How Do Skyscrapers Stay Upright?

SkyscrapersDubai’s Burj Khalifa, currently the world’s tallest building, stands at 2,723 feet from base to tip. Take that in for a moment. That’s about as tall as a low-rise mountain, for goodness’ sake. And the upcoming world’s tallest building, the Kingdom Tower in Jeddah, Saudi Arabia, is said to be at least 3,280 feet tall. That’s almost one kilometer.

Ever wondered how in the world these buildings stay upright? Well, the folks over at MPFP sure do, like others in their field. Today’s mega-tall skyscrapers require unimaginable feats of engineering and architectural ingenuity to become a reality. Here’s a look at what their construction entails.

Forces of Nature

Nature is the mega-tall skyscraper’s biggest enemy. It all begins with the foundation. But know this: many skyscrapers are actually not built on solid ground. One example is London’s 95-story Shard Tower, which stands on soft clay. To be able to stand, its foundations go deep underground — a monumental concrete slab held up by hundreds of concrete piles supports the Shard. These piles go 173 feet beneath the earth. In cities with more solid ground, piles only go as deep as 52 feet.

Next up is gale force winds. Up there in the atmosphere, wind speeds can get crazy enough to topple anything or blow planes off course. An extremely sturdy skeleton, either inside or outside, is needed for this purpose. China’s upcoming 1,535-foot Chengdu tower has an exoskeleton to help it resist winds. Dubai’s Burj Khalifa, on the other hand, has an intricate inner frame keeping it upright.

But it doesn’t stop there. Believe it when you’re told that these buildings sway in the wind (it’s also true in the case of earthquakes). The ability to go with natural forces lessens the stress on the entire building. So if you feel like the floor is moving while on the 38th floor of your office building or in your penthouse suite, that’s why. Some even use actual counterweights (like New York’s Citigroup Center Building). These weights are moved by a computer system based on which direction the wind comes from. The result is a “smart” building that adapts to the forces of nature.

Buildings seem to be only getting taller. Who knows? Advances in engineering and architecture might make 2-kilometer-tall skyscrapers a reality.