The involvement of architectural megastar Sir Norman Foster in the project, in joint venture with Buro Happold, may have helped the client to break through the 15-floor barrier.
Early sketches showed a tapering circular section tower at one end of the 55,000 site, flanked by retail malls, apartments, and
Riyadh's first five-star hotel. By the time the contract was won by the Jeddah-based Saudi Binladin group the design had evolved from circular, through triangular to a square plan-form tower, set diagonal to the axis of the site.
In the search for transparency the designers went for a large central core and substantial curving corner columns, all in concrete, the preferred construction material in the region. Thin floor plates are designed to be post-tensioned. Three stacks of 10 office floors are separated by cross-braced 'technical' floors, where loads from the relatively slim intermediate perimeter columns are transferred back to the core.
All external concrete is clad in silver anodised aluminium. Above the occupied floors an open steel structure some 60m high takes the final height up to 267m - slightly higher than Al Faisaliah's equivalent on London's Canary Wharf. Inside the steel spire will sit a glass-clad aluminium geodesic sphere housing restaurants and function rooms.
In all Al Faisaliah will provide 34,000m2 of office space and 45,000m2 of retail, together with a 224-room hotel, 96 apartments and 1,200 car parking spaces.