Burj Khalifa Burj Khalifa(Arabic:ةفيلخجرب"KhalifaTower"), [2]formerly known asBurj Dubai, isaskyscraperinDubai,United Arab Emirates, and thetallest man-made structureever built, at 828 m(2,717 ft). [2]Construction began on 21 September 2004, with the exterior of the structure completed on 1 October 2009. The building officially opened on 4 January 2010. [1][9]The building is part of the 2 km2(490-acre) flagship development calledDowntown Burj Khalifaat the "First Interchange" alongSheikh ZayedRoad, near Dubai's main business district. The tower's architecture and engineering were performed bySkidmore, Owings, and Merrill ofChicago.Adrian Smith, who worked with Skidmore, Owings and Merrill until 2006, was the chief architect, andBill Bakerwas the chief structural engineer for the project. [10][11]The primary contractor wasSamsungC&TofSouth Korea, who also built theTaipei 101andPetronas Twin Towers. [12]Major subcontractorsincludedBelgiangroupBesixandArabtecfrom theUAE.Turner Construction Companywas chosen asthe construction project manager. [13]Under UAE law, the Contractor and the Engineer of Record arejointlyand severally liablefor the performance of Burj Khalifa. Therefore, by adoption of SOM's design and bybeing appointed as Architect and Engineer of Record, Hyder Consultingis legally the Design Consultantfor the tower. The total cost for the Burj Khalifa project was aboutUS$1.5 billion; and for the entire new "DowntownDubai", US$20 billion. [14]Mohamed Ali Alabbar, theChairmanofEmaar Properties, speaking attheCouncil on Tall Buildings and Urban Habitat 8th World Congress, said in March 2009 that the price ofoffice space at Burj Khalifa had reached US$4,000 persq ft(over US$43,000 perm2) and that theArmaniResidences, also in Burj Khalifa, were selling for US$3,500 per sq ft (over US$37,500 per m2). [15]Thecompletion of the tower coincided with a worldwide economic slump and overbuilding, causing it to bedescribed as "the latest ... in [a] string of monuments to architectural vacancy
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Subsequent to the original design by Skidmore, Owings and Merrill, Emaar Properties chose Hyder
Consulting to be the supervising engineer .[35]
Hyder was selected for its expertise in structural
and MEP (mechanical, electrical and plumbing) engineering .[36]
Hyder Consulting's role was to supervise
construction, certify SOM's design, and be the engineer and architect of record to the UAE
authorities .[35] Emaar Properties also engaged GHD ,[37] an international multidisciplinary consulting firm, to
act as an independent verification and testing authority for concrete and steelwork.
The design of Burj Khalifa is derived from patterning systems [38]
embodied in Islamic architecture .
According to the structural engineer Bill Baker of Burj Khalifa, the building's design incorporates cultural
and historical elements particular to the region. The Y-shaped plan is ideal for residential and hotel
usage, with the wings allowing maximum outward views and inward natural light .[39]
The design architect
Adrian Smith has said the triple-lobed footprint of the building was inspired by the
flower Hymenocallis .[40]
The tower is composed of three elements arranged around a central core. As the
tower rises from the flat desert base, setbacks occur at each element in an upward spiralling pattern,
decreasing the cross section of the tower as it reaches toward the sky. There are 27 terraces in Burj
Khalifa. At the top, the central core emerges and is sculpted to form a finishing spire. A Y-shaped floor
plan maximizes views of the Persian Gulf . Viewed from above or from the base, the form also evokes
the onion domes of Islamic architecture. During the design process, engineers rotated the building 120
degrees from its original layout to reduce stress from prevailing winds. At its tallest point, the tower sways
a total of 1.5 m (4.9 ft).[41]
To support the unprecedented height of the building, the engineers developed a
new structural system called the buttressed core, which consists of a hexagonal core reinforced by three
buttresses that form the ‘Y' shape. This structural system enables the building to support itself laterally
and keeps it from twisting [42]
. The spire of Burj Khalifa is composed of more than 4,000 tonnes (4,400 ST;
3,900 LT) of structural steel. The central pinnacle pipe weighing 350 tonnes (390 ST; 340 LT) was
constructed from inside the building and jacked to its full height of over 200 m (660 ft) using a strand
jack system. The spire also houses communications equipment .[43]
More than 1,000 pieces of art will adorn the interiors of Burj Khalifa, while the residential lobby of Burj
Khalifa will have the artwork of 196 bronze and brass alloy cymbals representing the 196 countries of the
world. The visitors in this lobby will be able to hear a distinct timbre as the cymbals, plated with 18- carat gold , are struck by dripping water, intended to mimic the sound of water falling on leaves .
[44]
The exterior cladding of Burj Khalifa consists of 142,000 m 2
(1,528,000 sq ft) of reflective glazing ,
and aluminium and textured stainless steel spandrel p anels with vertical tubular fins. The cladding system
is designed to withstand Dubai's extreme summer temperatures. Additionally, the exterior temperature at
the top of the building is thought to be 6°C (11°F) cooler than at its base .[45]
reach 50 °C (122 °F). To combat this problem, the concrete was not poured during the day. Instead,
during the summer months ice was added to the mixture and it was poured at night when the air is cooler
and the humidity is higher. A cooler concrete mixture cures evenly throughout and is therefore less likely
to set too quickly and crack. Any significant cracks could have put the entire project in jeopardy.
The unique design and engineering challenges of building Burj Khalifa have been featured in a number of
television documentaries , including the Big, Bigger, Biggest series on the National
Geographic and Five channels, and the Mega Builders series on the Discovery Channel .
Labour controversy
Further information: Human rights in the United Arab Emirates
Burj Khalifa was built primarily by workers from South Asia .[72][73]
Press reports indicated in 2006 that
skilled carpenters at the site earned UK£ 4 .34 a day, and labourers earned UK£2.84 .[72]
According to a
BBC investigation and a Human Rights Watch report, the workers were housed in abysmal conditions,their pay was often withheld, their passports were confiscated by their employers, and they were working
in hazardous conditions that resulted in an apparently high number of deaths and injuries on site .[74]
On 21 March 2006, about 2,500 workers, who were upset over buses that were delayed for the end of
their shifts, protested, damaging cars, offices, computers, and construction equipment .[72]
A Dubai Interior
Ministry official said the rioters caused almost UK£500,000 in damage .[72]
Most of the workers involved in
the riot returned the following day but refused to work .[72]
On 17 June 2008, there were 7,500 skilled workers employed in the construction of Burj Khalifa .[32]
Milestones
January 2004: Excavation commences .[28]
February 2004: Piling starts .[28]
21 September 2004: Emaar contractors begin construction .[75]
March 2005: Structure of Burj Khalifa starts rising .[28]
June 2006: Level 50 is reached .[28]
February 2007: Surpasses the Sears Tower as the building with the most floors .
13 May 2007: Sets record for vertical concrete pumping on any building at 452 m (1,483 ft),surpassing the 449.2 m (1,474 ft) to which concrete was pumped during the construction o f Taipei
101, while Burj Khalifa reached 130 floor .[28][76]
21 July 2007: Surpasses Taipei 101, whose height of 509.2 m (1,671 ft) made it the world's tallest
building, and level 141 reached .[28][77]
12 August 2007: Surpasses the Sears Tower antenna, which stands 527.3 m (1,730 ft).
The opening ceremony of Burj Khalifa was held on 4 January 2010 .[84]
The ceremony featured a display
of 10,000 fireworks, light beams projected on and around the tower, and further sound, light and water effects .
[85] Using the 868 powerful stroboscope lights that are integrated into the facade and spire of the
tower, different lighting sequences were choreographed, together with more than 50 different
combinations of the other effects.
The event began with a short film which depicted the story of Dubai and the evolution of Burj Khalifa. The
displays of sound, light, water and fireworks followed .[85]
The portion of the show consisting of the various
pyrotechnic, lighting, water and sound effects was divided into three. The first part was primarily a light
and sound show, which took as its theme the link between desert flowers and the new tower, and was co-
ordinated with the Dubai Fountain and pyrotechnics. The second portion, called 'Heart Beat', represented the construction of the tower in a dynamic light show with the help of 300 projectors which generated a
shadow-like image of the tower. In the third act, sky tracers and space cannons enveloped the tower in a
halo of white light, which expanded as the lighting rig on the spire activated .[85]
The ceremony was relayed live on a giant screen on Burj Park Island, as well as several television
screens placed across the Downtown Burj Khalifa development. Hundreds of media outlets from around
the world reported live from the scene .[85]
In addition to the media presence, 6,000 guests were
expected .[86]
Purpose Burj Khalifa has been designed to be the centrepiece of a large-scale, mixed-use development that will
include 30,000 homes, nine hotels such as The Address Downtown Burj Khalifa , 3 hectares (7.4 acres ) of
parkland, at least 19 residential towers, the Dubai Mall , and the 12-hectare (30-acre) man-made Burj
Sculpture Spire of Dublin Ireland Dublin 120 393 2003
Wooden structureGliwice Radio
Tower
Poland Gliwice 118 387 1935
Aerial tramway support
tower
Pillar of third
section of
Gletscherbahn
Kaprun
Austria Kaprun 113.6 373 1966
Lighthouse
Yokohama Marine
Tower
Japan Yokohama 106 348 1961
Sphere Ericsson Globe Sweden Stockholm 85 279 1989
Statue (not including
pedestal)
The Mamayev
Monument
Russia Volgograd 82 269 1967
Brick lighthouse Torre della
Lanterna
Italy Genoa 77 253 1128
Brick minaret Qutub Minar India Delhi 72.5 237.8 1386
[ edit ] Tallest destroyed structures by category, not surpassed by existingstructures There are some destroyed architectural structures which were taller than the tallest existing structure of
Higher observation decks have existed on mountain peaks or cliffs , rather than on tall structures. For example, the Royal Gorge Bridge in Cañon City, Colorado , USA, was constructed in 1929 spanning
the Royal Gorge at a height of 321 m (1,050 ft) above the Arkansas River .
[ edit ] Timeline of guyed structures on land
As most of the tallest structures are guyed masts and the absolute height record of architectural
structures on land is since 1954 kept by them, here is a timeline of world's tallest guyed masts, since the
beginning of radio technology.
As many large guyed masts were destroyed at the end of World War II, the dates for the years between
1945 and 1950 may be incorrect. If Wusung Radio Tower survived World War II, it was the tallest guyed
The Chicago Spire (formerly Fordham Spire), under construction in Chicago , is expected to be
609.6 m (2,000 ft) and have 150 floors. If completed, it would surpass the CN Tower as the tallest
freestanding building in North America ,[16]
and would be the second tallest all-residential building in
the world (behind the aforementioned Pentominium ). Construction began in June 2007 and
completion is expected in early 2012, however, construction is on hold .[17]
The Abraj Al Bait Towers are under construction in Mecca , Saudi Arabia . The tallest tower is
expected to be 595 m (1,950 ft) tall when completed in 2010, becoming second-tallest building in the
world when completed. It will also be the largest building in the world with a floor area of
1,500,000 m 2
(1.61E+7 sq ft) and the tallest hotel in the world .
The Jakarta Tower (Menara Jakarta) is on-hold in Jakarta , Indonesia. It is expected to be 558 m
(1,830 ft) tall up to the antenna, thus may be tallest concrete tower. It was expected to be completed
in 2012, but has been put on hold .[18]
The Keangnam Hanoi Landmark Tower , under construction in Hanoi , Vietnam is expected to be 336 m (1,100 ft) tall. It will be completed on time in 2010 to celebrate Hanoi's 1000 anniversary.
The Federation Tower East , under construction in Moscow's International Business Centre , is
expected to be 242 m (790 ft) tall. Construction began in 2003 and completion is expected in 2010.