The Tuned Mass Damper (TMD) is a passive damper system designed to cope with the needs of Taipei 101. The steel pendulum is hung on the central area between the 87th to 91st floors. The design of TMD is to tune and reduce the vibration of the building caused by strong winds to enforce safety and comfort of people in the building. Differing from conventional hidden mass dampers, the Taipei 101 TMD was designed to integrate structural performances and functions. One can see the actual movement of the damper on 88th and 89th floors.

When the scale-17 Typhoon Maring hit Taipei on October 2nd, 2005, the damper finally moved 40 centimeters. Mr. Hong-Ming Lin, the president of the Taipei Financial Center Corp., specially gave us a copy of this rare clip to share with everyone. Although it is fun to watch the pendulum move inside the building, in reality, fiery wind and rain struck outside of the building.

When Typhoon Maring, which measured 17 on the wind scale, hit Taipei, everyone couldn’t help but fear that the strong wind will bring the world’s tallest building into a swing. The president of Taipei 101, Mr. Hong-Ming Lin, told us Typhoon Maring did not sway Taipei 101 a bit, but it did cause the “wind damper” in the building to move approximately 40 cm to offset the vibration. He even gave us the clip to share with everyone.

Not only is Taipei 101 the world’s tallest building but also it has the biggest wind damper in the world. Taipei 101’s TMD is the only mass wind damper open for public view and the only undisclosed pendulum in the world that is incorporated in the design of the building. The steel ball weighs 660 tons and is hung vertically by 16 steel rods from the 91st floor to the 89th floor, where the observation deck is located. The main purpose of the TMD is to balance off the impact of the wind on the building.

The TMD is estimated to move approximately 35 cm a few times in a year. The period of TMD movement corresponds to that of the building. Each full movement takes up 7 seconds to complete. It is not easy to see the pendulum work and sway under daily normal operation. Under the impact of a major typhoon that probably comes every 100 years, the wind damper will sway an approximately 150 cm in full motion. A bumper system is specially designed to prevent and reduce the effect of such 150 cm pendulum motion.

As stated by Chia-Hao Michael Liu, the quick visit of Typhoon Maring caused the TMD to have such a great movement for the first time! According to the computer monitoring system in the building, the wind damper swayed 40 cm in pendulum motion at 10 in the morning to balance off the impact on Taipei 101. When Typhoon Haitang and Talim hit Taiwan, the wind damper only moved a little, which proved that the instant wind force of Maring really had great impact on the building. However, thanks to the wind damper, the office buildings did not feel much movement.

Mr. Hui-Rong Chen, the deputy manger of the logistics department of Taipei 101, inspected the building when typhoons struck. He stated that the central areas of the building are all fairly stable. The impact of the wind could only be felt when one stands close to the window.