Geobear provided slab stabilisation to 100 slabs at Luton airport in 2018. With the expansion of operations at Luton and additional areas identified for flight traffic, in 2019, we proposed a preventative maintenance scheme of works to stabilise newly identified taxiways to be brought into use.
We had developed a good relationship with the client on the back of the successful 2018 stabilisation works. We were called in on a consultancy basis to consider the maintenance implications for the airport expansion. Following consideration with the client and engineer, we proposed a preventative maintenance scheme should be employed to avoid future disruption through unscheduled maintenance works.
A preventative maintenance scheme would enable Luton to pre-emptively stabilise new slabs brought into use by the expansion. In doing this, they could be sure that heavy flight traffic would not cause any cracking or breaking up of the slabs. This approach would reduce the requirement for future maintenance and minimise potential penalties to Luton Airport for unscheduled delays to air operators.
Following discussions with the client and their engineers, we proposed to project manage a scheme whereby ground-penetrating radar would identify problem areas across the expanded slab area. Geobear would then further validate the results and design a treatment plan for any areas deemed unstable. We shortlisted three GPR companies to complete the first phase of works with Luton Airport and the engineer taking the final decision.
We then acted as project manager for the selected GPR company as they completed surveys over 100,000sqm of slabs. The survey results identified a 3500sqm area where voiding was present, meaning the fill beneath the slabs in those specific areas had compacted or washed out; this could lead to cracking or break up of the slab under a load of an aircraft.
Geobear then validated the results of the GPR surveys. Our teams worked on a programme of coring samples across each of those slabs identified to have voiding beneath. We cored five areas on each affected slab and used inspection cameras to verify the voids. By introducing this procedure, we able to accurately reduce the affected area down to 1200sqm, 1.2% of the original 100,000 sqm.
In working with the supply chain, Geobear was able to identify the potential for failure across the 100,000sqm area and provide the full data analysis for Luton Airport to use in its expansion design works. Additionally, we designed a works proposal for the complete stabilisation of the slabs areas. The stabilisation project is due to be completed in 2020 following full sign off of the expansion scheme.