Condition Prediction for Cured-in-Place Pipe Rehabilitation of Sewer Mains

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 deterioration over time with respect to governing factors. A data set was randomly selected and put aside for validating the developed models. Models validation was based on the value of the coefficient of multiple determination (R2) ranging between 94 and 99%. The developed models are expected to be used by municipalities and contractors to forecast the condition of rehabilitated pipelines, plan inspections, and make informed budget allocation decisions.