Project in focus

Project Category
:Infrastructure, Transport
Project Name
:Blackburn Culvert Rehabilitation at Belfast International Airport
: Belfast International Airport (BIA), Main Contractor: White Mountain Quarries Ltd
: <£500,000


Project Brief  :The McAllister Goup was engaged in 2011 by White Mountain Quarries Ltd to carry out the rehabilitation on the Blackburn culvert at the International Airport. The project involved patch repairs on 900mm pipelines at 18 locations and the full relining of twin 675mm & 900mm culverts that ran directly under the main runway at BIA.
Client Brief   :Given that the Airport is the region’s principal airport for international flights, the client was adamant that subsequent works should in no way delay, disrupt or affect the airport’s operations; in particular, the work could not impact on the taxing and servicing of aircraft or affect emergency services at the airport.
Issues to consider: Possibility of unforeseen delays as a consequence of Emergency evacuations from site due to adverse weather conditions and/or emergency landings had to be factored into the project planning process. Our teams would be required to excavate the site within 30 mins leaving nothing behind on receiving the command from BIA. The McAllister teams were required to work to Civilian Aviation Authority Standards.
Works preparation:
Phase 1 invloved pre-cleaning, surveying and preparation on the lines. This work was completed without delay or incident. It included the removal
of a large piece of concrete that was located 90 metres from the nearest manhole and which necessitated a fully dressed and equipped six man-entry team to remove it with an emergency rescue team on stand-by.
Planning:Extensive planning from the outset was required including a series of meetings with the Airport’s teams to coordinate site access, egress through checkpoints and security zones. Additionally, the McAllister Group consulted with the CAA regarding legislation and safety/security requirements once airside. All works would be carried out in compliance with our Third Party Safety System procedures and a strict adherence to Risk Assessments & Method Statements (RAMS) which were developed specifically for each activity carried out.
Our Solution :Phase 2 involved the installation of 18 patch repairs at various locations in the 900mm culvert. All works required our team to work to CAA standards and ensure no delays or disruption was caused to aircraft. One difficulty encountered was positioning the packer before the resin hardened as some repairs were 90m from the manhole. We overcame this by setting up an electric winch and pulley system to manoeuvre the packer quickly through the pipe with a CCTV camera following behind to ensure the packer was positioned before inflating. All works were completed on time and without incident or disruption.

On several occasions we were required to move off site to allow certain aircraft use of the runway. On each occasion every item of equipment needed moved 150m from the runway. Whilst this caused delays we ensured only the necessary equipment and materials were on site to ensure a swift departure from the runway in case of an emergency.

Phase 3 involved the installation of 225mts of 675mm and 252mts of 900mm CIPP lining. It was decided to use UV curing to install these liners based on speed of installation and flexibility to move offsite. The 2 675mt sections ran underneath the runway and both sections had 30 degree sweeping bends. Our UV light-train towing rope and cable was an issue as the constant friction on the bend would have ripped the inner-film and caused the liner to deflate. To counter this problem, we designed an extra-strong double layered film to give extra resistance. We also powdercoated our towing rope and cable to ensure friction was reduced significantly.

During the lifespan of this project, we had to contend with Emergencies and Dense fog which meant evacuating the site with not so much as a screw left behind. We overcame these difficulties swiftly to the extent that they did not impact the deliverability of the project. In fact, we installed all liners in 5 working days without disruption or delay to the airport’s manifest. The fast actions of our personnel ensured we vacated the runway and left it safe for aircraft use on several occasions. The 900mm section was installed in 2 sections. The first was a 98m section which was installed without issue as we had good access at one manhole. The second section was more difficult as both manholes were located in grass with ground conditions swampy and unsuitable for vehicles. This section was 155m of 900mm liner with a box weight of 6.7 tonnes. It wasn’t possible to get the box close to either manhole. To overcome this, we used the 98m lined pipe as an access route for the installation of the 155m liner pulling the 6.7 tonne liner a distance of 253mts. The liners’ smooth surface ensured easy installation and works were completed without incident. This complex project was completed on time and within budget and allowed the ever changing nature of airport operations to run smoothly without causing delays to passengers. The Impreg GFRP UV cured liners are guaranteed for 50 years with a 100 + year lifespan ensuring the Blackburn Culvert will run through Belfast International Airport for the generations of passengers who use this as a gateway to the rest of the world.