Burj Khalifa - Every Civil Engineers dream
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| Burj Khalifa - Civil Engineers Dream Project |
Introduction:-
- Being the tallest building in the world and its beauty attracts anyone in the world.
- The edifice is located in Dubai, United Arab Emirates.
- With a total height of 829.8 m, the Burj Khalifa has been the tallest structure in the world since 2010.
- The building was built within a period of 6 years.
- The construction began on 6 January 2004 and ended in the year 2010.
- The building was earlier known as Burj Dubai but was renamed in honor of the ruler of Abu Dhabi and the president of the UAE, Khalifa Bin Zayed Al Nahyan.
Burj Khalifa Structure
- As the skyscraper has a floor plan of” Y” shape, this plan gives higher performance and provides a full view of the Persian Gulf.
- Due to the integration of aerodynamic shaping and the plan, the structure can reduce the effect of wind forces. The central core has a higher resistance to torsion.
- The total floor area of the building is 460000 sq meters.
- The whole structure is designed as a reinforced concrete building with High-Performance Concrete up to level 156 and up to the top it is designed as a structural steel braced frame.
- The C80 and C60 cube strength concrete is used with fly ash, portland cement, and the local aggregates.
- A Young’s Modulus of 43800N/mm2 is said to be granted by C80 concrete. The largest pumps in the world were used to pump concrete up to a height of 600 m at a single step
Burj Khalifa Project - height, storey, floors etc.
- 160 + storey tower
- Podium structure adjacent
- Have a six story office adjacent
- A two story pool facility near
- Concrete Used = 250000 cubic meter
- Curtain Walls = 83,600sq.m of glass and 27,900 sq.m of metal
- Steel Rebars Used = 39,000 tones
- Man-Hours = 22million man-hours
Burj Khalifa - shape of the tower
Adrian Smith is the man behind the structural and the architectural design of Burj Khalifa. The basic structure is a central hexagon core with three wings, which is clustered around it, as shown in figure-2. While moving up along the tower, one wing at each tier is set back. This makes decreasing cross section when moving up. The structure consists of 26 terraces.
Burj Khalifa - Cross section
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| Cross Section plan of Burj Khalifa |
Burj Khalifa - Structure system
The Burj Khalifa employs a ‘Y’ shaped floor plan. This plan provide higher performance and provides a full view of the Persian Gulf. The shape and the upward setbacks help the structure to reduce the wind forces that is acting on the structure. The shape was finally fixed based on the series of wind tunnel tests. The structural system employed for Burj Khalifa can be called as the Buttressed Core System. The whole system is constructed by using high performance concrete wall. Each wing buttresses the other through a hexagonal central core as shown in figure-2. The central core has a higher resistance towards the torsional resistance. The structure is more designed for wind force and related effects. There are corridor walls that extend from the central core to the end of the wing. At the end, these walls are thickened by means of hammer walls. These walls resist the wind shears and moments by acting like the web and the flanges of the beams. There are perimeter columns which are connected to the mechanical floors. The connection between the perimeter columns and the mechanical floors is provided by means of outrigger walls. This help to resists higher wind loads laterally. The outrigger depth is three storey heights. There is periodic encounter of outrigger system through the height of the tower.
Burj Khalifa - Concrete used in projects
The high-performance concrete used in Burj Khalifa guarantee low permeability and higher durability. The C80 and C60 cube strength concrete is used incorporating fly ash, Portland cement, and the local aggregates. A young’s modulus of 43800N/mm2 is said to be granted by the C80 concrete. The largest concrete pumps in the world were used to pump concrete to height up to 600 m at a single stage. Two numbers of this type of pump was used. As the temperature of the location (Dubai) is very high, there were chance of cracks due to shrinkage. So, the concrete pouring process was carried out at night at a cooler temperature. Ice was added to the concrete mix to facilitate the desired temperature. To withstand the excessive pressure caused due to the building weight, special concrete mixes were employed. Every batch was tested before placing.
Burj Khalifa - Foundation pile and raft
The superstructure of Burj Khalifa is supported over a large reinforced concrete raft. This raft is in turn supported by bored reinforced concrete piles. The raft has a thickness of 3.7m and was constructed in four separate pours. The grade of concrete raft is C50 which was self-consolidating concrete. The concrete volume used in the raft is 12,500 meter cube. The number of piles used were 194. The piles were 1.5m in diameter and have a length of 43m. Each pile has a capacity of 3000 tons. The concrete grade used in piles where C60 SCC concrete which were placed by tremie method. This utilized polymer slurry to carry out the process. To reduce the detrimental effects of chemicals, cathodic protection where provided under the raft.
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| Pile Raft Foundation in Burj Khalifa. Photos From the Construction Stage |
Did you know about :- Burj Khalifa facts
Burj Khalifa World Records
At over 828 metres (2,716.5 feet) and more than 160 stories, Burj Khalifa holds the following 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
Tallest of the Supertall - Burj Khalifa
Not only is Burj Khalifa the world's tallest building but it has also broken two other impressive records: tallest structure, previously held by the KVLY-TV mast in Blanchard, North Dakota, and tallest free-standing structure, previously held by Toronto's CN Tower. The Chicago-based Council on Tall Buildings and Urban Habitat (CTBUH) has established 3 criteria to determine what makes a tall building tall. Burj Khalifa wins by far in all three categories.
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Height to architectural top
- Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the architectural top of the building. This includes spires but does not include antennae, signage, flagpoles or other functional-technical equipment. This measurement is the most widely used and is used to define the Council on Tall Buildings and Urban Habitat rankings of the Tallest Buildings in the World.
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Highest occupied floor
- Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest continually occupied floor within the building. Maintenance areas are not included.
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Height to tip
- Height is measured from the level of the lowest, significant, open-air, pedestrian entrance to the highest point of the building, irrespective of material or function of the highest element. This includes antennae, flagpoles, signage and other functional-technical equipment.
Amazing facts about Burj Khalifa
- The skyscraper holds 900 apartments,3004 hotels, and 35 floor offices.
- The curtain wall of the whole building is equivalent to 17 football fields. It takes 3 months to 36 employees to clean the windows of the building from top to bottom
- It has 54 elevators which move with a speed of 40 miles per hour equivalent to 10 meters per second.
- Burj Khalifa is three times taller than Eiffel Tower and two times taller than the Empire State Building.
- It holds the World’s highest outdoor observation deck at about 452 meters above the ground.
- The skyscraper can be seen from a distance of 95 kilometers away from it.
- At the highest point of Burj Khalifa, visitors can enjoy the temperature different to 15 degrees lower.
The skyscraper with 163 floors is constructed within a period of 6 years.No one would have thought that the World’s tallest skyscraper would be built within a short period of time.
Burj Khalifa - Technology Used
The tower is consisted of 163 floors and followed a very tight schedule of a 3-day cycle. The key construction Technologies are-
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Auto Climbing formwork System(ACS)
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Rebar prefabrication
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High-performance concrete provides high strength, high durability, and high pumping
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Advance concrete pumping technology
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The formwork system can be dismantled and assembled quickly with minimum labor work
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Column/Wall proceeding method.
for More detail about burj khalifa visit following sites
source :
https://civilengineeringbible.com/article.php?i=281
https://theconstructor.org/structures/structural-details-burj-khalifa-concrete-grade-foundations/20512/
