Recently in my physics class, the teacher talks about waves and I suddenly remember a show that I watch on National Geography before about Taipei 101, now one of the world’s tallest buildings. Taiwan is a place where earthquakes happen frequently, thus it is very important to make buildings quakeproof, especially for Taipei 101 because of its extraordinary height. To understand how building is designed to be shockproof, we need to first understand how building collapses under the effect of waves, either winds or earthquakes.
So, how does building fail when it is under the effect of waves? Using an earthquake as an example, during an earthquake, the ground is shaking, and the lower part of a building shakes in the same direction as the ground. However, it takes some time for the waves to transfer to the upper part of the building, so the displacements of the lower part and upper part are different. The number of times that a building swings back and forth is called frequency. And all building has a natural frequency, which is a frequency that the energy of the quakes can be transferred most efficiently. When the frequency of quakes get closer to building’s natural frequency, the greater the building will swing, and more damage will be done to the building. (Thomas, “Quake-proof”)
Taipei 101 locates at a place where earthquakes happen frequently, and with its amazing height, wind vibration is also a problem. And how do the builders of Taipei 101 solve the issues of continuous vibrations of the building? They build a huge and heavy tuned mass damper (TMD) within the building. For building as big as Taipei 101, the TMD must be huge. In fact, the TMD in Taipei 101 is 5.5 meter in diameter and weights more than 600 ton. The damper is a pendulum hung from 92nd floor to 88th floor that is “tuned” to match the natural frequency of the building. It will vibrate in the opposite direction to the building, so the forces cancel each other out. Those people who are in IB Physics class might remember the video that Mr. Happer shows us in class on how two waves in opposite direction cancel each other out when they meet. (“Taiwan On Top”)
Why do people build architectures? The purpose is to protect us from the natural forces in the environment around us. The forces can be as small as a rain or as big as an earthquake, and buildings are supposed to shield us from those forces. Our ancestors develop different kinds of building styles in response to differnt dominated forces in a region; throughout time, the building styles become part of our culture. People live in different terrains build architectures differently because they have different problems to solve. However, the difference in building styles demonstrates a common attitude amongst all cultures. This attitude can be best described by a Daoism principle, to act like water. Water is soft and easily changable, and it can change to adapt its environment. The design of Taipei 101 reflects this attitude, since it doesn’t try to fight against nature, but rather the building “shakes” with it.