How do you build an Earthquake-proof building?

After the massive earthquake near Japan this morning one wonders if it’s possible to build an earthquake-proof building? The answer is yes and no. There are of course, engineering techniques that can be used to create a very sound structure that will endure a modest or even strong quake. However, during a very strong earthquake, even the best engineered building may suffer severe damage. Engineers design buildings to withstand as much sideways motion as possible in order to minimize damage to the structure and give the occupants time to get out safely.

Effect of isolating the base of a building subject to a sideways ground movement.

Buildings are basically designed to support a vertical load in order to support the walls, roof and all the stuff inside to keep them standing. Earthquakes present a lateral, or sideways, load to the building structure that is a bit more complicated to account for. One way to to make a simple structure more resistant to these lateral forces is to tie the walls, floor, roof, and foundations into a rigid box that holds together when shaken by a quake.

The most dangerous building construction, from an earthquake point of view, is unreinforced brick or concrete block.  Generally, this type of construction has walls that are made of bricks stacked on top of each other and held together with mortar.  The roof is laid across the top.  The weight of the roof is carried straight down through the wall to the foundation.  When this type of construction is subject to a lateral force from an earthquake the walls tip over or crumble and the roof falls in like a house of cards.

Construction techniques can have a huge impact on the death toll from earthquakes. An 8.8-magnitude earthquake in Chile in 2010 killed more than 700 people. On January 12, 2010, a less powerful earthquake, measuring 7.0, killed more than 200,000 in Haiti.

The difference in those death tolls comes from building construction and technology. In Haiti, the buildings were constructed quickly and cheaply. Chile, a richer and more industrialized nation, adheres to more stringent building codes.

Skyscrapers

730 ton motion damper inside the Taipei 101 skyscraper

As the buildings get bigger and taller other techniques are employed such as “base isolation.” During the past 30 years, engineers have constructed skyscrapers that float on systems of ball bearings, springs and padded cylinders. Acting like shock absorbers in a car, these systems allow the building to be decoupled from the shaking of the ground.

Watch the video below to see these system in action. These buildings don’t sit directly on the ground, so they’re protected from some earthquake shocks. In the event of a major earthquake, they can sway up to a few feet. The buildings are surrounded by “moats,” or buffer zones, so they don’t swing into other structures.

Another technique to dampen the swaying of a tall building is to build in a large (several tons) mass that can sway at the top of the building in opposition to the building sway. Known as “tuned mass dampers”, these devices can reduce the sway of a building up to 30 to 40 percent. The Taipei 101, formerly known as the Taipei World Financial Center, has just such a giant pendulum mounted between the 88th and 92nd floors. Weighing in at 730 tons and capable of moving 5ft in any direction, it takes the prize as the worlds largest and heaviest building damper. In fact, it is so heavy that it had to be constructed on site since it is to heavy to be lifted by a crane.

Can you build a better building?

At Imagination Station we have several shake tables in our Engineer It! exhibit that give visitors the chance to build various model structures and then test them on a shaking “earthquake” platform. Our Earthquake platform is large enough to stand on, but not nearly as big as the shake tables at some engineering test facilities. These things are really called shake platforms because they are much, much larger than a “table”.

Here is a great video from WIRED that shows how a large shake platform can be used to test a full-scale structure in response to the motion of an earthquake. I love the crazy shot at 1:17 into this video of a ball bearing base isolator scooting around to stabilize a structure!

For more information about earthquakes in general check out the United States Geological Survey’s earthquake website.

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About the author

Carl Nelson is the Chief Scientist at Imagination Station in Toledo, Ohio. He holds a Masters Degree in Experimental Physics from Michigan State University and has been having fun exploring (exploding?) science in Science Centers for the past 20 years.

Comments

81 Responses to “How do you build an Earthquake-proof building?”
  1. Liam says:

    Hi Ninja of dark, The schock absorbers, absorb the waves and steadily flow with the earth

  2. Liam says:

    I don’t really understand how the isolation base helps the quake. can explain it to me?

  3. ella jhonsen says:

    yeah I have to be a nerd I love these studies

  4. Katy says:

    For Liam:
    Base isolation is a collection of a building’s units resting on its foundation to provide separation of the building from shaking ground thus improving seismic performance.

  5. Karl Piessens says:

    Very helpful for my science project THANKS YOU GUYS ARE AWESOME

  6. I still don’t understand what exactly is the connection between building and foundation. What material or product. In Holland we use these poles to build upon. Is the flexibility arranged between those poles and the groundfloor?

  7. Faith Waples says:

    This was really helpful.. Thank you for doing this for us.. :)

  8. Faith Waples says:

    This was really helpful, and to be honest, this was the highlight of my day.. My science teacher, Mr. Campbell, trusted us to go in the pod, and work on this and answer some questions. I’ve been in a rough time…. BYe

  9. Bob Bobson says:

    Why is concrete and brick most dangerous?

  10. kiki says:

    this did not help me at all! but thanks eathier way

  11. Yoshiswag says:

    COOL

  12. Yoshiswag says:

    I am doing Tech Challenge 2015 and this was very helpful

  13. Thomas Tognolini says:

    cool

  14. Thomas Tognolini says:

    THANKS LIAM

  15. Carl says:

    Well, they are both heavy and dangerous when they fall from a distance.
    Carl

  16. Milly Da Mermaid & Alexa says:

    I still don’t understand… why do we need earthquake proof buildings?????

  17. Olivia Alfonso says:

    not very helpful. next time just tell us 2 things that can be done to make buildings/structures seismic safe. thanks:)

  18. Leiden Huber says:

    thanks very helpful

  19. Thank you for helping our grade in science for our project! :)

  20. AnonymousNerd says:

    Liam, the base isolation uses the building’s inertia to it’s advantage. The foundation is almost “floating” on top of the ground, or at least has a minimized amount of friction to allow it not to catch or stick. This makes it so that the movement of the ground cannot move the building. It’s almost as if in a hockey rink, a skater were standing in the middle of it and it began to move forward and back, because there is little friction between the slippery ice and the blades of the skates, they will not move as much as if they were standing on normal ground. There is a similar principle with the rocking of a boat.

  21. Engg.cds. says:

    I think,this technique should be better to reduce the effects of earthquake,..
    So governments should concer to develop this type buildings in their contries.

    We all only reduces the side effects of this natural disaster,
    Not completely destroyed.

  22. Great experiments & great videos.

  23. bob marquez says:

    im so confused!!!!! lol

  24. bob marque says:

    im so confused!!!!! lol

  25. anusha says:

    well, i am a civil engineering student (4th year). my country Nepal recently faced 7.9 richer scale earth quake and as Nepal is prone to earthquakes, i think base isolation may minimize the damage that has been occurring. I would like to know where i can find these base isolation units and the functions of the units, so i can help design earthquake proof building… thank you.

  26. dawson says:

    COOL

  27. subham suryaprakash says:

    I think spring can use to protect building from earthquake…

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  1. […] For buildings, we use: -Base Isolation (adds flexibility to buildings so they more sway than strain) -Ball bearings (shock absorber) -Springs (shock absorber) -Padded cylinder (shock absorber) http://www.imaginationstationtoledo.org/content/2011/03/can-you-build-an-earthquake-proof-building/ […]

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