Development of the Form

Many mechanical and structural developments in the last quarter of the 19th cent. contributed to its evolution. With the perfection of the high-speed elevator after 1887, skyscrapers were able to attain any desired height. The earliest tall buildings were of solid masonry construction, with the thick walls of the lower stories usurping a disproportionate amount of floor space. In order to permit thinner walls through the entire height of the building, architects began to use cast iron in conjunction with masonry. This was followed by cage construction, in which the iron frame supported the floors and the masonry walls bore their own weight.

The next step was the invention of a system in which the metal framework would support not only the floors but also the walls. This innovation appeared in the Home Insurance Building in Chicago, designed in 1883 by William Le Baron Jenney—the first building to employ steel skeleton construction and embody the general characteristics of a modern skyscraper. The subsequent erection in Chicago of a number of similar buildings made it the center of the early skyscraper architecture. In the 1890s the steel frame was formed into a completely riveted skeleton bearing all the structural loads, with the exterior or thin curtain walls serving merely as an enclosing screen.

Legal and Aesthetic Refinements

In 1892 the New York Building Law made its first provisions for skeleton constructions. There followed a period of experimentation to devise efficient floor plans and aesthetically satisfying forms. In New York City the Flatiron Building by D. H. Burnham was constructed in 1902, the Metropolitan Life Insurance Tower in 1909, and the Woolworth Building, 60 stories high, by Cass Gilbert, in 1913. The last, with Gothic ornamentation, exemplifies the general tendency at that time to adapt earlier architectural styles to modern construction. The radical innovator Louis Henry Sullivan gave impetus to a new, bold aesthetic for skyscrapers. An excellent example is his design for the Wainwright building in St. Louis (1890-91). Frank Lloyd Wright also contributed his unorthodox vision to such structures as the Price Tower (1953) in Bartlesville, Okla.

In 1916, New York City adopted the Building Zone Resolution, establishing legal control over the height and plan of buildings and over the factors relating to health, fire hazard, and assurance of adequate light and air to buildings and streets. Regulations regarding the setting back of exterior walls above a determined height, largely intended to allow light to reach the streets, gave rise to buildings whose stepped profiles characterize the American skyscraper of subsequent years.

With the complex structural and planning problems solved, architects still seek solutions to the difficulties of integrating skyscrapers with community requirements of hygiene, transportation, and commercial interest. In New York during the 1950s, public plazas were incorporated into the designs of the Lever House by Gordon Bunshaft and the Seagram Building of Mies van der Rohe. These International style buildings are also examples of the effective use of vast expanses of glass in skyscrapers. More recently, numerous skyscrapers have been constructed in a number of postmodern modes.

Outstanding Skyscrapers

The tallest skyscrapers are freestanding structures such as the CN Tower in Toronto (opened 1976), which measures 1,815 ft (553 m), and the Ostankino Tower in Moscow (opened 1967), which is 1,771 ft (540 m) high. By convention, however, a building is defined as being primarily for human habitation with the greatest majority of its height divided into occupiable floors. The height of a building is measured from the sidewalk level of the main entrance to the structural top of the building. This includes spires but does not include television antennas, radio antennas, or flagpoles. By this definition the tallest building is the Burj Khalifa, Dubai, United Arab Emirates, which was topped off in 2009 at 2,717 ft (828 m) and 160 stories; it is also tallest structure in the world. Taipei 101, Taipei, Taiwan, is the second tallest at 1,671 ft (509 m) and 101 stories in 2003. The twin Petronas Towers (opened 1997) in Kuala Lumpur, Malaysia, are the third tallest; 88 stories high and topped by twin spires, they stand 1,483 ft (456 m) tall. The Sears Tower (opened 1974, now the Willis Tower) in Chicago is the tallest building in the United States; its 110 stories rise 1,454 ft (443 m) with an additional 253 ft (77 m) for the television antenna on top.

Among the highest New York City skyscrapers are the Empire State Building, with 102 stories, 1,250 ft (381 m) high; the Chrysler Building, with 77 stories, 1,048 ft (319 m) high; 60 Wall Tower, with 67 stories, 950 ft (290 m) high; and the GE (formerly RCA) Building in Rockefeller Center, with 70 stories, 850 ft (259 m) high. The former World Trade Center, which was the tallest building in the city until it was destroyed (Sept., 2001) by a terrorist attack, had two unstepped, rectangular towers of 110 stories each, one 1,362 ft (415 m) and the other 1,368 ft (417 m) high.

Very tall multistoried building. The term originally applied to buildings of 10–20 stories, but now generally describes high-rises of more than 40–50 stories. James Bogardus (1800–1874) built the pioneering Cast Iron Building, New York (1848), with a rigid iron frame providing the main support for upper-floor and roof loads. The refinement of the Bessemer process for making steel (lighter and stronger than iron) made extremely tall buildings possible. Chicago's Home Insurance Co. Building (1884–85), by William Le Baron Jenney (1832–1907), was the first tall building to use a steel skeleton. Structurally, skyscrapers consist of a substructure supported by a deep foundation of piles or caissons beneath the ground, an aboveground superstructure of columns and girders, and a curtain wall hung on the structural framework. Tube structures, braced tubes, and trussed tubes were developed to give skyscrapers the ability to resist lateral wind and seismic forces. The bundled-tube system, developed by Fazlur Khan (1928–1982), uses narrow steel tubes clustered together to form exceptionally rigid columns, and has been used to build some of the world's tallest skyscrapers (e.g., Sears Tower). Skyscraper design and decoration have passed through several stages: Louis Sullivan emphasized verticality; the firm of McKim, Mead, & White (see Charles F. McKim, Stanford White) stressed Neoclassicism. The International Style was ideally suited to skyscraper design. Originally a form of commercial architecture, skyscrapers have increasingly been used for residential purposes as well. Seealso setback.

Learn more about skyscraper with a free trial on Britannica.com.

A skyscraper is a tall, continuously habitable building. There is no official definition or a precise cutoff height above which a building may clearly be classified as a skyscraper. However, as per usual practice in most cities, the definition is used empirically, depending on the relative impact of the shape of a building to a city's overall skyline. Thus, depending on the average height of the rest of the buildings and/ or structures in a city, even a building of 80 meters height (approximately 262 ft) may be considered a skyscraper provided that it clearly stands out above its surrounding built environment and significantly changes the overall skyline of that particular city.

The word "skyscraper" originally was a nautical term referring to a tall mast or its main sail on a sailing ship. The term was first applied to buildings in the late 19th century as a result of public amazement at the tall buildings being built in Chicago and New York City. The traditional definition of a skyscraper began with the "first skyscraper", a steel-framed ten storey building. Chicago's now demolished ten storey steel-framed Home Insurance Building (1885) is generally accepted as the "first skyscraper".

The structural definition of the word skyscraper was refined later by architectural historians, based on engineering developments of the 1880s that had enabled construction of tall multi-storey buildings. This definition was based on the steel skeleton—as opposed to constructions of load-bearing masonry, which passed their practical limit in 1891 with Chicago's Monadnock Building. Philadelphia's City Hall, completed in 1901, still holds claim as the world's tallest load-bearing masonry structure at 167 m (548 ft). The steel frame developed in stages of increasing self-sufficiency, with several buildings in Chicago and New York advancing the technology that allowed the steel frame to carry a building on its own. Today, however, many of the tallest skyscrapers are built almost entirely with reinforced concrete. Pumps and storage tanks maintain water pressure at the top of skyscrapers.

A loose convention in the United States and Europe now draws the lower limit of a skyscraper at 150 meters (500 ft). A skyscraper taller than 300 meters (984 ft) may be referred to as supertall. Shorter buildings are still sometimes referred to as skyscrapers if they appear to dominate their surroundings.

The somewhat arbitrary term skyscraper should not be confused with the slightly less arbitrary term highrise, defined by the Emporis Standards Committee as "...a multi-storey structure with at least 12 floors or 35 meters (115 feet) in height. Some structural engineers define a highrise as any vertical construction for which wind is a more significant load factor than earthquake or weight. Note that this criterion fits not only high rises but some other tall structures, such as towers.

The word skyscraper often carries a connotation of pride and achievement. The skyscraper, in name and social function, is a modern expression of the age-old symbol of the world center or axis mundi: a pillar that connects earth to heaven and the four compass directions to one another.

History

Modern skyscrapers are built with materials such as steel, glass, reinforced concrete and granite, and routinely utilize mechanical equipment such as water pumps and elevators. Until the 19th century, buildings of over six stories were rare, as having great numbers of stairs to climb was impractical for inhabitants, and water pressure was usually insufficient to supply running water above . An early example of high-rise housing is the 16th-century city of Shibam in Yemen, which is regarded as one of the earliest examples of urban planning based on the principle of vertical construction. Shibam was made up of over 500 tower houses, each one rising 5 to 11 storeys high, with each floor being an apartment occupied by a single family. The city was built in this way in order to protect it from Bedouin attacks. Shibam has the tallest mud buildings in the world, with some of them being over 100 feet high.

Another early example of high-rise housing was in 17th-century Edinburgh, Scotland, where a defensive city wall defined the boundaries of the city. Due to the restricted land area available for development, the houses increased in height instead. Buildings of 11 stories were common, and there are records of buildings as high as 14 stories. Many of the stone-built structures can still be seen today in the old town of Edinburgh. The oldest iron framed building in the world is The Flaxmill (also locally known as the "Maltings"), in Shrewsbury, England. Built in 1797, it is seen as the "grandfather of skyscrapers” due to its fireproof combination of cast iron columns and cast iron beams developed into the modern steel frame that made modern skyscrapers possible. Unfortunately, it lies derelict and needs much investment to keep it standing. On 31 March 2005, it was announced that English Heritage would buy the Flaxmill so that it could be redeveloped.

The first skyscraper was the ten-storey Home Insurance Building in Chicago, built in 1884–1885. While its height is not considered unusual or very impressive today, the architect, Major William Le Baron Jenney, created the first load-bearing structural frame. In this building, a steel frame supported the entire weight of the walls, instead of load-bearing walls carrying the weight of the building, which was the usual method. This development led to the "Chicago skeleton" form of construction. After Jenney's accomplishment the sky was truly the limit as far as building was concerned.

Sullivan's Wainwright Building building in St. Louis, 1891, was the first steel frame building with soaring vertical bands to emphasize the height of the building, and is, therefore, considered by some to be the first true skyscraper.

The United Kingdom also had its share of early skyscrapers. The first building to fit the engineering definition, meanwhile, was the then largest hotel in the world, the Grand Midland Hotel, now known as St Pancras Chambers in London, opened in 1873 with a clock tower 82 metres (269 ft) in height. The 12-floor Shell Mex House in London, at 58 metres (190 ft), was completed a year after the Home Insurance Building and managed to beat it in both height and floor count. 1877 saw the opening of the Gothic revival style Manchester Town Hall by Alfred Waterhouse. Its 87-metre-high clock and bell tower dominated that city's skyline for almost a century.

Most early skyscrapers emerged in the land-strapped areas of Chicago, London, and New York toward the end of the 19th century. A land boom in Melbourne, Australia between 1888-1891 spurred the creation of a significant number of early skyscrapers, though none of these were steel reinforced and few remain today and height limits and fire restrictions were later introduced. London builders soon found building heights limited due to a complaint from Queen Victoria, rules that continued to exist with few exceptions until the 1950s; concerns about aesthetics and fire safety had likewise hampered the development of skyscrapers across continental Europe for the first half of the twentieth century (with the notable exceptions of the 26-storey Boerentoren in Antwerp, Belgium, built in 1932, and the 31-storey Torre Piacentini in Genoa, Italy, built in 1940). After an early competition between New York City and Chicago for the world's tallest building, New York took a firm lead by 1895 with the completion of the American Surety Building. Developers in Chicago also found themselves hampered by laws limiting height to about 40 storeys, leaving New York to hold the title of tallest building for many years. New York City developers then competed among themselves, with successively taller buildings claiming the title of "world's tallest" in the 1920s and early 1930s, culminating with the completion of the Chrysler Building in 1930 and the Empire State Building in 1931, the world's tallest building for forty years. From the 1930s onwards, skyscrapers also began to appear in Latin America (São Paulo, Caracas, Mexico City) and in Asia (Tokyo, Shanghai, Hong Kong, Singapore).

Immediately after World War II, the Soviet Union planned eight massive skyscrapers dubbed "Stalin Towers" for Moscow; seven of these were eventually built. The rest of Europe also slowly began to permit skyscrapers, starting with Madrid, in Spain, during the 1950s. Finally, skyscrapers also began to appear in Africa, the Middle East and Oceania (mainly Australia) from the late 1950s and early 1960s.

Still today no city in the world has more completed individual free-standing buildings over 492 ft. (150 m) than New York City.. Hong Kong comes in with the most in the entire world, if one counts individually the multiple towers that rise from a common podium (as Emporis does), in buildings that rise several stories as a single structure before splitting into two or more columns of floors. The number of skyscrapers in Hong Kong will continue to increase, due to a prolonged highrise building boom and high demand for office and housing space in the area. A new building complex in Kowloon contains several mixed-use towers (hotel-shops-residential) and one of them will be 118 stories tall.

Chicago's skyline was not allowed to grow until the height limits were relaxed in 1960; over the next fifteen years many towers were built, including the massive 442-meter (1,451-foot) Sears Tower, leading to its current number of buildings over 492 ft. Chicago is currently undergoing an epic construction boom that will greatly add to the city's skyline. Since 2000, at least 40 buildings at a minimum of 50 stories high have been built. The Chicago Spire, Trump International Hotel and Tower (Chicago), Waterview Tower, Mandarin Oriental Tower, 29-39 South LaSalle, Park Michigan, and Aqua are some of the more notable projects currently underway in the city that invented the skyscraper. Chicago, Hong Kong, and New York City, otherwise known as the "the big three," are recognized in most architectural circles as having the most compelling skylines in the world. Other large cities that are currently experiencing major building booms involving skyscrapers include Shanghai in China, Dubai in the United Arab Emirates, and Miami, which now is third in the United States.

Today, skyscrapers are an increasingly common sight where land is scarce, as in the centres of big cities, because of the high ratio of rentable floor space per area of land. Skyscrapers, like temples and palaces in the past, are considered symbols of a city's economic power. In an overall basis, not only skyscrapers define a skyline, they also play an important role to define an identity of a city. (See Skyline)

History of tallest skyscrapers

At the beginning of the 20th century, New York City was a center for the Beaux-Arts architectural movement, attracting the talents of such great architects as Stanford White and Carrere and Hastings. As better construction and engineering technology become available as the century progressed, New York became the focal point of the competition for the tallest building in the world. The city's striking skyline has been composed of numerous and varied skyscrapers, many of which are icons of 20th century architecture:

• The Flatiron Building, standing 285 ft (87 m) high, was one of the tallest buildings in the city upon its completion in 1902, made possible by its steel skeleton. It was one of the first buildings designed with a steel framework, and to achieve this height with other construction methods of that time would have been very difficult.
• The Woolworth Building, a neo-Gothic "Cathedral of Commerce" overlooking City Hall, was designed by Cass Gilbert. At 792 feet (241 m), it became the world's tallest building upon its completion in 1913, an honor it retained until 1930, when it was overtaken by 40 Wall Street.
• That same year, the Chrysler Building took the lead as the tallest building in the world, scraping the sky at 1,046 feet (319 m). More impressive than its height is the building's design, by William Van Alen. An art deco masterpiece with an exterior crafted of brick, the Chrysler Building continues to be a favorite of New Yorkers to this day.
• The Empire State Building, the first building to have more than 100 floors (it has 102), was completed the following year. It was designed by Shreve, Lamb and Harmon in the contemporary Art Deco style. The tower takes its name from the nickname of New York State. Upon its completion in 1931, it took the top spot as tallest building, and at 1,472 feet (448 m) to the very top of the antenna, towered above all other buildings until 1973.
• When the World Trade Center towers were completed in 1973 many felt them to be sterile monstrosities, even though they were the world's tallest buildings at that time. But most New Yorkers became fond of "The Twin Towers", and with the loss of lives in the September 11, 2001 terrorist attacks there came great sadness for the loss of the buildings. The Empire State Building again became the tallest building in New York City.

Momentum in setting records passed from the Unites States to other nations in 1997 with the opening of the Petronas Twin Towers in Kuala Lumpur, Malaysia. The record for world's tallest building remained in Asia with the opening of Taipei 101 in Taipei, Taiwan, in 2004. A number of architectural records will reside in the Middle East from 2009 with the opening of the Burj Dubai in Dubai, UAE.

With this geographical transition a change can be seen in the approach to skyscraper design. For much of the twentieth century large buildings such as the Sears Tower and World Trade Center (New York) took the form of simple geometrical shapes. They were designed as large boxes. This reflected the "international style" or modernist philosophy shaped by Bauhaus architects early in the century. By the 1990s skyscraper design began to exhibit postmodernist influences. The newest record setters, though modern, incorporate traditional architectural features associated with the part of the world where they stand. Taipei 101 recalls the traditions of Asian pagoda architecture even as the Burj Dubai incorporates motifs from traditional Arabic art. The result in each case is a building that does not look equally at home in any skyline in any city in the world, but a building that reflects its own continent and culture.

For current rankings of skyscrapers by height, see List of tallest buildings in the world.

The following list measures height of the roof. The more common gauge is the highest architectural detail; such ranking would have included Petronas Towers, built in 1998. See List of tallest buildings in the world for details.

Source: emporis.com

Future skyscrapers

The following skyscrapers are either approved or due to be completed in the near future:

• Construction of the Burj Dubai is taking place in Dubai. Its exact future height has been kept secret, but it is expected to become high, making it the tallest building in the world. The Burj Dubai is due to be completed in June 2009.
• Construction of the Shanghai Center is due to start later this year. The tower will be high and have 127 floors. The building will feature a glass curtain wall and nine indoor gardens when it is completed in 2014.
• Construction has started for a skyscraper in Moscow to be completed in 2012. The Russia Tower, standing at with 118 floors, it will not only be the tallest in Europe, but will also be the tallest naturally ventilated building in the World.
• Construction has started for a skyscraper in Chicago, is estimated to be completed in 2012. The Chicago Spire with 150 floors, will be the second tallest residential building in the world. Designed by Santiago Calatrava, it will also hold the title of North America's tallest free-standing structure.
• The Freedom Tower is now under construction and is the tallest tower comprising the redevelopment of the site of the former World Trade Center following the attacks of September 11, 2001. Its antenna will reach a height of .
• At , the APIIC Tower, currently under-construction in Hyderabad, India, would be the tallest building in South Asia upon completion in 2010.
• The Tour Generali in Paris La Défense, scheduled to be completed in 2011, is an entirely green building office skyscraper that is set to be the tallest building in Paris and in the European Union.
• Construction is expected to start in January 2009, for the Shard London Bridge, also known as the Shard of Glass. At , it is set to be the tallest building in London and the United Kingdom and the second tallest in the European Union after the Tour Generali in Paris when completed in 2012.

Quotations

"What is the chief characteristic of the tall office building? It is lofty. It must be tall. The force and power of altitude must be in it, the glory and pride of exaltation must be in it. It must be every inch a proud and soaring thing, rising in sheer exaltation that from bottom to top it is a unit without a single dissenting line."

—Louis Sullivan's The Tall Office Building Artistically Considered (1896)

See also

• List of tallest buildings in the world
• List of tallest buildings and structures in the world
• Emporis Skyscraper Award
• Skyline
• Skyscrapers in film
• Skyscraper design and construction

References

Notes

Bibliography

• Skyscrapers: Form and Function, by David Bennett, Simon & Schuster, 1995.

External links

• Historical photos of skyscrapers in New York City
• Skyscraper Museum
• Tallest Building in the World
• SkyscraperPage Technical information and diagrams
• SkyScrapers.org High Resolution skyscraper illustrations.
• 1880s "skyscraper" citations from word researcher [[Barry Popik].]