Runway Reconstruction At Ronaldsway
Colas and Balfour Beatty have reached the half-way stage in a challenging runway construction and refurbishment project on the Isle of Man. Jon Masters reports
Phase one of runway reconstruction at Ronaldsway Airport on the Isle of Man has now finished and Colas and Balfour Beatty are starting their next major phase of work. This project has already involved an intense period of activity, meticulously planned in 2008, and this year will feature the construction of a new promontory bund extending 250m out into the Irish Sea.
The runway will then be fully lengthened ready for new safety regulations due to be introduced from 2010. A longer runway end safety area (RESA) will be built on the promontory, matching the new RESA and starter strip now finished at the landward end. These were built with new taxiways and a reconstructed and re-profiled runway pavement – all between March and October 2008.
‘Tackling this sort of project tests resources and logistics but is something we are specialists at,’ said Colas airfields business manager Carl Fergusson. ‘We carried out a huge amount of work on the island last year, mostly at night during runway possession periods. All went well, partly because we have a very collaborative team environment incentivized by an NEC Target Cost contract – and because we have actively adopted a ‘right first time’ approach. Such an intense level of activity in the middle of the night requires commitment and a positive attitude.’
Chronologically, this is the third in a series of similar projects Colas have carried out in as many years. Sumburgh airfield on the Shetlands was the first in 2006 – also working with Balfour Beatty on lengthening a runway on a new promontory – followed by runway resurfacing on Tiree in the Inner Hebrides in 2007. Colas also started work on a fourth island-based project at Jersey Airport after beginning work on the Isle of Man, but the Jersey scheme was completed in December 2008, as Colas reached the end of phase one at Ronaldsway Airport.
For each project, large quantities of resources have been mobilized from Colas’ Birmingham depot, including an Ermont TSM mobile asphalt plant for dealing with the high outputs of material needed to meet the construction programme. According to Mr Fergusson, Colas achieved some impressive asphalt production at Ronaldsway Airport during July and October 2008, when the runway’s new binder and surface-course materials were being laid, generally between the hours of 9.00pm and 6.00am each night.
‘The project involves mixing 62,000 tonnes of asphalt to construct 158,000m2 of new pavement, using local sources of aggregate where possible,’ commented Mr Fergusson. ‘Sub-base and drainage material has come from Colas’s Billown Quarry on the island and we are also using the local DLO’s quarry at Poortown for some aggregate, although the majority of high-quality stone needed for the runway asphalt is being imported from hardstone quarries in Ireland.’
Asphalt production at the airport starts well ahead of the night shift, to ensure sufficient material is available for servicing the paving crews right from the start. The planing and paving crews are ready to move before the allotted possession time, with spare items for every piece of plant fuelled-up in case needed,’ said Mr Fergusson.
‘Nightly movement of traffic on and off a runway needs everyone to be working together, knowing exactly what they have to do. We have a detailed planning meeting prior to each shift, which cascades down to briefings with all of the paving crews. Every vehicle use and operation is worked out, with contingencies in case anything breaks down, together with plans for getting everything off the runway at the end of the shift. We are leaving nothing to chance and everyone is reminded at the meetings and briefings of the importance of workmanship, because this is potentially a high-risk environment.’
Mr Fergusson likens each night’s work to an individual project in its own right because of the amount of planning involved for every shift. The work has followed a pattern, although in detail it has been different every night depending on the depths, areas and types of surfacing planned for that night.
‘The surfacing teams have been working flat out at night laying binder and surface-course asphalt,’ he said. ‘Generally, working down the runway, a section of the old runway surface is first planed off and replaced with a new regulating binder course – in various thicknesses to re-profile the runway for improved drainage – followed by the laying of surface-course asphalt produced to the French BBA (Béton Bitumeux Aéronautique) specification.
‘The use of BBA asphalt allows the runway to be used in its temporary state, suitable for flights to take off and land safely,’ said Mr Fergusson.
Colas were given the green light to use asphalt produced to the BBA specification after its successful use by the company at Sumburgh and on Tiree. Initially, Colas introduced BBA materials for their workability and high outputs in mixing and laying – in comparison with the Marshall Asphalt traditionally used on UK airfields. The company has carried this on through to the Isle of Man project, increasing quantities of surfacing possible in a given length of time, with further performance benefits confirmed by independent technical studies by leading UK pavement consultants.
The studies found BBA material to be substantially better in terms of strength and durability, and other leading consultants and airport operators are taking notice. More projects taking BBA use further are likely this year, according to Mr Fergusson, and Colas will be surfacing the new promontory on the Isle of Man to lengthen and complete the Ronaldsway Airport runway.
For the promontory, Balfour Beatty will reclaim land from the Irish Sea. The heart of the promontory will be built up first and then protected against the sea with a barrier of 35,000m3 of 42-tonne rock armour; this will be imported from Norway as no UK source has rock massive enough. Inside the barrier, the promontory will be built up to level using marine-dredged material together with fill supplied from Colas’s Turkeyland Quarry on the Isle of Man.