A skyscraper (English skyscraper copies) is a Immeuble of very large Height. To facilitate the comparisons it is considered sometimes that they are the buildings moreover 150 meters or more than 500 feet (152 meters). However, the concept of skyscraper is primarily relative: what is perceived as scrapes sky can strongly vary according to the time or from the place.
History
There exists since old times of the high buildings. Generally, they are not buildings. The Pyramid of Khéops, of which the height reached almost 150 meters was a tomb. With the unquestionable Middle Ages Keep S, like that of the Castle of Vincennes, reaches 50 meters height.The skyscraper, itself, is born in the United States towards the end from the 19th century. The rebuilding of Chicago after the large fire allowed the emergence of an new approach of the construction of buildings in order to reduce the associated costs to the raising of prices of the grounds. It was necessary to find a means to be protected at the same time from water (heightening) and fire (wood and steel framework either), this means was to be fast, solid, easy of assembly. Thus the Baron Jenney was brought to work out a system of internal structure on which all the building rests, the external wall not having more anything to carry. The first architects of what one called later the school of Chicago created by their works and their influence an urban development model which characterized all the American cities at the 20th century.
It is difficult to say which was the first skyscraper of the history. Some think that it is about the New York Tribune Building, drawn by Richard Morris Hunt (New York, 1873, 78 meters). What does not make no doubt on the other hand is the great movement of construction of skyscraper with New York as of the end of the 19th century but especially at the beginning of XXe. With the construction of the New York World Building (94 meters), New York begins its incredible development as regards skyscraper. It is a true race with the most building which starts: Manhattan Life Insurance Building (1894, 106 meters), the Park Row Building (1899, 119 meters), then the Metropolitan Life Tower crosses the bar of the 200 meters in 1909 but is finally exceeded by the Woolworth Building (1913, 241 meters). The movement continues after the First World War by the 40 Wall Street but especially by the Chrysler Building then the Empire State Building which reaches 381 meters, in 1931.
Stopped by the economic crisis of the years 1930, the movement of construction of skyscraper includes in the years 1960, in New York and Chicago and, on a less level, in other cities of the world. The World Trade Center (New York) becomes the most skyscraper of the World in 1973 with 417 meters, it is exceeded in 1974 by the Sears Tower (Chicago) which measures 442.3 meters. It is a true battle between these two cities.
In the years 1990, and especially 2000, the construction of skyscraper very strongly includes. It is in Asia, in areas with strong growth which the development is most spectacular. Many towers were born or are in construction in the Chinese world. The Taipei 101, inaugurated in 2004 in Taiwan is currently the most completed skyscraper of the world. The countries of the Gulf, and spectacularly the emirate of Dubai also multiplied constructions. The Burj Dubai, currently (2007) in construction should border the 800 meters.
Design
The traditional tower
The skyscrapers are traditionally built in the form of a monolithic tower organized around a core in particular including the lanes vertical (staircases, Ascenseur S) and the conduits (water, electrical communications and of communication…). The carrying structure can be concentrated in this core, or distributed on Pilier S. Certains buildings also profited from an entirely metal reinforcement.The concentration of circulations in a point of the building poses the problem of its evacuation in the event of urgency if these circulations are made impracticable (in particular because of a fire). Same manner, the concentration of the carrying structures can make the building vulnerable if they are damaged. Another encountered problem is the lighting of the zones more centrales : beyond of a certain distance, the natural light is not sufficient any more so that one can do without illumination.
New prospects
- the polycentric tower
This concept was however not applied yet.
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the exosquelette
The exosquelette conceived by the French architect Herve Tordjman and the engineers of SETEC TPI (Jean-Marc Jaeger) for the project of the twin towers of Canton is a true revolution for the construction of works great height.
It guarantees a resistance of the work to particularly great mechanical efforts (typhoons, earthquakes) while integrating a real protection vis-a-vis the external aggressions (planes, missiles).
This exosquelette is assisted by a double concrete core, which offers a real dynamic stability and an exceptional resistance to the fires.
This structural principle allows a flexibility of interior spaces (disassemblings of 60% of the internal floors) which guarantees an exploitation programming science and economic in the long run. This constructive new approach made it possible to propose a project economically very advantageous which, assisted by the morphological configuration of the work, removes the use of the scaffolding for its construction.
It acts there, of a revolution in constructive technologies of the skyscrapers.
Geographical variations
the North America
See also: List of highest constructions of the United States
The skyscraper had become a symbol of the United States, its country of origin. It is there that the majority of highest world buildings until the years 1980. Chicago was and New York are today as yesterday the two cities of the continent where the density of skyscraper is highest but the majority of the cities have a CBD including/understanding several turns relatively high.
Today, the rate/rhythm of construction news is quite lower than that of Asia, but rather constant all the same, and this in spite of the traumatism which the destruction of the World Trade Center represented. Two turns currently (September 2007) in construction should exceed the Sears Tower, higher tower of the continent: it is of the Freedom Tower of New York and about the Chicago Spire. In other cities of the important projects are also in hand, although the buildings are of less dimensions. Since 2005, the town of Miami (Florida) thus knows an important urban renewal with approximately 80 buildings great heights currently in construction.
the East Asia
The development of the skyscrapers is there, except in some cities, rather recent, but of great width.It is in HongKong and Japan that were created the first very high buildings of the area. In Japan, the lack of place pushed with construction in height, but the seismic risks imposed importantec technical constraints. HongKong is historically the city of the skyscraper in the Chinese world, and today one of the cities cash the most buildings very great height in the world. Constructions especially multiplied as from the years 1980. The prosperity and the lack of space can explain this phenomenon. The movement of continuous structure to HongKong but it especially extended to other Chinese cities, where it is stimulated by urban strong growth and the economic expansion. The skyscraper represents a symbol of the economic success of cities such as Shenzen or Shanghai.
The Malaysia held during several years the title of the largest skyscraper, with its twin towers, the Petronas Twin Towers with Kuala Lumpur, built in 1998. The roof reaches only 378 m, but the mast culminates to 452 Mr.
Certain important projects are currently being studied in South Korea.
the the Middle East
In the field of the skyscrapers, the rise of the Middle East is more recent still than that of Asia, but particularly marked. In these areas little densément populated, the construction of skyscraper is justified primarily by a will of prestige, of architectural and tourist development. One thus finds there turns particularly high and spectacular.They are the United Arab Emirates, and in particular Dubai, which held the attention the most. To Dubai the construction of skyscraper is only one shutter of great projects aiming at making emirate a tourist center and businesses of foreground. In 2007,2 buildings of more than 300 meters were completed and 13 were in construction. Among those the Burj Dubai is which will be the most building of the world, but of which the height was not revealed yet. and being finished the June 30th 2009 |- ! Row!! Name!! Cities!! Country!! Height (antenna)!! Height (roof)!! Stages!! Years of constructions |- | 1 || Burj Dubai || Dubai || || align=Center| 817 m (estimate) || align=Center|787 || align=Center|200 (estimate) || align=Center|2004-2008 |- | 2 || Chicago Whorl || Chicago || || align=Center|no the antenna || align=Center| 609.7 m || align=Center|150 || align=Center|2007-2010 |- | 3 || Abraj Al Bait Towers || Mecque || || align=Center| 577 m || align=Center|+ 500 m || align=Center|76 || align=Center|2008 |- | 4 || Freedom Tower || New York || || align=Center| 541.3 m (antenna television) || align=Center| 417 m || align=Center|108 || align=Center|2006-2012 |- | 5 || Shanghai World Financial Center || Shanghai || || Centeralign=Center|no the antenna || align=Center| 492 m || align=Center|101|| align=Center|1997-2008 |}
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