New York’s skyscrapers have been generally built to withstand winds and other impacts far greater than the earthquakes generally seen on the East Coast, said Elisabeth Malsch, a managing principal at Thornton Tomasetti, a New York engineering firm that’s done major work on the Empire State Building, Chrysler Building and the Brooklyn Bridge, among other major city landmarks.
“The earthquake that we design for is one that’s unlikely to happen. It’s a thousand-year event,” she explained. “So we don’t expect it to happen more than once in a thousand years.”
Skyscrapers, by design, are less susceptible to the ground-shaking action of earthquakes than shorter structures because they’re made to sway ever so slowly and slightly to protect themselves against powerful, hurricane force winds, Malsch said.
“Taller buildings just are more flexible because they’re designed for the push and pull from the wind, which has a bigger effect on tall buildings than the push and pull of an earthquake does,” she explained. “So regardless of when it was designed, the wind continually tests them. It’s a double check that they’re strong enough and flexible enough to handle earthquakes.”
Even the oldest skyscrapers are, by necessity, made of high strength concrete and steel to withstand the gravitational load on the massive structures, added Ahmad Rahimian, an executive vice president at the engineering firm WSP Global who was involved in the construction of One World Trade Center, this hemisphere’s tallest building, and The Shard in London, which is Europe’s tallest building.
“High-rise buildings can be one of the safest places you can be in an earthquake,” he said.
The skyscrapers of New York City are generally built to withstand an earthquake of 6.5 magnitude and larger, Rahimian said.
More modern high-rises also have dampers located on their roofs that can balance the sway and help absorb any shock from extreme events, said Borys Hayda, a…
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