Dubai is the fastest-growing city in the Global Village world. An army of cranes and laborers work 24-7 to turn the city and the whole world will look up to the centerpiece. Dubai is the tallest skyscraper in the world. Majestic Burj Khalifa is facing a strong Sandstorm of more than 100 kilometers per hour. Its foundation is a structure with a whopping depth of a 10-story building. The electricity of the foundation is the lifeline of the Burj Khalifa. It has to carry electricity 24 7. Any minor issue with the flow of electricity will weaken its foundation and the result could be catastrophic on a heavy windy day.
Raft Of Foundation
The raft of the foundation of Burj Khalifa is as thick as two human beings. The raft looks like a simple structure. But its construction was a massive task. Because a huge amount of concrete had to be poured in a single volume. The construction of this raft started with the placement of Steel rebars. Pouring concrete was not easy in the 40-degree heat in Dubai. Engineers executed this work during the nighttime when the temperature was normal. Ice cubes were also mixed with concrete while pouring it. The process of concreting the entire raft was done in four separate parts.
Soil Settlement Of Burj Khalifa
Engineers faced many challenges during the construction of Burj Khalifa. Engineer Mr. Bill Baker was the Chief design engineer of the Burj Khalifas. The first biggest challenge was soil settlement. In normal building construction Engineers always find something called hard strata. Solid soil where the structure of the building can rest during the construction phase and what happens when the weight increases. Because it’s obvious that the building settles down by a few inches. During this process, the soil below the foundation gets compressed and settled now the soil can produce proper reaction force and balance the building weight. However, this settlement should be within a safe limit. If the Burj Khalifa Engineers had constructed a normal raft foundation on this site it would settle down a lot and a catastrophe would have inevitably happened.
Solution Of Soil Settlement
They take a cross-section of Dubai’s soil it’s just loose sand and weak sedimentary rock even after digging 140 meters deep the engineers failed to find strong hard strata. The chief engineer Bill Baker came up with a simple solution for such a massive issue. The frictional force of the surrounding soil. Mr. Bill Baker tried to pierce through the sand using a sharp and thin rod. It’s a common observation that after a distance the rod won’t go down. This is due to the increased frictional force provided by the surrounding sand. As the rod goes down to generate the frictional force. He added a number of piles below the raft Foundation of Burj Khalifa.
10-Story Building Deep in the Earth
The depth of these RCC piles is equal to 10 floors of the Burj Khalifa. These piles generate frictional force against the weight of the building with the help of the soil reaction force and additional frictional force. The Raft Pile Foundation would reach settlement earlier and within safe settlement limits. When the Burj Khalifa’s construction was complete it had a settlement of just around five centimeters. Which is quite safe.
Construction Of Piles
The next big challenge to construct the Burj Khalifa was how to construct these piles with perfection. Making the design a reality for the construction of the piles. Firstly they started by drilling a hole with an auger excavator. The blades of this device perfectly remove the soil. However, Mr. Baker faced an issue with the groundwater of Dubai. This creates a slurry the slurry being denser than water. It exerts hydrostatic pressure on the walls of the borehole. It resists the soil collapsing. They placed a temporary hollow steel cylinder to hold the ground intact for concreting. They are placed in steel reinforcement bars welded as long cylinders.
In normal concreting, the laborers must use concrete vibrators to make the concrete compact. The usage of these machines is impossible in such deep boreholes. This is why the SCC C60 a special kind of concrete that flows like a liquid is used for the piles. The concrete was poured in with the help of a tremie pipe. The construction of the foundation alone took two years. The entire sequence of foundation construction for the Burj Khalifa achieved a good foundation design to hold up the tallest building in the world.
Dubai`s Heavy Sand Storms
In loose Dubai soil although this piled raft stands against the gravitational pole. Dubai’s heavy sandstorms are yet another test of the piled raft design. It can fail during a heavy sandstorm. Any design suggestions to overcome this issue to strengthen the Tower of Burj Khalifa to prevent it from falling? would you add glue to the center of the base plate or to the edges?
The experiment shows when the Burj Khalifa is glued at the center it is falling down because of the wind Force and when the building is glued at its Edge it’s standing strong. The original Burj Khalifa design also applies a similar technique. The pile’s design just increases the number of piles in the wing area. Due to this neat design change, the Burj Khalifa is able to withstand wind velocities of up to a whopping 240 kilometers per hour. Engineers performed rigorous pile load tests. Which involved applying a heavy load on a temporary test pile and studying the settlement. These tests took over six months and occurred at 23 spots in this Burj Khalifa.
Life Line Of Burj Khalifa
The Burj Khalifa Foundation has to carry electricity continuously. Otherwise, the salty water seeping from the sea will corrode the rebars inside the piles. The electricity of the foundation is the lifeline of the Burj Khalifa. It has to carry electricity 24 7. Any minor issue with the flow of electricity will weaken its foundation and the result could be catastrophic on a heavy windy day.