Bristol Wildscreen World, part of the Bristol initiative, presents the natural world in an exciting new building which is the result of a design competition won in 1996 by Michael Hopkins with Buro Happold.
The challenging site sits alongside Bristol 2000 Watershed, astride an old dry dock, and is occupied by listed stone leadworks and a brick-built bonded warehouse.
The leadworks is being retained and restored, and other buildings are being demolished. To the northern end, a brick-built rotunda will house an Omnimax theatre. Load-bearing brick walls support concrete floor slabs, with loads transferred through visible precast padstones set in the wall. A steel roof of radial trusses sits on a ring beam around the top of the wall.
A second building south of the rotunda houses the Electronic Zoo, which follows similar construction principles to the rotunda, with load-bearing brick walls and concrete floors spanning up to 9m.
Further south, a Botanical House will be covered by a lightweight cable- net roof raised by two masts and a ridge cable acting as a 'spine'. The cable net is clad in inflated triple-skin panels of clear sheets of etfe (Ethylene Tetra Fluoro Ethylene). These provide insulation and direct daylight to ensure optimum conditions for the plants beneath. The slab for the Botanical House lifts off the ground in a huge sprayed-concrete vault. This allows public access to the heart of the building without fighting though the jungle, and provides a dramatic first experience of the complex.
The renovated leadworks provides office accommodation, a cafe and a shop. These elements are united by a stressed fabric canopy over the foyer area and a glazed band which connects the rotunda to the Electronic Zoo.
The whole project has called for imaginative engineering. The materials that are visible are those which do the work. The brick carries the floors and roof. The roofs clearly express their job and use different materials to serve different needs.
Environmental conditions are to be carefully controlled to suit different area requirements. A specialised control system in the Botanical House will control low-level perimeter trench heating, opening and closing of blinds and vents, high-level irrigation, and a fogging system injecting water particles into the atmosphere. This will maintain optimum conditions of 22degreesC/ 75 per cent relative humidity in winter and 26degreesC/90 per cent relative humidity in summer.
The Electronic Zoo is essentially a 'black box' space, with mechanical ventilation with comfort cooling offsetting heat gains from occupants and exhibits. The adaptable ductwork layout may be altered to suit exhibition layouts. The theatre employs a displacement system. Low-level diffusers under each seat supply low-velocity cooled air for extraction at high level.
The client is keen to have a low-energy building. Where possible, natural ventilation has been chosen, but a high level of cooling is still required. Water in the nearby floating harbour will be used as a heat sink, which reduces plant space requirements as well as having a high coefficient of performance. Pumped water will pass through heat exchangers and waste heat will be rejected into it. Licences were granted by the Environment Agency and a wayleave applied for to lay pipework in the harbour.
Mike Cook, Jo Tilston, Adrian Robinson
Architect: Sir Michael Hopkins & Partners
Structural and building-services engineer: Buro Happold
National Centre for Popular Music, Sheffield
The National Centre for Popular Music is a bold and imaginative response to a competition held by Music Heritage Ltd in 1996. With an Arts Council grant and corporate sponsorship, it has been built in the burgeoning 'cultural quarter' of Sheffield. Popular-music themes are represented within four main, stainless steel-clad drums linked by a glazed foyer, sitting above a ground floor of cafes, bars and a shop. Further ancillary accommodation is contained within a basement level.
The building is arranged around a clear diagram. The four drums sit over four corners of the site. A cruciform roof connects enclosed spaces, reaching beyond the centre to form entrances. The visually exciting structure is carefully arranged for economic construction, with reinforced-concrete construction employed from basement to first floor and steel construction for the four drums and glazed foyer roof.
Reinforced-concrete elements feature handsome tapered and mushroom-headed columns supporting the first-floor slab. Profiled tongues protrude between the drums, providing an entrance feature and protection. The first-floor slab contains light slots arranged to reflect the foyer's cruciform arrangement.
The strikingly profiled, clad drums sit on the first-floor slab. Each drum is structured with 30 steel universal beam sections. The profile is produced from a combination of faceting and curving the beams. Ribs connect across each drum, producing a platform for air-handling plant, and a stiff element around which the cowl rotates to make maximum use of positive and negative wind pressures to aid air-conditioning.
The glazed foyer roof uses attractive curved and profiled circular hollow sections supported on the four drums via brackets off rib members. Stainless- steel panels clad the drums and cowls, insulated, stiffened and fixed to the ribs to provide a rainscreen. Importantly, each drum tilts about the diagonals by four degrees. Junction quality of the stainless steel, glass, structure and gutter arrangement is key to the envelope's success. With this in mind, Buro Happold produced a three-dimensional computer model, in conjunction with the architect, incorporating node points for the steel drums and cruciform roof structure. Offsets for layers of cladding were specified with each trade working to the 3D model.
The building will open next year. As a visitor attraction, and indicator of the architect's bold vision, it will be a success. In the meantime, it has been clear to us that with close working of the design team, working to common models, it has been possible to realise a complex scheme successfully.
Matthew Lovell, Ian Maddox, Steve Tanno
Architect: Branson Coates Architecture
Geotechnical, structural, fire-engineering advice and facade-specification consultancy: Buro Happold