This project involved the extension of the bulk water main in Halswell to provide increased water supply to the rapidly expanding suburb.

The project involved the supply and installation of a PE100 DN560 PN12.5 bulk water main. Sections of the pipeline were installed within a level 2 carriageway, grass berm and in designated NZTA land. Included in the project were the connections to the existing bulk water main and hydrant and air valve structures. In-situ poured thrust and anchor bocks were also constructed at strategic locations along the pipe route. The pipeline varied in depth along the route, the shallowest sections were at 1.5m depth to invert, whereas the deepest sections were at 5.5m depth to invert.

The deeper sections of the pipeline required extensive de-watering to ensure the trench was dry and suitable for compaction. Certified trench shields were utilised to ensure the safety of workers when the trench depth exceeded 1.5m.

Considerable existing service crossings were encounted including but not limited to high voltage power, fibre optic cables and 750dia fully submerged storm water reticulation. A 100 lineal meter section of 750dia class 2 concrete pipe were also installed at a depth of 5.5m where the PE pipe was sleeved through as to protect the PE bulk water main from a proposed future extension to the southern motorway.

Spartan also undertook comprehensive commissioning of the pipework pre-livening. This involved the pigging, flushing, chlorination and pressure testing of the line to 12.5bar.

Client: Christchurch City Council

Consultant: Becca Ltd

Value: $1.1m

Duration: 22 Feb 2014 to 28 Jul 2014

Role: Main Contractor