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  • In 1956, architect Frank Lloyd Wright proposed a mile-high skyscraper.

  • It was going to be the world's tallest building, by a lot, five times as high as the Eiffel Tower.

  • But many critics laughed at the architect, arguing that people would have to wait hours for an elevator, or worse, that the tower would collapse under its own weight.

  • Most engineers agreed, and despite the publicity around the proposal, the titanic tower was never built.

  • But today, bigger and bigger buildings are going up around the world.

  • Firms are even planning skyscrapers more than a kilometer tall, like the Jeddah Tower in Saudi Arabia, three times the size of the Eiffel Tower.

  • Very soon, Wright's mile-high miracle may be a reality.

  • So what exactly was stopping us from building these megastructures 70 years ago, and how do we build something a mile high today?

  • In any construction project, each story of the structure needs to be able to support the stories on top of it.

  • The higher we build, the higher the gravitational pressure from the upper stories on the lower ones.

  • This principle has long dictated the shape of our buildings, leading ancient architects to favor pyramids with wide foundations that support lighter upper levels.

  • But this solution doesn't quite translate to a city skyline–a pyramid that tall would be roughly one-and-a-half miles wide, tough to squeeze into a city center.

  • Fortunately, strong materials like concrete can avoid this impractical shape.

  • And modern concrete blends are reinforced with steel-fibers for strength and water-reducing polymers to prevent cracking.

  • The concrete in the world's tallest tower, Dubai's Burj Khalifa, can withstand about 8,000 tons of pressure per square meterthe weight of over 1,200 African elephants!

  • Of course, even if a building supports itself, it still needs support from the ground.

  • Without a foundation, buildings this heavy would sink, fall, or lean over.

  • To prevent the roughly half a million ton tower from sinking, 192 concrete and steel supports called piles were buried over 50 meters deep.

  • The friction between the piles and the ground keeps this sizable structure standing.

  • Besides defeating gravity, which pushes the building down, a skyscraper also needs to overcome the blowing wind, which pushes from the side.

  • On average days, wind can exert up to 17 pounds of force per square meter on a high-rise buildingas heavy as a gust of bowling balls.

  • Designing structures to be aerodynamic, like China's sleek Shanghai Tower, can reduce that force by up to a quarter.

  • And wind-bearing frames inside or outside the building can absorb the remaining wind force, such as in Seoul's Lotte Tower.

  • But even after all these measures, you could still find yourself swaying back and forth more than a meter on top floors during a hurricane.

  • To prevent the wind from rocking tower tops, many skyscrapers employ a counterweight weighing hundreds of tons called a "tuned mass damper."

  • The Taipei 101, for instance, has suspended a giant metal orb above the 87th floor.

  • When wind moves the building, this orb sways into action, absorbing the building's kinetic energy.

  • As its movements trail the tower's, hydraulic cylinders between the ball and the building convert that kinetic energy into heat, and stabilize the swaying structure.

  • With all these technologies in place, our mega-structures can stay standing and stable.

  • But quickly traveling through buildings this large is a challenge in itself.

  • In Wright's age, the fastest elevators moved a mere 22 kilometers per hour.

  • Thankfully, today's elevators are much faster, traveling over 70 km per hour with future cabins potentially using frictionless magnetic rails for even higher speeds.

  • And traffic management algorithms group riders by destination to get passengers and empty cabins where they need to be.

  • Skyscrapers have come a long way since Wright proposed his mile-high tower.

  • What were once considered impossible ideas have become architectural opportunities.

  • Today it may just be a matter of time until one building goes the extra mile.

In 1956, architect Frank Lloyd Wright proposed a mile-high skyscraper.

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B2 US TED-Ed tower building mile wright wind

Will there ever be a mile-high skyscraper? - Stefan Al

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    shuting1215 posted on 2019/03/10
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