The Taipei 101 has endured a typhoon that reached speed of 233 kmh, thanks to the tuned mass damper, a huge hanging steel ball able to neutralize 40% of the oscillations.
Requirements to build occupying less space is pushing the construction of skyscrapers of great height with very narrow base. How can a building like that resist wind and seismic forces? An answer comes from the famous Taipei 101: 508 meters in height (the tallest skyscraper in the world until 2008), 101 floors (hence the name), located in Taiwan, one of the locations most prone to the risk of typhoons in the world.
The skyscraper passed an important test on August 8th. It resisted a gust of wind among the strongest recorded in the island (more than 233 mph), without suffering structural damage and not even minimum consequencesfor the people inside. This excellent performance obviously gave a reason to technical experts to explain once again that the 'secret' is not only the Taipei 101, but the technology that allows a structure of great height to withstand extreme oscillations.
The innovation is called tuned mass damper - it is a large balanced mass generally eqipped with springs, weights and hydraulic shock absorbers, which reacts to the harmful frequencies of the oscillations with reverse vibrations.
The one mounted on the Taipei 101 skyscraper, between 87th and 92nd floor, is the world's largest mass damper. It 'a huge steel ball of 5.5 meters in diameter, consisting of 41 flat discs, making a weight of 660 tons and hanging inside the structure by cables.
The principle of its operation is simple. The enormous mass of the steel ball hanging, thanks to its inertia, is opposed to the displacement of the top of skyscraper, counteracting the displacement of the structure through hydraulic pistons. The energy input caused by the earthquake and wind, is dissipated through the hydraulic pistons that connect the ball to the structure of the Taipei 101.
In case of strong winds, such as occurred last August, the ball moves in countertrend, or in the opposite direction to that of the external fluctuations, absorbing the energy and balancing the buildings, reducing their movement by 40% .