8 km
drainage installed
Infrastructure
Engine Ground Run Facility, Cambridge Airport
Aircraft maintenance generally requires testing engines running under high power settings. This is undertaken in purpose-built three or four-sided enclosures designed to improve noise attenuation. Collaborating with the specialist designer, we coordinated and produced the concept design for the civil aspects of the ground running enclosure and provided technical support to Marshall Aerospace during the construction period.
Our role involved designing foundations, taxiway pavement, hard standing, drainage, producing the Employer’s Requirements and managing the tender period.
The test facility is a four-sided 20m high steel frame structure that supports acoustic panels for the reduction of noise and deflection of engine jet wash from the surrounding environment. The enclosure is suitable for all commercial and military aircraft, with the largest design aircraft being the B777-300ER.
Key details
Project name
Engine Ground Run Facility, Cambridge Airport
Client
Marshall Aerospace – Cambridge Airport
Location
Cambridge
Services provided
- Airfield Planning
- Civil and structural engineering
- Tender project management
Challenge
The requirements of the enclosure included restrictive movement tolerances to ensure that the doors of the enclosure would operate unhindered. The location of the enclosure required the removal of an existing 10m high earth mound. Heave was a significant concern and we specified and managed a ground testing regime to assess the likely impact of heave against the weight of the proposed structure.
Site testing indicated that the earth mound was acting as a surcharge to the underlying strata to a depth of approximately 15m. Initial modelling showed that once the earth mound material was removed, significant heave could be expected over a period of time, with the majority occurring over an initial short period.
Due to timescales, the project could not wait for the heave to occur naturally, so we were tasked with finding a solution that could accommodate the heave and the impact on the structure.
Solution
Our team considered a number of different foundation solutions which needed to take into account the potential heave of the underlying clay material and the long-term creep heave over a period of circa six months.
The final solution was a bored piled system installed below the walls to the ground run enclosure and the gate structure.
We incorporated two systems of piles into the design. The first system used short un-sleeved piles placed within the heaving zone to resist compressive loads from the walls - these piles needed to be heavily reinforced to resist the stresses and transmit the tension loads into the underlying strata. The second system used longer un-sleeved sleeved piles through the heave zone to resist structural movement due to heave and/or settlement.
Project statistics
555
piles
10000 m3
concrete
10000 +
bolts to secure the structure
130000 m3
earth related on site
