Subscribe to RSSBridge Only Has 20 Years Left, NZTA Moves For Harbour Tunnel
Major developments this afternoon on a third Auckland harbour crossing as concerns grows about how long the present bridge can function. 
The transport agency says in 20 years time the present Auckland Harbour Bridge will be nearing its life as a state highway. Strengthening of the clip on lanes has given those lanes a finite life of 20 to 40 years.
The agency revealed this afternoon it’s having to spend double to complete strengthening work on the box girders(clip ons) supporting the Auckland harbour bridge’s outer lanes but insists the bridge is safe.
But because the life of the bridge is in doubt, NZTA today lodged notices of requirement with Auckland City Council and North Shore city seeking a sub strata (underground) designation for four separate tunnels beneath the harbour, two each for road and rail.
The NZTA board is now favouring a tunnel crossing which includes rail but says while that it’s preferred option, the government could still opt for another bridge instead.
And NZTA says there’s still no funding from the government for either option.
Today’s tunnel move comes as the NZTA reveals it will now need an extra $41m to complete the strengthening work on the northbound box girder but says it can cover that from present budgets. The agency admitted it was halfway through the work before it realised this because it had been “working on imperfect information.”
It claimed it had to start the work to find out what was involved and this increase from the original estimate of $43m was because of a 43% increase on the amount of steel required to complete the job, difficult access inside the box girders, the number of labour hours required for the work, shortage of skilled labour and having to adjust the position of water mains under the bridge because of the extra weight of the box girders above them.
The strengthening work will take another year extending the life of the girders, allowing current weight trucks to use the clip on lanes for 10 to 20 years but still not allowing heavier trucks currently banned to use them.
If there were early morning restrictions placed on the northbound lane, the life may be 20 to 30 years and the transport agency is also looking at new technology involving spraying water on the bridge to control its temperature. If this was possible, the life may be 30 to 40 years plus.
The agency says it’s spent the last two years looking at 160 options including tunnels, bridges, sky cabs, monorails and ferries. But its preferred option is four driven tunnels, two each for road and rail from the Tank Farm to Esmonde Rd. Today’s move to lodge notices of requirement was to protect the underground route from future development in the Wynyard Quarter (tank farm) at the southern end of the next crossing.
The Wynyard hearings start in February.
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