Drilling at the Waterview Connection project in Auckland is stopping for three weeks while workers get ready for the next stage of the massive motorway project.
During the break, a giant white gantry will be pushed into the tunnel behind Alice, the project’s tunnel boring machine.
The gantry will be used to lift into place large concrete culverts each about 2 metres tall and weighing 5 tonnes that will create a passageway on the tunnel floor to carry services like water, electricity and telecommunications links below the new motorway.
“We had originally planned to stop tunnelling for 6 weeks to get the gantry into place, but thanks to a lot of preparatory work and clever innovation on site we’ve managed to cut the time in half,” says the NZ Transport Agency’s Highway Manager, Tommy Parker.
The gantry is the first of its kind in the world and was designed by Herrenknecht, the German company that constructed Alice.
It arrived in New Zealand in parts and was re-assembled outside the entrance to the southern portal. It will be moved into the tunnel in the next few days. It is 95m long – the same length as Alice – and weighs 400 tonnes.
“Waterview is the country’s largest roading project, and the gantry is another example of the size and complexity of the work that’s underway there,” says Mr Parker.
Twin 2.4km-long tunnels, both 13.1m in diameter, are being constructed to connect Auckland’s Southwestern (SH20) and Northwestern (SH16) motorways as part of the city’s Western Ring Route, one of the Government’s flagship Roads Of National Significance (RONS). Each tunnel will carry three lanes of motorway traffic.
Alice has now reached the 500m mark on her journey north to construct the first of the two tunnels. She is 30m below ground, and will eventually reach a depth of 45m.
Mr Parker says the lifting gantry has been designed so that Alice can continue her work uninterrupted when tunnelling resumes. Supplies, like the concrete segments of tunnel linings that Alice installs, will be transported along a special “tunnel trail” running over the new culvert and the gantry, down a ramp to the tunnel floor and then on to the TBM.
“The priority will always be to keep Alice moving north a few hundred metres ahead of the gantry.”
The Waterview project is being delivered by the Well-Connected Alliance which includes the Transport Agency, Fletcher Construction, McConnell Dowell, Parsons Brinckerhoff, Beca Infrastructure, Tonkin & Taylor and Japanese construction company Obayashi Corporation. Sub-alliance partners are Auckland-based Wilson Tunnelling and Spanish tunnel controls specialists SICE.
Four other related projects on the Northwestern Motorway to complete the Western Ring Route RONS – upgrades of the Lincoln Road and Te Atatu Road interchanges, the Causeway Upgrade Project and widening the motorway between the St Lukes and Great North Road interchanges – are underway or about to start construction.
Mr Parkers says those projects will be completed before the tunnels at Waterview open in early 2017.
For more project information visit the Waterview Connection project site(external link)
For more information please contact:
Auckland/Northland Media Manager
NZ Transport Agency
T: 09 928 8720
M: 027 213 7616