McConnell Dowell, in partnership with Fletcher Construction, was awarded the Waterview Connection project by the NZTA on 19 August 2011 as part of the Well Connected Alliance. The Waterview Connection is a Road of National Significant (RoNS) project that provides the ‘missing link’ between SH20 and SH16. Once completed, it will provide a 48 km motorway route that links Manukau, Auckland, Waitakere, and North Shore and provides an alternative state highway route through the Auckland Region. The project includes construction of 4.5 km of new motorway, 2.5 km of which will be built as two 3-lane tunnels - a first for New Zealand.
The construction of a major infrastructure project in an urbanised area is a challenging task which will result in some impacts on the surrounding environment. The Alliance is committed to mitigating the effects of motorway construction and facilitating improvements to the surrounding environment by:
• Constructing 2.5 km of motorway underground (more than half of the new section of motorway);
• Minimising the number of properties affected through the project design process;
• Replacement of public open space impacted by the project along with amenity improvements, including planting and landscaping and restoration and rehabilitation work; and
• Implementing stringent construction management practices to minimise effects on the local environment, traffic network and communities
A 3,600 t, 14.5 m diameter Herrenknecht EPB TBM will bore twin tunnels at depths of between 10 m and 45 m – the largest diameter tunnel to be built in Australasia and 11th largest TBM constructed to date worldwide. The TBM will arrive in segments and be assembled in the southern approach, 30 m below the surrounding ground. Boring will commence from the southern portal in the southbound tunnel and drive northbound for 2.4 km. When the TBM reaches the northern portal it will be turned around on a turntable platform, moved across to the north bound alignment and relaunched to complete the drive back to the southern portal. Tunnel spoil will be transported by conveyor back down the south bound tunnel to a loading facility at the southern portal. This will involve a 180 degree u-turn of the conveyor at the northern portal.
Key to Success
The successful award of this contract following a protracted competitive alliance process can be attributed to good partner selection and interaction and the early resolution of options, which allowed us to develop an attractive, single option to a higher level than the competition.
Key project stats
• 550,000 m3 bulk excavation
• 800,000 m3 tunnel spoil
• 25,000 m2 bridges
• 22 km road barriers
• 100,000 m3 (24,000 segments) tunnel lining concrete
• 80,000 m3 structural concrete
• 600 km cabling
• 32 km pipework
• 64 jet fans
Location: Waterview, Auckland
Currency: October 2011 – October 2016 (estimated)