute error (MAE) calculation, which was minimal. To optimize the intervention decisions for various units of the WWTP, the binary integer programming was used. These models are expected to enhance the evaluation of WWTPs and facilitate intervention plans based on an optimized methodology.

Sewer assets are subject to deterioration due to environmental and physical factors. Existing industry practices show that there is a lack of proper scheduling of rehabilitation projects ba...

Improper asset management practices increase the probability of water main failures due to inactive intervention actions. The annual number of breaks of each pipe segment is known as one of the most important criteria for the condition assessment of water pipelines. This metric is also considered one of the major performance measures in levels of service (LoS) studies. In an effort to maximize the benefits of historical data, this research utilized the evolutionary polynomial regression (EPR) method in determining the best mathematical expression for predicting water pipeline failures. The prediction model was trained and tested on the city of Montreal water network. After determining the best independent variables through the best subset regression, pipelines were clustered based on their attributes (length, diameter, age, and material). The majority of the models provided high R2 values, but the highest performing model's R2 was 89.35%. Further, a sensitivity analysis was also performed and showed that the most sensitive parameter was the diameter, and the most sensitive material type to age was ferrous material. The tools and stages performed in this research showed promising results in predicting the expected water main failures using four different asset attributes. Therefore, this research can be implemented in asset management best practices and in LoS performance measures to predict the number of water pipeline failures. To further improve the prediction model, additional explanatory variables could be considered along with leveraging multiple artificial intelligence tools. 2020 American Society of Civil Engineers. Scopus

Although manholes are significant assets in sewer networks, their assessment is receiving little attention compared to sewer pipelines. It was reported that more than three-million manholes in the United States (US) were structurally weak and prone to collapse. To avoid sudden failure, systematic manhole condition assessment model is required. Therefore, the primary objective of this study was to develop a component-based condition assessment model for sewer access holes. The methodology was based on integrating the Quality Function Deployment (QFD), Decision-Making Trial Evaluation Laboratory (DEMATEL) techniques to study the causality relationship between the defects in the nine identified components of the manhole. The relative importance weights of the components were found by deploying the Analytic Network Process (ANP) and were used to compute the overall condition of the asset. Based on the results, the roots were the highest influence power in many of the components. In addition, the wall, cone, cover and frame, and seals components were higher importance weights compared to the remaining components. This model was tested on an actual case study from the city of Edmonton in Canada and compared with actual values. The model produced an average validity percentage (AVP) of 76.24%. The developed model is expected to enhance the assessment of manholes and therefore provide robust conclusions. Besides, the model offers a backward analysis to pinpoint critical components in the manhole. Consequently, better decisions are made pertinent to maintenance, rehabilitation, and replacement interventions.

Regular inspection, assessment, and rehabilitation are necessary to maintain the performance levels of sewer pipelines. The primary objective of this research is to develop a causality-based model by incorporating twenty-two sewer defects, including erosion voids. The Decision Making Trial Evaluation Laboratory (DEMATEL) was used to study the causality relationship between the defects, based on a designed questionnaire, to conclude the influencing and influenced distress. The results suggested that 59% of the sewer structural and operational defects were influencing ones. Besides, the existing state of the sewer pipelines was evaluated on a scale from 1 (Excellent) to 5 (Critical) by integrating the DEMATEL technique with the Quality Function Deployment (QFD) method. The QFD-DEMATEL model was implemented on a case study to compare the model’s classifications of the pipelines’ states with the actual ones. Based on the comparison, the average accuracy and true negative rate (TNR) of the classifications were 74% and 79% respectively. Also, the average invalidity percentage (AIP) was 41.32%, causing the validity percentage to exceed 50%. The integrated approach keeps decision-makers informed about their sewer pipelines to prioritize pipelines rehabilitation. Thus, defective sewers are reduced and so are the exfiltration cases.

Sewer pipelines are a major component of any infrastructure. In fact, they are subject to deterioration through their service lives. Although researchers are pointing out the consequences o...

Infrastructure assets are essential in urban cities; their purpose is to facilitate the public needs. As a result, their conditions and states shall always be monitored to avoid any sudden malfunction. Sewer systems, one of the assets, are an essential part of the underground infrastructure as they transfer sewer medium to designated areas. However, their conditions are subject to deterioration due to ageing. Therefore, it is of great significance to assess the conditions of pipelines to avoid sudden collapses. Current practices of sewer pipeline assessment rely on industrial protocols that consider distinct defects and grades to conclude the limited average or peak score of the assessed assets. This research aims to enhance the evaluation by integrating the Quality Function Deployment (QFD) and the Decision-Making Trial and Evaluation Laboratory (DEMATEL) methods in assessing the condition of sewer pipelines. The methodology shall study the cause and effect relationship of the systems’ defects to deduce the relative influence weights of each defect. Subsequently, the overall grade is calculated by aggregating the WHAT’s and HOW’s of the House of Quality (HOQ) using the computed relative weights. Thus, this study shall enhance the evaluation of the assets to conclude informative rehabilitation and maintenance plans for decision makers., {"references":["K. Kaddoura, Automated Sewer Inspection Analysis and Condition Assessment. Montreal, QC, 2015.","R. Wirahadikusumah, D. Abraham, T. Iseley, and R. K. Prasanth, \"Assessment technologies for sewer system rehabilitation,\" Automation in Construction, vol. 7, 1998, pp. 259 -270.","R. Kirkham, P. D. Kearney, K. J. Rogers, and J. Mashford, \"PIRAT—a system for quantitative sewer pipe assessment,\" The International Journal of Robotics Research, vol. 19, 2000, pp. 1033 – 1053.","Y. 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Different techniques have been used to maintain and rehabilitate pipes and manholes of the sewer networks in the province of Quebec, including several trenchless rehabilitation techniques in the past two decades. In an effort to predict the future performance of trenchless rehabilitations, this paper presents condition prediction models for chemical grouting rehabilitation of both pipelines and manholes in the city of Laval, Quebec, Canada. The models were developed using regression analysis, based on gathered and analyzed closed circuit television (CCTV) inspection reports for the Laval city sewer network. Different defects in the chemical grouting rehabilitated sewer mains and manholes in this city are presented. The developed regression models are capable of predicting the structural and operational conditions; they are also utilized to generate deterioration curves over time for chemical grouting rehabilitation of sewer pipes and manholes based on basic governing factors such as pipe material ...

Authorities in Quebec, Canada, have been making considerable efforts to improve sewer networks across the province by using up-to-date technologies. To rehabilitate its sewer mains, Quebec has used several rehabilitation methods including slip lining, cement and epoxy lining, and cured-in-place pipe (CIPP).These replacement and rehabilitation techniques have been developed over the last four decades, with many arbitrary declarations made about the efficiency and performance of different rehabilitation techniques. This paper presents condition prediction models for CIPP rehabilitation of sewer mains. Regression analysis technique is used to develop these models, based on gathered and analyzed closed-circuit television (CCTV) inspection reports for Quebec CIPP rehabilitations. The models can predict the structural and operational conditions of CIPP rehabilitation on the basis of basic input such as pipe material, and rehabilitation type and date. They can also generate curves illustrating condition ...