The Burj Khalifa (Arabic: برج خليفة, Arabic for "Khalifa Tower"; pronounced English: /ˈbɜːrdʒ kəˈliːfə/), known as the Burj Dubai before its inauguration, is a megatall skyscraper in Dubai, United Arab Emirates. With a total height of 829.8 m (2,722 ft) and a roof height (excluding antenna) of 828 m (2,717 ft), the Burj Khalifa has been the tallest structure in the world since its topping out in late 2008.[4][9]
Construction of the Burj Khalifa began in 2004, with the exterior completed five years later in 2009. The primary structure is reinforced concrete. The building was opened in 2010 as part of a new development called Downtown Dubai. It is designed to be the centrepiece of large-scale, mixed-use development. The decision to construct the building is reportedly based on the government's decision to diversify from an oil-based economy, and for Dubai to gain international recognition. The building was originally named Burj Dubai but was renamed in honour of the ruler of Abu Dhabi and president of the United Arab Emirates, Khalifa bin Zayed Al Nahyan;[3] Abu Dhabi and the UAE government lent Dubai money to pay its debts. The building broke numerous height records, including its designation as the tallest tower in the world.
Burj Khalifa was designed by Adrian Smith, then of Skidmore, Owings & Merrill (SOM), whose firm designed the Willis Tower and One World Trade Center. Hyder Consulting was chosen to be the supervising engineer with NORR Group Consultants International Limited chosen to supervise the architecture of the project. The design is derived from the Islamic architecture of the region, such as in the Great Mosque of Samarra. The Y-shaped tripartite floor geometry is designed to optimize residential and hotel space. A buttressed central core and wings are used to support the height of the building. Although this design was derived from Tower Palace III, the Burj Khalifa’s central core houses all vertical transportation with the exception of egress stairs within each of the wings.[10] The structure also features a cladding system which is designed to withstand Dubai's hot summer temperatures. It contains a total of 57 elevators and 8 escalators.
Critical reception to Burj Khalifa has been generally positive, and the building has received many awards. There have been complaints concerning migrant workers from South Asia who were the primary building labor force. These center on free market wages[citation needed] deemed by third parties to be insufficient.[11][citation needed] Several instances of suicides have been reported, which is not uncommon for migrant construction workers in Dubai.[12]
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[hide]Development[edit]
Construction began on 6 January 2004, with the exterior of the structure completed on 1 October 2009.The building officially opened on 4 January 2010,[2][13] and is part of the new 2 km2 (490-acre) 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 Souffian AL-Jabiry of Chicago, with Adrian Smith as chief architect, and Bill Baker as chief structural engineer.[14][15] The primary contractor was Samsung C&T of South Korea.[16] The tower's construction was done by the construction division of Al Ghurair Investment group.[17][18]
Conception[edit]
Burj Khalifa was designed to be the centrepiece 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) artificial Burj Khalifa Lake. 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] The tower was known as Burj Dubai ("Dubai Tower") until its official opening in January 2010.[20] It was renamed in honour of the ruler of Abu Dhabi and president of the United Arab Emirates, Khalifa bin Zayed Al Nahyan; Abu Dhabi and the federal government of UAE lent Dubai tens of billions of USD so that Dubai could pay its debts – Dubai borrowed at least $80 billion for construction projects.[20] In the 2000s, Dubai started diversifying its economy but it suffered from an economic crisis in 2007–2010, leaving large-scale projects already in construction abandoned.[citation needed]
Records[edit]
- Tallest existing structure: 828 m (2,717 ft) (previously KVLY-TV mast – 628.8 m or 2,063 ft)
- Tallest structure ever built: 828 m (2,717 ft) (previously Warsaw radio mast – 646.38 m or 2,121 ft)
- Tallest freestanding structure: 828 m (2,717 ft) (previously CN Tower – 553.3 m or 1,815 ft)
- Tallest skyscraper (to top of spire): 828 m (2,717 ft) (previously Taipei 101 – 509.2 m or 1,671 ft)
- Tallest skyscraper to top of antenna: 828 m (2,717 ft) (previously the Willis (formerly Sears) Tower – 527 m or 1,729 ft)
- Building with most floors: 211 (including spire) previously World Trade Center – 110[21]
- Building with world's highest occupied floor: 584.5 m (1,918 ft)[22][23] (surpassed by Shanghai Tower in 2015)
- World's highest elevator installation (situated inside a rod at the very top of the building)[24]
- World's longest travel distance elevators: 504 m (1,654 ft)[24][25]
- Highest vertical concrete pumping (for a building): 606 m (1,988 ft)[26]
- World's tallest structure that includes residential space[27]
- World's highest observation deck: 148th floor at 555 m (1,821 ft)[28][29] (surpassed by Shanghai Tower in 2015)
- World's highest outdoor observation deck: 124th floor at 452 m (1,483 ft) [30]
- World's highest installation of an aluminium and glass façade: 512 m (1,680 ft)[31]
- World's highest nightclub: 144th floor[32]
- 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)[33]
- World's highest New Year display of fireworks.[34]
History of height increases[edit]
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).[35] 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.[36]
The architect who designed it, 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.[37] 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.[38] An Emaar spokesperson said that "[t]he luxury finishes that were decided on in 2004, when the tower was initially conceptualised, 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."[39] A revised completion date of 2 December 2009 was then announced.[40] However, Burj Khalifa was opened on 4 January 2010, more than a month later.[2][13]
Architecture and design[edit]
The tower was designed by Skidmore, Owings and Merrill (SOM), who also designed the Willis Tower (formerly the Sears Tower) in Chicago and the One World Trade Center in New York City. Burj Khalifa uses the bundled tube design of the Willis Tower, invented by Fazlur Rahman Khan.[41][42]Proportionally, the design uses half the amount of steel used in the construction of the Empire State Building thanks to the tubular system.[41][43]Dr. Khan’s contributions to the design of tall buildings have had a profound impact on architecture and engineering. It would be difficult to find any worldwide practices in the design of tall buildings that have not been directly or indirectly influenced by his work.[44] Its design is reminiscent of Frank Lloyd Wright's vision for The Illinois, a mile-high skyscraper designed for Chicago, as well as Chicago's Lake Point Tower. According to Marshall Strabala, a 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.[36]
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 Ltd chosen to supervise the architecture of the project.[45] Hyder was selected for their expertise in structural and MEP (mechanical, electrical and plumbing) engineering.[46] Hyder Consulting's role was to supervise construction, certify SOM's design, and be the engineer and architect of record to the UAE authorities.[45] 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,[47] an international multidisciplinary consulting firm, to act as an independent verification and testing authority for concrete and steelwork.
The design is derived from Islamic architecture.[24] As the tower rises from the flat desert base, there are 27 setbacks in a spiralling pattern, decreasing the cross section of the tower as it reaches toward the sky and creating convenient outdoor terraces. These setbacks are arranged and aligned in a way that minimizes vibration wind loading from eddy currents and vortices.[10] At the top, the central core emerges and is sculpted to form a finishing spire. At its tallest point, the tower sways a total of 1.5 m (4.9 ft).[48]
As part of a study which reveals the unnecessary "vanity space" added to the top of the world's tallest buildings by the Council on Tall Buildings and Urban Habitat (CTBUH), it was revealed that without its 244-metre spire, the 828-metre Burj Khalifa would drop to a substantially smaller 585-metre height without any reduction in usable space. As the report states, the spire "could be a skyscraper on its own".[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 weighs 350 tonnes (390 short tons; 340 long tons) and has a height of 200 m (660 ft). The spire also houses communications equipment.[49]
In 2009, architects announced that more than 1,000 pieces of art would adorn the interiors of Burj Khalifa, while the residential lobby of Burj Khalifa would display the work of Jaume Plensa.[50]
The cladding system consists of 142,000 m2 (1,528,000 sq ft) of more than 26,000 reflective glass panels and aluminium and textured stainless steel spandrel panels with vertical tubular fins.[49] The architectural glass provides solar and thermal performance as well as an anti-glare shield for the intense desert sun, extreme desert temperatures and strong winds. In total the glass covers more than 174,000 m2 (1,870,000 sq ft)[citation needed].
The exterior temperature at the top of the building is thought to be 6 °C (11 °F) cooler than at its base.[51]
A 304-room Armani Hotel, the first of four by Armani, occupies 15 of the lower 39 floors.[4][52] The hotel was supposed to open on 18 March 2010,[53][54] but after several delays, it finally opened to the public on 27 April 2010.[55] The corporate suites and offices were also supposed to open from March onwards,[56] yet the hotel and observation deck remained the only parts of the building which were open in April 2010.
The sky lobbies on the 43rd and 76th floors house swimming pools.[57] Floors through to 108 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 is 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 are located respectively. In January 2010, it was planned that Burj Khalifa would receive its first residents from February 2010.[57][58]
A total of 57 elevators and 8 escalators are installed.[49] The elevators have a capacity of 12 to 14 people per cabin, the fastest rising and descending at up to 10 m/s (33 ft/s) for double-deck elevators. However, the world's fastest single-deck elevator still belongs to Taipei 101 at 16.83 m/s (55.2 ft/s). Engineers had considered installing the world's first triple-deck elevators, but the final design calls for double-deck elevators.[27] The double-deck elevators are equipped with entertainment features such as LCD displays to serve visitors during their travel to the observation deck.[59] The building has 2,909 stairs from the ground floor to the 160th floor.[60]
Plumbing systems[edit]
The Burj Khalifa's water system supplies an average of 946,000 L (250,000 U.S. gal) of water per day through 100 km (62 mi) of pipes.[24][61] 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.[61] The waste water system uses gravity to discharge water from plumbing fixtures, floor drains, mechanical equipment and storm water, to the city municipal sewer.[62]
Air conditioning[edit]
The air conditioning has been provided by Voltas. 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 short tons (26,000,000 lb) of melting ice in one day,[61] or about 46 MW.[clarification needed] Water is collected via a condensate collection system and is used to irrigate the nearby park.[24]
Window cleaning[edit]
To wash the 24,348 windows, totaling 120,000 m2 (1,290,000 sq ft) of glass, the building has three horizontal tracks which each hold a 1,500 kg (3,300 lb) bucket machine. Above level 109, and up to tier 27, traditional cradles from davits are used. The top of the building is cleaned by a crew who use ropes to descend from the top to gain access.[64][65]Under normal conditions, when all building maintenance units are operational, it takes 36 workers three to four months to clean the entire exterior façade.[49][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 CoxGomyl, a manufacturer of Building Maintenance Units.[67]
Elevator system[edit]
The elevator operating chart of the Burj Khalifa
- H1–H4 (4 Hotel Passenger Elevators): G, 1, 3, 5-16, 38, 39
- HS1, HS2 (2 Hotel Service Elevators): C, G, 1–39
- HS3, HS4 (2 Hotel Service Elevators): B1, C, G, 1–3
- HS5 (1 Hotel Service Elevator): C, G, 1–3
- HR1 (1 Hotel Restaurant Passenger Elevator): C, G, 1
- HF3 (1 Hotel Spa Elevator): C, G, 1, 1M, 2, 3
- HB1, HB2 (2 Ballroom Elevators): C, G, 1
- HP1–HP4 (4 Hotel Parking Elevators): B2, B1, C, G, 1, 3
- HA1–HA3 (3 Serviced Apartment Passenger Elevators): G, 1, 3, 9–16, 18–39
- R1–R3 (3 Residential Sky Lobby Shuttle Elevators): G, 43
- R4–R6 (3 Residential Sky Lobby Shuttle Elevators): G, 76
- R7–R9 (3 Residential Passenger Elevators): 43–72
- R10–R12 (3 Residential Passenger Elevators): 76–108
- RP1, RP2 (2 Residential Parking Elevators): B2, B1, C, G, 1
- OB1, OB2 (2 Corporate Suite & Observatory Shuttle Elevators, Double Deck): C/G, 123/124
- BO1–BO3 (3 Corporate Suite Passenger Elevators): 112–123
- BO4–BO6 (3 Corporate Suite Passenger Elevators): 123–135, 139–154
- OP1, OP2 (2 Corporate Suite Parking Elevators): B2, B1, G, 1
- BS1/F (1 Firemen & Service Elevator): C, G, 1–40, 42–73, 75–136, 138
- BS2/F (1 Service Elevator): C, G, 1–40, 42–73, 75–109, 111
- BS3/F (1 Service Elevator): 138–160
Features[edit]
The Dubai Fountain[edit]
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Outside, WET Enterprises designed a fountain system at a cost of Dh 800 million (US$217 million). Illuminated by 6,600 lights and 50 coloured projectors, it is 270 m (900 ft) long and shoots water 150 m (500 ft) into the air, accompanied by a range of classical to contemporary Arabic and world music. It is the world's second largest choreographed fountain.[68] On 26 October 2008, Emaar announced that based on results of a naming contest the fountain would be called the Dubai Fountain.[69]
Observation deck[edit]
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An outdoor observation deck, named At the Top, opened on 5 January 2010 on the 124th floor. At 452 m (1,483 ft), it was the highest outdoor observation deck in the world when it opened.[70] Although it was surpassed in December 2011 by Cloud Top 488 on the Canton Tower, Guangzhou at 488 m (1,601 ft),[71] Burj Khalifa opened the 148th floor SKY level at 555 m (1,821 ft), once again giving it the highest observation deck in the world on 15 October 2014.[28][29] This was until the Shanghai Tower opened in June 2016 with an observation deck at a height of 561 metres. The 124th floor observation deck also features the electronic 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.[72][73][74] 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 on tickets purchased on the spot.[75]
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.[76][77] Despite rumours of the observation deck reopening for St. Valentine's Day (14 February),[78] it remained closed until 4 April 2010.[79][80][81] During low tides and clearness, people can see the shores of Iran from the top of the skyscraper.[82]
Burj Khalifa park[edit]
Burj Khalifa is surrounded by an 11 ha (27-acre) park designed by landscape architects SWA Group.[83] Like the tower, the park's design was based on the flower of the Hymenocallis, a desert plant.[84] At the centre of the park is the water room, which is a series of pools and water jet fountains. Benches and signs incorporate images of Burj Khalifa and the Hymenocallis flower.[85]
The plants are watered by water collected from the building's cooling system. The system provides 68,000,000 L (15,000,000 imp gal) annually.[85] WET Enterprises, who also developed the Dubai Fountain, developed the park's six water features.[86]
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