Burj Khalifa – United Arab Emirates, Asia
Burj Khalifa (“Khalifa Tower”), known as Burj Dubai prior to its inauguration, is a skyscraper in Dubai, United Arab Emirates, and is currently the tallest structure in the world, at 829.84 m (2,723 ft). 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, and is part of the new 2 km2 (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. The primary contractor was Samsung C&T of South Korea.
The total cost for the project was about US$1.5 billion; and for the entire “Downtown Dubai” development, US$20 billion. 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).
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. 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.
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.
Burj Khalifa has been designed to be the centrepiece of a large-scale, mixed-use development that would include 30,000 homes, nine hotels such as 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.
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). 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.
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. 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.
Burj Khalifa is surrounded by an 11 ha (27-acre) park designed by landscape architects SWA Group. 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. The park has six water features, gardens, palm lined walkways, and flowering trees. 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. WET designers, who also developed the Dubai Fountain, developed the park’s six water features.
The tower was constructed by South Korean company, Samsung Engineering & Construction, which also did work on the Petronas Twin Towers and Taipei 101. 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.
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 m3 (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. Burj Khalifa’s construction used 330,000 m3 (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. 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. In May 2008 concrete was pumped to a then world record delivery height of 606 m (1,988 ft), the 156th floor. Three tower cranes were used during construction of the uppermost levels, each capable of lifting a 25-tonne load. 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.
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.
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.
In June 2010, Burj Khalifa was the recipient of the 2010 Best Tall Building Middle East & Africa award by the Council on Tall Buildings and Urban Habitat. On 28 September 2010 Burj Khalifa won the award for best project of year at the Middle East Architect Awards 2010.
The Council on Tall Buildings and Urban Habitat bestowed a new award for Burj Khalifa at its annual “Best Tall Buildings Awards Ceremony” on 25 October 2010 when Burj Khalifa honored as first recipient of CTBUH’s new Tall Building “Global Icon” Award. According to CTBUH the new “Global Icon” award recognizes those very special supertall skyscrapers that make a profound impact, not only on the local or regional context, but on the genre of tall buildings globally. Which is innovative in planning, design and execution, the building must have influenced and reshaped the field of tall building architecture, engineering, and urban planning. It is intended that the award will only be conferred on an occasional basis, when merited by an exceptional project perhaps every ten or fifteen years.
CTBUH Awards Chair Gordon Gill, of Adrian Smith + Gordon Gill Architecture said:
“There was discussion amongst members of the jury that the existing ‘Best Tall Building of the Year’ award was not really appropriate for the Burj khalifa. We are talking about a building here that has changed the landscape of what is possible in architecture a building that became internationally recognized as an icon long before it was even completed. ‘Building of the Century’ was thought a more appropriate title for it”.