SHROPSHIRE GAINED a stunning new tourist attraction this week following the opening of RAF Cosford's latest aircraft hangar.
The 135m long angular steel hangar is to become part of the RAF Museum and will house the National Cold War Exhibition.
The hangar's jarring geometry was created by placing a pair of hyperbolic parabaloids back to back.
'The design enables an apparently complex form to be achieved with a consistent and economic structural system, ' said project engineer Louise Crick, of structural designer Michael Barclay Partnership.
Each side of the hangar is identical about the central axis of rotation.
Its skeleton consists of a central braced frame spine, supported by steel truss rafters spaced at 8.4m centres. Along each side the pitch of the rafters steepens, from 25° to vertical (see diagram).
Crick said that depth of the rafters had been kept to a consistent 1.5m over most of the structure for aesthetic reasons and to save on materials. This enabled 50t to be pared from the roof's 550t weight.
Structural depth was increased to 2.1m for the two longest, flattest spans.
To cope with loading variations, wall thickness of the circular hollow section tubes making up the truss rafters varies from 6.3mm to 25mm.
Wind loading on the unusual structure will impose major overturning and uplift forces, particularly near the ends and ridge of the building, Crick added. Wind tunnel testing involved measuring load at 240 different points on the hangar's surface, with wind direction from 24 different angles.
The roof must also support the weight of a 9t Dakota and a 13t Canberra aircraft slung from its rafters.
Steel fabrication and erection was carried out by SH Structures, which used three mobile cranes to lift each rafter into place. Bolted connections between each element were made using a cherry picker.
Cladding is a standing seam steel sheet system.
Architect was Feilden Clegg Bradley LLP and main contractor was Galliford Try.