A big pendulum of 730 tons, suspended inside the famous Taipei 101 skyscraper in Taiwan, played a crucial role in protecting the structure during the recent 7.4 magnitude earthquake that hit the region. This pendulum, visible to the public in the 89th floor observatory, has not only become a popular tourist attraction, but also serves as a “tuned mass damper”: that is, it dampens oscillations due to the earthquake; but it is also useful for strong people.
The remarkable creation has been known for a long time, even for the Taipei 101 was built about 20 years ago. However we are amazed every time faced with an idea that is as simple as it is brilliant and effective. An effectiveness that was demonstrated spectacularly during this week’s earthquake, counteracting forces that could have put the stability of the skyscraper at risk.
In addition to the pendulum, the structure of Taipei 101 is designed with a series of 380 poles that sink many meters into the ground, down to the bedrock. They give valuable support to the entire structure and form its foundation.
Many other skyscrapers use a variety of mobile counterweights and “floating” structures to resist even very powerful earthquakes. These techniques, based on Physics and achieved thanks to sophisticated structural engineering, demonstrate the human ability to exploit science to do incredible things.
How does the Taipei 101 pendulum work?
Taipei 101 is a 508 meter tall building and was the tallest building in the world until 2009. Building a similar structure in an earthquake-prone area is a truly complex challenge, and perhaps without the idea of the pendulum it would not have been possible.
The pendulum of Taipei 101, also known as tuned mass damper, works according to the principles of oscillation physics. It is suspended inside the skyscraper and can swing sideways in response to external forces, such as wind or earthquakes. If the building is pushed in one direction the pendulum “responds” with a contrary oscillation.
In practice, it acts like a dynamic counterweight, reducing the amplitude of the building’s oscillations and protecting the structure from deformation and collapse. Something we can all at least guess at, but it becomes impressive when you consider the proportions at play.
Cover image: siraphol
