Westfield London - Glazed Roof, London
Westfield London - Glazed Roof, London
Westfield London - Glazed Roof in the heart of London is a new shopping centre that provides an unparalleled experience. The 350,000 m2 centre encompasses 270 shops, 40 restaurants, 14 large cinemas and spa and fitness facilities under one roof. In addition to the complex shop-window glazing, the spectacular canopy over the luxury shopping arcade is particularly eye-catching.
Inspired by the overlapping wave movements of water in nature, the Buchan Group International pty Ltd and Benoy planned a curved, undulating glass roof for the arcades. The free-form roof's intricate design and the slight movement of the waves bring it to life. Translating this architectural concept into reality was the project’s major technical challenge, because neither SHEV vents nor drainage pipes could be used since they would have interrupted the roof’s harmonious flow. The arcade roofing was optimised in the design process so that each point on the roof is drained via downward slopes to the outside and, in the event of fire, fumes collect on the underside of the slope and are shunted outside through a double-shell smoke apron where they are then exhausted. The architectural concept and technical requirements were combined seamlessly, enabling a clean roof structure to be created with no technical distractions.
The structure in detail: 12,000 rectangular sections with very few support points combine through 7,000 or so nodes to form a delicate grid. Geometrically, the shell structure is based on a grid of equilateral triangles. The nodes of the roof shell sit at different heights on the standard structure of this grid network, and virtually no triangle or node is the same as the others.
Inspired by the overlapping wave movements of water in nature, the Buchan Group International pty Ltd and Benoy planned a curved, undulating glass roof for the arcades. The free-form roof's intricate design and the slight movement of the waves bring it to life. Translating this architectural concept into reality was the project’s major technical challenge, because neither SHEV vents nor drainage pipes could be used since they would have interrupted the roof’s harmonious flow. The arcade roofing was optimised in the design process so that each point on the roof is drained via downward slopes to the outside and, in the event of fire, fumes collect on the underside of the slope and are shunted outside through a double-shell smoke apron where they are then exhausted. The architectural concept and technical requirements were combined seamlessly, enabling a clean roof structure to be created with no technical distractions.
The structure in detail: 12,000 rectangular sections with very few support points combine through 7,000 or so nodes to form a delicate grid. Geometrically, the shell structure is based on a grid of equilateral triangles. The nodes of the roof shell sit at different heights on the standard structure of this grid network, and virtually no triangle or node is the same as the others.
Grids like this are typically welded together on-site. For the London arcade, however, the complete roof structure was delivered ready to assemble and bolted into place. The accuracy required in the length of the lattice struts of 2/10 millimetre corresponds to a tolerance standard that is typical in engineering. The thickness of the struts varies depending on the structural requirements. This design kept the outer cross-section profile consistent, producing a precise, uniformly sized grid.
All the nodes are unique. They are composed of 20 individual parts that are welded together and precisely milled for angle and size on a CNC milling machine. Sixty per cent of the surface consists of thermal insulation panels, and the remaining area is double-glazed. The roof panels are arranged so that the glazed areas are shaded when the sun is low. The triangular roof panels are placed on the grid structure with sealing strips, clamped with two point fittings on each side and wet-jointed.
All the nodes are unique. They are composed of 20 individual parts that are welded together and precisely milled for angle and size on a CNC milling machine. Sixty per cent of the surface consists of thermal insulation panels, and the remaining area is double-glazed. The roof panels are arranged so that the glazed areas are shaded when the sun is low. The triangular roof panels are placed on the grid structure with sealing strips, clamped with two point fittings on each side and wet-jointed.
