sources from www.YouTube.com
Burj Dubai is currently under construction.
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 man-made 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.
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 who worked with Skidmore, Owings and Merrill (SOM) until 2006. The architecture and engineering firm SOM is in charge of the project. The primary builders are Samsung Engineering & Construction and Besix along with Arabtec. Turner Construction Company was chosen as the construction manager.
The total budget for the Burj Dubai project is about US$4.1 billion 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).
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). 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.
Picture: sources from www.jaradite.com
History of height increases
A small comparison of the Burj Dubai's height between 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, considering the building seeks to acquire the designation as 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, 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.
Burj Dubai aerial closeup in March 2008.The tower is being constructed by a South Korean company, Samsung Engineering & Construction 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. 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.
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).
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.
extracted from: wikipedia official website (www.wikipedia.com)
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