Challenging the Limits: Class D Pipe Bursting – Connecting Research and Practice

Abstract

In 2024, the City of Chilliwack, British Columbia, undertook a significant sanitary sewer upgrade, utilizing pipe bursting to increase capacity in the growing Sardis neighbourhood. The project involved upsizing 350m (1,150') of 300mm (12”) ID PVC pipe to 500mm (20”) OD HDPE, a quadruple upsize and increase of approximately 178% in cross-sectional area. The work was carried out in a high groundwater environment, adjacent to structures and a 750mm (30”) concrete storm sewer, necessitating a trenchless approach to mitigate settlement risks. The Chilliwack project is a recent example among several IPBA Class D “Developmental” pipe bursting projects, successfully completed by PW Trenchless Construction, a British Columbia based trenchless contractor. By presenting a history of 15 successfully completed Class D pipe bursting projects since 2017, and combining this with the findings of academic literature, the paper aims to challenge the expectations and limitations of pipe bursting. The paper questions if current pipe bursting classifications and feasibility criteria are too conservative, and highlights the anecdotal evidence which may suggest the need for revision. It is hoped that by presenting this anecdotal evidence in the form of contractor experience, alongside the findings of previous studies, this will trigger the final steps in research towards the development of scientifically proven pipe bursting feasibility and design guidelines. Moreover, by proposing systematic field monitoring, pre & post density testing and more collaboration between industry and academia, it is hoped that progress can been made towards developing evidence-based approaches to pipe bursting project design, with predictable outcomes.