|Project Name:||Gatwick Airport Main Runway Rehabilitation|
||Gatwick Airport, West Sussex|
||August 2012 to November 2012|
Scope of Works:
Gatwick Airport operates the busiest single runway commercial airport in the world, the second largest airport in the UK and the seventh busiest international airport globally. Approximately 58 take offs and landings take place every hour on the runway, Gatwick Airport’s primary asset.
In 2012, Colas undertook surfacing operations for a major runway rehabilitation project as the 3.3km runway at Gatwick Airport approached the end of its 12 year serviceable life. This involved removing the existing surface course on the runway and taxiways before laying a high quality Marshall Asphalt, specially designed by Colas. In addition, the main runway and taxiways were grooved and temporary runway lines were installed.
Upon the completion of the project (68 shifts), Colas had carried out the following:
- 43,710 tonnes of Marshall Asphalt mixed
- Over 4,000 tonnes of planings recycled
- 301,500m2 total area surfaced
- Over 150,000 m2 total area grooved
As Gatwick Airport is a major international airport, Colas was required to follow rigorous security procedures during the runway rehabilitation project.
Prior to the commencement of the works, all personnel that were to be a part of the project team had to undergo security vetting and be proposed to the London Gatwick Airport ID Centre who further investigated the validity of the details provided. They checked the minimum 5 years of employment history references as well as personal references to ensure that all personnel working on the project had clear backgrounds.
As part of the vetting process, all Colas personnel received General Security Awareness Training (GSAT) so that they were aware of current security requirements and procedures to be followed when operating on commercial airports.
An Airport Operators Licence was required to operate vehicles and equipment airside. Each vehicle and piece of mobile plant to be used on the contract had to have an airside vehicle pass, subject to age and emissions of the vehicle.
In order to avoid any difficulties associated with the application for personnel and vehicle passes, all resources for the contract were confirmed at an early stage. This allowed Colas to promptly gather the necessary documentation to be submitted and provided Gatwick Airport with sufficient time to process the applications.
Colas’ technical knowledge of Marshall Asphalt mix design was central to the success of the runway resurfacing works. Colas’ technical team designed the Marshall Asphalt mix, procuring the best quality aggregates from France to create an optimum surfacing material. Prior to the commencement of the runway resurfacing works, comprehensive trials and tests were carried out landside to ensure the best possible mix was delivered to the client.
To produce the quantities of Marshall Asphalt required for the works, Colas procured a brand new, state of the art £2million Intrame UM280 mobile asphalt plant. As our existing fleet of mobile asphalt plants was in use on other airport contracts, Colas ordered the high capacity Intrame UM280, a resource commitment which facilitated the runway resurfacing at Gatwick Airport.
The logistics of transporting the brand new mobile asphalt plant (shipped in from Spain) and materials (some aggregates where shipped from France) was carefully coordinated and managed. Once the plant was on site, Colas’ experienced team of fitters, mechanics and electricians installed the asphalt plant with ease despite working to the client’s tight deadlines to commission the plant in readiness for the surfacing works.
Once established, the Intrame plant provided a dedicated, uninterrupted and reliable source of asphalt. The 4 tonne batch mixing plant produced up to 280 tonnes of Marshall Asphalt per hour.
Manufacturing the asphalt on-site eliminated the need to have asphalt delivered. This significantly reduced lorry and vehicle movements around the site, minimising disruption to local road networks, residents and other vehicle users.
Colas began the runway resurfacing works by removing the existing surface course. Colas engaged with industry leaders in planing/cold milling to remove 10mm of existing surface course on the main runway, using state of the art machinery. This time critical operation was managed with military precision by the experienced Colas team to ensure a feasible working window for the surfacing works. Surface course was also removed on the taxiways in addition to regulating to achieve the desired levels required by the client. All planings on the project were re-used on the site or recycled locally.
To lay the Marshall Asphalt, Colas used 3 pavers, including a brand new industry leading Vogele 1803-2. The 3 pavers worked in echelon formation to provide a high surfacing output and seamless longitudinal joints. Colas used a team of skilled and experienced operatives and high performance compaction equipment to ensure quality resurfacing was delivered on time and to the client’s satisfaction. At the peak of the works, Colas had over 30 surfacing operatives, 3 pavers, 9 rollers and over 15 asphalt lorries, all operating on the runway simultaneously.
To groove the Marshall Asphalt on the runway and taxiways, specialist grooving machines were utilised. This was the first time a contractor had used the machines in the UK which were able to self-extract the resultant grooving slurry and pump it in to a tank for disposal off site. In addition, this equipment was able to groove the runway and taxiways at an impressive rate of up to 75m per shift, per machine. Having completed the surfacing works, Colas installed temporary lines to ensure runway compliance upon hand back.
Testing of the Marshall Asphalt was carried out in the on-site Colas Laboratory throughout the contract. Prior to work commencing on site, preliminary trials were conducted. Raw materials for the asphalt mix were identified and checked to ensure that they complied with the required standard. The materials were then blended and the mix design tested by Colas before batching plant trials began on on-site.
These tests confirmed that the material sample met the necessary requirements. Laying trials were conducted with core samples taken and analysed by our team of lab technicians to confirm the properties of the surfacing material after laying.
Colas’ airports team appreciated that the runway was the airport’s primary asset and so it was essential that measures were taken to ensure that its operation was not adversely affected by our works.
As Gatwick Airport’s runway remained live throughout the contract, Colas was required to conduct the resurfacing works during restricted night time possessions of 22:30pm to 05:30am. The purpose of operating at night was to prevent disruption to flights at the airport.
Meticulous planning and organisation of the mobilisation and demobilisation of plant, equipment and personnel on and off the runway each night was critical. The large amount of plant and vehicles involved in the operations also meant that vehicle movements had to be managed with accuracy to avoid time loss and maintain material flow on site.
Prior to taking possession of the runway, at 19:00pm Colas’ site management personnel met with the client to discuss the activities to be undertaken during the shift. This ensured that each member of the team was aware of what they were required to carry out, the equipment to be used and the amount of works to be completed before the handover of the runway the following morning.
At 21:40pm all Colas personnel, plant and equipment had passed through the airport’s security and was lined up airside in the order in which they needed to be deployed on to the runway. This allowed our team to promptly begin the night’s works.
Colas’ airports team took possession of the 3.3km runway once flights had ceased at 10:30pm each night and were permitted to work until 05:30am. It was critical that all works were completed at this time to allow normal flying operations to commence. At 04:30am each morning, the team began to demobilise, leaving the runway in reverse order.
A key aspect of Colas’ operation on the airport was the use of our Intrame mobile asphalt plant which was set up on the edge of the airport. By the time the team entered the runway each night hundreds of tonnes of asphalt had been produced and loaded on to trucks ready for use. Batching started at 18:30pm which ensured that enough asphalt was produced to replace materials planed out from the runway. An average of 900 tonnes was mixed and laid per night with a maximum tonnage of 1514 tonnes batched and surfaced in a shift. In total, the plant provided 70,000 tonnes of asphalt for the time critical project where productivity, reliability and material standards needed to be guaranteed.
Awareness and appreciation of airfield safety was paramount with traffic management systems for each work area being planned out and implemented. This ensured that the project was completed with no safety issues, on time and to the highest quality standards.
Due to the careful management of the operation, all deadlines were achieved and no flights at the live airport were delayed or disrupted despite ever changing conditions on site, inclement weather and the restricted time scale. The experience gained on previous contracts and the resources available within Colas enabled our team to overcome all the challenges encountered and successfully produce a high quality product on time and to budget with zero defects.