Burj khalifa- world tallest building
known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and is the tallest manmade structure in the world, at
829.84 m (2,723 ft). [3][8] 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] and is part of the
new 2 km 2 (490-acre) flagship development called Downtown Dubai at the 'First Interchange' along Sheikh Zayed Road, near Dubai's main business district. The tower's architecture and engineering were performed by Skidmore, Owings and Merrill of Chicago, with Adrian Smith as chief architect, and Bill
Baker as chief structural engineer. [10][11] The primary contractor was Samsung C&T of South
Korea. [12]
The total cost for the project was about US$1.5 billion; and for the entire "Downtown Dubai"
development, US$20 billion. [13] In March 2009, Mohamed Ali Alabbar, chairman of the project's developer, Emaar Properties, said office space pricing at Burj Khalifa reached US$4,000 per sq ft (over US$43,000 per m²) and the Armani Residences, also in Burj Khalifa, sold for US$3,500 per sq ft (over
US$37,500 per m²). [14]
The project's completion coincided with the global financial crisis of 2007–2010, and with vast overbuilding in the country, led to high vacancies
and foreclosures. [15] With Dubai mired in debt from its huge ambitions, the government was forced to seek multibillion dollar bailouts from its oil-rich neighbor Abu Dhabi. Subsequently, in a surprise move at its opening ceremony, the tower was renamed Burj Khalifa, said to honour the UAE President Khalifa bin Zayed Al Nahyan for his crucial
support. [16]
Due to the slumping demand in Dubai's property market, the rents in the Burj Khalifa plummeted 40% some ten months after its opening. Out of 900 apartments in the tower, around 825 were still
empty at that time. [17][18]
Hide Conception
Burj Khalifa was designed to be the centerpiece of a large-scale, mixed-use development that would include 30,000 homes, nine hotels (including The Address Downtown Dubai), 3 hectares (7.4 acres) of parkland, at least 19 residential towers, the Dubai Mall, and the 12-hectare (30-acre) man-made Burj Khalifa Lake.
The building has returned the location of Earth's tallest freestanding structure to the Middle East where the Great Pyramid of Giza claimed this achievement for almost four millennia before being surpassed in 1311 by Lincoln Cathedral in England.
The decision to build Burj Khalifa is reportedly based on the government's decision to diversify from an oil based economy to one that is service and tourism based. According to officials, it is necessary for projects like Burj Khalifa to be built in the city to garner more international recognition, and hence investment. "He (Sheikh Mohammed bin Rashid Al Maktoum) wanted to put Dubai on the map with something really sensational," said Jacqui Josephson, a tourism and VIP delegations executive at Nakheel
Properties. [19]
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Hide Height
Records
Tallest extant structure: 829.84 m (2,723 ft) (previously KVLY-TV mast – 628.8 m/2,063 ft) Tallest structure ever built: 829.84 m (2,723 ft) (previously Warsaw radio mast –646.38 m/2,121 ft) Tallest freestanding structure: 829.84 m (2,723 ft) (previously CN Tower – 553.3 m/1,815 ft) Tallest skyscraper (to top of spire): 829.84 m (2,723 ft) (previously Taipei 101 – 509.2 m/1,671 ft) Tallest skyscraper to top of antenna: 829.84 m (2,723 ft) (previously the Willis (formerly Sears) Tower – 527 m/1,729 ft) Building with most floors: 160 (previously
Willis (formerly Sears) Tower – 108) [20]
Building with world's highest occupied
floor [21]
World's highest elevator installation (situated inside a rod at the very top of the
building) [22][23]
World's fastest elevators: 64 km/h (40 mph)
or 18 m/s (59 ft/s) [23] (previously Taipei 101 –16.83 m/s) Highest vertical concrete pumping (for a
building): 606 m (1,988 ft) [24] (previously Taipei 101 – 449.2 m/1,474 ft) First world's tallest structure in history to
include residential space [25]
World's highest outdoor observation deck:
124th floor at 452 m (1,483 ft) [26][27]
World's highest installation of an aluminium
and glass façade: 512 m (1,680 ft) [28]
World's highest nightclub: 144th floor [29]
World's highest restaurant (At.mosphere): 122nd floor at 442 m (1,450 ft) (previously 360, at a height of 350 m/1,148 ft in CN
Tower) [30][31]
World's highest New Year display of
fireworks. [32]
World's second highest swimming pool: 76th
floor [33] (world's highest swimming pool is located on 108th floor of Ritz-Carlton Hotel at International Commerce Centre, Hong-Kong).
History of height increases
Burj Khalifa compared to some other well-known tall structures
There are unconfirmed reports of several planned height increases since its inception. Originally proposed as a virtual clone of the 560 m (1,837 ft) Grollo Tower proposal for Melbourne, Australia's Docklands waterfront development, the tower was redesigned by Skidmore, Owings and Merrill
(SOM). [34] Marshall Strabala, an SOM architect who worked on the project until 2006, in late 2008 said that Burj Khalifa was designed to be 808 m (2,651 ft)
tall. [35]
The design architect, Adrian Smith, felt that the uppermost section of the building did not culminate elegantly with the rest of the structure, so he sought and received approval to increase it to the current
height. [citation needed] It has been explicitly stated that this change did not include any added floors, which is fitting with Smith's attempts to make the
crown more slender. [36]
Delay
Emaar Properties announced on 9 June 2008 that construction of Burj Khalifa was delayed by upgraded finishes and would be completed only in
September 2009. [37] An Emaar spokesperson said "The luxury finishes that were decided on in 2004, when the tower was initially conceptualized, is now being replaced by upgraded finishes. The design of the apartments has also been enhanced to make them more aesthetically attractive and functionally
superior." [38] A revised completion date of 2
December 2009 was then announced. [39] However,
Burj Khalifa was opened on 4 January 2010. [1][9]
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Hide Architecture and design
Cross-section comparisons
A Hymenocallis flower showing six spokes, as pattern for the three-lobed design
The tower is designed by Skidmore, Owings and Merrill, which also designed the Willis Tower (formerly the Sears Tower) in Chicago and the new One World Trade Center in New York City among numerous other famous high-rises. The building resembles the bundled tube form of the Willis Tower, but is not a bundle tube structure. Its design is reminiscent of Frank Lloyd Wright's vision for The Illinois, a mile high skyscraper designed for Chicago. According to Marshall Strabala, an SOM architect who worked on the building's design team, Burj Khalifa was designed based on the 73 floor Tower Palace Three, an all residential building in Seoul. In its early planning, Burj Khalifa was intended to be
entirely residential. [35]
Subsequent to the original design by Skidmore, Owings and Merrill, Emaar Properties chose Hyder Consulting to be the supervising engineer with NORR Group Consultants International Limited chosen to
supervise the architecture of the project. [40] Hyder was selected for its expertise in structural and MEP (mechanical, electrical and plumbing)
engineering. [41] Hyder Consulting's role was to supervise construction, certify SOM's design, and be the engineer and architect of record to the UAE
authorities. [40] NORR's role was the supervision of all architectural components including on site supervision during construction and design of a 6-storey addition to the Office Annex Building for architectural documentation. NORR was also responsible for the architectural integration drawings for the Armani Hotel included in the Tower.
Emaar Properties also engaged GHD, [42] 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 embodied in Islamic architecture. [22]
According to the structural engineer, Bill Baker of SOM, 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. [22] The design architect, Adrian Smith, has said the triple lobed footprint of the building was inspired by the flower
Hymenocallis. [43] 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 a 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. At its tallest
point, the tower sways a total of 1.5 m (4.9 ft). [44]
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. [22]
The spire of Burj Khalifa is composed of more than 4,000 tonnes (4,400 short tons; 3,900 long tons) of structural steel. The central pinnacle pipe weighing 350 tonnes (390 short tons; 340 long tons) 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. [45]
More than 1,000 pieces of art will adorn the interiors of Burj Khalifa, while the residential lobby of Burj Khalifa will display the work of Jaume Plensa, featuring 196 bronze and brass alloy cymbals
representing the 196 countries of the world. [46] 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. [47]
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 panels 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. [48] Over 26,000 glass panels were used in the exterior cladding of Burj Khalifa. Over 300 cladding specialists from China were brought in for the cladding work on the
tower. [45]
A 304 room Armani Hotel, the first of four by
Armani, occupies 15 of the lower 39 floors. [3][49] The hotel was supposed to open on 18 March
2010 [50][51] but after several delays the hotel finally
opened the public on 27 April 2010. [52] The corporate suites and offices were also supposed to
open from March onwards [53] but the hotel and observation deck remain the only parts of the building which are open.
The sky lobbies on the 43rd and 76th floors will
house swimming pools. [54] Floors through to 108 will have 900 private residential apartments (which, according to the developer, sold out within eight hours of being on the market). An outdoor zero-entry swimming pool will be located on the 76th floor of the tower. Corporate offices and suites fill most of the remaining floors, except for a 122nd, 123rd and 124th floor where the At.mosphere restaurant, sky lobby and an indoor and outdoor observation deck is located respectively. Burj Khalifa will receive its first residents from February 2010. They will be among the first of 25,000 people who
will live there. [54][55]
Burj Khalifa is expected to hold up to 35,000 people
at any one time. [22][56] A total of 57 elevators and 8
escalators are installed. [45] The elevators have a capacity of 12 to 14 people per cabin, the fastest rising and descending at up to 18 m/s (59 ft/
s). [22][57] Engineers had considered installing the world's first triple-deck elevators, but the final
design calls for double-deck elevators. [25] The double-deck elevators are equipped with entertainment features such as LCD displays to serve visitors during their travel to the observation
deck. [58] The building has 2,909 stairs from the
ground floor to the 160th floor. [59]
The graphic design identity work for Burj Khalifa is the responsibility of Brash Brands, who are based in Dubai. Design of the global launch events,
communications, and visitors centers [60] for Burj Khalifa have also been created by Brash Brands as well as the roadshow exhibition for the Armani Residences, which are part of the Armani Hotel within Burj Khalifa, which toured Milan, London,
Jeddah, Moscow and Delhi. [61]
Water supply system
The Burj Khalifa's water system supplies an average of 946,000 l (250,000 USgal) of water per day
through 100 km (62 mi) of pipes. [22][62] An additional 213 km (132 mi) of piping serves the fire emergency system, and 34 km (21 mi) supplies
chilled water for the air conditioning system. [62]
Air conditioning
The air conditioning system draws air from the upper floors where the air is cooler and cleaner than
on the ground. [63] At peak cooling times, the tower's cooling is equivalent to that provided by 13,000 t
(29,000,000 lb) of melting ice in one day. [62] The condensate collection system, which uses the hot and humid outside air, combined with the cooling requirements of the building, results in a significant amount of condensation of moisture from the air. The condensed water is collected and drained into a holding tank located in the basement car park; this water is then pumped into the site irrigation system
for use on the Burj Khalifa park. [22]
Window cleaning
To wash the 24,348 windows, totaling 120,000 m 2
(1,290,000 sq ft) of glass, [64] a horizontal track has been installed on the exterior of Burj Khalifa at levels 40, 73 and 109. Each track holds a 1,500 kg (3,300 lb) bucket machine which moves horizontally and then vertically using heavy cables. Above level 109, up to tier 27 traditional cradles from davits are used. The top of the spire, however, is reserved for specialist window cleaners, who brave the heights and high winds dangling by ropes to clean and inspect the top
of the pinnacle. [65] Under normal conditions, when all building maintenance units will be operational, it will take 36 workers three to four months to clean
the entire exterior façade. [45][66]
Unmanned machines will clean the top 27 additional tiers and the glass spire. The cleaning system was developed in Melbourne, Australia at a cost of
A$8 million. [66] The contract for building the state-of-the-art machines was won by Australian company
Cox Gomyl. [64]
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Hide Features
The Dubai Fountain
The Dubai Fountain
Main article: The Dubai Fountain
Outside, and at a cost of Dh 800 million (US$217 million), a record-setting fountain system was designed by WET Design, the California-based company responsible for the fountains at the Bellagio Hotel Lake in Las Vegas. Illuminated by 6,600 lights and 50 coloured projectors, it is 275 m (902 ft) long and shoots water 150 m (490 ft) into the air, accompanied by a range of classical to
contemporary Arabic and world music. [67] On 26 October 2008, Emaar announced that based on results of a naming contest the fountain would be
called the Dubai Fountain. [68]
Observation deck
An outdoor observation deck, named At the Top,
opened on 5 January 2010 on the 124th floor. [69] It is the third highest observation deck in the world and the second highest outdoor observation deck in
the world, at 452 m (1,483 ft). [70] The observation deck also features the Behold Telescope, an augmented reality device developed by gsmprjct° of Montréal, which allows visitors to view the surrounding landscape in real-time, and to view previously saved images such as those taken at different times of day or under different weather
conditions. [71][72] To manage the daily rush of sightseers, visitors are able to purchase tickets in advance for a specific date and time and at a 75%
discount over tickets purchased on the spot. [73]
On 8 February 2010, the observation deck was closed to the public after power supply problems caused an elevator to become stuck between floors, trapping a
group of tourists for 45 minutes. [74][75] Despite rumours of the observation deck reopening for St.
Valentine's Day (14 February), [76] it remained closed
until 4 April 2010. [77][78][79]
Burj Khalifa park
Burj Khalifa is surrounded by an 11 ha (27-acre) park designed by landscape architects SWA
Group. [80] The design of the park is also inspired by the core design concepts of Burj Khalifa which is based on the symmetries of the desert flower,
Hymenocallis. [81] The park has six water features, gardens, palm lined walkways, and flowering
trees. [82] At the centre of the park and the base of Burj Khalifa is the water room, which is a series of pools and water jet fountains. In addition the railing, benches and signs incorporate images of Burj Khalifa and the Hymenocallis flower.
The plants and the shrubbery will be watered by the buildings's condensation collection system that uses water from the cooling system. The system will provide 68,000,000 L (15,000,000 imp gal)
annually. [82] WET designers, who also developed the Dubai Fountain, developed the park's six water
features. [83]
Floor plans
The following is a breakdown of floors. [45][84]
Floors Use 160 and above Mechanical
156–159 Communication and broadcast 155 Mechanical 139–154 Corporate suites 136–138 Mechanical 125–135 Corporate suites 124 At the Top observatory 123 Sky lobby 122 At.mosphere restaurant 111–121 Corporate suites 109–110 Mechanical 77–108 Residential 76 Sky lobby 73–75 Mechanical 44–72 Residential 43 Sky lobby 40–42 Mechanical 38–39 Armani Hotel suites 19–37 Armani Residences 17–18 Mechanical 9–16 Armani Residences 1–8 Armani Hotel Ground Armani Hotel Concourse Armani Hotel
B1–B2 Parking, mechanical
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Hide Construction
Animation of construction process
Aerial closeup of Burj Khalifa under construction in March 2008
The tower was constructed by South Korean company, Samsung Engineering & Construction, which also did work on the Petronas Twin Towers
and Taipei 101. [85] Samsung Engineering & Construction built the tower in a joint venture with Besix from Belgium and Arabtec from UAE. Turner is the Project Manager on the main construction
contract. [86]
Under UAE law, the Contractor and the Engineer of Record, Hyder Consulting, is jointly and severally liable for the performance of Burj Khalifa.
The primary structural system of Burj Khalifa is
reinforced concrete. Over 45,000 m 3 (58,900 cu yd) of concrete, weighing more than 110,000 tonnes (120,000 short tons; 110,000 long tons) were used to construct the concrete and steel foundation, which features 192 piles; each pile is 1.5 metre diameter x
43 m long, buried more than 50 m (164 ft) deep. [25]
Burj Khalifa's construction used 330,000 m 3 (431,600 cu yd) of concrete and 55,000 tonnes (61,000 short tons; 54,000 long tons) of steel rebar, and
construction took 22 million man-hours. [10] A high density, low permeability concrete was used in the foundations of Burj Khalifa. A cathodic protection system under the mat is used to minimize any detrimental effects from corrosive chemicals in local
ground water. [45] In May 2008 concrete was pumped to a then world record delivery height of 606 m
(1,988 ft), [24] the 156th floor. Three tower cranes were used during construction of the uppermost
levels, each capable of lifting a 25-tonne load. [87]
The remaining structure above is constructed of lighter steel.
Burj Khalifa is highly compartmentalised. Pressurized, air-conditioned refuge floors are located approximately every 35 floors where people can shelter on their long walk down to safety in case
of an emergency or fire. [45][88]
Special mixes of concrete are made to withstand the extreme pressures of the massive building weight; as is typical with reinforced concrete construction, each batch of concrete used was tested to ensure it could withstand certain pressures. CTLGroup, working for SOM, conducted the creep and shrinkage testing
critical for the structural analysis of the building. [89]
The consistency of the concrete used in the project was essential. It was difficult to create a concrete that could withstand both the thousands of tonnes bearing down on it and Persian Gulf temperatures that can 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.
Milestones
January 2004: Excavation commences. [28]
February 2004: Piling starts. [28]
21 September 2004: Emaar contractors begin
construction. [90]
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 of Taipei 101, while Burj Khalifa reached the
130th floor. [28][91]
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][92]
12 August 2007: Surpasses the Sears Tower antenna, which stands 527.3 m (1,730 ft). 12 September 2007: At 555.3 m (1,822 ft), becomes the world's tallest freestanding structure, surpassing the CN Tower in
Toronto, and level 150 reached. [28][93]
7 April 2008: At 629 m (2,064 ft), surpasses the KVLY-TV Mast to become the tallest man-
made structure, level 160 reached. [28][94]
17 June 2008: Emaar announces that Burj Khalifa's height is over 636 m (2,087 ft) and that its final height will not be given until it is
completed in September 2009. [37]
1 September 2008: Height tops 688 m (2,257 ft), making it the tallest man-made structure ever built, surpassing the previous record-holder, the Warsaw Radio Mast in
Konstantynów, Poland. [95]
17 January 2009: Topped out at 829.84 m
(2,723 ft). [96]
1 October 2009: Emaar announces that the
exterior of the building is completed. [97]
4 January 2010: Burj Khalifa's official launch ceremony is held and Burj Khalifa is opened. Burj Dubai renamed Burj Khalifa in honour of the President of the UAE and ruler of Abu
Dhabi, Sheikh Khalifa bin Zayed al Nahyan. [
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