Earthquake Resistant Buildings
Seismic Dampers
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The Taipei 101, one of the tallest skyscrapers in the world, is located in Taipei, Taiwan. Now, if you imagine a skyscraper or building as tall as that - about 1,671 feet, the building's got to sway, and it does. The Taipei 101 is located to the coast of Taiwan, and winds and typhoons are common there. The building sways a result - but no one can notice or feel it - all because of tuned mass dampers. Seismic dampers (also called vibration absorbers or vibration dampers) reduce low and high frequency vibrations in machines, systems, and structures. Not only installing it would help prevent buildings from shaking and toppling over in earthquakes, but it can also absorb unnecessary everyday vibrations such as motorcycles or plain old strong storms which occur frequently in Issaquah and other parts of the Pacific Northwest. They absorb the seismic energy waves to reduce the sway, damage, and failure of structures.
The function of the damper is based on a spring/mass system, which counteracts and reduces extraneous vibrations. The weight of the damper is based on the weight of the system, or building, that is being damped.
The function of the damper is based on a spring/mass system, which counteracts and reduces extraneous vibrations. The weight of the damper is based on the weight of the system, or building, that is being damped.
To the right is a picture of the tuned mass damper hanging from the ceiling of the Taipei 101. Of course, the size of this is due to the size of the entire building - we won't have mass dampers the size of this hanging from the ceiling of our homes and buildings. Sizes of mass dampers for buildings can vary from being a mere a few grams to a thousand kilograms.
However, tuned mass dampers are just only one kind of seismic dampers that occur in the world. Some, like this example, are hung from the ceiling of buildings, whereas some are buried underneath buildings or placed throughout the buildings. |
Different Types of Seismic Dampers
Here's a quick overview on the two most common kinds of seismic dampers:
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In our community, using viscous dampers would be the most appropriate option, since we have numerous homes and buildings rather than tall skyscrapers that need to be weighed down.
Shear Walls
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Reinforced concrete (RC) buildings, just like their name, buildings reinforced with concrete, often have vertical plate-like walls called "shear walls." They usually start at foundation level and are continuous throughout building height. Their thickness could be as low as 150mm to 400mm. The vertically-positioned wide, concrete beams carry the seismic waves and shock of the waves down towards the strong foundation, rather than the top of the buildings.
The diagram at the left shows what shear walls would look like as they are laid out in a RC building. These shear walls would help strengthen the structure and absorb the shock that the buildings would receive during an earthquake.
The diagram at the left shows what shear walls would look like as they are laid out in a RC building. These shear walls would help strengthen the structure and absorb the shock that the buildings would receive during an earthquake.
Analysis on Design Constraints
Would building earthquake resistant buildings actually be able to be built in the community of Issaquah? Do the pros (advantages) outweigh the cons (disadvantages)? The acronym "SAFE" will help analyze the solution to best match each situtation. Go to to home page to learn more about this acronym.
Safety - Viscous dampers are very safe; they have stable and predictable performance at any temperature. All companies test their dampers first before assembling them to be part of a building, which ensure the safety of the building and the ones living in the building. Viscous dampers are filled with silicone fluid, which is compacted together so they won't break down, ensuring the safety of the environment as well.
Aesthetics - Viscous dampers are either placed at the bottom of the structure or hidden underground as part of the base isolation, so visual would not matter for the people living in the area. The same would apply for the sheer walls, since they are hidden from view as part of the walls of a house.
Function - Viscous dampers are stable and have a long life, and reduce both stress and deflection in a structure during a seismic event. They are easily installed and produced and work their full potential when placed. Shear walls are easy to construct, because reinforcement detailing of walls is relatively straight-forward and therefore easily implemented at site. Shear walls are efficient, both in terms of construction cost and effectiveness in minimizing earthquake damage in structural and non-structural elements.
Economics - Since viscous dampers have a long life, they don't require a lot of maintenance, decreasing the amount of money that needs to be spent. Both viscous dampers and shear walls cost quite a bit of money, but it's nothing compared to the cost after an earthquake strikes.
Safety - Viscous dampers are very safe; they have stable and predictable performance at any temperature. All companies test their dampers first before assembling them to be part of a building, which ensure the safety of the building and the ones living in the building. Viscous dampers are filled with silicone fluid, which is compacted together so they won't break down, ensuring the safety of the environment as well.
Aesthetics - Viscous dampers are either placed at the bottom of the structure or hidden underground as part of the base isolation, so visual would not matter for the people living in the area. The same would apply for the sheer walls, since they are hidden from view as part of the walls of a house.
Function - Viscous dampers are stable and have a long life, and reduce both stress and deflection in a structure during a seismic event. They are easily installed and produced and work their full potential when placed. Shear walls are easy to construct, because reinforcement detailing of walls is relatively straight-forward and therefore easily implemented at site. Shear walls are efficient, both in terms of construction cost and effectiveness in minimizing earthquake damage in structural and non-structural elements.
Economics - Since viscous dampers have a long life, they don't require a lot of maintenance, decreasing the amount of money that needs to be spent. Both viscous dampers and shear walls cost quite a bit of money, but it's nothing compared to the cost after an earthquake strikes.