Mott MacDonald expand The Hong Kong International Airport
Marking a significant milestone in Hong Kong's International Airport expansion plans, the North Satellite Concourse heralded a new gateway for short haul carrier services to mainland China and other nearby Asian destinations. Its introduction as a 10 aircraft stand remote concourse enabled more long haul aircraft to then occupy the main terminal gates made available, improving levels of service.
Mott MacDonald Hong Kong Ltd led the design team and undertook all planning and building engineering design services. The client is Airport Authority Hong Kong and architect Aedas. It was built by Gammon Construction Ltd.
From the outset, tough constraints on the building's design were met with considered solutions each working in concert to deliver a beguiling design. Arraying 10 aircraft stands around a facility in an area not previously envisaged for a concourse, was the first challenge, overcome by chevron parking of aircraft. The next was squeezing in a plant room pod onto the roof, the height of which was limited by aeronautical safeguarding surfaces and soffit dictated by interior spatial demands. An elegant solution is derived from interlacing the roof structure under the fixed central pod to create a flowing roof form which moved naturally beneath the pod.
The roof flowing profile is reflected in simple but constructible curved steel trusses. Truss geometry was researched by the engineers based on a balance of efficient arching and spanning capability with calculated I-section bending radii that did not buckle the chord flanges.
The services pod relies on free air cooling so it is rounded and set above the roof line for better airflow. This accentuates its visual independence from the roof. A further refinement appeared late in design when a lowering of safeguarding surfaces necessitated chamfering the ends of the pod. Through closely integrated 3D design of structure with services, a functional plant space is retained whilst yielding improved pod aesthetics.
The flowing roof could not have been a success without a clear uninterrupted facade appearance beneath. Structural engineers maintained focus on this tenet by working with the architects to locate roof columns outside the facade line and reducing mullions to a minimum with a clever transom hanging system. Transoms are hung from the roof eaves via rods exploiting the thinner section properties of steel in tension. To set-off the facade from the mullions, the architect called for a twisted bracket articulating vertical mullion fixing to horizontal transom fixing. Its finite element structural design took on a twist of its own when the phenomenon of section thinning through the bracket twisting process was appreciated. The complexity of design capacity is hidden in its simplicity of form.