Westfield Shopping Mall

Freeform Steel-Glass Roof Construction
Great Britain

For the new Westfield Shopping mall in London a 18.000 m2 free-formed glass roof and 5,000 m2 vertical glass façade had been developed. Based on a new generation of nonvisible node connections, the shape and mesh segmentation of the roof responds to the architectural vision, the constructive requirements, dewatering as well as smoke exhaust. The structural design and generation of fabrication information for the free-formed steel grid was largely automated using a custom software tools developed specifically for the task. The steel nodes which all had a different geometry and were made up of 26 individual plates were all prefabricated. The thickness of each plate as well as the size of the bolts were optimized for the specific loading of the node. Final adjustments to the geometry were made by maching the face plates.
A complex automated process was devised in which the structural model of the grid served as a database for the shop drawings. The nodes were bolted to the straight members on site without any means of adjustment. After assembly, a deviation of 15mm from the reference geometry over a length of 164 m was measured. The high degree of prefabrication, the accuracy of the bolted connectors and shop applied corrosion protection allowed for fast installation.