History
By 1963, a new structural system of framed tubes had appeared in skyscraper design and construction. Fazlur Khan defined the framed tube structure as "a three dimensional space structure composed of three, four, or possibly more frames, braced frames, or shear walls, joined at or near their edges to form a vertical tube-like structural system capable of resisting lateral forces in any direction by cantilevering from the foundation." Closely spaced interconnected exterior columns form the tube. Horizontal loads, wind for example, are supported by the structure as a whole. About half the exterior surface is available for windows. Framed tubes allow fewer interior columns, and so create more usable floor space. Where larger openings like garage doors are required, the tube frame must be interrupted, with transfer girders used to maintain structural integrity.
The first building to apply the tube-frame construction was the DeWitt-Chestnut apartment building which Khan designed and which was completed in Chicago by 1963. This laid the foundations for the tube structural design of many later skyscrapers, including his own John Hancock Center and Willis Tower, and the construction of the World Trade Center, Petronas Towers, Jin Mao Building, and most other supertall skyscrapers since the 1960s.
Read more about this topic: Tube (structure)
Famous quotes containing the word history:
“The principle office of history I take to be this: to prevent virtuous actions from being forgotten, and that evil words and deeds should fear an infamous reputation with posterity.”
—Tacitus (c. 55–117)
“Social history might be defined negatively as the history of a people with the politics left out.”
—G.M. (George Macaulay)
“The one duty we owe to history is to rewrite it.”
—Oscar Wilde (1854–1900)