Buro Happold's involvement with British Airways Waterside started with advice on site reclamation. All waste was removed from the area beneath the proposed building, and much of it was re-used, using methods that were cost-effective for both the client and the environment.
Sixty thousand m2 of underground parking had to be provided beneath the building. Buro Happold engineers designed the car park to ensure efficiency of arrangement, structural behaviour, materials and construction, and designed a 'value-engineered' foundation which was considerably more cost- effective than the standard approach to buildings of this type.
The building itself consists of six four-storey office buildings, or 'houses', linked by an environmentally controlled glazed street approximately 170m long and 12m wide. Structural and civil engineers worked together to ensure that the houses had the required stability and appearance, and liaised with building-services engineer Cundall Johnston to ensure comfort for occupants.
The structure of the street is an agile, lightweight web, which extends to the 'side streets' between houses and to the roof. With the steelwork contractor, Spacedecks, Buro Happold designed an elegant, flexible structure, in which structural elements are of the same width as the glazing mullions to allow clear views of the surrounding landscape.
A large triangular central plaza area intersects the central street. Here, glass is slung under 1.5m deep tubular steel trusses on a sloping grid, taking support from a tower which, tenuously connected to one of the office houses by further fine glazing, breaks through the roof of the plaza.
To accommodate the relative thermal movements between the six concrete- framed offices the roof is treated as a separate 'floating' structure, jointed to its own requirements and taking lateral support from the buildings where required.
The lightweight bridges running between the adjacent houses at each level are partially supported by a 'hangar-system' from each side-street truss. A barrel connector detail in the hanger support to the bridges allows the hanger bars to be tightened and locked in place, securing the bridge and adjusting to the different stresses and movements in the joints. The bridges provide lateral support to the glass walls, spanning horizontally between houses to act as diaphragms.
At the main entrance, the front end wall supports a glass canopy and this is supported by tubular steel trusses that cantilever from the primary wall trusses.
The lift towers support a pair of scenic glass lifts for each of the office houses. For each lift, the overall support structure is concentrated on the door side, so that the back of the lift is open to allow views of the street. The lift motor room on the top of each lift tower rises to penetrate the roof glazing.