Tower block

From Wikipedia, the free encyclopedia

"High-rise" redirects here. For other uses, see High Rise (disambiguation).

A high-rise residential apartment building in Hong Kong

A 16 floor tower block in Charlestown, Greater Manchester, United Kingdom

A tower block, high-rise, apartment tower, office tower, apartment block, or block of flats, is a tall building or structure used as a residential and/or office building. In some areas they may be referred to as "MDU" standing for "Multi Dwelling Unit".^[1]
High-rise buildings became possible with the invention of the elevator (lift) and cheaper, more abundant building materials. The materials used for the structural system of high-rise buildings are reinforced concrete and steel. Most North American style skyscrapers have a steel frame, while residential blocks are usually constructed out of concrete. There is no clear definition of any difference between a tower block and a skyscraper though a building lower than about thirty stories is not likely to be a skyscraper and a building with fifty or more stories is certainly a skyscraper. [1]
High-rise structures pose particular design challenges for structural and geotechnical engineers, particularly if situated in a seismically active region or if the underlying soils have geotechnical risk factors such as high compressibility or bay mud. They also pose serious challenges to firefighters during emergencies in high-rise structures. New and old building design, building systems like the building standpipe system, HVAC systems (Heating, Ventilation and Air conditioning), fire sprinkler system and other things like stairwell and elevator evacuations pose significant problems.
Apartment blocks have technical and economic advantages in areas with high population density. They have become a distinguished form of housing accommodation in virtually all densely populated urban areas around the world. In contrast with low-rise and single-family houses, apartment blocks accommodate more inhabitants per unit of area of land they occupy and also decrease the cost of municipal infrastructure.

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[edit] History

These tower blocks were built in Shibam, Yemen in the 16th century, and are the tallest mudbrick buildings in the world

High-rise apartment buildings had already appeared in antiquity: the insulae in ancient Rome and several other cities in the Roman Empire, some of which might have reached up to 10 or more storeys,^[2] one reportedly having 200 stairs.^[3] Because of the destruction caused by poorly-built high-rise insulae collapsing,^[4] several Roman emperors, beginning with Augustus (r. 30 BC - 14 AD), set limits of 20–25 metres for multi-story buildings, but met with limited success,^[5]^[6] as these limits were often ignored despite the likelihood of taller insulae collapsing.^[7] The lower floors were typically occupied by either shops or wealthy families, while the upper storeys were rented out to the lower classes.^[8] Surviving Oxyrhynchus Papyri indicate that seven-storey buildings even existed in provincial towns, such as in 3rd century AD Hermopolis in Roman Egypt.^[9]^[10]
In Arab Egypt, the initial capital city was Fustat. It housed many high-rise residential buildings, some seven storeys tall that could reportedly accommodate hundreds of people. Al-Muqaddasi in the 10th century described them as resembling minarets, while Nasir Khusraw in the early 11th century described some of them rising up to 14 storeys, with roof gardens on the top storey complete with ox-drawn water wheels for irrigating them.^[11]^[12] By the 16th century, Cairo also had high-rise apartment buildings where the two lower floors were for commercial and storage purposes and the multiple storeys above them were rented out to tenants.^[13]
The skyline of many important medieval cities was dominated by large numbers of high-rising urban towers which fulfilled defensive, but also representative purposes. The residential Towers of Bologna numbered between 80 to 100 at a time, the largest of which still rise to 97.2 m. In Florence, a law of 1251 decreed that all urban buildings should be reduced to a height of less than 26 m, the regulation immediately put into effect.^[14] Even medium-sized towns such as San Gimignano are known to have featured 72 towers up to 51 m height.^[14]
Tower blocks were built in the Yemeni city of Shibam in the 16th century. The houses of Shibam are all made out of mud bricks, but about 500 of them are tower houses, which rise 5 to 16 storeys high,^[15] with each floor having one or two apartments.^[16]^[17] This technique of building was implemented in order to protect residents from Bedouin attacks. While Shibam has existed for around 2,000 years, most of the city's houses come mainly from the 16th century. The city has the tallest mud buildings in the world, with some of them over 30 metres (100 feet) high.^[18] Shibam has been called "one of the oldest and best examples of urban planning based on the principle of vertical construction" or "Manhattan of the desert".^[17]
Currently, the tallest high-rise apartment building in the world is Chicago's John Hancock Center, constructed under the supervision of Skidmore, Owings & Merrill and completed in 1969. The building has 100 stories and stands at 344 meters tall.^[19]

[edit] Modern development

[edit] United Kingdom

The three tower blocks of the Crossways Estate in Bow, London, United Kingdom

Tower blocks were built in the UK after the Second World War. The first residential tower block, "The Lawn" was constructed in Harlow, Essex in 1951; it is now a Grade II listed building. In many cases Tower Blocks were seen as a "quick-fix" to cure problems caused by crumbling and unsanitary 19th century dwellings or to replace buildings destroyed by German aerial bombing. Initially, they were welcomed, and their excellent views made them popular living places. Later, as the buildings themselves deteriorated, they grew a reputation for being undesirable low cost housing, and many tower blocks saw rising crime levels, increasing their unpopularity. One response to this was the great increase in the number of housing estates built, which in turn brings its own problems. In the UK, tower blocks particularly lost popularity after the partial collapse of Ronan Point in 1968. Glasgow, the largest city in Scotland, is believed to contain the highest concentration of tower blocks in the UK - examples include the Hutchesontown C blocks in the Gorbals, the 20-storey blocks in Sighthill, and the 31-storey Red Road (flats) in the city's north east.^{[citation needed]} However, on the whole, London has the largest number of high-rise residential buildings in the UK.^{[citation needed]}

The post-war British tower block vision

Post-war Britain was the stage for a tower block building ‘boom’; from the 1950s to the late 1970s there was a dramatic increase in tower block construction. During this time, local authorities desired to impress their voters by building futuristic and imposing tower blocks, which would signify post-war progress.^[20] Both Patrick Dunleavy and Lynsey Hanley agree that architects and planners were influenced by Le Corbusier’s promotion of high-rise architecture.^[21]^[22] The modern tower blocks were to include features that would foster desired forms of resident interaction, an example being the inclusion of Le Corbusier’s streets in the sky in some estates.^[23]
As well as inspiring residents, local authority planners believed that the way tower blocks were constructed would save money.^[24] Generally, the tower blocks were built on cheap greenfield land skirting established cities.^[25] Although the property prices for these periphery sites were markedly cheaper than their inner city counterparts, they often had little access to public amenities, such as public transport.^[22] It was thought that the implementation of industrialised building techniques would lower costs too, as similar tower blocks would be replicated over many sites.^[25] Uniform and standardised parts, such as toilet fittings and door handles, would be fitted throughout many tower blocks – planners deemed that buying in bulk would reduce overall costs.^[25]
Another key aspect of the tower block vision was the 'Brutalist' architectural method, popular with architects and planners at the time. The Brutalist emphasis led to the construction of stark and striking tower blocks with large sections of exposed concrete.^[26] Concrete was to be an integral part of the tower block designs; it could be poured on site, offering boundless flexibility to the building designers.^[27] To the planners, concrete was a silver bullet for the construction process – it was economical, and 'was vaunted as being long-lasting, if not indestructible'.^[28]

The post war British tower block reality

Elmet Towers in Swarcliffe, Leeds, showing the dereliction that led to its demolition.

Coleman's 1985 work argues that in trying to emulate Le Corbusier's ideas, the tower block planners only succeeded in encouraging social problems.^[29] Although architects and local authorities intended the opposite, tower blocks quickly became, as Hanley sharply stated, 'slums in the sky'.^[22] Due to demanding deadlines, complicated construction practices were rushed and many tower blocks experienced structural decay as a result – roofs leaked, concrete suffered spalling, steel corroded, and damp penetrated the buildings.^[30] Unfortunately, by replicating tower blocks across the nation, planners 'disastrously' replicated design faults.^[25] In many tower blocks, concrete quickly exhibited signs of decay; cracks soon formed and destabilised the buildings.^[27] The partial collapse of the Ronan Point tower block is an infamous example of the hasty and substandard construction that occurred in a number of the towers. The tower blocks quickly lost their 'futuristic' look; concrete turned from the crisp white the designers had imagined to a dull grey, stained by pollution.^[31]
Poor design decisions ruined the anticipated benefits of the buildings. Open spaces, which were supposed to benefit the residents, were instead unattractive, unused and inadequately supervised.^[32] Residents felt it was difficult to maintain the large open spaces around the blocks because they realistically belonged to no one.^[33] Social problems increased as the tower blocks quickly degraded through poor maintenance and an insecure communal environment.^[34] Apart from frequent break-downs, communal lifts were a source of fear for people travelling alone.^[35] It was a rarity to 'enter a clean-smelling, undefaced lift'.^[36] The tower blocks, many of which were located on the periphery of the city, made residents feel isolated and cut off from society.^[37] Outsiders and newcomers were also affected; they felt the overbearing design of the tower blocks made them fearsome and unsociable.^[38]
Power argues that as a direct consequence of their design and construction, security problems were prevalent in many of the tower blocks.^[30] Break-ins, vandalism and muggings were common, which were aided by the buildings' concealed areas, the mazes of internal corridors, and dark corners.^[39] Police were often required in the tower blocks,^[22] but their infrequent presence did little to pacify towers rife with delinquency. In order to contain disruptive behaviour, local authorities began to place 'problem families' in the same blocks; Hanley argues that this policy only led to 'further alienation …nihilism and a creeping sense of lawlessness'.^[40] Dunleavy seconds this, suggesting that the mental health of long term tower block residents may have been detrimentally affected.^[41]
While local authorities and their architects intended to create tower blocks that encouraged harmonious and vibrant communities, often the results were far from ideal. Post-war tower blocks were compromised from the outset by a combination of faults: local authorities advocated impractical architectural methods; design and construction faults were frequently reproduced; and there appeared to be a lack of understanding about the social consequences of certain design features. Collectively, these oversights transformed many tower blocks into undesirable places to live.

High-rise apartment buildings of the "Komplex Leipziger Straße" in Berlin-Mitte.

Fire safety

The lives of residents in London Tower blocks are at risk because London councils have not done proper fire safety checks and the problem is probably widespread in the UK. ^[42] North Ayrshire Council has decided to remove plastic cladding from its buildings following a fatal fire in a tower block.^[43] Poor maintenance of electrical equipment, fire doors and other features has caused widespread fire hazards and residents are asked to pay part of the cost of putting this right although residents did not cause the hazards.^[44] Tower blocks may be inherently more prone to fire because people living high up can escape fires less easily and the fire brigade can less easily reach them. In buildings with more than a hundred residents ensuring that every single resident acts responsibly to minimize fire risk is impossible, poorer residents in tower blocks may be tempted to use cheaper flammable fuels rather than electricity also are more likely to be smokers and carelessness with cigarettes is a major cause of home fires, furthermore poor residents of tower blocks are more likely to have old furniture which was not made to modern fire safety standards. Fire safety legislation introduced in London in 2006 requires new high rise buildings to be built to higher safety standards with sprinkler systems, these new buildings are mainly luxury accommodation for richer people. The legislation is not retrospective and does not protect poor people living in existing tower blocks.^[45]

Towards the present day

In recent years, some council or ex-council high-rises in the United Kingdom, including Trellick Tower, Keeling House, Sivill House and The Barbican Estate, have become popular with young professionals due to their excellent views, desirable locations and architectural pedigrees, and now command high prices. There are plans to redevelop the Little London and Lovell Park areas on the fringes of Leeds city centre into luxury flats for 'Young Urban Professionals'. The plans entail demolishing all of the council housing and refurbishing the highrise flats. This demand has led to many councils rethinking plans regarding their demolition.
After a gap of around 30 years, new high-rise flats are once again being built in Belfast, Birmingham (some are for wealthy people, e.g. The Mailbox, others are student accommodation.), Cardiff, Aberdeen, Glasgow, Leeds, Liverpool, London, Manchester and Newcastle; but this time sometimes for wealthy professionals, rather than the `lower classes`. Their developers market these properties by using the American term 'apartment buildings', perhaps in an effort to distance these newer buildings from the older tower blocks from the 1950s and 1960s. These are usually taller than their older counterparts and generally built in and around these provincial city centres. They are often glass and aluminum clad. Tonight with Trevor McDonald highlighted that in Leeds and Manchester (perhaps the cities that had seen most development) only approximately half were occupied and with owner occupation often being as low as 10%. In Southend there are controversial plans to build new tower blocks for social housing, a supporter claims this will be cheaper than paying to house poor people with private landlords while opponents fear the creation of Ghettos.^[46]
Tower blocks in Northern Ireland were never built to the frequency as they were in other cities in Britain and Ireland. Most tower blocks and flat complexes are found in Belfast and Derry, although many of these have been demolished in recent years and replaced with traditional public housing units. The Divis flats complex in west Belfast was built in between 1968 and 1972 was demolished in the early 1990s as the residents demanded new houses due to mounting problems with the flats. Divis Tower, built separately in 1966, still stands, however; and, in 2007, work began to convert the former British Army base at the top two floors into new dwellings.
In the north of the City, the iconic 7 towers complex in the New Lodge remains, although so too the problems that residents face, such as poor piping and inadequate sanitation. Farther north, the 4 tower blocks in Rathcoole still dominate the local skyline, while in south Belfast, the tower blocks in Seymour Hill also remain standing.

[edit] Ireland

Flats in Ballymun, Dublin, Ireland

Most of the tower blocks in Northern Ireland are in Belfast. All of Belfast's flat complexes were built by Belfast Corporation as part of Belfast slum clearances and to solve the housing problem. The Ballymun Flats were built between 1966 and 1969 consisting of seven 15-storey towers, nineteen 8 storey blocks and ten 4 storey blocks.^[47] Inner Dublin flat complexs include Sheriff Street (demolished), Fatima Mansions (demolished and redeveloped), St. Joseph's Gardens (demolished; replaced by Killarney Court flat complex), St. Teresa's Gardens, Dolphin House, Liberty House, St. Michael's Estate and O'Devaney Gardens and a lot more mainly throughout the North and South Inner City of Dublin. Suburban flat complexes were built exclusively on the northside of the city in Ballymun, Coolock and Kilbarrack. These flats were badly affected by a heroin epidemic that hit working-class areas of Dublin in the 1980s and early 90s.
Over the last five years the largest cities such as Dublin, Cork, Limerick and Galway have witnessed new large apartment building. Some large towns such as Navan, Drogheda, Dundalk and Mullingar have also witnessed lots of modern apartments being built.

[edit] Eastern Europe

[edit] East Asia

The unpopularity of tower blocks in Europe is in marked contrast to many Asian countries.

Typical Tower block apartment in South Korea

In South Korea the tower blocks are called "Apartment Complex (Apartment Danji)". The first residential towers began to be built after the Korean War. The South Korean government needed to build many apartment complexes in the cities to be able to accommodate the citizens. In the 60 years since, as the population increased considerably, tower blocks have become more common. This time however the new tower blocks integrated shopping malls, parking system and other convenient facilities.
In Singapore and urban Hong Kong, land prices are so high that almost the entire population lives in high-rise apartments. In fact, over 60% of Hong Kong residents live in apartments, many of them condominiums. Tower Palace in Seoul, South Korea, is the tallest apartment complex in Asia.

[edit] Canada

In Canada large multi-family buildings are usually known as apartment buildings or apartment blocks if they are rented from one common landowner, or condominiums or condo towers if each dwelling unit is individually owned; they may be called low-rise (or walk-up), mid-rise, high-rise, or skyscraper depending on their height. Tall residential towers are a staple building type in all large cities. Their relative prominence in Canadian cities varies substantially, however. In general, more populated cities have more high-rises than smaller cities, due to a relative the scarcity of land and a greater demand for housing. However, some cities such as Quebec City, Ottawa, and Halifax have fewer high-rise buildings due to several factors: a focus on historic preservation, height restrictions, and lower growth rates. In middle-sized cities with a relatively low population density, such as Calgary, Edmonton, Winnipeg, or Hamilton, there are more apartment towers but they are greatly outnumbered by single-family houses. Most of the largest residential towers in Canada are found in Toronto, Vancouver, and (to a lesser extent) Montreal: the most densely-populated cities. Toronto contains the second largest concentration of high-rise apartment buildings in North America (after New York). In Canada, like in other New World countries, but unlike Western Europe, most high-rise towers are located in the city centre (or "downtown"), where smaller, older buildings were demolished to make way in redevelopment schemes. Toronto, however has many high-rise apartment and condominium communities in its denser suburbs in addition to downtown. Greenfield high-rise development in the suburbs of Canadian cities in much more rare, although it does happen, particularly in transit-oriented developments.

[edit] United States

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In the United States tower blocks are commonly referred to as "midrise" or "highrise apartment buildings", depending on their height, while buildings that house fewer flats (apartments), or are not as tall as the tower blocks, are called "lowrise apartment buildings".
Some of the first residential towers were the Castle Village towers in New York City completed in 1939. Their cross-shaped design was copied in towers in Parkchester and Stuyvesant Town residential developments.
The government's experiments in the 1960s and 70s to use high-rise apartments as a means of providing the housing solution for the poor resulted in a spectacular failure. All but a few high-rise housing projects in the nation's largest cities, such as Cabrini–Green and Robert Taylor Homes in Chicago, Penn South in New York and the Desire projects in New Orleans, fell victim to the "ghettofication" and are now being torn down, renovated, or replaced.
In contrast to their public housing cousins, commercially developed high-rise apartment buildings continue to flourish in cities around the country largely due to high land prices and the housing boom of the 2000s. The Upper East Side in New York City and Chicago's Gold Coast, both featuring high-rise apartments, are the wealthiest urban neighborhoods in the United States.
Currently, the tallest high-rise apartment building and tower block in the world is Chicago's John Hancock Center, constructed by Bangladeshi engineer Fazlur Khan in 1969. The building has 100 stories and stands at 344 meters tall.^[19]

[edit] Australia

Housing commission towers in Waterloo, Sydney, Australia

High-rise living in Australia was limited to small pockets of bohemian inner Sydney until the 1960s, where a short-lived fashion saw public housing tenants located in new high-rise developments, especially in Sydney and Melbourne. The buildings pictured along with four other 16 storey blocks were constructed on behalf of the Royal Australian Navy and were avaliable to sailors and there families for accomodation. Due to social problems within these blocks the Navy left and the Department of Housing took charge and flats were let to low income and immigrant families. During the 1980's many people escaping communisum in Eastern block countries were housed in these buildings. Developers have enthusiastically adopted the term 'apartment' for these new high-rise blocks, perhaps to avoid the stigma still attached to housing commission flats.

[edit] Definition

Although there is no precise definition that is universally accepted, various bodies have tried to define what 'high-rise' means:

Emporis Standards defines a high-rise as "A multi-story structure between 35-100 meters tall, or a building of unknown height from 12-39 floors."^[48]
According to the building code of Hyderabad, India, a high-rise building is one with four floors or more, or one 15 meters or more in height.^[49]
The New Shorter Oxford English Dictionary defines a high-rise as "a building having many stories".
The International Conference on Fire Safety in High-Rise Buildings defined a high-rise as "any structure where the height can have a serious impact on evacuation"^{[citation needed]}
Massachusetts, United States General Laws define a high-rise as being higher than 70 feet (21 m).^{[citation needed]}
Most building engineers, inspectors, architects and similar professions define a high-rise as a building that is at least 75 feet (23 m) tall.^{[citation needed]}

[edit] Streets in the sky

"Street in the sky" at Park Hill

Streets in the sky is a term used to describe a style of architecture that emerged in Britain in the 1960s and 1970s. Generally built to replace run-down terraced housing, the new designs included not only modern improvements such as inside toilets, but also shops and other community facilities within high-rise blocks.^[50] Examples of the buildings and developments are Trellick Tower, Balfron Tower, Robin Hood Gardens and Keeling House in London, Hunslet Grange in Leeds and Park Hill, Sheffield. These were an attempt to develop a new architecture, differentiated from earlier large housing estates, such as Quarry Hill flats in Leeds.^[51]^[52]
Alison and Peter Smithson were the architects of Robin Hood Gardens.^[53] Another large example, the Aylesbury Estate in South London, built in 1970, is about to be demolished.^[54]^[55]

[edit] Deck access

Deck access is a term used to describe flats that are accessed from a walkway that is open to the elements, as opposed to flats that are accessed from fully enclosed internal corridors. Deck access blocks of flats are usually fairly low-rise structures. The decks can vary from simple walkways, which may be covered or uncovered, to decks wide enough for small vehicles. The best known example of deck-access flats in the UK is Park Hill, Sheffield, where the decks are wide enough to allow electric vehicles; however, the design is inspired by French Modernist architect Le Corbusier, particularly his Unite D'Habitation in Marseilles.^[56]

Skyscraper

From Wikipedia, the free encyclopedia

For other uses, see Skyscraper (disambiguation).

A skyscraper is a tall, continuously habitable building of many stories, often designed for office and commercial use. There is no official definition or height above which a building may be classified as a skyscraper. One common feature is that skyscrapers tend to make use of a steel framework structure from which walls are suspended, rather than having load-bearing walls as seen in conventional buildings.
As there is no official definition of what constitutes a skyscraper, a relatively small building may be considered one if it protrudes well above its built environment and changes the overall skyline. The maximum height of structures has progressed historically with building methods and technologies. 'Supertall' has arisen as a contemporary expression for exceptionally tall buildings, although again there is no formal definition.

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[edit] Definition

The word "skyscraper" originally was a nautical term referring to a small triangular sail set above the skysail on a sailing ship. The term was first applied to buildings of steel framed construction of at least 10 storeys in the late 19th century, a result of public amazement at the tall buildings being built in major cities like Chicago, New York City, Detroit, and St. Louis.^[1] The first steel frame skyscraper was the Home Insurance Building (originally 10 storeys with a height of 42 m or 138 ft) in Chicago, Illinois in 1885. Some point to New York's seven floor Equitable Life Assurance Building, built in 1870, as an early skyscraper for its innovative use of a kind of skeletal frame, but such designation depends largely on what factors are chosen. Even the scholars making the argument find it to be purely academic.^[2]
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. 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.^[3] Pumps and storage tanks maintain water pressure at the top of skyscrapers.

[edit] Skyscraper and supertall

The Emporis Standards Committee defines a high-rise building as "a multi-storey structure between 35–100 metres tall, or a building of unknown height from 12–39 floors"^[4] and a skyscraper as "a multi-storey building whose architectural height is at least 100 metres."^[5] 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.^[6]
A loose convention of some in the United States and Europe draws the lower limit of a skyscraper at 150 metres (~500 ft).^[7] A skyscraper taller than 300 meters (~1000 ft) is sometimes referred to as supertall^{[citation needed]}.

[edit] History

The Two Towers of Bologna in the 12th century reached 97.2 m in height.

The 16th-century city of Shibam consisted entirely of over 500 high-rise tower houses.

[edit] Before the 19th century

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 50 m (164 ft).
The tallest building in ancient times was the Great Pyramid of Giza in ancient Egypt, which was 146 metres (479 ft) tall and was built in the 26th century BC. Its height was not surpassed for thousands of years, possibly until the 14th century AD with the construction of Lincoln Cathedral (though its height is disputed),^[8] which in turn was not surpassed in height until the Washington Monument in 1884. However, being uninhabited buildings, none of these buildings actually complies with the definition of a skyscraper.
High-rise apartment buildings already flourished in classical antiquity: ancient Roman insulae in Rome and other imperial cities reached up to 10 and more stories.^[9] Several emperors, beginning with Augustus (r. 30 BC-14 AD), attempted to establish limits of 20–25 m for multi-storey buildings, but met with only limited success.^[10]^[11] The lower floors were typically occupied by either shops or wealthy families, while the upper stories were rented out to the lower classes.^[9] Surviving Oxyrhynchus Papyri indicate that seven-storey buildings even existed in provincial towns, such as in 3rd century AD Hermopolis in Roman Egypt.^[12]
The skylines of many important medieval cities had large numbers of high-rise urban towers. Wealthy families built these towers for defensive purposes and as status symbols. The residential Towers of Bologna in the 12th century, for example, numbered between 80 to 100 at a time, the largest of which (known as the "Two Towers") rise to 97.2 metres (319 ft). In Florence, a law of 1251 decreed that all urban buildings should be reduced to a height of less than 26 m, the regulation immediately put into effect.^[13] Even medium-sized towns at the time such as San Gimignano are known to have featured 72 towers up to 51 m height.^[13]
The medieval Egyptian city of Fustat housed many high-rise residential buildings, which Al-Muqaddasi in the 10th century described as resembling minarets. Nasir Khusraw in the early 11th century described some of them rising up to 14 stories, with roof gardens on the top floor complete with ox-drawn water wheels for irrigating them.^[14] Cairo in the 16th century had high-rise apartment buildings where the two lower floors were for commercial and storage purposes and the multiple stories above them were rented out to tenants.^[15] An early example of a city consisting entirely of high-rise housing is the 16th-century city of Shibam in Yemen. Shibam was made up of over 500 tower houses,^[16] each one rising 5 to 11 storeys high,^[17] 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.^[16] Shibam still has the tallest mudbrick buildings in the world, with many of them over 30 m (98 ft) high.^[18]
An early modern 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, although only partially iron framed, is The Flaxmill (also locally known as the "Maltings"), in Shrewsbury, England. Built in 1797, it is seen as the "grandfather of skyscrapers”, since 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.

Oriel Chambers, Liverpool. The world's first glass curtain walled building. The stone mullions are decorative.

The Wainwright Building, a 10-story red brick office building in St. Louis, Missouri, built in 1891

Built in 1931, The Empire State Building in New York City is one of the oldest, yet tallest skyscrapers.

[edit] Early skyscrapers

An early development was Oriel Chambers in Liverpool. Designed by local architect Peter Ellis in 1864, the building was the world's first iron-framed, glass curtain-walled office building. It was only 5 floors high.^[19]^[20]^[21] Further developments led to the world's first skyscraper, the ten-storey Home Insurance Building in Chicago, built in 1884–1885. While its height is not considered very impressive today, it was at that time. 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 development led to the "Chicago skeleton" form of construction.
Louis Sullivan's Wainwright Building in St. Louis, Missouri, 1891, was the first steel-framed building with soaring vertical bands to emphasize the height of the building and is therefore considered by some to be the first true skyscraper.
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. 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 1898 Witte Huis (White House) in Rotterdam; the Royal Liver Building in Liverpool, completed in 1911 and 90 m (300 ft) high;^[22] and the 17-storey Kungstornen (Kings' Towers) in Stockholm, Sweden, which were built 1924–25^[23], the 15-storey Edificio Telefónica in Madrid, Spain, built in 1929; 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 Chicago and New York City for the world's tallest building, New York took the lead by 1895 with the completion of the American Surety Building, leaving New York with the title of tallest building for many years. 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 Chrysler Building in 1930 and the Empire State Building in 1931, the world's tallest building for forty years. The first completed World Trade Center tower became the world's tallest building in 1972. However, it was soon overtaken by the Sears Tower (now Willis Tower) in Chicago within two years. The Sears Tower stood as the world's tallest building for 24 years, from 1974 until 1998, until it was edged out by Petronas Twin Towers in Kuala Lumpur, which held the title for six years.

[edit] Modern skyscrapers

From the 1930s onwards, skyscrapers also began to appear in Latin America (São Paulo, Santiago, Caracas, Bogotá, Mexico City) and in Asia (Tokyo, Shanghai, Hong Kong, Manila, Singapore, Mumbai, Seoul, Kuala Lumpur, Taipei, Bangkok). 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, during the 1950s. Finally, skyscrapers also began to be constructed in cities of Africa, the Middle East and Oceania (mainly Australia) from the late 1950s.
In the early 1960s structural engineer Fazlur Khan realized that the rigid steel frame structure that had "dominated tall building design and construction so long was not the only system fitting for tall buildings", marking "the beginning of a new era of skyscraper revolution in terms of multiple structural systems."^[24] His central innovation in skyscraper design and construction was the idea of the "tube" structural system, including the "framed tube", "trussed tube", and "bundled tube".^[25] These systems allowed far greater economic efficiency,^[26] and also allowed efficient skyscrapers to take on various shapes, no longer needing to be box-shaped.^[27] Over the next fifteen years, many towers were built by Khan and the "Second Chicago School",^[28] including the massive 442-meter (1,451-foot) Willis Tower.^[29] 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 or planned.^[30] The Trump International Hotel and Tower, 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. Chicago, Hong Kong, and New York City, otherwise known as "the big three," are recognized in architectural circles as having especially compelling skylines. A landmark skyscraper can inspire a boom of new high-rise projects in its city, as Taipei 101 has done in Taipei since its opening in 2004. In 2010, The Bank of America Tower at One Bryant Park became the world's first commercial LEED Platinum skyscraper.

[edit] History of tallest skyscrapers

Burj Khalifa in Dubai is the tallest building in the world at 828 m (2,717 ft).

Main article: History of the tallest buildings in the world

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 became available as the century progressed, New York and Chicago became the focal point of the competition for the tallest building in the world. Each city's striking skyline has been composed of numerous and varied skyscrapers, many of which are icons of 20th century architecture:

The Flatiron Building, designed by Daniel Hudson Burnham and 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 1889 Tower Building, designed by Bradford Gilbert and considered by some to be New York's first skyscraper, may have been the first building to use a skeletal steel frame.)^[31] Subsequent buildings such as the Singer Building, the Metropolitan Life Tower were higher still.
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).^[32] Designed by William Van Alen, an Art Deco style masterpiece with an exterior crafted of brick,^[33] the Chrysler Building continues to be a favorite of New Yorkers to this day.^[34]
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 at 1,250 feet (381 m), it took the top spot as tallest building, and towered above all other buildings until 1972. The antenna mast added in 1951 brought pinnacle height to 1,472 feet (449 m), lowered in 1984 to 1,454 feet (443 m).^[35]
The World Trade Center officially reached full height in 1972, was completed in 1973, and consisted of two tall towers and several smaller buildings. For a short time, the first of the two towers was the world's tallest building. Upon completion, the towers stood for 28 years, until the September 11 attacks destroyed the buildings in 2001. Various governmental entities, financial firms, and law firms called the towers home.
The Willis Tower (formerly Sears Tower) was completed in 1974, one year after the World Trade Center, and surpassed it as the world's tallest building. It was the first building to employ the "bundled tube" structural system, designed by Fazlur Khan.^[27] The building was not surpassed in height until the Petronas Towers were constructed in 1998, but remained the tallest in some categories until Burj Khalifa surpassed it in all categories in 2010. It is currently the tallest building in the United States.

Momentum in setting records passed from the United States to other nations with the opening of the Petronas Twin Towers in Kuala Lumpur, Malaysia, in 1998. 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, including those of the world's tallest building and tallest free-standing structure, moved to the Middle East with the opening of the Burj Khalifa in Dubai, United Arab Emirates.
This geographical transition is accompanied by a change in approach to skyscraper design. For much of the twentieth 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 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.
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.

Built	Building	City	Country	Roof		Floors	Pinnacle		Current status
1870	Equitable Life Building	New York City	United States	142 ft	43 m	8			Destroyed by fire in 1912
1889	Auditorium Building	Chicago	United States	269 ft	82 m	17	349 ft	106 m	Standing
1890	New York World Building	New York City	United States	309 ft	94 m	20	349 ft	106 m	Demolished in 1955
1894	Manhattan Life Insurance Building	New York City	United States	348 ft	106 m	18			Demolished in 1930
1895	Milwaukee City Hall	Milwaukee	United States	353 ft	108 m	15			Standing
1899	Park Row Building	New York City	United States	391 ft	119 m	30			Standing
1901	Philadelphia City Hall	Philadelphia	United States	511 ft	155.8 m	9	548 ft	167 m	Standing
1908	Singer Building	New York City	United States	612 ft	187 m	47			Demolished in 1968
1909	Met Life Tower	New York City	United States	700 ft	213 m	50			Standing
1913	Woolworth Building	New York City	United States	792 ft	241 m	57			Standing
1930	40 Wall Street	New York City	United States			70	927 ft	283 m	Standing
1930	Chrysler Building	New York City	United States	927 ft	282.9 m	77	1,046 ft	319 m	Standing
1931	Empire State Building	New York City	United States	1,250 ft	381 m	102	1,454 ft	443 m	Standing
1972	World Trade Center (North tower)	New York City	United States	1,368 ft	417 m	110	1,727 ft	526.3 m	Destroyed in 2001
1974	Willis Tower (formerly Sears Tower)	Chicago	United States	1,450 ft	442 m	108	1,729 ft	527 m	Standing
2004	Taipei 101	Taipei	Taiwan	1,474 ft	449 m	101	1,671 ft	509 m	Standing
2010	Burj Khalifa	Dubai	United Arab Emirates	2,717 ft	828 m	160	2,717 ft	828 m	Standing