What is Taipei 101’s tuned mass damper made to reduce?

Taipei 101’s tuned mass damper is designed to reduce building sway.

The skyscraper contains a large steel sphere suspended between the 87th and 92nd floors. The approximately 660-metric-ton damper moves in response to the tower’s motion, helping counteract sway caused by strong winds and earthquakes. It is a passive system, meaning it does not need motors to create the opposing movement.

Taipei 101’s height and location make wind and seismic engineering especially important. Taiwan lies in an active earthquake region, and typhoons can produce powerful gusts. The damper does not make the tower motionless; instead, it reduces acceleration and improves occupant comfort.

Visitors can see the sphere from an observation area, making a normally hidden engineering system part of the attraction. The device is sometimes called a pendulum damper, but its purpose is not to hold the building rigid. It works by absorbing and opposing some of the tower’s movement.