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The World Trade Center

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Vital Statistics of the World Trade Center

Location:
New York, New York, USA
Completion Date: 1972 (Tower One), 1973 (Tower Two); destroyed 2001
Cost: $400 million
Height: 1,368 feet (Tower One), 1,362 feet (Tower Two)
Stories: 110
Materials: Steel
Facing Materials: Aluminum, steel
Primary Engineering Firm: Skilling, Helle, Christiansen & Robertson

The World Trade Center (designed by Yamasaki and Associates, with Emery Roth and Sons) was constructed in a joint venture between the Port Authorities of New York and New Jersey. In the early 1970s, the World Trade Center towers were, for their time, the best known examples of "tube" or "column" buildings. "Tube" buildings are strengthened by closely spaced columns and beams in the outer walls. The closely spaced columns and beams in each tower formed a steel tube that, together with an internal core, is designed to withstand the tremendous wind loads that affect buildings of this height.

The World Trade Center  From Harbor

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Aside from enormous wind loads, the World Trade Center towers were also designed to withstand massive settlement loads. Because the towers were built on over five acres of landfill, the foundation of each tower had to extend more than 70 feet below the surface to rest on solid bedrock.

The twin towers were the first supertall buildings designed without any masonry. Worried that the intense air pressure created by the building's high speed elevators might buckle conventional shafts, engineers designed a solution using a drywall system fixed to the reinforced steel core. For the elevators, to serve 110 stories with a traditional configuration would have required half the area of the lower stories be used for shaftways. Otis Elevators developed an express and local system, whereby passengers would change at "sky lobbies" on the 44th and 78th floors, halving the number of shaftways.

The World Trade Center  - Collapse

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Surprisingly, the World Trade Center towers were actually engineered to withstand the impact of a airliner collision. The most likely cause of the complete failure of the towers was the enormous heat generated by the ignited jet fuel (the reinforced steel core would likely have reached temperatures of 800°C or more). The resultant explosion and extremely intense fire would have substantially decreased the tower's ability to maintain it's structural integrity. The collapse of the upper floors and the inability of the lower floors to bear the load resulted in the catastrophic failure of both towers.

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Other Architectural works by Minoru Yamasaki

  • St. Louis Airport, at St. Louis, Missouri, 1951 to 1956.
  • American Concrete Institute, at Detroit, Michigan, 1958.
  • Dhahran Air Terminal, at Dhahran, Saudi Arabia, 1959 to 1961.
  • Century Plaza Hotel, at Century City, Los Angeles, California, 1961 to 1966.
  • Temple Beth-El, at Bloomfield Township, Michigan, 1968 to 1974.
  • Performing Arts Center, at Tulsa, Oklahoma, 1973 to 1976.
  • Saudi Arabian Monetary Agency Headquarters, at Riyadh, Saudi Arabia, 1973 to 1982.
 
Additional Images

The World Trade Center  - Site

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The World Trade Center  - Sky Chart

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The World Trade Center  Ground Zero
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