History and museums
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. It is the tallest structure in the world, standing at 829.8 m (2,722 ft).
Construction of the Burj Khalifa began in 2004, with the exterior completed 5 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 build 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 named in honour of the ruler of Abu Dhabi and president of the United Arab Emirates, Khalifa bin Zayed Al Nahyan; 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 of Burj Khalifa is derived from patterning systems embodied in Islamic architecture, incorporating cultural and historical elements particular to the region, such as in the Great Mosque of Samarra. The Y-shaped plan is designed for residential and hotel usage. A buttressed core structural system is used to support the height of the building, and the cladding system is designed to withstand Dubai's 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. However, the labour issues during construction were controversial, since the building was built primarily by workers from South East Asia, who were allegedly treated poorly.
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, 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 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 tower's construction was done by the construction division of Al Ghurair Investment group.
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. The tower was known as Burj Dubai ("Dubai Tower") until its official opening in January 2010. 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. In 2000s, Dubai started diversifying its economy but it suffered from an economic crisis in 2007–2010, leaving large scale projects already in construction abandoned.
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 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. 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.
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. 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." A revised completion date of 2 December 2009 was then announced. However, Burj Khalifa was opened on 4 January 2010, more than a month later.
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. Proportionally, the design uses half the amount of steel used in the construction of the Empire State Building due to the tubular system. Its design is reminiscent of Frank Lloyd Wright's vision for The Illinois, a mile-high skyscraper designed for Chicago. 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.
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. Hyder was selected for their expertise in structural and MEP (mechanical, electrical and plumbing) engineering. Hyder Consulting's role was to supervise construction, certify SOM's design, and be the engineer and architect of record to the UAE authorities. 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, 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. According to the structural engineer, Bill Baker of SOM, the building's design incorporates cultural and historical elements particular to the region such as the spiral minaret. The spiral minaret spirals and grows slender as it rises. The Y-shaped plan is ideal for residential and hotel usage, with the wings allowing maximum outward views and inward natural light. 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. 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).
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".
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.
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.
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, featuring 196 bronze and brass alloy cymbals representing the 196 countries of the world. It was planned that the visitors in this lobby would 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.
The cladding system is designed to withstand Dubai's extreme summer temperatures, and consists of 142,000 m2 (1,528,000 sq ft) of reflective glazing, and aluminium and textured stainless steel spandrel panels with vertical tubular fins. Over 26,000 glass panels were used in the exterior cladding of Burj Khalifa, and more than 300 cladding specialists from China were brought in for the cladding work on the tower. 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).
The exterior temperature at the top of the building is thought to be 6 °C (11 °F) cooler than at its base.
A 304-room Armani Hotel, the first of four by Armani, occupies 15 of the lower 39 floors. The hotel was supposed to open on 18 March 2010, but after several delays, it finally opened to the public on 27 April 2010. The corporate suites and offices were also supposed to open from March onwards, 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. 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 is located respectively. In January 2010, it was planned that Burj Khalifa would receive its first residents from February 2010.
A total of 57 elevators and 8 escalators are installed. 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. The double-deck elevators are equipped with entertainment features such as LCD displays to serve visitors during their travel to the observation deck. The building has 2,909 stairs from the ground floor to the 160th floor.
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 centres 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.
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. 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. The waste water system uses gravity to discharge water from plumbing fixtures, floor drains, mechanical equipment and storm water, to the city municipal sewer.
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. 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, or about 46 MW. 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.
To wash the 24,348 windows, totaling 120,000 m2 (1,290,000 sq ft) of glass, 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, and 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 on ropes to clean and inspect the top of the pinnacle. 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.
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. The contract for building the state-of-the-art machines was won by Australian company Cox Gomyl.
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. On 26 October 2008, Emaar announced that based on results of a naming contest the fountain would be called the Dubai Fountain.
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. Although it was surpassed in December 2011 by Cloud Top 488 on the Canton Tower at 488 m (1,601 ft), 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. The 124th floor observation deck also features the Tellscope 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. 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.
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. Despite rumours of the observation deck reopening for St. Valentine's Day (14 February), it remained closed until 4 April 2010. During low tides and clearness, people can see the shores of Iran from the top of the skyscraper.
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 Enterprises, who also developed the Dubai Fountain, developed the park's six water features.
The following is a breakdown of floors.
The tower was constructed by Samsung C&T from South Korea, who also did work on the Petronas Twin Towers and Taipei 101. Samsung C&T 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 (manual structural analysis professionals which used Flash Analysis authored by Allen Wright), is jointly and severally liable for the performance of Burj Khalifa.
The primary structure is reinforced concrete. Putzmeister created a new, super high-pressure trailer concrete pump, the BSA 14000 SHP-D, for this project. 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. In May 2008 Putzmeister pumped concrete with more than 21 MPA ultimate compressive strength of gravel that would surpass the 600 meters weight of the effective area of each column from the foundation to the next fourth level, and the rest is by metal columns jacketed or covered with concreted 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.
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. The foundation is designed to support the total building weight of approximately 450,000 tonnes (500,000 short tons; 440,000 long tons) 4,500 MegaNewtons or 4,500 MegaPascal. This weight is then divided by the compressive strength of concrete of which is 30 MPa which yield a 450 sq.meters of vertical normal effective area which then yield to a 12 meters by 12 meters dimensions. A high density, low permeability concrete was used in the foundations of Burj Khalifa in which the Ultimate Compressive Strength reach as much as 30 MPa, an effective area in which concrete is sandwiched by the pile, the column is 12 meters by 12 meters and the thickness as low as possible. A cathodic protection system under the mat is used to minimise any detrimental effects from corrosive chemicals in local ground water.
The 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 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). He estimated the total cost for the project to be about US$1.5 billion.
The project's completion coincided with the global financial crisis of 2007–2012, and with vast overbuilding in the country; this 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.
Because of 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, 825 were still empty at that time. However, over the next two and a half years, overseas investors steadily began to purchase the available apartments and office space in Burj Khalifa. By October 2012, Emaar reported that around 80% of the apartments were occupied.
The opening of Burj Khalifa was held on 4 January 2010. The ceremony featured a display of 10,000 fireworks, light beams projected on and around the tower, and further sound, light and water effects. The celebratory lighting was designed by UK lighting designers Speirs and Major. Using the 868 powerful stroboscope lights that are integrated into the façade and spire of the tower, different lighting sequences were choreographed, together with more than 50 different combinations of the other effects.
The event began with a short film which depicted the story of Dubai and the evolution of Burj Khalifa. The displays of sound, light, water and fireworks followed. The portion of the show consisting of the various pyrotechnic, lighting, water and sound effects was divided into three. The first part was primarily a light and sound show, which took as its theme the link between desert flowers and the new tower, and was co-ordinated with the Dubai Fountain and pyrotechnics. The second portion, called 'Heart Beat', represented the construction of the tower in a dynamic light show with the help of 300 projectors which generated a shadow-like image of the tower. In the third act, sky tracers and space cannons enveloped the tower in a halo of white light, which expanded as the lighting rig on the spire activated.
The ceremony was relayed live on a giant screen on Burj Park Island, as well as several television screens placed across the Downtown Dubai development. Hundreds of media outlets from around the world reported live from the scene. In addition to the media presence, 6,000 guests were expected.
In June 2010, Burj Khalifa was the recipient of the 2010 "Best Tall Building Middle East & Africa" award by the CTBUH. On 28 September 2010 Burj Khalifa won the award for best project of year at the Middle East Architect Awards 2010.
A new award was bestowed on the Burj Khalifa by the CTBUH at its annual "Best Tall Buildings Awards Ceremony" on 25 October 2010 when the building was honored as first recipient of CTBUH’s new Tall Building "Global Icon" Award. According to the CTBUH, the new "Global Icon" award recognises 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:
Beside these awards, Burj Khalifa was the recipient of following awards.
The building has been used by several experienced BASE jumpers for both authorised and unauthorised BASE jumping:
On 28 March 2011, Alain "Spiderman" Robert scaled the outside of Burj Khalifa. The climb to the top of the spire took six hours. To comply with UAE safety laws, Robert, who usually climbs in free solo style, used a rope and harness for the climb.
Within 17 months of the building's official opening, a man described as "an Asian in his mid-30s" who worked at one of the companies in the tower, died by suicide on 10 May 2011 by jumping from the 147th floor. He fell 39 floors, landing on a deck on the 108th floor. Dubai police confirmed the act as a suicide, reporting that "[they] also came to know that the man decided to commit suicide as his company refused to grant leave."
The Daily Mail reported that on 16 November 2014, Laura Vanessa Nunes, a Portuguese national who was in Dubai on a tourist visa, fell to her death from Burj Khalifa's "At the Top" observation deck on the 148th floor. However, on 18 May 2015, Dubai police disputed the report made by the Daily Mail on this incident and said that this incident took place in Jumeirah Lakes Towers.
The Burj Khalifa was built primarily by workers from South Asia and East Asia. This is generally because the current generation of UAE locals prefer governmental jobs and do not have a good attitude towards private sector employment. On 17 June 2008, there were 7,500 skilled workers employed at the construction site. Press reports indicated in 2006 that skilled carpenters at the site earned £4.34 a day, and labourers earned £2.84. According to a BBC investigation and a Human Rights Watch (HRW) report, the workers were housed in abysmal conditions, and worked long hours for low pay. During the construction of Burj Khalifa, only one construction-related death was reported. However, workplace injuries and fatalities in the UAE are "poorly documented", according to HRW.
On 21 March 2006, about 2,500 workers, who were upset over buses that were delayed for the end of their shifts, protested and triggered a riot, damaging cars, offices, computers and construction equipment. A Dubai Interior Ministry official said the rioters caused almost £500,000 in damage. Most of the workers involved in the riot returned the following day but refused to work.