Seismic activity occurs every day all around the earth. With the growing number of mega structures, it is necessary to have protection. This protection is not just for the sake of saving a couple billion dollars to rebuild or repair a structure, but also serves to save human lives.
The method of protection emphasized here is using dampers to keep a building from collapsing. Below is a diagram of the massive damper suspended from the top of the Taipei 101.
Passive – This type of damper does not need any external energy to work. Passive dampers may be cheaper, but have limited flexibility to meet a building’s needs.
Active – An active damper uses large amounts of external energy to operate. This damper pushes on the building to counteract the motion of the structure. As the building sways one way, the damper pushes in the opposite direction.
Semi-Active – This type does not need much power and is fully controllable. Semi-active dampers do not push on the building, they only counteract the swaying of it by moving their weight the opposite way of the building’s motion.
Once sensors on the building detect motion, the dampers begin to sway to help the building absorb the vibrations. Using dampers will make the vibrations last longer, therefore decreasing the amount of energy being released per vibration.
Different size buildings require different arrangements of dampers; there may be hundreds in a single building or just a few.
Here is a photo of the world’s largest damper, in the Taipei 101.
Taipei 101, Taiwan