Jacobs Associates announced last week that the last shaft cover had been lowered into place on the Northern Sewerage Project in Melbourne, Australia. The event marked the end of the five-year, AUD 650M (USD 663.6M) project, which began in August 2007 and was completed six months ahead of schedule. It was AUD 135M (USD 137.8M) under budget.

John Holland was contractor, Aurecon was project manager and Jacobs was the designer with Sinclair Knight Merz.

A Jacobs spokesman said, “Most construction work for the new sewer took place between 15 and 64 meters underground. Three specially assembled TBMs were used to construct seven tunnels through a variety of ground conditions ranging from basalt to weak, interbedded siltstone and sandstone.

“The TBMs included a 3m-diameter hard rock machine and two earth pressure balance machines, one 3m and the other 4m in diameter.

The spokesman added, “A fiberglass reinforced polymer (FRP) lining was installed within the new sewer tunnels that connect the project’s eight main access shaft sites. This lining provides a finished diameter ranging from 1.6 to 2.5m across the system. Works also include smaller connections to the existing sewerage system, several of which were installed using trenchless methods.”

Melbourne Water delivered stage one of the project, Yarra Valley Water delivered stage two.