In 1956, architect Frank Lloyd Wright proposed the idea of a nearly 2,000-meter skyscraper. And it will be the tallest building in the world at that time, very tall - five times the height of the Eiffel Tower. But many critics laughed at the architect, arguing that people would have to wait for elevators for hours or worse, the tower would collapse by its own weight and although the proposal was made public, the court This gigantic tower has never been built.
Nowadays, more and more large buildings are growing all over the world. Many contractors have planned for buildings over 1,000 meters high such as the Jeddah tower in Saudi Arabia, three times the size of the Eiffel Tower. Soon, Wright's miracle may come true. So what stopped us from building these super architectures 70 years ago and today, how do we build thousands of meters tall?
In any construction project, each floor of the building must support the floor above it. The higher the building, the greater the gravity from the upper layer to the lower floor. This law, which has long shaped our buildings, ancient architects built pyramids with wide foundations to support lighter, higher floors. But this solution does not apply to city buildings - a pyramid of such height requires a 3-meter-wide base that is difficult to squeeze into the city center.
Fortunately a newly discovered material is concrete, they are very solid and highly resistant, so not designed in this unrealistic shape. Modern concrete mortars are reinforced with steel piles to increase strength and chemical polymers reduce water composition to avoid cracking. Concrete in the world's tallest tower in Dubai - Burj Khalifa, can withstand 8,000 tons of pressure per square meter by the weight of 1,200 African elephants!
Of course, even if a building can support itself, it still needs support from the ground. Without the foundations, buildings of such weight would sink, collapse, or tilt. To prevent the nearly half a million-ton tower from sinking, 192 steel-core concrete piles were buried more than 50 meters deep. The friction between the steel pile and the ground keeps the giant structure standing.
In addition to defeating gravity, which is the factor that pulls the building down, a building also needs to withstand the wind blowing from the sides. On normal days, the wind can exert a force of more than 7kg on each square meter of a building as the force of a bowling ball is running.
The project is designed by aerodynamics, such as the Shanghai torsion tower in China, that can reduce the impact force by a quarter. In addition, another design is that the frame under the wind load inside and outside the building can absorb the remaining wind forces, such as Lotte Tower in Seoul.
But even with these measures, you can still find yourself wobbling with amplitude more than a meter at the top of the tower during the storm. To avoid the wind wobbling the top of the building, many buildings used a hundred-ton counterweight called a "volume damper". For example, the Taipei 101 tower, hung a giant metal sphere on the 87th floor. When the wind blew into the tower, the giant heavy mass in the building would oscillate, absorb the kinetic energy of the building and stabilize the ant block. bamboo is swinging.
With all these technologies, superstructures can stand up and be stable. But moving quickly in a building is also a challenge. In the age of Wright, the fastest elevator could move only 22 km / h. Fortunately, nowadays, elevators travel faster than 70 km / h with future cabins using frictionless magnetic rails for higher speeds.
The building has come a long way from Wrigh's proposal, once thought impossible to open up new architectural opportunities. Today, a building nearly 2,000 meters high seems to be right in front of you and it is only a matter of time.