The Burj Dubai is a skyscraper currently being constructed in Dubai, United Arab Emirates. Construction began in September 2004 and is expected for completion by late 2008.^[1] Estimated construction costs are US$1 billion^[2] requiring 22 million man-hours^[3].

While the building has yet to be completed it is already the tallest man-made structure on Earth.^[4] The final height is clouded in secrecy. According to the architecture and engineering firm in charge of the project, Skidmore, Owings & Merrill (SOM), the height is kept secret to ensure no other building adds more height to outdo their tower in the process.

The developer, Emaar Properties, wants 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. Estimates on the finished height vary from 2,300 feet^[5] (701 m) to over 3,000 feet^[6] (914 m).

The word “burj” in Arabic means, “tower,” so in translation the Burj Dubai is the Dubai Tower. It is to be the centerpiece of a larger Dubai construction project including the world’s largest mall and swimming pool, with estimated construction costs of US$20 billion.^[7]

Contents 1 Construction History 1.1 Key Players 1.2 Architectural Design and Layout 1.3 Preparing the Foundation 1.4 Jump Forming 1.5 Pumping the Concrete 1.6 Window Technology 1.7 Elevators 1.8 In Case of Emergency 1.9 Protests/Strikes 2 Equipment Used 3 References

[edit] Construction History

[edit] Key Players

The Burj Dubai’s project developer is Emaar Properties, the largest land and real estate developer in the gulf region.^[8] 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.^[9] The key architect on the project was Adrian Smith, an SOM employee until 2006.

The construction process is being 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.^[10]

[edit] Architectural Design and Layout

The tower’s design was based on a desert flower native to the region, known as the Hymenocallis genus.^[11] 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. ^[12]

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.”^[13]

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.”^[14]

The tower will include 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 Dubai website says the hotel will consist of the first 17 floors^[15], while other sources claim it will utilize the first 37 floors^[16].

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

[edit] Preparing the Foundation

The Burj Dubai sits on a concrete podium of 192 piles, each of which sits 164 feet (50 m) deep.^[17] A total of 58,500 cubic yards (44,726 m³) of concrete was used in the foundation, weighing 110,000 tons.^[18]

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 Dubai 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.^[19]

[edit] Jump Forming

In building the Burj Dubai, 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.^[20]

Essentially, the Burj Dubai ends up being cast in concrete layer by layer like a wedding cake.^[21]

[edit] Pumping the Concrete

Pumping concrete for skyscrapers becomes more and more difficult with each consecutive floor. (The Burj Dubai currently holds the world record for highest pump height, which continues to grow floor by floor.) Also, pouring concrete in Dubai is more difficult than most projects because of the extremely hot and humid temperatures.

It is because of these factors that the consistency of the concrete be exact. Any variance in mixture could severely alter the concrete’s ability to withstand the great pressure necessary to be successful. It could also create concrete incapable of being pumped to great heights.

To aid the cooling process, concrete is pumped and poured at night when temperatures are cooler. Ice is even added to mixture to help the process. Properly cooled concrete cures evenly, eliminating cracks that could put the whole tower in jeopardy. They need 630 horsepower concrete pumps to cope with the 25 tons of concrete contained in each pipe. Even with that much power it takes approximately 40 minutes for the concrete to travel 155 floors.^[22]

A new floor is completed every three days.^[23]

Putzmeister AG, of Aichtal, Germany, has 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 would need to be taken beyond air conditioning.

Special two-paned windows were designed for use in the Burj Dubai. 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 will be covered in 30,000 glass panels or enough to cover 17 soccer fields. ^[24]

[edit] Elevators

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 Dubai is expected to have anywhere from 53^[25] to 56^[26] double deck elevators capable of holding as many as 42^[27] or 46^[28] passengers.

Sources vary on the max speed capacity of the elevators. Some claim they will reach speeds of 26 miles (42 km) per hour ^[29], others claim 35 miles (56 km) per hour capable of traveling 120 floors in 50 seconds^[30], while the Burj Dubai official site claims they will peak at 40 miles (64 km) per hour.

[edit] In Case of Emergency

The Burj Dubai 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.^[31] 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.^[32]

[edit] Equipment Used

• Articulated dump truck
• Boring machine
• Concrete mixer
• Concrete pump
• Crawler loader
• Hydraulic excavator
• Kangaroo crane
• Tower crane
• Wheel loader

[edit] References

1. ↑ Christopher, Jim. The Sky's The Limit. Primavera.com, 2008-09-23.
2. ↑ Official Burj Dubai website, 2008-09-23.
3. ↑ Emaar Properties. Burj Dubai reaches a record high, July, 2007. (accessed: 2008-09-23)
4. ↑ Emaar Properties. Burj Dubai surpasses KVLY-TV mast to become the world's tallest man made structure, April, 2008. (accessed: 2008-09-23)
5. ↑ MacLeod, Scott. On Top of the World. Time/CNN, July, 2007. (accessed: 2008-09-23)
6. ↑ Discovery Channel Megabuilders: Burj Dubai, 2008-09-23.
7. ↑ Official Burj Dubai website, 2008-09-23.
8. ↑ Christopher, Jim. The Sky's The Limit. Primavera.com, 2008-09-23.
9. ↑ Official Skidmore, Owings & Merrill website, 2008-09-23.
10. ↑ Turner Internationl. Projects: Burj Dubai, 2008-09-23.
11. ↑ Dowdey, Sarah. Whats the new tallest building in the world? How Stuff Works Inc., 2008-09-23.
12. ↑ Emporis.com Burj Dubai, 2008-09-23.
13. ↑ AndrewBlum.net The Ultrabuilder: Bill Baker. Wired, November, 2007. (accessed: 2008-09-23)
14. ↑ Official Burj Dubai website, 2008-09-23.
15. ↑ Official Burj Dubai website, 2008-09-23.
16. ↑ Christopher, Jim. The Sky's The Limit. Primavera.com, 2008-09-23.
17. ↑ Emporis.com Burj Dubai, 2008-09-23.
18. ↑ Emporis.com Burj Dubai, 2008-09-23.
19. ↑ National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
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. ↑ National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
24. ↑ National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
25. ↑ National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
26. ↑ Reuters Burj Dubai becomes tallest building on earth, July, 2007. (accessed: 2008-09-23)
27. ↑ Official Burj Dubai website, 2008-09-23.
28. ↑ National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
29. ↑ Dark Roasted Blend Burj Dubai: Now the Tallest Building in the World, May, 2007. (accessed: 2008-09-23)
30. ↑ National Geographic, Building the Burj Dubai: Big, Bigger, Biggest
31. ↑ Krane, Jim. Workers Riot at Site of Dubai Skyscraper. Breitbart.com, March, 2006. (accessed: 2008-09-23)
32. ↑ Krane, Jim. Workers Riot at Site of Dubai Skyscraper. Breitbart.com, March, 2006. (accessed: 2008-09-23)