Burj Khalifa | The Secrets of its incredibly Strong Foundation

Summary

The video explains the engineering marvel behind the construction of the Burj Khalifa's foundation, which can withstand strong sandstorms and other environmental challenges. Engineers had to design a deep, reinforced foundation using piles to counter weak Dubai soil and ensure minimal settlement. The video also explores the innovative methods used, such as mixing concrete with ice to counteract heat, and employing cathodic protection to prevent corrosion of the steel reinforcements. These techniques allow the Burj Khalifa to endure wind speeds of up to 240 km/h, making it an engineering masterpiece.

Takeaways

• 🏙️ The Burj Khalifa can withstand sandstorms with wind speeds up to 100 kilometers per hour due to its robust foundation.
• 🏗️ The foundation of the Burj Khalifa is as deep as a 10-story building and requires constant electricity to prevent weakening.
• 🌡️ Engineers faced challenges with extreme heat in Dubai, leading them to work at night and mix ice cubes into the concrete for the foundation.
• 🧱 The raft foundation of the Burj Khalifa was constructed in four phases, each lasting 24 hours, to ensure proper concrete pouring.
• 📏 Dubai's soil is weak, requiring engineers to use friction piles to prevent excessive settlement of the building.
• 🛠️ The piles beneath the foundation extend to a depth equivalent to 10 floors of the Burj Khalifa to generate frictional force and provide stability.
• 💧 Groundwater posed a challenge during construction, leading engineers to use slurry to prevent soil collapse in the boreholes.
• 🧬 A special type of liquid concrete (SCC C60) was used for the piles to ensure proper compaction at such deep levels.
• ⚡ Constant electricity supply is essential to prevent the rebars in the foundation from corroding due to salty groundwater.
• 🔋 Engineers implemented a cathodic protection system using DC current to prevent corrosion of the rebars but had to carefully balance the electricity supply to avoid hydrogen embrittlement.

Q & A

What is the primary challenge faced by the Burj Khalifa during strong sandstorms?

The primary challenge during strong sandstorms is the wind pressure, which can reach speeds of up to 240 kilometers per hour. The building must have a strong foundation and structure to resist these winds.

How deep is the foundation of the Burj Khalifa, and why is it significant?

The foundation of the Burj Khalifa is as deep as a 10-story building. This depth is significant because it provides the necessary support for such a massive structure and helps distribute the weight evenly.

Why is the continuous flow of electricity essential for the Burj Khalifa’s foundation?

The continuous flow of electricity is crucial to prevent the rebars (reinforcement bars) in the foundation from corroding due to the salty water seeping from the Persian Gulf. This is achieved through a cathodic protection system using electrolysis.

What technique was used to overcome the lack of hard strata under the Burj Khalifa?

Engineers used a piled raft foundation to overcome the lack of hard strata. They added piles under the raft to increase the frictional force with the surrounding soil, preventing excessive settlement.

Why was the concrete mixed with ice cubes during the construction of the foundation?

The concrete was mixed with ice cubes to counter the extreme heat in Dubai, which could otherwise affect the quality of the concrete during the pouring process, especially in temperatures of 40 degrees Celsius.

How did engineers prevent soil collapse during the construction of piles?

Engineers prevented soil collapse by using a drilling fluid to create a slurry that exerted hydrostatic pressure on the walls of the borehole. This technique stopped the soil from collapsing into the boreholes.

What is SCC C60 concrete, and why was it used for the piles?

SCC C60 is a self-compacting concrete that flows like a liquid. It was used for the piles because it can fill deep boreholes without the need for mechanical vibration, which is difficult to achieve at such depths.

What role did pile load tests play in the construction of the Burj Khalifa?

Pile load tests were conducted to analyze the optimal placement and performance of the piles. These tests helped engineers determine the settlement limits and ensure the foundation could handle the building’s weight and wind forces.

How did engineers modify the pile design to withstand high wind velocities?

Engineers increased the number of piles in the wing areas of the foundation to distribute the wind forces more effectively, allowing the building to withstand wind speeds of up to 240 kilometers per hour.

What is hydrogen embrittlement, and why must it be avoided in the cathodic protection system?

Hydrogen embrittlement occurs when too much current is supplied to the cathodic protection system, causing the rebars to become brittle and crack. This phenomenon can severely weaken the foundation, so the current flow must be carefully controlled.