Q: Going north on the Harbour Bridge, sometimes it is five lanes wide. When you are in the fifth lane, there is a strip of about 150m of road (when you are just about off the bridge) between lanes four and five where there is no road marking between the
Ask Phoebe: Markings on Harbour Bridge lanes queried
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Photo / Kellie Blizard
A: It appears that Alice is making steady progress. By December 11, the 2200-tonne machine had chewed through 12 metres of soil. The first of the 2414 reinforced concrete rings that will line the two tunnels has been installed. The machine stops work every two metres to lift the concrete tunnel lining rings into position. Each completed ring is then grouted into place.
NZ Transport Agency highways manager for Auckland Tommy Parker says that Alice is boring at 40mm a minute, compared with her top speed of 80mm but will work at a faster pace when more lining rings are installed.
A conveyor system will remove about 800,000cu m of excavated material from the tunnels and take it to a building almost one kilometre from the tunnel portal.
From there it will be taken to a disused quarry in Wiri which is being rehabilitated for industrial development.
Alice operates 24 hours a day with crews of about 20 people and at least as many others working in support of the tunnelling operations.
Tunnelling will be put on hold for several weeks in the new year to prepare for the construction of a ventilation shaft building at the southern portal. The tunnels are due to open in early 2017.
(Source: Central Leader)
• This is the last Ask Phoebe column for the year. As always, I would like to thank readers and contributors for their continuing support, and wish you all a happy and safe festive season.