Science Fair Project Encyclopedia
World Trade Center
- This article is about the World Trade Center complex in New York City; see this article for the many other buildings around the world that have also been called "world trade centers".
The World Trade Center in New York City is a complex of several buildings around a central plaza, near the south end of Manhattan in the downtown financial district. Three of the original buildings were destroyed in the September 11, 2001 attacks.
The complex towers were designed by Japanese American architect Minoru Yamasaki with Antonio Brittiochi , and was one of the most striking American implementations of the architectural ethic of Le Corbusier, as well as the seminal expression of Yamasaki's gothic modernist tendencies. Constructed in the early 1970s under the auspices of the semi-autonomous Port Authority of New York and New Jersey, the WTC had its ribbon-cutting ceremony on April 4, 1973. Ultimately the complex came to consist of 7 buildings, but its most notable features were the main twin towers. On any given day, some 50,000 people worked in the towers, with another 200,000 passing through as visitors. The complex was so large that it had its own ZIP Code, 10048.
Although the towers became an undeniable icon of New York City, they were not without their flaws and were troubled in many ways. Initially conceived (as the name suggests) as a complex dedicated to companies and organizations directly involved in "world trade," they at first failed to attract the anticipated clientele; during the WTC's early years various governmental organizations became key tenants. It was not until the 1980s that the city's perilous financial state eased, after which an increasing number of private companies - mostly financial firms tied to Wall Street - became tenants.
Moreover, the immense "superblock" plaza they sat upon, which replaced a more traditional, dense-packed neighborhood, was regarded by some critics as an inhospitable environment that disrupted the intricate flows of traffic typical of Manhattan. For example, in his book The Pentagon of Power , the technical historian Lewis Mumford denounced the center as an "example of the purposeless giantism and technological exhibitionism that are now eviscerating the living tissue of every great city." However, the spectacular views available from the WTC's observation deck (located on top of the South Tower) and the Windows on the World restaurant (located on top of the North Tower) made up for its flaws, by offering city-dwellers and tourists alike a perspective on the region that became central to the city's identity.
The Twin Towers
Each of the WTC towers had 110 stories. The heights of the towers were 417 metres (1368 ft) (tower one, the North Tower with a huge antenna on top) and 415 m (1362 ft) (tower two, the South Tower with the observation deck). When the towers were completed in 1972 (tower one) and 1973 (tower two) they were the tallest buildings on earth, 30 m (100 ft) taller than the Empire State Building. Their size was the subject of a joke during a press conference unveiling the landmarks. Minoru Yamasaki was asked: "Why two 110-story buildings? Why not one 220-story building?" His response was: "I didn't want to lose the human scale."
For a time the local television station on Channel 11 used the towers as a graphic representation of its channel number.
The WTC towers held the height record only briefly. As the building neared completion in 1973, work had already begun on Chicago's Sears Tower, which ultimately reached 442 m (1,450 ft). With the World Trade Center's destruction, the Empire State Building again became the tallest building in New York, after spending almost 30 years as the third-tallest.
To solve the problem of wind sway or vibration in the construction of the towers, chief engineer Leslie Robertson took a then unusual approach - instead of bracing the buildings corner-to-corner or using internal walls, the towers were essentially hollow steel tubes. Each tower thus contained 240 vertical steel columns called Vierendeel trusses around the outside of the building, which were bound to each other using ordinary steel trusses. In addition, 10,000 dampers were included in the structure. With a strong shell such as this, the internal floors could be simply light steel and concrete with internal walls not needed for structural integrity, creating a tower that for its size was extremely light. This method of construction also meant that the twin towers had the world's highest load-bearing walls. The exterior steel supports were spaced 22 inches (559 mm) apart, and narrow windows filled the gaps in between.
Of the 110 stories, eight were set aside for technical services (mechanical floors), in four two-floor areas evenly spread up the building. All the remaining floors were free for open-plan offices. Each tower had 350,000 m² (3.8 million ft²) of office space, ample room for companies to set up shop. Altogether the entire complex of seven buildings had 1.04 km² (11.2 million ft²) of space. During the 1990s some 500 companies, especially financial firms, had offices in the complex, including Morgan Stanley, Aon Corporation, Salomon Brothers, and the Port Authority itself.
The Twins were also the first supertall buildings to use sky lobbies, spaces where commuters can switch from one local elevator to another. Located on the 44th and 77th floors of each tower, those sky lobbies enabled the elevators (each tower had 104) to be used efficiently while taking up a minimum of valuable office space.
At least five smaller buildings stood around the 65,000 m² (16 acre) superblock. One was the 22-floor Vista Hotel, later a Marriott Hotel, that was squeezed between the two towers. Three low-rise buildings in the same hollow tube design as the towers also stood around the plaza; they housed the US Customs Service and the US Commodities Exchange. In 1987, a 46-floor office building called 7 WTC was built north of the superblock. Under the superblock was a highly profitable underground shopping mall, which in turn led to various mass transit facilities, particularly the New York City subway system and the Port Authority's own PATH trains connecting Manhattan to Jersey City.
The excavation of the foundations of the building, known as the Bathtub, located on the former Radio Row, was particularly complicated since there were two subway tubes close by needing protection without service interruption. A six-level basement was built in the foundations. The excavation of about 760,000 m³ (1 million cubic yards) of earth and rock created a $90 million real estate asset for the project owner, the Port Authority of New York and New Jersey, which helped offset the enormous loss in revenues which came from the tax breaks given to the Trade Center itself. The soil was used to create 23 acres (93,000 m²) of landfill in the Hudson river next to the World Trade Center site, which became the site of Battery Park City (still under development).
One of the world's largest gold depositories was stored underneath the World Trade Center, owned by a group of commercial banks. The 1993 bomb detonated close to the vault, but it withstood the explosion, as did the towers. One source estimates the 1993 value of the gold at one billion dollars, believed to be owned by Kuwaiti interests. That same source claims that when the World Trade Center was destroyed, the amount of gold "far exceed[ed] the 1993 levels." The gold was finally recovered in its entirety in late 2001.
See World Trade Center site for reconstruction news.
1993 terrorist attack
1993 World Trade Center bombing: On February 26, 1993, a Ryder truck filled with explosives was planted by terrorists and exploded in the underground garage of the north tower, opening a 30m hole through 4 sublevels of concrete. Six people were killed and over a thousand injured. Six Islamist extremist conspirators were convicted of the crime in 1997 and 1998 and given prison sentences of 240 years each.
To commemorate the bombing of the tower, a reflecting pool was installed with the names of those who had been killed in the blast. Following the September 11, 2001 terrorist attacks, relief works found a single fractured piece of this fountain; to date it is the only remaining part of the 1993 memorial that survived the collapse of the towers.
2001 terrorist attack
The twin towers and 7 World Trade Center collapsed in a terrorist attack on September 11, 2001, when two commercial jetliners were deliberately crashed into the twin towers. For details on this terrorist attack, see September 11, 2001 attacks; for details of the towers' collapse, see Collapse of the World Trade Center. For details of the tenants at the time of the attack, see One World Trade Center tenants and Two World Trade Center tenants. As of February 2005, a total of 2,749 death certificates related to the WTC attacks had been filed. All but 13 persons died on September 11; of the 13 persons who were injured on September 11 and died subsequently, persons died in other states, one each in Massachusetts, Missouri, and New Jersey. Of these 2,749 decedents, 2,117 (77%) were males and 632 (23%) were females. Remains of 1,588 of the 2,749 people who died at the World Trade Center, or 58%, were identified on the basis of recovered physical remains. The median age for these decedents was 39 years (range: 2--85 years); the median age was 38 years for females (range: 2--81 years) and 39 years for males (range: 3--85 years). Three people were aged <5 years, and three were aged >80 years.
The World Trade Center is slated to be rebuilt as a new mixed-use complex of buildings called Memory Foundations, including the 1776 ft (541 m) Freedom Tower (which is currently under construction. Note that the height of 1776 ft (541 m) was chosen as a reference to the year of American independence. The new 7 World Trade Center is now under construction, and has recently been "topped-off" (meaning the structural steel has reached the full height of the building).
The Lower Manhattan Development Corporation, the agency tasked with coordinating the reconstruction of the WTC site sponsored an international design competition for the World Trade Center Memorial in spring 2003. The winning design, Michael Arad and Peter Walker's Reflecting Absence, was chosen in January 2004.
The Norwegian architecture company Sn°hetta was chosen for design of the Performing Arts Complex and the Museum Complex, also to be erected on the site.
While the master plan has been named Memory Foundations, the future site will continue to use the name of the World Trade Center, as will the New York City subway and PATH train stations that serve the complex.
World Trade Center buildings
- 1 World Trade Center (North Tower)
- 2 World Trade Center (South Tower)
- 3 World Trade Center (Marriott Vista Hotel)
- 4 World Trade Center
- 5 World Trade Center
- 6 World Trade Center (US Customs House)
- 7 World Trade Center
- PBS - Building Big: Databank: World Trade Center
- "Complete 9/11 Timeline" by Center for Cooperative Research
- Emporis - Special Coverage of the World Trade Center in New York City
- Wired New York - The World Trade Center
- A View On Cities - World Trade Center, New York City
- NEW YORK SCRAPERS - INTERNATIONAL STYLE III
- SkyscraperCity Forums - World Trade Center, New York - WTC Paper Model
- 9/11 Video Archive - Free Press International
- SkyscraperCity Forums - THE MEGA WTC Picture Thread
- Here Is New York - Gallery
- World Trade Center - Minoru Yamasaki - Great Buildings Online
- View from the top
- New York's World Trade Center: A Living Archive
- World Trade Center North tenants - from boston.com
- World Trade Center South tenants - from boston.com
- World Trade Center Facts, FOX News, September 12, 2001
- Rebuild the Twin Towers
- Max X. Miller Online's September 11th Memorial - News Reports from September 11, 2001
- Website documenting the politics behind the WTC rebuilding process
- The collapse of World Trade Center Building 7
- 9/11 and the politics of oil
- "Conspiracy Theory" Website Regarding the 9/11 Attacks
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