Hunua 4: McConnell Dowell/Watercare – $7 Million

JOB NAME:  Hunua 4

CLIENT:  McConnell Dowell/Watercare

CLIENT REFEREE:  Richard Atkin

START DATE:  November 2018

CONTRACT COMPLETION DATE:  November 2019

ACTUAL  COMPLETION DATE:  Ongoing

CONTRACT VALUE:  $ 5.9 Million

FINAL VALUE:  $ 6.1 Million

Starting in 2012 Watercare have been installing a new water pipeline called Hunua 4.  This watermain runs from the Redoubt Road Reservoir in Manukau City and will terminate at Khyber Pass in the Central City.  CB Civil were engaged as Subcontractor to McConnell Dowell to complete the open trench portion of the Hunua 4 Section 11 Project.  This is the final stage of the over 400-million-dollar infrastructure project.  The completion of the new watermain will ensure that water supply will keep up with demand and provide high quality uninterrupted water to a growing Auckland Super City.

M3 EARTHWORK/CONCRETE
CB Civil will excavate, shore and install 700m of DN1575 watermain.  There will also be the installation of 2 air valves and an off-take scour valve.  Due to the varying ground conditions two different methods will be used for shoring the up to 4.5m deep trenches. These are conventional aluminium shoring boxes 7m in length and double stacked and driven king post and mild steel plates.  During the excavation process there will be close to 10000m3 of material excavated and removed from site.

The pipes that are being installed are 12m in length and weigh 8.5T each.  These are concrete lined mild steel pipes that are primed and double wrapped in a polyken tape.  This insures complete isolation from the in ground material which will ensure longevity of the pipes internal integrity.  The complexities around handling such a large pipe mean that to lift them into the trench requires a dual lift utilising a Hiab mounted truck and the onsite 35T excavator.

TRAFFIC MANAGEMENT
Traffic management is a part of our scope and we have some major diversions and closure of level 1 and level two roads.  Along with the numerous residents and stakeholders along the pipe route CB Civil will interact with Auckland Transport, Auckland Council and Watercare.

INNOVATION
CB Civil has provided another crew to work two areas concurrently, this will not only allow our scope of the works to be completed in a timely manner but may also benefit McConnell Dowell getting into areas ahead of programmed dates;  in turn, lessening the disruption to residents, road users and stakeholders.