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Why Windy Cities Don't Fall Down

The next time you're buffeted by a strong gust of wind, think how much more difficult it would be if you were up on stilts, a hundred stories high.

For architects who design skyscrapers, strong wind is no laughing matter.

Wind speed increases the higher you go, so what feels like a mild breeze on the sidewalk might be a strong gale at the top of a building. All this wind can add up to hundreds of tons of sideways pressure on a windblown skyscraper.

How do tall buildings stay upright in high winds?

One engineering trick that helps keep some tall buildings upright is something you probably do yourself. If a gust of wind pushes you suddenly backward, you instinctively shift your weight and lean into the wind. Many of the tallest skyscrapers are designed to do something similar.

For example, near the top of the Citicorp building in New York is a room with a four hundred ton block resting on a very slippery floor. The block is connected to the walls by a system of springs and pistons. When the wind pushes the building one way, the heavy block slides along the floor in the opposite direction, shifting the building's weight. When the building rocks back the other way, the block moves again. This type of system is called a mechanical dampener, and many very tall buildings use something like it.

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