Equipment Specs
Content
Languages

Burj Khalifa

From RitchieWiki

Projects > Buildings
The Burj Khalifa, Partially Lit Up At Night
The Burj Khalifa, formerly known as the Burj Dubai, is a skyscraper in Dubai, United Arab Emirates. Construction began in September 2004, and the tower was officially opened on January 4, 2010.[1] Estimated construction costs were US$1.5 billion[2] requiring 22 million man-hours[3].

No matter how you measure it, the Burj Khalifa is the tallest man-made structure on Earth. The developer, Emaar Properties, wanted the tower to be the world’s largest building according to all four criteria set out by the Chicago-based Council on Tall Buildings and Urban Habitat. These criteria include height of the structural top of the building, its highest occupied floor, height to the top of the roof and to the tip of the building’s spire or flagpole. The official height, which was a closely guarded secret during construction, was announced during the official opening as 2716.5 ft (828 m).

The word “burj” in Arabic means, “tower,” so in translation the Burj Khalifa is the Khalifa Tower. It is to be the centerpiece of a larger Dubai construction project including the world’s largest mall, with estimated construction costs of US$20 billion.[4]

Contents

[edit] Construction History

[edit] Key Players

The Burj Khalifa’s project developer was Emaar Properties, the largest land and real estate developer in the gulf region.[5] They employed Skidmore, Owings & Merrill (SOM) to develop the tower’s design. SOM, since its establishment in 1936, has completed more than 10,000 architecture, engineering, interior design, and planning projects in over 50 countries.[6] The key architect on the project was Adrian Smith, an SOM employee until 2006.

The construction process was carried out by Korean company Samsung Engineering and Construction, who were also involved in the building of the Petronas Twin Towers in Malaysia. Turner Construction Co. is the project’s construction manager.

Turner is involved a wide variety of services including preconstruction consulting, program management, project management and construction management for all building market segments.[7]

[edit] Architectural Design and Layout

Tower cranes working atop the Burj Khalifa
The tower’s design was based on a desert flower native to the region, known as the Hymenocallis genus.[8] Apparently the designers were inspired by the flower’s spidery, layered form. The Burj also displays subtle references to the onion-shaped domes of Islamic architecture. [9]

The tower is a modular Y-shaped structure, with setbacks along each of its three wings. With three separate wings, the building utilizes what is called a “buttressed core,” which is described as:

“Three structural ‘wings’ extend out of a central hub. The wings provide support for the building, and the core keeps the wings firmly anchored so they don't twist in the wind.”[10]

Wind resistance was essential to the tower’s design. To ensure the safety of the design, numerous wind tunnel tests were undertaken. In fact, the building was apparently put through a thorough review process.

“All major technical aspects of the project were examined by experts in tall building design to confirm the safety and effectiveness of the structural systems. This extensive program included three separate peer review programs on the project’s geotechnical engineering, wind engineering/testing, and structural engineering.”[11]

The tower includes the first Armani Hotel, which will be designed entirely by Giorgio Armani. However, the size of the hotel varies between sources. An article on the official Burj Khalifa website says the hotel will consist of the first 17 floors[12], while other sources claim it will utilize the first 37 floors[13].

An outdoor swimming pool is located on the 78th floor, a lobby on the 123rd, and the 124th floor will has an indoor/outdoor observation deck. The remaining floors will be individually owned apartments, as well as suites and corporate offices.

The Burj Khalifa under construction

[edit] Preparing the Foundation

The Burj Khalifa sits on a concrete podium of 192 piles, each of which sits 164 feet (50 m) deep.[14] A total of 58,500 cubic yards (44,726 m3) of concrete was used in the foundation, weighing 110,000 tons.[15]

Building a foundation this large is extremely important because otherwise the tower may sink into the unstable desert sand. There is some rock at the Burj Khalifa site, but it is fragile and saturated with ground water making it incapable of withstanding a lot of weight.

So, large boreholes were dug 164 feet (50 m) deep and then filled with viscous polymer slurry to maintain the stability of the hole. The slurry is denser than water, but lighter than concrete. The concrete, when poured into the hole, displaces the slurry and hardens to form a foundation pile.[16]

[edit] Jump Forming

In building the Burj Khalifa, the construction company utilized a process known as jump forming. It is a process whereby strong concrete walls can be made quickly and efficiently using hydraulic molds.

It begins at the floor of the site with steel workers building large steel cages, which will form the backbone of the floors and walls. These cages are lifted by kangaroo cranes up to the required height and placed in special molds called jump forms. Concrete is then poured into the mold. Twelve hours later, when the concrete has hardened, hydraulic pistons push the mold (jump form) up leaving a new portion of wall. It takes about two hours for the form to elevate to the next level.[17]

Essentially, the Burj Khalifa was cast in concrete, layer-by-layer, like a wedding cake.[18]

[edit] Pumping the Concrete

Pumping concrete for skyscrapers becomes more and more difficult with each consecutive floor. (The Burj Khalifa currently holds the world record for highest pump height, at 1985 feet (605 meters)).[19] Also, pouring concrete in Dubai is more difficult than most projects because of the extremely hot and humid temperatures.

Due to these factors, the consistency of the concrete had be exact. Any variance in mixture could severely alter the concrete’s ability to withstand the great pressure necessary to be structurally sound. It could also create concrete incapable of being pumped to great heights.

To aid the cooling process, concrete was pumped and poured at night when temperatures were cooler. Ice was even added to mixture to help the process. Properly cooled concrete cures evenly, eliminating cracks that could put the whole tower in jeopardy. They used 630 horsepower concrete pumps to cope with the 25 tons of concrete contained in each pipe. Even with that much power it took approximately 40 minutes for the concrete to travel 155 floors.[20]

During the peak of construction, a new floor was completed every three days.[21]

Putzmeister AG, of Aichtal, Germany, provided concrete pumps, pipelines, and booms.

[edit] Window Technology

When constructing any skyscraper the control of heat is an extremely important factor. With the introduction of air conditioning builders were able to avoid their towers becoming large glass greenhouses cooking the people inside. However, the heat of Dubai, which reaches 104 degrees Fahrenheit in the shade with 90 percent humidity, as well as the height of the tower means new measures needed to be taken beyond air conditioning.

Special two-paned windows were designed for use in the Burj Khalifa. The outside face reflects daily solar heat. It is coated with a thin layer of metal, which deflects ultra-violet radiation. However, this first pane is useless again infrared radiation. So, the inner pane is coated with a thin layer of silver, which keeps the infrared rays out.

The building is covered in 30,000 glass panels; enough to cover 17 soccer fields. [22]

[edit] Elevators

Construction continues
With such a large building, capable of holding as many as 35,000 people at any one time, transportation is of the utmost importance. The Burj Khalifa has 57[23] double deck elevators capable of holding as many as 42[24] or 46[25] passengers.  These elevators feature LCD screens and dramatic music for entertainment, and climb at a speed of 22.4 mph (36 kmph).  The main service elevator can travel 504 meters, which is the most of any elevator in the world.[26]

[edit] In Case of Emergency

The Burj Khalifa is equipped with state of the art emergency facilities. The tower was designed with nine refuge rooms in case of any emergency. They are constructed with layers of reinforce concrete and fireproof sheeting that can withstand the heat of a fire for two hours. Each room receives a special supply of oxygen pumped in through fire resistant pipes. Every room is enclosed with fireproof doors to ensure no smoke will leak in.

The tower is also outfitted with a fire early warning system that is activated by smoke detectors. In the case of a fire occurring, sprinklers will be activated and high-powered fans, located in the stairwells, kick in to clear evacuation routes of smoke. The fans pump in cool air through fire resistant ducts.

[edit] Protests/Strikes

On March 21st, 2006, 2,500 migrant laborers walked off Dubai construction sites and rioted for increased pay. Skilled carpenters were being paid US$7.60 per day while laborers were paid US$4 per day.[27] The workers demanded better wages, overtime pay, improved medical care, and better treatment from their foremen. All workers were employed by a Dubai based firm called Al Naboodah.

The rioting workers beat security officers, smashed computers and files in offices, and destroyed about two dozen cars and construction machines at a cost of about $1 million in damages.[28]

[edit] 2009 Dubai Financial Crisis

Near the end of 2009, mainstream media reports indicated that Dubai was undergoing financial distress.  Without outside assistance, Dubai would become illiquid and unable to make payments to settle its debt.[29]  A default on debt would put a hault to Dubai's other massive construction projects, including The Globe Islands.  On December 21, 2009, Dubai got the assistance it required in the form of a $10billion bailout from Sheikh Khalifa bin Zayed al-Nahyan, head of the entire United Arab Emirates and ruler of the neighboring state Abu Dhabi.[30]

[edit] Grand Opening and Name Change

The Burj Khalifa was opened with a lavish ceremony on January 4, 2010.  The ceremony included a 10 minute fireworks display; where due to the building's massive size, some fireworks were actually discharged downwards towards the audience.[31]  The official height of the building, 2716.5 ft (828 m), was revealed when the number was projected onto the building's side.[32]

Dubai's leader, Sheikh Mohammed, made a surprise announcement during the opening; indicating the name of the tower would be changed from the Burj Dubai to the Burj Khalifa, in honour of Sheikh Khalifa bin Zayed al-Nahyan and the $10billion bailout his government provided to Dubai in December, 2009.[33]

[edit] Equipment Used

[edit] Unique Facts

[edit] World Records

  • Tallest building in the world
  • Tallest free-standing structure in the world
  • Highest number of stories in the world
  • Highest occupied floor in the world
  • Highest outdoor observation deck in the world
  • Elevator with the longest travel distance in the world
  • Tallest service elevator in the world
  • Highest mosque in the world

[edit] Other Facts

  • The Burj Khalifa's spires can be seen from up to 59 miles (95 km) away
  • During peak of construction, 12,000 workers were employed on the Burj Khalifa project
  • 28,261 glass cladding panels adorn the buildings exterior.  Cleaning these panels is a three month task for a crew of 36 workers.
  • 31,400 metric tonnes of steel rebar was used in the Burj Khalifa's structure
  • Volume of concrete used was 11,650,000 cubic feet
  • Number of parking spots: 3000
  • Maximum occupency: 12000
  • Number of apartments: 1044
  • Total area: 5.7 million sqft
  • Residential area: 1.83 million sqft
  • Office area: 300,000 sqft

[edit] References

  1. Christopher, Jim. The Sky's The Limit. Primavera.com, 2008-09-23.
  2. Dubai opens world's tallest building 680 News [January 7, 2009].
  3. Emaar Properties. Burj Dubai reaches a record high, July, 2007. (accessed: 2008-09-23)
  4. Official Burj Dubai website, 2008-09-23.
  5. Christopher, Jim. The Sky's The Limit. Primavera.com, 2008-09-23.
  6. Official Skidmore, Owings & Merrill website, 2008-09-23.
  7. Turner Internationl. Projects: Burj Dubai, 2008-09-23.
  8. Dowdey, Sarah. Whats the new tallest building in the world? How Stuff Works Inc., 2008-09-23.
  9. Emporis.com Burj Dubai, 2008-09-23.
  10. AndrewBlum.net The Ultrabuilder: Bill Baker. Wired, November, 2007. (accessed: 2008-09-23)
  11. Official Burj Dubai website, 2008-09-23.
  12. Official Burj Dubai website, 2008-09-23.
  13. Christopher, Jim. The Sky's The Limit. Primavera.com, 2008-09-23.
  14. Emporis.com Burj Dubai, 2008-09-23.
  15. Emporis.com Burj Dubai, 2008-09-23.
  16. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  17. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  18. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  19. Dubai hits the heights again. The Star [January 7, 2010].
  20. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  21. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  22. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  23. Dubai hits the heights again. The Star [January 7, 2010].
  24. Official Burj Dubai website, 2008-09-23.
  25. National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
  26. Dubai hits the heights again. The Star [January 7, 2010].
  27. Krane, Jim. Workers Riot at Site of Dubai Skyscraper. Breitbart.com, March, 2006. (accessed: 2008-09-23)
  28. Krane, Jim. Workers Riot at Site of Dubai Skyscraper. Breitbart.com, March, 2006. (accessed: 2008-09-23)
  29. Dubai financial crisis reverberates across the globe. DailyStar.com [January 7, 2010].
  30. Dubai's Burj Khalifa: Built out of opulence; named for its saviour. The Globe and Mail [January 7, 2010].
  31. Dubai ruler officially opens world's tallest building. 24Dunia.com [January 7, 2010].
  32. Dubai opens half-mile-high tower, world's tallest. News.Yahoo.com [January 7, 2009].
  33. Dubai's Burj Khalifa: Built out of opulence; named for its saviour. The Globe and Mail [January 7, 2010].

[edit] External Links