Kings Cross Western Concourse Roof, UK

The transformation of King’s Cross station was one of London’s most challenging infrastructure projects in recent years. Updating this building involved a combination of modernisation, restoration and place making. The most significant challenge was creating the new 8,000m2 concourse needed to increase the station’s capacity. Opened in time for the London 2012 Olympics, the new Western Concourse provides a fitting and elegant addition to Lewis Cubitt’s magnificent train shed and a modern multi-modal transport hub. The design for the Western Concourse roof evolved through collaboration between Arup and John McAslan and Partners, the architects. Together they developed a spectacular, slender and carefully detailed diagrid shell roof that sweeps among listed buildings without imposing loads on them.

Constructing this roof on a constrained, operational site required careful planning and sequencing. Prefabricated ladders of the roof structure were dropped onto a scaffold and connected in situ. Maximising off-site fabrication ensured the high quality needed for such a visible structure. Once the shell was complete, the scaffold was gradually removed to let the roof settle under its own weight. Recorded deflections were within the limits predicted, demonstrating the accuracy of understanding of the analysis. Opened in March 2012, the new concourse represents a stunning new landmark for London that redefines the station as a modern transport hub. The lightness with which the roof touches the ground and its careful integration with the surrounding historic buildings is a triumph of collaborative engineering and architecture.