Auckland Harbour Bridge costs double

JOHN SELKIRK/Stuff.co.nz

COST CLIPPING: The cost of strengthening Auckland Harbour Bridge's clipon lanes has suddenly doubled, the Transport Agency Board says.

The cost of strengthening Auckland Harbour Bridge's clip on lanes has suddenly doubled and its going to require 43 percent more steel, the Transport Agency Board says.

In a statement they also reveal that they have sought to protect the routes of four new tunnels under the Waitemata Harbour.

In 2007 NZTA announced a $45 million in maintenance work on the clip-on sections and today board regional director Wayne McDonald said they had approved another $41 million to complete strengthening.

The clip-ons carry four lanes, two north, and two south.

The strengthening will bring the box girders up to current design standards and extend their service life, allowing current legal weight trucks to use the clip-on lanes for 20 years or more, the NZTA said.

It would take 43 percent more steel than originally estimated and the complexity of the work has required more labour hours than anticipated.

The strengthening is expected to be completed next year.

"The scale and complexity of this project is huge. The initial funding approval was an urgent measure to address an urgent need. As the work has progressed the need for further investment to complete it to the required standard and extend the service life of the bridge has become apparent," Mr McDonald said.

Strengthening would ensure the bridge could be a key link for the next 20 years, Mr McDonald said it was important to recognise that the bridge cannot continue to carry heavy vehicles or serve as the city's main harbour crossing indefinitely.

A new engineering report assessing the effects of future traffic growth on the bridge had confirmed that the box girders could not be strengthened any further and the bridge has a finite service life in its current configuration, emphasising the need to secure the future of an additional harbour crossing.

"In 20 years' time the bridge will be nearing the end of its life as a state highway and the need for a viable additional harbour crossing to efficiently move increasing volumes of freight and a growing population through Auckland will be critical. The process of route protection, funding, design and construction for a new crossing is expected to take up to 20 years - the time to act is now."

NZTA said Auckland could get up to four separate harbour tunnels linking the city and the North Shore.

They had filed documents with the Auckland City Council and North Shore City Council seeking a "sub strata" designation for four separate tunnels, two for road and two for rail, under the harbour.

This protects the routes planned across the harbour for the tunnels.

Mr McDonald said their tunnel action did not they were ruling out a new bridge.

But it was important, he said, to preserve the tunnel options by protecting the underground route from future development in the Wynyard Quarter of down town Auckland.

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