A diagrid (a portmanteau of diagonal grid) is a framework of diagonally intersecting metal, concrete, or wooden beams that is used in the construction of buildings and roofs. It requires less structural steel than a conventional steel frame. Hearst Tower in New York City, designed by Norman Foster, uses 21 percent less steel than a standard design. The diagrid obviates the need for columns and can be used to make large column-free expanses of roofing. Another iconic building designed by Foster, 30 St Mary Axe, in London, UK, known as "The Gherkin", also uses the diagrid system. British architect Ian Ritchie wrote in 2012: Buildings utilizing diagrid Shukhov Tower in Polibino, Polibino, Russia (1896) Shukhov Rotunda at the All-Russia exhibition, Nizhny Novgorod, Russia (1896) Shukhov Tower, Moscow, Russia Hearst Tower, New York, USA 30 St Mary Axe, London, England 1 The Avenue, Manchester, England CCTV Headquarters, Beijing, China The Bow, Calgary, Canada Seattle Central Library, Seattle, USA Capital Gate, Abu Dhabi, United Arab Emirates Aldar headquarters, Abu Dhabi, United Arab Emirates Guangzhou International Finance Center, Guangzhou, China Queen Elizabeth II Great Court at the British Museum, London, England Nagoya Dome, Nagoya, Japan Westhafen Tower, Frankfurt, Germany Merdeka 118, Kuala Lumpur, Malaysia MyZeil, Frankfurt, Germany The Crystal, Copenhagen, Denmark United Steelworkers Building, Pittsburgh, USA Tornado Tower, Doha, Qatar Newfoundland Quay, London, England Lotte World Tower, Seoul, Republic of Korea See also References Bibliography Design and construction of steel diagrid structures by K. Moon, School of Architecture, Yale University The diagrid system of Hearst Tower by the Steel Institute of New York Building Construction Building engineering Roofs Structural system