Burj Dubai

Burj Dubai
Aerial view of Burj Dubai on 2008-10-26
Information
Status	Under construction
Groundbreaking	September 21, 2004
Estimated completion	2009[1]
Opening	September 2009 (est.)[2]
Height
Antenna/Spire	818 m (2,684 ft)[1]
Technical details
Floor count	160 habitable floors[3]
Floor area	334,000 m2 (3,595,100 sq ft)
Companies
Architect	Skidmore, Owings and Merrill
Structural Engineer	Bill Baker at SOM[4]
Contractor	Samsung Besix Arabtec Turner
Developer	Emaar

Burj Dubai (Arabic: برج دبي‎ "Dubai Tower") is a supertall skyscraper under construction in the Business Bay district of Dubai, United Arab Emirates, and is the tallest artifical structure ever built, despite being incomplete. Construction began on September 21, 2004 and is expected to be completed and ready for occupation in September 2009.^[1][2]

The building is part of the 2 km² (0.8 sq mi) development called "Downtown Dubai", at the "First Interchange" (aka "Defence Roundabout") along Sheikh Zayed Road at Doha Street. The tower's architect is Adrian Smith^[5] who worked with Skidmore, Owings and Merrill (SOM) until 2006.^[6] The architecture and engineering firm SOM is in charge of the project.^[5] The primary builders are Samsung Engineering & Construction and Besix along with Arabtec.^[7] Turner Construction Company was chosen as the construction manager.^[8]

The total budget for the Burj Dubai project is about US$4.1 billion^[9] and for the entire new 'Downtown Dubai', US$20 billion. Mohamed Ali Alabbar, the CEO of Emaar Properties, speaking at the Council on Tall Buildings and Urban Habitat 8th World Congress, said that the price of office space at Burj Dubai had reached $4,000 per sq ft (over $43,000 per sq m) and that the Armani Residences, also in Burj Dubai, were selling for $3,500 per sq ft (over $37,500 per sq m).^[10]

Height

Current height

As of September 26, 2008, Burj Dubai had reached a height of 707 m (2,320 ft).^[11]

Current records

Burj Dubai in March 2008.

• Tallest structure: 707 m (2,320 ft) (previously KVLY-TV mast - 628.8 m (2,063 ft))
• Tallest freestanding structure: 707 m (2,320 ft) (previously CN Tower - 553.3 m (1,815 ft))
• Building with most floors: 160 (previously Sears Tower / World Trade Center - 110)^[17][3]
• Highest vertical concrete pumping (for a building): 601 m (1,972 ft) (previously Taipei 101 - 449.2 m (1,474 ft))
• Highest vertical concrete pumping (for any construction): 601 m (1,972 ft) (previously Riva del Garda Hydroelectric Power Plant - 532 m (1,745 ft)^[18])

Note: Additional records for tallest skyscraper are considered unofficial. On July 20, 2007, the head of the Council on Tall Buildings and Urban Habitat (CTBUH), Antony Wood, said "We will not classify it as a building until it is complete, clad and at least partially open for business to avoid things like the Ryungyong [sic] project. Taipei 101 is thus officially the world's tallest until that happens."^[19]

Projected height

Projected height of the completed Burj Dubai, compared to the height of some other well-known tall structures.

The projected final height of Burj Dubai is officially being kept a secret due to competition from other buildings under construction or proposed; however, figures released by a contractor on the project have suggested a height of around 818 m (2,684 ft).^[20] Based on this height, the total number of habitable floors is expected to be around 162. However, Burj Dubai's construction manager, Greg Sang, has said only that the final height would be greater than 700 m (2,297 ft), a height already exceeded, and that it would be the world's tallest free-standing structure when completed.^[21]

History of height increases

A visual comparison of the Burj Dubai's (far right) height with that of surrounding buildings at dusk.

Though unconfirmed, Burj Dubai has been rumoured to have undergone 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 with an original design by Skidmore Owings and Merrill seen above and discussed below. Contradictory information abounds regarding the official height of the building, which is to be expected given builders' plans to acquire the designation of the world's tallest structure upon completion in 2009.

The design architect, Adrian Smith, felt that the upper-most 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 currently planned height. It has been explicitly stated that this change did not include any added floors,^[22] which is fitting with Smith's attempts to make the crown more slender. However, the top of the tower has a steel frame structure, unlike the lower portion's reinforced concrete. The developer, Emaar, has stated this steel section may be extended to beat any other tower to the title of tallest; however, once the tower is complete, height increases will not be recognised.Since its conception the final height of the Burj Dubai, the world's tallest tower, one of the architects behind the mega-project told Arabian Business the Burj Dubai was designed to be 808 metres tall.^[23]

Delay

Emaar Properties announced on June 9, 2008 that construction of Burj Dubai was delayed by upgraded finishes and will be completed only in September 2009.^[2] 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".^[24]

Architecture and design

The tower is designed by Skidmore, Owings and Merrill, who also designed the Sears Tower in Chicago and the Freedom Tower in New York City, among numerous other famous high-rises. The building resembles the bundled tube form of the Sears Tower, but is not a tube structure. The design of Burj Dubai is reminiscent of the Frank Lloyd Wright vision for The Illinois, a mile high skyscraper designed for Chicago, Illinois. Emaar has also engaged GHD,^[25] an international multidisciplinary consulting firm, to assist with the design, review and assessment involved in the construction process.

Supertall cross-section comparisons.

The design of Burj Dubai is derived from patterning systems embodied in Islamic architecture, with the triple-lobed footprint of the building based on an abstracted version of the flower Hymenocallis.^[3] 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. 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. The tower, at its tallest point, sways a total of 1.2 m (3.9 ft).^[3]

The exterior cladding of Burj Dubai will consist of 142,000 m² (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, at its projected height, the exterior temperature at the top of the building will be noticeably cooler than at its base, by 6 °C (11 °F).^[26]

The interior will be decorated by Giorgio Armani. An Armani Hotel, the first of four by Armani,^[27] will occupy the lower 37 floors. Floors 45 through 108 will have 700 private apartments on 64 floors (which, according to the developer, sold out within eight hours of going on sale). An outdoor zero-entry swimming pool will be located on the 78th floor of the tower. Corporate offices and suites will fill most of the remaining floors, except for a 123rd floor lobby and 124th floor (about 440 m (1,444 ft)) indoor/outdoor observation deck. The spire—itself over 200 m (700 ft) tall—will hold communications equipment.

It will also feature the world's fastest elevator, rising and descending at 18 m/s (59 ft/s).^[28] The world's current fastest elevator (in the Taipei 101) travels at 16.83 m/s (55.2 ft/s). Engineers had considered installing the world's first triple-decker elevators, but the final design calls for double-deck elevators.^[1] A total of 56 elevators will be installed that can each carry 42 people at a time.^[5]

Dubai Fountain

Outside, and at a cost of Dh 800 million (US $ 217 m), a record setting fountain system is to be 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 colored projectors, it will be 275 m (900 ft) long and will shoot water 150 m (490 ft) into the air, accompanied by a range of classical to contemporary Arabic and world music.^[29] On October 26, 2008 Emaar announced that based on results of a naming contest the fountain would be called the Dubai Fountain.^[30]

Construction

Burj Dubai aerial closeup in March 2008.

The tower is being constructed by a South Korean company, Samsung Engineering & Construction^[31] which also built the Petronas Twin Towers and the Taipei 101. Samsung Engineering & Construction is building the tower in a joint venture with Besix from Belgium and Arabtec from UAE. Turner is the Project Manager on the main construction contract.

The primary structural system of Burj Dubai is reinforced concrete. Over 45,000 m³ (58,900 cu yd) of concrete, weighing more than 110,000 tonnes (120,000 ST/110,000 LT) were used to construct the concrete and steel foundation, which features 192 piles buried more than 50 m (164 ft) deep.^[1] When completed, Burj Dubai's construction will have used 330,000 m³ (431,600 cu yd) of concrete and 39,000 tonnes (43,000 ST/38,000 LT) of steel rebar (enough to extend over a quarter of the way around the world if laid end-to-end); and construction will have taken 22 million man hours.^[5]

As construction of the tower progresses, it becomes increasingly difficult to vertically pump the thousands of cubic metres of concrete that are required. The previous record for pumping concrete on any project was set during the extension of the Riva del Garda Hydroelectric Power Plant in Italy in 1994, when concrete was pumped to a height of 532 m (1,745 ft). Burj Dubai now holds this record as of August 19, 2007, as it has a height of 536.1 m (1,759 ft), to hold the record for concrete pumping on any project; and as of November 8, 2007 concrete was pumped to a delivery height of 601 m (1,972 ft).^[32]

Special mixes of concrete are made to withstand the extreme pressures of the massive weight of the tower; as typical with reinforced concrete construction, each batch of concrete is tested and checked to see whether it can withstand certain pressures. The head of Concrete Quality Checking on the Burj Dubai project is Alam Feroze, who is in charge of concrete on the whole project. The concrete pumps, pipelines and booms are provided by Putzmeister, of Aichtal, Germany.

The consistency of the concrete on the project is essential. It was difficult to create a concrete that could withstand the thousands of tonnes bearing down on it and also withstand Gulf temperatures that can reach 50 °C (122 °F). To combat this problem, the concrete is not poured during the day. Instead, ice is added to the mixture and it is poured at night when it is cooler and the humidity is higher. A cooler concrete mixture cures evenly throughout and therefore is less likely to set too quickly and crack. Any significant cracks could put the whole project in jeopardy.

The unique design and engineering challenges of building Burj Dubai have been featured in a number of TV 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 Dubai is being built primarily by immigrant engineers and workers from India, Pakistan, Bangladesh, China and the Philippines.^[33] Press reports indicate that skilled carpenters at the site earn US$7.60/day, and laborers earn US$4.00.^[33][34]

On March 21, 2006, around 2,500 workers upset over buses that were delayed for the end of their shifts rioted, damaging cars, offices, computers, and construction equipment.^[33] A Dubai Interior Ministry official said the rioters caused almost US$1m in damage.^[33] Most of the workers involved in the riot returned the following day but refused to work.^[33]

As of June 17, 2008 there are 7,500 skilled workers employed in the construction of Burj Dubai.^[2]

Purpose

Burj Dubai has been designed to be the centerpiece of a large-scale, mixed-use development that will include 30,000 homes, nine hotels such as the Burj Dubai Lake Hotel & Serviced Apartments, 3 hectares (7.4 acres) of parkland, at least 19 residential towers, the Dubai Mall, and the 12-hectare (30-acre) man-made Burj Dubai Lake.

The silvery glass-sheathed concrete building will return the title of Earth's tallest free-standing structure to the Middle East—a title not held by the region since 1311 CE when Lincoln Cathedral in England surpassed the height of the Great Pyramid of Giza, which had held the title for almost four millennia.

The decision to build Burj Dubai is reportedly based on the government's decision to diversify from a trade-based economy to one that is service- and tourism-oriented. According to officials, it is necessary for projects like Burj Dubai 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.^[35]

Gallery

See also

• Skyscraper design and construction
• List of buildings with 100 floors or more
• List of tallest buildings and structures in the world
• List of tallest freestanding structures in the world
• List of tallest structures in the world
• List of tallest buildings in Dubai
• List of tallest towers in Southwest Asia

References

External links

• Official website
• Skidmore, Owings & Merrill LLP, architects
• Burj Dubai Skyscraper, construction photos and information
• Emporis page on Burj Dubai
• "The Burj Dubai Tower Wind Engineering"PDF (597 KiB) (Irwin, Baker, June 2006) STRUCTURE magazine
• "The Burj Dubai Tower - Wind Channel Testing of Cladding and Pedestrian Level"PDF (620 KiB) (Erwin, etal, November 2006) STRUCTURE magazine
• Otis Worldwide, Signature Projects, information on the project's elevators at the Otis Elevator Company
• Wind and Other Studies performed by RWDI