Huge steel ball made Taiwan skyscraper more earthquake resistant

 Futurism:

A 730-ton steel ball suspended inside Taiwan's iconic Taipei 101 skyscraper protected the structure during the region's 7.4-magnitude earthquake this week.

The ball is visible to the public on the skyscraper's 89th-floor observatory and has become a popular tourist attraction. While it's also a beautiful object in and of itself, it serves an important role as a "tuned mass damper," which is a pendulum that reduces "violent swinging" and "vigorous shaking" of the building in strong winds — and during earthquakes.

And as CCTV footage of the city's skyline shows, the system works astonishingly well, stopping the 101-floor tower from significantly swaying — a magnificent feat of engineering that relies only on simple physics.

Seismic Safety

The earthquake, the strongest in 25 years, struck Taiwan early Wednesday morning, killing at least nine people. Many structures fared far worse than the skyscraper, with videos showing several mid-rise buildings collapsing.

Taipei 101, however, was well equipped to survive the earthquake — and not just due to its massive, suspended dampener. The building's foundations are connected to the ground below via 380 piles that were driven over 260 feet into the ground and almost 100 feet straight into the bedrock.

A video shows the damper dramatically swaying during a 6.8-magnitude earthquake in 2022.

Plenty of other tall structures also rely on tuned mass dampers, which can sway side to side to counteract oscillations caused by earthquakes. Other approaches include diagonal braces between floors, shear walls that take the brunt of the forces, and dampers that physically reduce vibrations.
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It is an interesting engineering feat that is likely to be adopted by other construction projects in earthquake prone areas.