A DRUM-SHAPED STEEL STRUCTURE WITH A GLAZED GALLERY
The 500-seat auditorium is housed in a steel drum, 40m in diameter and 20m high.
The IMAX screen wraps around a third of the inside walls and rises to over five storeys of the drum; other areas contain raked seating, ticket halls and foyers. To achieve acoustic attenuation, drum walls are lined with several layers of plasterboard, which are 750mm thick behind the IMAX screen and 1m thick where directly exposed. A 15m-high glazed gallery runs around the outside of the drum.
For speed of construction, the structural engineer, SKM Anthony Hunts, chose a steel structure. This consists of a series of braced UC columns which circle the drum's perimeter and support a primary roof structure of radiating steel lattice trusses.
They rise in a curve to the central apex and are connected by concentric steel-ring beams that support a secondary lattice truss roof structure. The raked seating is formed of precast concrete units on a steel frame.
To avoid large struts at its base, the delicate steel structure which supports the gallery is suspended from the roof's eaves.
It consists of a series of lozengeshaped, 15m-high steel ties, just inside the perimeter and braced with horizontal steel brackets.
The glass units are supported by bolts fixed to cast-steel arms, then welded to the columns.
By Susan Dawson Perspective drawing produced by Bison Structures