Trenchless Rehabilitation of the Upper Hobsons Bay Main Sewer

Abstract

Rehabilitation of the 110-year-old Upper Hobsons Bay sewer in Melbourne saw the completion of one of the world’s largest UV-cured fibreglass CIPP lining projects. The project included 32 lengths of ovoid sewer with internal dimensions of up to 1200m x 825mm over a total of some 3.5 kilometres. In addition, 1,100 metres of 600mm nominal diameter circular sewer was lined and 43 manholes rehabilitated along the route. Complicating the project was the location – mostly near the shoreline of Brighton Beach, home of Melbourne’s iconic bathing boxes. The full length of the rehabilitated section of the Hobson Bay Main was sited within Beach Rd and St Kilda St which serves as a major arterial road for commuters from Melbourne’s South-Eastern suburbs. The ovoid shaped sewers were rehabilitated with high strength, UV cured CIPP fibreglass liners, while PVC spiral wound liners were installed in the circular sewers. Manholes were repaired and internally coated with calcium aluminate cement. The challenge of installing the fibreglass CIPP liners was exacerbated by the heavy infiltration (tidal) of the sewers as well as heavy calcification built up around the walls and roof of the pipe. These needed to be addressed with special measures to be taken to ensure successful, heat-dependent UV light curing. Other challenges including flow and traffic management to minimise community disruption were completed by cooperation between the contractor, subcontactors, the Client and other stakeholders including Bayside City Council , Bicycle Victoria and Vicroads. This paper tells the story of another successful Australian industry leading Trenchless Technology project Page 1 of 12 No-Dig Down Under 2019 Trenchless Rehabilitation of the Upper Hobsons Bay Main Sewer Matthew Pratt and John Monro