Contractor Project

Night Moves

To prevent disrupting flights in and out of Gisborne, a specialist team from Downer recently resealed the town’s runway in sections, over 14 nights, while the airport was closed. BY MARY SEARLE BELL

GISBORNE IS A UNIQUE TOWN, its individuality derived by its sheer beauty, the local characters and the fact it’s so hard to get to. It’s not a town you drive through; it’s a destination. Around three hours by car from Tauranga or Napier, its closest neighbours are acres of rolling farmland, vineyards, sleepy villages and the big blue Pacific Ocean.

It’s a popular holiday destination for wine drinkers and surfers alike. And unless you’ve got plenty of time and enjoy driving on winding roads, it’s far better to get there by air. It’s a quick and scenic one-hour flight from either Auckland or Wellington.

First-time pilots into Gisborne Airport are known to experience a moment of fright when they spot the railway line which crosses the runway, but once they realise there’s no train coming they laugh it off as part of Gisborne’s uniqueness. And unique it is too – locals will tell you it’s the only runway in the Southern Hemisphere with a railway line running through it. Apparently there’s an airport in India somewhere that also boasts this feature, but airport manager Murray Bell says he hasn’t been able to confirm that for certain.

Gisborne’s airport, which is operated and managed by the Eastland Group, has a 1310-metre-long sealed runway and three grass runways, suitable for light aircraft. Regardless of whether you fly in on one of Air New Zealand’s 50-seat Q300 planes or the rather-more-exciting-to-fly-in 19-seat Beech 1900s, the landing on the asphalt runway is now smoother thanks to a large section of it being resealed in March.

A specialist crew from Downer in Tauranga undertook the $2.5 million design and build contract in conjunction with the Eastland Group and Beca.

The last runway reseal was finished in 1998 and had a life expectancy of about 15 years. Murray says they had waited as long as possible before undertaking the reseal, making do with patches and repairs… “but it had got to the point where we needed to reseal it now”.

He says the asphalting took place at night to minimise disruption at the busy regional airport.

Asphalting took place at night to minimize interruptions
Asphalting took place at night to minimize interruptions

“Work started on Sunday, March 29 and, during the three-week period of the project, the airport was closed from 8.15pm until 6am the following morning to all traffic, except helicopters.”

The work involved milling out the current runway asphalt to a depth of 100mm, then overlaying with a new 100mm asphalt layer. Each night Downer’s specialist crew finished a section 30 metres wide and 65 metres long to ensure the material was sufficiently cooled prior to the first aeroplane of the day.

“We needed to make sure each section was completed and the lines repainted on the runway by 5am, in time for the first scheduled flight of the day,” says Murray.

Downer says that it had back-up plans to cater for any eventuality, such as a breakdown or adverse weather. “The runway had to be open at 5am no matter what.”

To guarantee this would happen Downer employed its specialist paving team from Tauranga, with support from the Downer National Airport team, the local Downer branch and local subcontractors.

“Our asphalt production facility, located within a few hundred metres of the main runway was a significant part of the solution,” Downer told Contractor. “The close proximity to the project reduced the environmental footprint of hauling asphalt over a longer distance and assisted with the tight delivery timeframe each shift.”

To confirm the quality of the asphalt supplied, Downer established a mobile testing laboratory to undertake all asphalt compliance and control testing for the project. This provided immediate access to results for the production teams, engineers and the client.

Downer says the results from the field were exceptionally consistent, providing full compliance to the contract specification.

The total width of the runway is 45 metres, built to requirements from the 1950s and ’60s, however, Murray explains, just the central 30 metres have been replaced as that is all that would be required if they were to build a new runway to today’s construction standards.

This project saw an 870-metre section of the runway’s length completely replaced. In addition, some patch repairs outside the 30-metre strip and taxiway repairs were done, a total of 27,000 square metres.

Downer says that, following milling, the exposed surface was swept clean and benkleman beam testing undertaken to identify any areas requiring further attention. Then a polymer modified waterproofing membrane seal was applied. Once this was all approved and passed, asphalt placement began.

Using its Super 1603 Vogele paver with multiplex ski Downer achieved the required thickness and slope targets while ensuring a superior, smooth finish.

“Compaction of the mix was led by our Bomag Asphalt Manager roller, which continuously gave live compaction data to the operator to ensure consistency of compaction targets. This was supported by a Cat tandem roller with GPS mapping technology to ensure full and consistent coverage.”

The contract was divided into three separate stages involving more than 40,000 square metres of asphalt being laid.

The work that was finished in April comprises the first two portions of the contract – the 30-metre wide strip from the railway line north and the patching work. Murray says the final portion of the runway from the railway line south will be completed at a later date as it has not deteriorated at the
same rate.

Eastland Group recently celebrated its 10th anniversary of the operation of Gisborne Airport. The Gisborne-based company, whose business interests include Eastland Network and Eastland Port, has been operating the airport since April 1, 2005, on lease from Gisborne District Council.

Since that time, Gisborne District Council has remained the asset owner, but Eastland Group has operated, managed and developed the airport.

Eastland Group chief executive Matt Todd says that in 2005, Gisborne Airport was costing Gisborne ratepayers money: “Today Gisborne Airport makes a small profit and is able to commercially stand on its own feet.”

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