Trenchless Rehabilitation of City of Gold Coast’s DN600 Sewer Rising Main

Abstract

Rehabilitation of the Eastern Force Main for the City of Gold Coast (City) saw the Southern Hemisphere’s first installation of a kevlar reinforced Primus Line pressure liner in a sewer rising main. The City experienced a failure of the critical DN600 mild steel, cement lined main running under Biggera Creek just upstream of the Broadwater, one of the Gold Coast’s most popular marine recreational areas. The sewer rising main was submerged, encased in concrete and had four vertical bends along its length and a horizontal bend on each side of the creek. Dry weather flows were able to be diverted, but this was only a short term measure as peak wet weather flows would overload the system. A long-term, rapid response solution was required. Construction of a new sewer using HDD was ruled out as too time consuming. Slip lining was not an option as an adequate size HDPE pipe could not be accommodated within the host pipe due to the bends. Thorough evaluation by the City’s Water and Waste directorate resulted in Primus Line being chosen for the project despite it never having been used in a sewer rising main in Australia. Cooperation between the City, Queensland Urban Utilities (QUU) and Sydney Water (SW) resulted in a suitable class and size of Primus Line being rapidly made available, along with the connections and tools needed for installation. Site specific challenges including tidal conditions limited work on the pipe to a 3 hour window during low tide. Despite this, the relining portion of the project was completed in only 3 days. Page 1 of 10 No-Dig Down Under 2019 Trenchless Rehabilitation of Gold Coast’s Water and Waste DN600 Sewer Rising Main Zillmann, Truscott & Spencer