SHEFFIELD Working details
The centre has been described as 'four drums connected by a glass- roofed foyer'. The drums have convex, non-symmetrical walls, resembling a flattened orange in shape. They are set at the corners of the site and contain galleries. The foyer, at first-floor level, forms the centre and extends between the drum walls to form entrance canopies. On the ground floor are cafes, bars and a shop. Below, a basement contains ancillary accommodation.
The roof of each drum is fitted with a large wind-cowl. Fresh air is drawn through the 'mouth' of the cowl into the building and used air is discharged through the 'tail'. The 11m-diameter cowls rest on steel rails fixed to concrete roof slabs which are driven to face the prevailing wind.
The ground- and first-floor slabs are constructed of cast in-situ concrete resting on tapered, mushroom-headed concrete columns. Each drum is formed of 30 'ribs' - curved and faceted 406 x 176mm universal beams. Ten of these ribs extend to a hub to support the concrete roof deck. The ribs are infilled with corrugated steel sheeting and covered with a vapour barrier and mineral-wool insulation. This system is overclad by a 'Brodscreen' cladding system of stainless-steel panels supported on an extruded aluminium carrier system fixed back to the steel ribs by an adjustable plate of U-shaped brackets. The panel joints are silicone-sealed with the carrier forming a back-up drainage channel. Set inside the steel frame is a blockwork drum with the space between forming the supply air plenums feeding fresh air down to floor level .
The roof of the foyer is made of double-glazed laminated glass panels on an extruded aluminium carrier system, supported by a tubular steel framework. The junction between the glass roof and the faceted cladding is formed by a gutter of galvanised steel lined with Sarnafil.