Skyscraper

A skyscraper is a tall continuously habitable building having multiple floors. Most modern sources define skyscrapers as being at least 100 metres (330 ft)^[1] or 150 metres (490 ft)^[2] in height, though there is no universally accepted definition, other than being very tall high-rise buildings. Skyscrapers may host offices, hotels, residential spaces, and retail spaces.

One common feature of skyscrapers is having a steel frame that supports curtain walls. These curtain walls either bear on the framework below or are suspended from the framework above, rather than resting on load-bearing walls of conventional construction. Some early skyscrapers have a steel frame that enables the construction of load-bearing walls taller than of those made of reinforced concrete.

Modern skyscraper walls are not

As of September 2023[update], fifteen cities in the world have more than 100 skyscrapers that are 150 m (492 ft) or taller.^[a] As of 2024, there are over 7 thousand skyscrapers over 150 m (492 ft) in height worldwide.^[4]

The term "skyscraper" was first applied to buildings of steel-framed construction of at least 10 stories in the late 19th century, a result of public amazement at the tall buildings being built in major American cities like New York City, Philadelphia, Boston, Chicago, Detroit, and St. Louis.^[5][6]

The first steel-frame skyscraper was the

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-story 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.

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)

Some structural engineers define a high-rise 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.

Different organizations from the United States and Europe define skyscrapers as buildings at least 150 m (490 ft) in height or taller,

The tallest structure in ancient times was the 146 m (479 ft) Great Pyramid of Giza in ancient Egypt, built in the 26th century BC. It was not surpassed in height for thousands of years, the 160 m (520 ft) Lincoln Cathedral having exceeded it in 1311–1549, before its central spire collapsed.^[14] The latter in turn was not surpassed until the 555-foot (169 m) Washington Monument in 1884. However, being uninhabited, none of these structures actually comply with the modern definition of a skyscraper.^{[citation needed]}

High-rise apartments flourished in

The skylines of many important medieval cities had large numbers of high-rise urban towers, built by the wealthy for defense and status. The residential Towers of 12th century Bologna numbered between 80 and 100 at a time, the tallest of which is the 97.2 m (319 ft) high Asinelli Tower. A Florentine law of 1251 decreed that all urban buildings be immediately reduced to less than 26 m (85 ft).^[19] Even medium-sized towns of the era are known to have proliferations of towers, such as the 72 towers that ranged up to 51 m (167 ft) height in San Gimignano.^[19]

The

Early skyscrapers

Wainwright Building (1891) in St. Louis

Flatiron Building (1902), in New York City

Royal Liver Building (1911), in Liverpool

In 1857,

Further developments led to what many individuals and organizations consider the world's first skyscraper, the ten-story Home Insurance Building in Chicago, built from 1884 to 1885.^[29] While its original height of 42.1 m (138 ft) does not qualify as a skyscraper today, it was record setting for the day. The building of tall buildings in the 1880s gave the skyscraper its first architectural movement, broadly termed the Chicago School, which developed what has been called the Commercial Style.^[30]

The architect, Major William Le Baron Jenney, created a 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. This was then draped with a stone curtain for aesthetic purposes. This development led to the "Chicago skeleton" form of construction. In addition to the steel frame, the Home Insurance Building also utilized fireproofing, elevators, and electrical wiring, key elements in most skyscrapers today.^[31]

Most early skyscrapers emerged in the land-strapped areas of New York City and Chicago toward the end of the 19th century. A land boom in Melbourne, Australia between 1888 and 1891 spurred the creation of a significant number of early skyscrapers, though none of these were steel reinforced and few remain today. Height limits and fire restrictions were later introduced. In the late 1800s, London builders found building heights limited due to issues with existing buildings. High-rise development in London is restricted at certain sites if it would obstruct protected views of St Paul's Cathedral and other historic buildings.^[33] This policy, 'St Paul's Heights', has officially been in operation since 1927.^[34]

After an early competition between New York City and Chicago for the world's tallest building, New York took the lead by 1895 with the completion of the 103 m (338 ft) tall American Surety Building, leaving New York with the title of the world's tallest building for many years. America by far produced the most skyscrapers in this period.

Modern skyscrapers are built with

Stalinist skyscrapers

Main building of Moscow State University (1953), in Moscow

Palace of Culture and Science (1955), in Warsaw

Grand Hotel International (1956), in Prague

The construction of very tall skyscrapers entered a three-decades-long era of stagnation in 1930 due to the

From the 1930s onward, skyscrapers began to appear in various cities in East and Southeast Asia as well as in Latin America. Finally, they also began to be constructed in cities in Africa, the Middle East, South Asia, and Oceania from the late 1950s.

Skyscraper projects after World War II typically rejected the classical designs of the

German-American architect Ludwig Mies van der Rohe became one of the world's most renowned architects in the second half of the 20th century. He conceived the glass façade skyscraper^[38] and, along with Norwegian Fred Severud,^[39] designed the Seagram Building in 1958, a skyscraper that is often regarded as the pinnacle of modernist high-rise architecture.^[40]

Postwar modernist skyscrapers

UN Secretariat Building (1952), in New York City

Seagram Building (1958), in New York City

Chałubińskiego 8 (1978), in Warsaw

Skyscraper construction surged throughout the 1960s. The impetus behind the upswing was a series of transformative innovations[41] which made it possible for people to live and work in "cities in the sky".^[42]

In the early 1960s

Many buildings designed in the 1970s lacked a particular style and recalled ornamentation from earlier buildings designed before the 1950s. These design plans ignored the environment and loaded structures with decorative elements and extravagant finishes.

Postmodern skyscrapers

Messeturm (1990), in Frankfurt

Petronas Towers (1998), in Kuala Lumpur

Jin Mao Tower (1999), in Shanghai

Modern building practices regarding supertall structures have led to the study of "vanity height".

Contemporary skyscrapers

The Shard (2012), in London

One World Trade Center (2013), in New York City

Shanghai Tower (2014), in Shanghai

Other contemporary styles and movements in skyscraper design include

3 September is the global commemorative day for skyscrapers, called "Skyscraper Day".[62]

New York City developers 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 318.9 m (1,046 ft)

The design and construction of skyscrapers involves creating safe, habitable spaces in very tall buildings. The buildings must support their weight, resist wind and earthquakes, and protect occupants from fire. Yet they must also be conveniently accessible, even on the upper floors, and provide utilities and a comfortable climate for the occupants. The problems posed in skyscraper design are considered among the most complex encountered given the balances required between

The concept of a skyscraper is a product of the industrialized age, made possible by cheap fossil fuel derived energy and industrially refined raw materials such as steel and concrete. The construction of skyscrapers was enabled by steel frame construction that surpassed brick and mortar construction starting at the end of the 19th century and finally surpassing it in the 20th century together with reinforced concrete construction as the price of steel decreased and labor costs increased.

The steel frames become inefficient and uneconomic for supertall buildings as usable floor space is reduced for progressively larger supporting columns.^[63] Since about 1960, tubular designs have been used for high rises. This reduces the usage of material (more efficient in economic terms – Willis Tower uses a third less steel than the Empire State Building) yet allows greater height. It allows fewer interior columns, and so creates more usable floor space. It further enables buildings to take on various shapes.

Advances in construction techniques have allowed skyscrapers to narrow in width, while increasing in height. Some of these new techniques include mass dampers to reduce vibrations and swaying, and gaps to allow air to pass through, reducing wind shear.^[64]

Good structural design is important in most building design, but particularly for skyscrapers since even a small chance of catastrophic failure is unacceptable given the tremendous damage such failure would cause. This presents a paradox to civil engineers: the only way to assure a lack of failure is to test for all modes of failure, in both the laboratory and the real world. But the only way to know of all modes of failure is to learn from previous failures. Thus, no engineer can be absolutely sure that a given structure will resist all loadings that could cause failure; instead, one can only have large enough margins of safety such that a failure is acceptably unlikely. When buildings do fail, engineers question whether the failure was due to some lack of foresight or due to some unknowable factor.

The load a skyscraper experiences is largely from the force of the building material itself. In most building designs, the weight of the structure is much larger than the weight of the material that it will support beyond its own weight. In technical terms, the

By 1895, steel had replaced cast iron as skyscrapers' structural material. Its malleability allowed it to be formed into a variety of shapes, and it could be riveted, ensuring strong connections.^[65] The simplicity of a steel frame eliminated the inefficient part of a shear wall, the central portion, and consolidated support members in a much stronger fashion by allowing both horizontal and vertical supports throughout. Among steel's drawbacks is that as more material must be supported as height increases, the distance between supporting members must decrease, which in turn increases the amount of material that must be supported. This becomes inefficient and uneconomic for buildings above 40 stories tall as usable floor spaces are reduced for supporting column and due to more usage of steel.^[63]

A new structural system of framed tubes was developed by

Khan pioneered several other variations of the tube structure design. One of these was the concept of

Bundled tube: An important variation on the tube frame is the bundled tube, which uses several interconnected tube frames. The Willis Tower in Chicago used this design, employing nine tubes of varying height to achieve its distinct appearance. The bundled tube structure meant that "buildings no longer need be boxlike in appearance: they could become sculpture."^[49]

Tube in tube: Tube-in-tube system takes advantage of core shear wall tubes in addition to exterior tubes. The inner tube and outer tube work together to resist gravity loads and lateral loads and to provide additional rigidity to the structure to prevent significant deflections at the top. This design was first used in One Shell Plaza.^[72] Later buildings to use this structural system include the Petronas Towers.^[73]

Outrigger and belt truss: The outrigger and belt truss system is a lateral load resisting system in which the tube structure is connected to the central core wall with very stiff outriggers and belt trusses at one or more levels.^[74] BHP House was the first building to use this structural system followed by the First Wisconsin Center, since renamed U.S. Bank Center, in Milwaukee. The center rises 601 feet, with three belt trusses at the bottom, middle and top of the building. The exposed belt trusses serve aesthetic and structural purposes.^[75] Later buildings to use this include Shanghai World Financial Center.^[74]

Concrete tube structures: The last major buildings engineered by Khan were the

Khan developed the shear wall frame interaction system for mid high-rise buildings. This structural system uses combinations of shear walls and frames designed to resist lateral forces.^[77] The first building to use this structural system was the 35-stories Brunswick Building.^[75] The Brunswick building (today known as the "Cook County Administration Building") was completed in 1965 and became the tallest reinforced concrete structure of its time. The structural system of Brunswick Building consists of a concrete shear wall core surrounded by an outer concrete frame of columns and spandrels.^[78] Apartment buildings up to 70 stories high have successfully used this concept.^[79]

The invention of the elevator was a precondition for the invention of skyscrapers, given that most people would not (or could not) climb more than a few flights of stairs at a time. The elevators in a skyscraper are not simply a necessary utility, like running water and electricity, but are in fact closely related to the design of the whole structure: a taller building requires more elevators to service the additional floors, but the elevator shafts consume valuable floor space. If the service core, which contains the elevator shafts, becomes too big, it can reduce the profitability of the building. Architects must therefore balance the value gained by adding height against the value lost to the expanding service core.^[80]

Many tall buildings use elevators in a non-standard configuration to reduce their footprint. Buildings such as the former World Trade Center Towers and Chicago's John Hancock Center use sky lobbies, where express elevators take passengers to upper floors which serve as the base for local elevators. This allows architects and engineers to place elevator shafts on top of each other, saving space. Sky lobbies and express elevators take up a significant amount of space, however, and add to the amount of time spent commuting between floors.

Other buildings, such as the Petronas Towers, use double-deck elevators, allowing more people to fit in a single elevator, and reaching two floors at every stop. It is possible to use even more than two levels on an elevator, although this has never been done. The main problem with double-deck elevators is that they cause everyone in the elevator to stop when only person on one level needs to get off at a given floor.

Buildings with sky lobbies include the

Skyscrapers are usually situated in city centres where the price of land is high. Constructing a skyscraper becomes justified if the price of land is so high that it makes economic sense to build upward as to minimize the cost of the land per the total floor area of a building. Thus the construction of skyscrapers is dictated by economics and results in skyscrapers in a certain part of a large city unless a building code restricts the height of buildings.

Skyscrapers are rarely seen in small cities and they are characteristic of large cities, because of the critical importance of high land prices for the construction of skyscrapers. Usually only office, commercial and hotel users can afford the rents in the city center and thus most tenants of skyscrapers are of these classes.

Today, skyscrapers are an increasingly common sight where land is expensive, as in the centres of big cities, because they provide such a high ratio of rentable floor space per unit area of land.

Another disadvantage of very high skyscrapers is the loss of usable floorspace, as many elevator shafts are needed to enable performant vertical travelling. This led to the introduction of express lifts and sky lobbies where transfer to slower distribution lifts can be done.

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Constructing a single skyscraper requires large quantities of materials like steel, concrete, and glass, and these materials represent significant embodied energy. Skyscrapers are thus material and energy intensive buildings.

Skyscrapers have considerable mass, requiring a stronger foundation than a shorter, lighter building. In construction, building materials must be lifted to the top of a skyscraper during construction, requiring more energy than would be necessary at lower heights. Furthermore, a skyscraper consumes much electricity because

Skyscrapers can be artificially lit and the energy requirements can be covered by

• More structure – because it must be stronger to support more floors above
• The elevator conundrum creates the need for more lift shafts—everyone comes in at the bottom and they all have to pass through the lower part of the building to get to the upper levels.
• Building services
  – power and water enter the building from below and have to pass through the lower levels to get to the upper levels.

In low-rise structures, the support rooms (

The building sector accounts for approximately 50% of greenhouse gas emissions, with operational energy accounting for 80-90% of building related energy use.

A portion of the operational energy increase in tall buildings is related to the usage of elevators because the distance traveled and the speed at which they travel increases as the height of the building increases. Between 5 and 25% of the total energy consumed in a tall building is from the use of elevators. As the height of the building increases it is also more inefficient because of the presence of higher drag and friction losses.^[87]

The embodied energy associated with the construction of skyscrapers varies based on the materials used. Embodied energy is quantified per unit of material. Skyscrapers inherently have higher embodied energy than low-rise buildings due to the increase in material used as more floors are built. Figures 2 and 3^[where?] compare the total embodied energy of different floor types and the unit embodied energy per floor type for buildings with between 20 and 70 stories. For all floor types except for steel-concrete floors, it was found that after 60 stories, there was a decrease in unit embodied energy but when considering all floors, there was exponential growth due to a double dependence on height. The first of which is the relationship between an increase in height leading to an increase in the quantity of materials used, and the second being the increase in height leading to an increase in size of elements to increase the structural capacity of the building. A careful choice in building materials can likely reduce the embodied energy without reducing the number of floors constructed within the bounds presented.^[88]

Similar to embodied energy, the

As urban centers continue to expand upward and outward, the present velocity fields will continue to trap polluted air close to the tall buildings within the city. Specifically within major cities, a majority of air pollution is derived from transportation, whether it be cars, trains, planes, or boats. As urban sprawl continues and pollutants continue to be emitted, the air pollutants will continue to be trapped within these urban centers.^[91] Different pollutants can be detrimental to human health in different ways. For example, particulate matter from vehicular exhaust and power generation can cause asthma, bronchitis, and cancer, while nitrogen dioxide from motor engine combustion processes can cause neurological disfunction and asphyxiation.^[92]

Like with all other buildings, if special measures are taken to incorporate

• The E. V. Haughwout Building in Manhattan was the first building to successfully install a passenger elevator, doing so on 23 March 1857.^[95]
• The Equitable Life Building in Manhattan was the first office building to feature passenger elevators.^[96][97]
• The Home Insurance Building by William Le Baron Jenney in Chicago, which was built in 1884, was the first tall building with a steel skeleton.^[98]
• The Singer Building, an expansion to an existing structure in Lower Manhattan was the world's tallest building when completed in 1908. Designed by Ernest Flagg,^[99] it was 612 feet (187 m) tall.^[100]
• The
  Madison Square Park from the Flatiron Building, was the world's tallest building when completed in 1909. It was designed by the architectural firm of Napoleon LeBrun & Sons and stood 700 feet (210 m) tall.^[101]
• The Woolworth Building, a neo-Gothic "Cathedral of Commerce" overlooking New York 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.^[102]
• 40 Wall Street, a 71-story, 927-foot-tall (283 m) neo-Gothic tower designed by H. Craig Severance, was the world's tallest building for a month in May 1930.^[103][104]
• The Chrysler Building in New York City took the lead in late May 1930 as the tallest building in the world, reaching 1,046 feet (319 m).^[105] Designed by William Van Alen, an Art Deco style masterpiece with an exterior crafted of brick,^[106] the Chrysler Building continues to be a favorite of New Yorkers to this day.^[107]
• The
  New York State. The antenna mast added in 1951 brought pinnacle height to 1,472 feet (449 m), lowered in 1984 to 1,454 feet (443 m).^[108]
• The World Trade Center by Minoru Yamasaki officially surpassed the Empire State Building in 1970, was completed in 1973, and consisted of two tall towers and several smaller buildings. For a short time the World Trade Center's North Tower―completed in 1972―was the world's tallest building, until surpassed by the Sears Tower in 1973. Upon completion, the towers stood for 28 years, until the September 11 attacks destroyed the buildings in 2001.
• The
  Fazlur Khan. It was surpassed in height by the Petronas Towers in 1998, but remained the tallest in some categories until Burj Khalifa surpassed it in all categories in 2010. It is currently the third tallest building in the United States, after One World Trade Center (which was built following 9/11), and Central Park Tower in New York City
  .

This geographical transition is accompanied by a change in approach to skyscraper design. For much of the 20th century large buildings took the form of simple geometrical shapes. This reflected the "international style" or modernist philosophy shaped by Bauhaus architects early in the century. The last of these, the Willis Tower and World Trade Center towers in New York, erected in the 1970s, reflect the philosophy. Tastes shifted in the decade which followed, and new skyscrapers began to exhibit postmodernist influences. This approach to design avails itself of historical elements, often adapted and re-interpreted, in creating technologically modern structures. The Petronas Twin Towers recall Asian pagoda architecture and Islamic geometric principles. Taipei 101 likewise reflects the pagoda tradition as it incorporates ancient motifs such as the ruyi symbol. The Burj Khalifa draws inspiration from traditional Islamic art. Architects in recent years^[when?] have sought to create structures that would not appear equally at home if set in any part of the world, but that reflect the culture thriving in the spot where they stand.^{[citation needed]}

The following list measures height of the roof, not the pinnacle.^{[109][failed verification]} The more common gauge is the "highest architectural detail"; such ranking would have included Petronas Towers, built in 1996.

Built	Building	City	Country	Official Height		Floors	Pinnacle		Current status
1870	Equitable Life Building	New York	United States	43 m	142 ft	8			Destroyed by fire in 1912
1889	Auditorium Building	Chicago		82 m	270 ft	17			Standing
1890	New York World Building	New York		94 m	309 ft	20	106 m	349 ft	Demolished in 1955
1894	Philadelphia City Hall	Philadelphia		155.8 m	511 ft	9	167 m	548 ft	Standing
1908	Singer Building	New York		187 m	612 ft	47			Demolished in 1968
1909	Met Life Tower			213 m	700 ft	50			Standing
1913	Woolworth Building			241 m	792 ft	57			Standing
1930	40 Wall Street			282 m	925 ft	70	283 m	927 ft	Standing
1930	Chrysler Building			319 m	1046 ft	77	319 m	1,046 ft	Standing
1931	Empire State Building			381 m	1,250 ft	102	443 m	1,454 ft	Standing
1972	World Trade Center (North Tower)			417 m	1,368 ft	110	526.8 m	1,728 ft	Destroyed in 2001 in the September 11 attacks
1974	Willis Tower (formerly Sears Tower)	Chicago		442 m	1,450 ft	110	527.3 m	1,729 ft	Standing
1996	Petronas Towers	Kuala Lumpur	Malaysia	451.9 m	1,483 ft	88	451.9 m	1,483 ft	Standing
2004	Taipei 101	Taipei	Taiwan	508.3 m	1,667 ft	101	509.2 m	1,668 ft	Standing
2010	Burj Khalifa	Dubai	United Arab Emirates	828 m	2,717 ft	163	829.8 m	2,722 ft	Standing

• 
  The Empire State Building was the tallest from 1931 to 1971. It was the first skyscraper to have over 100 floors.
• 
  The original 1 World Trade Center (North Tower) was the tallest in the world from 1971 to 1974
• 
  The Willis Tower in Chicago was the world's tallest building from 1974 to 1998
• 
  The Petronas Towers in Kuala Lumpur were the tallest from 1998 to 2004.
• 
  Taipei 101 in Taipei, the world's tallest skyscraper from 2004 to 2010, was the first to exceed the 500 m (1,600 ft) mark.

Proposals for such structures have been put forward, including the Burj Mubarak Al Kabir in Kuwait and Azerbaijan Tower in Baku. Kilometer-plus structures present architectural challenges that may eventually place them in a new architectural category.^[110] The first building under construction and planned to be over one kilometre tall is the Jeddah Tower.

Several wooden skyscraper designs have been designed and built. A 14-story housing project in Bergen, Norway known as 'Treet' or 'The Tree' became the world's tallest wooden apartment block when it was completed in late 2015.^[112] The Tree's record was eclipsed by Brock Commons, an 18-story wooden dormitory at the University of British Columbia in Canada, when it was completed in September 2016.^[113]

A 40-story residential building 'Trätoppen' has been proposed by architect Anders Berensson to be built in

• CTBUH Skyscraper Award
• Earthscraper
• Emporis Skyscraper Award
• Groundscraper
• List of cities with the most skyscrapers
• List of tallest buildings
• List of tallest buildings and structures
• Pencil tower
• Plyscraper
• Seascraper
• Skyscraper design and construction
• Skyscraper Index
• Skyscraper Museum in NYC
• Skyscrapers in film
• Skyline
• Vertical farming, "farmscrapers"
• World's littlest skyscraper
• drag-coefficient
• material-fatigue
• down-force
• Steel frame

Further reading

• Adam, Robert. "How to Build Skyscrapers". City Journal. Archived from the original on 23 September 2015. Retrieved 4 April 2014.
• ISBN 978-1-57912-942-2
• Skyscrapers: Form and Function, by David Bennett, Simon & Schuster, 1995.
• Landau, Sarah; Condit, Carl W. (1996). Rise of the New York Skyscraper, 1865–1913. New Haven, CT: Yale University Press.
  OCLC 32819286
  .
• Willis, Carol, Form Follows Finance: Skyscrapers and Skylines in New York and Chicago. Princeton Architectural Press, 1995. 224 P.
  ISBN 1-56898-044-2
• Van Leeuwen, Thomas A P, The Skyward Trend of Thought: The Metaphysics of the American Skyscraper, Cambridge: MIT Press, 1988.

External links

Wikimedia Commons has media related to Skyscrapers.

Wikiquote has quotations related to Skyscraper.

• Council on Tall Buildings and Urban Habitat
• SkyscraperCity construction updates magazine
• Skyscraper definition on Phorio Standards
• Skyscraper Museum
• SkyscraperPage Technical information and diagrams