In 1956, architect Frank Lloyd Wright proposed the idea of a skyscraper nearly 2,000 meters high. And it would be the tallest building in the world at that time, very tall – five times the size of the Eiffel Tower. But many critics laughed at the architect, arguing that people would have to wait for the elevators for hours or worse, the tower would collapse under its own weight and, although the proposal was made public, the court This huge tower was never built.
Nowadays, more and more huge buildings are springing up all over the world. Many contractors have planned for buildings over 1,000m high like the Jeddah tower in Saudi Arabia, which is three times the size of the Eiffel Tower. Soon, Wright’s miracle could come true. So what stopped us from building these megastructures 70 years ago and how do we build things that are thousands of feet tall today?
In any construction project, each floor of the building must support the floor above it. The higher the building, the greater the force of gravity acting from the upper floor to the lower floor. This law, which has long shaped our buildings, ancient architects built pyramids with wide foundations to be able to support lighter floors. But this solution cannot be applied to buildings in the city – a pyramid of such height requires a base more than 3km wide to be difficult to squeeze into the city center.
Fortunately, a newly discovered material is concrete, they are very strong and have high bearing capacity, so it is not designed under this unrealistic shape. Modern concrete mortars are reinforced with steel piles to increase strength and chemical polymers to reduce water content to prevent cracking. The concrete in the world’s tallest tower in Dubai – Burj Khalifa, can withstand 8,000 tons of pressure per square meter equal to the weight of 1,200 African elephants!
Of course, even if a building can support itself, it still needs support from the ground. Without a foundation, a building with that weight would sink, collapse, or tilt. To prevent the tower of nearly half a million tons from sinking, 192 steel core piles mixed with concrete mortar were buried more than 50m deep. Friction between the steel pile and the ground keeps the giant structure standing.
In addition to defeating gravity, which pulls buildings 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 every square meter of a building like the force of a bowling ball going.
Aerodynamically designed buildings, such as the Shanghai torsion tower in China, can reduce the impact force by up to a quarter. In addition, another design is a wind-loaded frame inside and outside a building that can absorb the remaining wind force, such as Lotte Tower in Seoul.
But even with these measures, you could still find yourself wobbling by more than a meter at the top of the tower during a storm. To prevent the wind from shaking the top of the building, many buildings use counterweights weighing hundreds of tons called “mass damper”. For example, the Taipei 101 tower, which hangs a giant metal ball on the 87th floor. When the wind blows into the tower, the massive mass in the building vibrates, absorbing the building’s kinetic energy and stabilizing the anthill. the bamboo is swaying.
With all these technologies, super buildings can stand and stay stable. But moving quickly in the building is also a challenge. In Wright’s time, the fastest elevator could only travel 22 km/h. Fortunately, today, elevators travel faster than 70 km/h with future cabins using frictionless magnetic rails for higher speeds.
High-rise construction has come a long way from Wrigh’s proposal, which was once considered impossible to open up new architectural opportunities. Today, a building nearly 2,000 meters high seems to be in sight and it is only a matter of time.