McConnell Dowell, as a part of the Well Connected Alliance, is designing and constructing and will operate the Waterview Connection project, the largest road project ever undertaken in New Zealand. The 5 km, six lane motorway includes 2.5 km of constructed underground as two 3-lane tunnels – a first for New Zealand. These twin tunnels are the largest diameter tunnels built in Australasia, and utilised ‘Alice’, the world’s 10th largest TBM with an excavation diameter of 14.46m, to break through. The five year design and construction phase is followed by a 10 year operation and maintenance alliance agreement, with NZ Transport Agency assuming full operation in 2026.
The Waterview Connection is considered New Zealand’s most challenging infrastructure project to date. The project was delivered in a constrained urban environment requiring extensive stakeholder and traffic management and had the potential to impact on the surrounding environment. North of the tunnel portal is the Great North Road Interchange, which comprises four ramp structures (similar in size to ‘Spaghetti Junction’ in the Auckland CBD) directing traffic into and out of the tunnel and connecting to SH16. This work required significant coordination with the existing motorway and causeway contract being delivered by others. The ramps also traverse a Coastal Marine Area with various archaeological features that have been preserved throughout construction.
The TBM commenced tunnelling in November 2013 after 21 months of preparation involving the removal of 100,000 m3 of basalt and 200,000 m3 of sandstone at the southern portal. The length of the back-up gantries behind the 2,800 t TBM is almost 90 m and facilitates the installation of the tunnel lining which consists of 10 t two metre wide pre-cast concrete segments in rings of 10 and temporary electrical and mechanical services installation.
McConnell Dowell is thrilled to have received recognition from the NZ Transport Agency for ‘Going the Extra Mile’ on the Waterview Connection. For the second year running, Waterview won the Connecting with Our Community Award, reflecting the project team’s commitment to engaging with the community beyond normal expectations. With the project area spanning five suburbs, the team has “walked with the community” in small and large ways including formation of a community design group, management of cultural impacts in partnership with key mana whenua partners, and co-designing a playground with the local school, a process which won the team the Best Practice Award from the NZ Planning Institute.
Key to Success
The Alliance has been committed to mitigating the effects of motorway construction and facilitating improvements to the surrounding environment by:
- Constructing 2.5 km of motorway (more than half of the new section of motorway) underground
- 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
- Implementing stringent construction management practices to minimise effects on the local environment, traffic network and communities.
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.