Taiwan's tallest skyscraper uses a massive pendulum to protect itself from earthquakes
Taiwan's tallest skyscraper's is standing strong after a 7.4-magnitude earthquake struck the island nation, killing nine people and injuring at least 946 others on Wednesday.
The Taipei 101 building, once recognized as the tallest skyscraper in the world, uses an enormous tuned mass damper (basically a giant pendulum) to protect itself from earthquakes.
The 660-ton pendulum hangs over 1,000 feet above the ground and allows the structure to withstand tremors and typhoon winds. The massive steel sphere moves back and forth slightly, enough to counter any movement.
The device reduces the tower's movements by up to 40%, according to its builder and tester, A+H Tuned.
"Tuned mass dampers, also called harmonic absorbers, are simple yet effective mechanisms that allow us to design and live in skyscrapers," A+H Tuned says on its website. "Without them, the lifespan, structural integrity, and comfort of these high rise buildings would be seriously reduced."
Damper hangs between several floors
The golden mass damper hangs between the 87th and 92nd floors in the center of the Taipei 101.
The device is constructed of 41 layers, each almost 5 inches thick, and is around 18 feet in diameter, according its website. Ninety-two steel cables are used to hang it, with each being about 3.5 inches wide and 138 feet long.
The sphere also uses a bumper ring to limit its back-and-forth swing to around 59 inches in the event of an intense earthquake or typhoon-force winds.
Once known as the Taipei World Financial Centre, the skyscraper was the tallest skyscraper in the world when it was completed in 2004. It held the title until 2009, when the Burj Khalifa in Dubai dethroned it.
Why earthquakes are common in Taiwan
Taiwan is prone to earthquakes because it sits on the Pacific "Ring of Fire." The tectonic belt is home to 90% of the world's temblors.
The densely populated island nation has garnered a reputation for being prepared for earthquakes, according to Joseph Barbera, an emergency physician and professor of engineering management and systems engineering at George Washington University.
Barbera said the damage from Wednesday's quake would potentially be far worse if it weren't for the readiness from emergency services and strict enforcement of the nation's seismic building codes. Other critical buildings are built on foundations to protect them from tremblors.
"There's a dramatic difference between building failures – structural failures, not just buildings – in Taiwan versus other other countries that have similar size earthquakes," Barbera told USA TODAY. "They’ve had a true commitment for decades to risk reduction."
Contributing: John Bacon and Jeanine Santucci
This article originally appeared on USA TODAY: Taiwan's tallest skyscraper unscathed in major earthquake. Here's why.
