Burj Khalifa

FACTSFact sheet

01A height kept secret

When Emaar began excavating the site, in January 2004, the building about to become the tallest in the world was Taipei 101, in Taiwan, at 509 meters, opened at the end of that year. The Dubai tower would be the centerpiece of an entire district, Downtown Burj Dubai, with a mall, an artificial lake and apartment buildings, and it had to beat Taipei by a wide margin. By how much, nobody would say. In 2008, the engineers themselves wrote that the final height was a closely guarded secret.

The design came out of the Chicago firm Skidmore, Owings & Merrill. Architect Adrian Smith drew a three-armed plan which, according to SOM, was inspired by a desert flower and by the spiral imagery of Islamic architecture. The construction was awarded to a consortium led by South Korea's Samsung C&T, with Belgium's BESIX and the Emirati firm Arabtec, after eleven months of bidding, according to Gulf News.

02Confusing the wind

Above 500 meters, a building's enemy is not weight, it is wind. When air flows around a tower, it forms vortices that shed first from one side, then from the other, and push the building sideways in a regular rhythm. If that rhythm repeats from the ground to the top, the tower sways. Engineer William F. Baker, of SOM, answered with a structure he called a buttressed core: a hexagonal concrete core at the center and three wings, each with its own walls and columns, bracing one another like the legs of a tripod.

The wings do not rise evenly. They step back in a clockwise spiral, and the width of the tower changes at each setback. In the words of Baker and his colleagues, the advantage of the shape is that it confuses the wind: the vortices never get organized, because at each level the wind meets a different building. The tests were carried out in RWDI's wind tunnel, in Guelph, Canada, with models almost all at a scale of 1 to 500. After each round of tests, according to the engineers, the data were analyzed and the building was redesigned; they changed the number of setbacks, the spacing between them and the shape of the wings.

03Weak rock and water saltier than the sea

Beneath Dubai's sand there is no solid rock at shallow depth, only weak sandstone and siltstone. The site investigation went as deep as a 140-meter borehole. The solution was a raft, a reinforced-concrete slab 3.7 meters thick, poured in four stages of at least 24 hours each, on bored piles 1.5 meters in diameter and about 43 meters long. They do not reach hard rock: they hold the tower up by friction with the surrounding ground. The SOM engineers speak of 194 piles; other sources, of 192.

The worst of it was the water. According to SOM, the groundwater had up to 4.5% chlorides and 0.6% sulfates, concentrations higher than those of seawater, which corrode the steel reinforcement and break down ordinary concrete. The foundation was given special waterproofing, thicker concrete cover over the reinforcement, a corrosion inhibitor in the mix and a cathodic protection system: a titanium mesh under the raft, connected to an electric current that keeps the structure's metal from being the side that rusts.

04Concrete at night, with ice

The tower is reinforced concrete up to about 586 meters, and only above that does it turn to steel. Getting concrete all the way up there, in the Gulf summer, was another problem: the temperature tops 50 °C in the shade, and high-strength concrete can set suddenly inside the pipe and clog it. A test in February 2005 pumped concrete through 600 meters of pipe laid out on the ground, to measure the friction before going up.

On site, all the concrete for the walls and columns was poured at night. According to engineer James Aldred, of GHD, the maximum temperature allowed was 33 °C, and in summer almost all the water in the mix was flaked ice. Three Putzmeister pumps, connected to 150-millimeter steel pipes, pushed the concrete at a working pressure of 250 bar, which could reach 350 or 400. Aldred recorded 601 meters in a single stage, a world record; the manufacturer speaks of 606 meters, up to the 156th floor. The previous vertical pumping record, according to Aldred, was 532 meters, at an Italian hydroelectric plant in 1994.

With self-climbing formwork and reinforcement assembled on the ground in eight-meter sections, the structure rose, on average, one floor every three days in 2007, according to Architectural Record. On 21 July 2007, at 141 floors and 512.1 meters, Emaar announced that Burj Dubai had become the tallest building in the world. The tower would still rise more than 300 meters.

05Who raised the tower

At the peak, there were about 12,000 people on site, according to the Associated Press and Turner, the project manager; Gulf News spoke of 10,000, and Architectural Record counted 6,800 in July 2007. They were, for the most part, migrants from South Asia, from India, Pakistan, Bangladesh and Nepal. In 2006, according to the AFP news agency, a carpenter earned US$7.60 a day and a laborer US$4. A Human Rights Watch report that year on the construction industry in the Emirates described workers who paid up to US$3,000 to recruitment agencies and had their passports held by their employer.

On 21 March 2006, about 2,500 workers of Al Naboodah Laing O'Rourke, who worked on the site of the Burj and the buildings around it, rioted at the end of their shift, smashed offices and destroyed cars and machinery. The next day they came back and refused to work. In October 2007 it was the turn of Arabtec's workers, with an average wage of 700 dirhams a month, in a country where strikes and unions are banned.

How many died, there is no public record. No total from Emaar or the consortium was found published. The Gulf press reported two deaths during construction: on 15 June 2007, a worker fell from the formwork, and Emaar confirmed the death, saying there had been no breach of safety rules; on 20 May 2008, according to Arabian Business, the worker Qiwen Li was crushed by a facade panel. The same Human Rights Watch report showed that, in the Emirates of that period, Dubai Municipality recorded a few dozen construction deaths a year, while an independent count found 880 migrant deaths in the country in 2004.

06The crisis and the name

In January 2009 the tower topped out. But Dubai was in crisis. In November 2009 the state-owned Dubai World asked for a debt standstill, and on 14 December the neighboring emirate of Abu Dhabi handed over US$10 billion so that it could pay US$4.1 billion in bonds maturing that day.

Three weeks later, on 4 January 2010, Sheikh Mohammed bin Rashid Al Maktoum opened the tower and announced its name: Burj Khalifa, in honor of Sheikh Khalifa bin Zayed Al Nahyan, ruler of Abu Dhabi and president of the Emirates. The press read the change as gratitude for the bailout. Only then was the height revealed: 828 meters. The tower cost US$1.5 billion, according to the Associated Press.

07The architect against his own tower

In January 2025, after about seven years at a standstill, construction resumed in Jeddah, Saudi Arabia, on the Jeddah Tower, which aims to pass 1,000 meters. The design is by the firm Adrian Smith + Gordon Gill, of the same Adrian Smith who designed the Burj Khalifa at SOM. According to Thornton Tomasetti, the project's engineer, the Saudi tower has a concrete structure and a 5-meter raft on 270 piles.

On 2 September 2026, according to Arabian Business, it reached 454 meters and 113 floors, rising about one floor a week, with completion expected in 2028. On that date, it was still more than 370 meters short of the Burj Khalifa. If it gets there, the tallest building in the world will lose the title to a work by its own architect.

MYTHSWhat people say and what the record shows

• What people say

  Officially, only one worker died building the Burj Khalifa.

  What the record shows

  There is no public document with that total. No figure published by Emaar or by the consortium was found. The Gulf press reported two deaths during construction, in June 2007 and in May 2008.

• What people say

  The Burj Khalifa's concrete broke the pumping record held by Taipei 101.

  What the record shows

  According to the project's concrete engineer, James Aldred, the vertical pumping record before the Burj was 532 meters, at an Italian hydroelectric plant in 1994. Taipei 101 had pumped concrete to more than 470 meters. The Burj took the record to 601 or 606 meters, depending on the source.

• What people say

  The height of 828 meters was set and announced from the start.

  What the record shows

  The final height was Emaar's secret during construction; in 2008 the SOM engineers called it a closely guarded secret. It was only revealed at the opening, in January 2010.

• What people say

  The tower bears Khalifa's name because Abu Dhabi paid for it.

  What the record shows

  Abu Dhabi bailed out the government of Dubai and the state-owned Dubai World in 2009, with US$10 billion, to pay debts of Nakheel, a company of the Dubai World group. The tower belongs to Emaar. The link between the name and the bailout was the press's reading at the opening.

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SOURCESSources

1. William F. Baker, D. Stanton Korista and Lawrence C. Novak (SOM), "Engineering the World's Tallest — Burj Dubai", CTBUH 8th World Congress, Dubai, 2008 — archive.org
2. James Aldred (GHD), "Pumping concrete to 601 metres in a single lift", 2008 — thbbakademi.org
3. Lawrence C. Novak, "A Tall Adventure: The Burj Khalifa, the World's Tallest Structure", Building Safety Journal, International Code Council — iccsafe.org
4. Council on Tall Buildings and Urban Habitat, The Skyscraper Center, "Burj Khalifa" — skyscrapercenter.com
5. Skidmore, Owings & Merrill, "Burj Khalifa" — som.com
6. Turner Construction, "Burj Khalifa" — turnerconstruction.com
7. Putzmeister, "Concrete Pumps Reach Record-Breaking Heights at Burj Khalifa", Pumps & Systems, 2015 — pumpsandsystems.com
8. Associated Press, "World's tallest building opens in Dubai", January 2010 — nbcnews.com
9. David Sadighian, "Burj Dubai Breaks Record... and Keeps Going", Architectural Record, 24 July 2007 — architecturalrecord.com
10. Gulf News, "Samsung gets Burj Dubai contract", 9 December 2004 — gulfnews.com
11. Gulf News, Aya Lowe, "Keeping the Burj Dubai site safe for workers" — gulfnews.com
12. Gulf News, "Burj Dubai renamed as Burj Khalifa", 4 January 2010 — gulfnews.com
13. Al Jazeera and AFP, "Asian workers riot in Dubai", 23 March 2006 — aljazeera.com
14. Al Jazeera, "Burj Dubai owners say strike over", 12 November 2007 — aljazeera.com
15. Human Rights Watch, "Building Towers, Cheating Workers: Exploitation of Migrant Construction Workers in the United Arab Emirates", 2006 — hrw.org
16. Construction Week, "Worker dies after fall on Burj Dubai", June 2007 — constructionweekonline.com
17. Arabian Business, "Burj worker crushed to death", May 2008 — arabianbusiness.com
18. CNN, "Abu Dhabi gives Dubai $10 billion bailout", 14 December 2009 — cnn.com
19. Arabian Business, "Jeddah Tower set to become world's tallest building as construction advances towards 2028 completion", September 2026 — arabianbusiness.com
20. Adam Williams, "Future world's tallest skyscraper surpasses 100 floors in Saudi Arabia", New Atlas, 4 June 2026 — newatlas.com
21. TechEBlog, "Jeddah Tower Crosses 430 Meters and Presses On Toward the One-Kilometer Mark", 5 August 2026 — techeblog.com
22. U.S. Bureau of Labor Statistics, consumer price index (CPI-U), annual averages for 2010 and 2025 — bls.gov
23. Wikipedia, "Burj Khalifa" (starting point) — en.wikipedia.org

Images

• Fig. 01 — The tower under construction seen from a plane, in March 2008, when it was already the tallest building in the world and its final height was still a secret: Aheilner · CC BY-SA 3.0
• Fig. 02 — December 2005, the first year of the structure: the core and the wings rise together, with the cranes mounted on top: Soonadracula · CC BY-SA 3.0
• Fig. 03 — December 2007: the glass facade climbed floors below the concrete, which kept ahead along with the cranes: Joi Ito · CC BY 2.0
• Fig. 04 — The concrete top in March 2008, with the cranes that climbed along with the structure: Aheilner · CC BY-SA 4.0
• Fig. 05 — Dubai construction workers on their lunch break, in June 2008, with the tower in the background: Piotr Zarobkiewicz · CC BY-SA 3.0
• Fig. 06 — Camel racing at the Nad Al Sheba track, in March 2007, with the tower under construction behind: Ryan Lackey · CC BY 2.0