'Significant progress' made on fixing Transmission Gully pavement defects

Parts of the road have been ripped up for repairs on Transmission Gully. Photo / Waka Kotai NZH

"Significant progress" has been made towards fixing construction defects and pavement issues on Transmission Gully - the new motorway out of Wellington that's yet to open.

The four-lane-highway has been plagued by flawed chipseal and water seeping through the road's surface, according to independent inspection reports carried out towards the end of last year.

The chipseal defect played a significant part in the road's opening being pushed back once again just before Christmas; originally expected to open in April 2020, the road is now expected to open this year.

In an update this morning on the troubled road, Waka Kotahi NZ Transport Agency said recent on-site investigations by roading experts reported these issues were being addressed.

The builder has had more than 150 people on site since December working on a range of tasks.

Transmission Gully. Photo / Mark Tantrum

Remedial work to manage water seepage on the asphalt surface is underway and the warmer temperature and lack of rain in recent days has allowed rollers to resume the task of rolling the chipseal road surface.

Last week Waka Kotahi released photos of parts of the road being ripped up, drainage being dug, and rollers at work.

Waka Kotahi also reported this morning that good progress has been made on contractually required safety and quality assurance tests, with many close to completion.

There are 100 of these in total.

As of the end of last week, 57 final safety and quality assurance test submissions have been received from the builder, of which 45 have now been accepted by the Independent Reviewer as meeting the required standards.

All three remaining consent tasks have been submitted to Greater Wellington Regional Council for certification or confirmation.

Te Ara a Toa bridge over Cannons Creek Transmission Gully in June last year. Photo / Mark Coote

Transmission Gully is being built through a public-private partnership (PPP), the Wellington Gateway Partnership (WGP), with CPB Contractors and HEB Construction subcontracted to carry out the design and construction.

It is the builder's responsibility to ensure these consents, as well as safety and quality assurance tests, are completed to the agreed standard.

Waka Kotahi said it was working with the other PPP parties to reach a "pragmatic solution" for the road.

"That meets the legal requirements of the PPP contract to ensure the long term safety and reliability of the road and safeguards public liability, while also getting the road open to the public as soon as possible," the agency said in a statement.

Last month Waka Kotahi hoped to provide an update in mid-February as to just when Transmission Gully will finally open.

Today, Waka Kotahi said it expected the builder will provide an update on the timeframe for road-opening in the next few weeks.