Some £4m over budget when tendering for an aircraft wing test facility with two hangars and an open plan office, Jason Hunt clearly had a mountain to climb to get this scheme off the drawing board and into construction.
The objective of the facility is to allow engineers to test full-size aircraft wings in the main hangar by bolting them to a matrix of 1,326 anchors in a heavily reinforced concrete slab and to a 10m-high, 13m-wide and 4m-deep steel wall weighing 240 tonnes and equipped with hydraulic loading and measurement systems – a strong floor and wall system.
Jason started the value engineering campaign by reducing the overall project floor area and the size of the main hangar. But the real gain came from his unbundling of the strong floor package. The single specialist offering turnkey design and installation was ditched in favour of a number of standard material suppliers and supply chain partners.
It was inevitably a more challenging route. Jason spent nine months working out how to install the bolts to phenomenally exacting tolerances (+/-3mm in three dimensions), place and fix the heavy reinforcement, and then cast the entire 40m-long, 18m-wide and 2m-thick concrete floor within 24 hours (a logistical nightmare of getting one lorry after another in a 250-strong fleet lined up to pour a load every six minutes). However, it was a significantly more cost-effective approach and got the project onto site.
Another big win came from Jason doing something similar with the bespoke hydraulic installation, having it designed and delivered by a local specialist rather than a much more expensive national company. He also carried out a cut, store and fill exercise that benefited the logistics as well as the budget by ensuring no excavated material had to be removed from site.
He gained two months on the programme by redesigning the foundations and steelwork around the basement so the frame could be erected before the reinforced concrete basement slab and walls were cast. It made the basement construction logistically more challenging but allowed the frame, floor planks, roofing and cladding to progress without having to wait for the completion of the basement.
Accepting that designing the complex strong floor would be a much longer process than originally planned, he erected the hangar’s steel frame first. It helped maintain project momentum and allowed the strong floor to be built in a more controlled environment, with roofing and cladding offering works protection.
Likewise, he got his quality response in first with the top surface of the strong floor – the concrete mix design created extreme difficulties for level and finish. Keeping the surface 3mm lower than the final level allowed for concrete grinding and the application of an epoxy resin to achieve tolerance. It also provided a decorative finish for the floor and a fittingly smart on-budget and on-time finish to the project.