The Arthur Ashe Stadium's new octagonal roof is supported by an independent structure incorporating some 5000 tonnes of structural steelwork to span up to 158m and cover an area of 22,000m2. The 57m x 57m central roof opening can be closed off by two symmetrical rolling roof panels to provide a fully-enclosed playing venue.
The principal roof structure comprises four structural steel bowstring box trusses that intersect above the lower tiers of spectator seating to form the frame of the operable roof opening. The trusses then continue outward and downward to land on eight triangulated springings, each comprising three tubular steel ‘mega members’. These carry static and dynamic forces, including seismic loads, down to ground level.
As if the sheer size of the structure were not a sufficient challenge, the ground conditions also proved particularly difficult. The site was originally tidal marshland, which during the previous century had been used as a tip for fly ash generated by coal-fired power stations. In addition, the site had previously hosted several world fair events, leaving a legacy problem of buried obstructions that imposed significant positional limitations on the foundations. The loads from the new roof structure bear onto eight massive reinforced concrete bases, each supported by piles driven through the marshy, variable subsoil to depths of up to 60m.