Construction Cost Comparison between Trenchless Cured-in-Place Pipe (CIPP) Renewal and Open-Cut Replacement for Sanitary Sewer Applications

Renewal and replacement of aging sanitary sewers is one of the vital issues for the North American municipalities every day. Conventional replacement of these aging pipelines utilizes open-cut trenching methods that could be expensive both in rural and urban areas. In trenchless cured-in-place pipe (CIPP) pipeline renewal method, a liquid thermoset resin-saturated material is put inside the deteriorated pipe by hydrostatic, air inversion, or pulling inside mechanically and inflating. Then, the curing of the liner material used could be done in-place using three different ways such as hot water, steam-, or UV-cured to result in a final cured product. Trenchless methods are considered much more cost-effective; however, to make a comprehensive comparison, engineers and project owners want more data. The objective of this study is to review past studies dealing with CIPP renewal method and open-cut pipeline replacement, and to compare their construction costs for renewing the small, medium, and large diameter sanitary sewer pipelines with the help of statistical analysis. It was found that mean construction costs of CIPP renewal are 57%, 63%, and 18% less as compared to the open-cut pipeline replacement for small, medium, and large diameter sanitary sewer pipes, respectively. It can be concluded that using CIPP method, municipalities can save millions of dollars in the renewal of underground utility systems. A life cycle cost analysis to evaluate and compare the construction, environmental, and social costs between CIPP renewal method and open-cut pipeline replacement is recommended.