- The desert-like climate of Dubai is very hot and arid. Very little rainfall (less than 4 inches, compare to New York City’s 1,200 inches or Austin’s 870) means the Burj Khalifa is in sunlight almost the entire year, causing huge problems for keeping out solar radiation. However, this dryness also means that people inside the building can tolerate higher temperatures than they would in a temperate climate.

- Because of the relatively small depth of the floor sections in the Burj Khalifa, the goal is not to get light deep into the space as would be expected in an office tower, but to allow views out of the tower.

- The type of glass used in the Burj Khalifa is Guardian Industries’ Solar Silver 20 and Guardian ClimaGuard NLT low-E. These types of glass have a relatively low  R-Values of 2.63, meaning it acts as a very efficient insulator.

- However, despite the excellent performance of this glass, with 1.8 million square feet of glass covering the building’s façade, the Burj Khalifa collects heat very easily.

 

HVAC/Water Management

- The tower is cooled via chilling towers on the ground less than 100 yards from the building. This cooled water is pumped into the building and up to the desired floor where it is used to cool air pulled inside from the upper mechanical floors of the tower (where the air is cooler and cleaner.) Air handlers spaced every 30 floors service the building’s HVAC requirements.

- The path of air through each floor varies depending on the plan and the use of the floor, but is controlled using a centralized Building Management System that work to optimize the building’s heating and cooling.

- In an attempt to conserve water in this dry climate, SOM incorporated a system that takes condensate water from the air handlers and uses that to water the nearby gardens rather than to use water from Dubai’s city system.

 

 

Monitoring and Safety

- The building is monitored using a complex GPS system that triangulates how far the building sways due to wind and seismic loads. Additionally, sensors in every room and most connections where vertical supports terminate monitor the building for cracking and fire.

- In the case of a fire, the elevators will still function to allow people to escape to the emergency rooms on 9 different floors. These fireproofed, ultrareinforced rooms are sealed from any possible air infiltration and have their own sources of oxygen.

 

Construction Process

- Day One: The double-steel reinforcement is dropped into place using a crane. Workers do not have to actually handle the reinforcement except to attach it to the floor below.

- Day Two: The wooden formworks are installed around the reinforcement.

- Day Three: Concrete is pumped using incredibly high-pressure to take the mixture from the ground to the top of the current construction phase. Once the concrete has cured, the formwork is moved to the next floor.

- Spire: like the Chrysler Building, the spire of the Burj Khalfa was constructed inside the top floors of the structure then mechanically lifted into place.

 

 

 

 

Structure

- The Burj Khalifa uses reinforced concrete as its primary structure. Special double reinforcement of high-strength structural concrete allows the building to reach such amazing heights. Because the foundation is so secure and Dubai is not in a seismically active area, the main structural consideration for lateral loading involves bracing against high wind speeds. The tower uses almost 330,000 m³ of concrete.

- Because of the strength of the materials used in the building, the structural diagram of the Burj Khalifa is actually relatively simple, acting as a monolithic bundled tube, much in the same way that the Willis Tower in Chicago behaves.

- The very top of the tower is constructed of structural steel. This allows the spire to achieve its freestanding height at 829 meters.

- Rigidity in the structure is achieved thanks to its monolithic design. Any concrete wall can act as a shear wall and the columns are integrated into the same structure as the floors.

- The diagram also shows some of how the construction process took place; after the floors were laid and the cranes had moved up to continue work on the taller parts of the structure, the floors below had already started to receive windows and finishes.

 

Wind Testing

- Various tests were conducted to ensure the building would not fail from lateral stresses caused by wind loads. This regimen of testing on 1:50 scale models drove two important design considerations:

- Because the nose of the structure cuts the wind and greatly reduces the lateral forces placed on the building, these tests essentially determined the orientation of the tower with regards to predominant winds in Dubai. The goal here was to have the wind cut by one of the towers’ wings rather than to blow straight into an interior corner between two wings.

- The termination of lobes in each wing at certain points in the structure not only gives the building its distinct form, but prevents winds from forming any distinct vortex patterns which could potentially push the building too hard on one face then create a vacuum on the reverse face.

 

 

 

Foundation

- Consisting mainly of a raft supported by concrete piles underneath, the foundation extends 43 meters to the bedrock below Dubai. Each pile is 1.5 meters in diameter and has a capacity of 3,000 metric tons (over 6.6 million pounds).

- Because of the highly corrosive nature of Dubai’s waterbed, each pile is given special waterproofing and concrete mixture that ensures the longevity of the foundation.

- The raft (the true bottom floor of the building, on top of which sits the rest of the structure) consists of 3.7 meters of a unique reinforced concrete mixture that can support up to 7,255 psi. Due to the thickness of the slab, this mixture was manipulated to ensure that it would cure quickly enough for the construction schedule, using a water-to-cement ratio of 3.4. Average ratios range from .4 to .6.

 

Records Broken

- Height: The Burj Khalifa is the tallest skyscraper all three CTBUH categories. It is boasts the highest architectural top, the highest occupied floor, and the highest tip of any land-based manmade structure in the world.

 

 - Other accomplishments include: the worlds highest mosque, nightclub, and swimming pool; longest elevator in the world; most floors of any skyscraper; and the highest pumped concrete for any construction ever completed.