Diagrid

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: 