13 September 2011

Costain is close to handing over a newly refurbished main runway at Manchester Airport, after using a new surfacing material for the first time on the UK mainland.

The £18.6 million contract involved Costain renewing the ground lighting on and around the 3km-long, 45-metre wide runway and resurfacing it in the process. This involved closing the main runway five nights a week, with aircraft using the secondary runway while Costain personnel worked on the renewal.

“The project driver was the wiring and cabling around the runway, which was getting towards the end of its design life,” explained Project Manager Paul Hancock. “One of the knock-on effects is that we had to cut up the asphalt surface and re-lay it.”

The project involved installing ducting around the edge of the runway and laying new lighting cabling in it. From these ducts the team then saw-cut channels 120mm deep to the runway’s centreline where they installed the lighting that helps guide aircraft.

The team also installed a new electricity sub-station for the lighting system.
Cutting into the runway meant that resurfacing also had to be undertaken. “We planed off 50mm of material and then replaced that,” said Hancock. “One of the main innovations is that we’re using a new French product called BBA (Béton Bitumineux Aéronautique). It’s widely used abroad, but Manchester is the first mainland UK airport to use it.

“Whereas with new runway asphalt you normally have to cut grooves into it to help water drain off and improve friction, BBA is self-draining and has instant friction characteristics when it’s laid.”

BBA has aroused considerable interest: “Lots of other UK airports have been here, looking at it,” said Hancock. Some 20,000 tonnes of material were used in the resurfacing programme.

Work on the runway began in January and has continued five nights a week, from Sunday to Thursday. Costain took possession of the runway at 9.30pm, and handed it back by 6:30am. “The time allowance was never exceeded as a result of meticulous planning and programming”, said Hancock.

Although the civils side of the job was fairly straightforward, he added, three factors complicated matters.

Although the main runway was closed, some taxiways from the secondary runway had to be kept open to allow flights to continue: “Aircraft have to taxi across my worksite to get to the terminal and, as we have to do work on the taxiway entrances, there was a complex sequence of closing them.”

Secondly, the excavations found many underground obstructions and services that were not marked on any drawings and plans or were detectable using traditional cable avoidance techniques or newer Ground Penetration Radar surveys.  Finally, the runway had to be left scrupulously clean at the end of work each morning. Even quite small stones, if sucked into a jet engine, can cause considerable – and expensive – damage. Ensuring the runway was clear involved up to a dozen sweeper vehicles and careful checking of the surface before it was handed back.

One unlikely vehicle to appear recently on the runway was a double-decker bus.

This was carrying around 50 councillors representing the airport authority, together with local residents groups’ representatives, who were given a tour of the work. Hancock and airport representatives provided the commentary as the group undertook a two-hour visit: “We’ve had some good feedback,” he said.

The runway is due to be handed back in late October, when all the commissioning of the new systems is complete and the client’s new ILS (Instrument Landing System) becomes operational.

• Please see attached BBC North West news film clip to see the project in action http://www.bbc.co.uk/news/uk-england-manchester-14087090