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.
Related articles
If you found this interesting, check out some of these related articles.
- Squishy Circuits with Play-Doh
- Make your own hovercraft
- The Earthquake Platform
- Breaking Glass
- The Blade Paper Tower Challenge
Comments
14 Responses to “How do you build an Earthquake-proof building?”Speak Your Mind
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i dont really get it. Iam doing geography home to make a earthquake resistant building!!!!?????
Seriously?!?!?!?! I cant understand this stuff! Make it easier to understand.
HOW DO U DO THIS!!!!!!!!!!!! with 30 straws and some sring
WITH CARDBOARD?!
I get this…but u arent giving clear directions how to build one. But this is helping me on my science project.Thanks
I think that this site is really helpful as I am currently doing a geography project and would like to thank you!
Thanks! This really helped me with my science project! btw lionheart…. u know warriors?
what is the authors full name, im writing a research paper and i need his full name as a requirment?!?
Hi Devon,
My full name is Carl Nelson.
Carl
Well what is the name of the design and I was wondering if I can use it for a science project.. or if u can’t give it out have any good names for designs
Love the videos!
Hello
can you give me a brief explanation on how physics was applied on the tower, like equilibrium, and what other units can be measured if ever i’ll try to make an experiment like this.. ^_^
would cheeseballs be a good name for the building my friend and i are writing about and designing?!?!?!?!?!?!?!!?!?!?!?
1.The largest recorded earthquake in the United States was a magnitude 9.2 that struck Prince William Sound, Alaska on Good Friday, March 28, 1964 UTC.
2.The largest recorded earthquake in the world was a magnitude 9.5 (Mw) in Chile on May 22, 1960.
3.The earliest reported earthquake in California was felt in 1769 by the exploring expedition of Gaspar de Portola while the group was camping about 48 kilometers (30 miles) southeast of Los Angeles.
4.Before electronics allowed recordings of large earthquakes, scientists built large spring-pendulum seismometers in an attempt to record the long-period motion produced by such quakes. The largest one weighed about 15 tons. There is a medium-sized one three stories high in Mexico City that is still in operation.
5.The average rate of motion across the San Andreas Fault Zone during the past 3 million years is 56 mm/yr (2 in/yr). This is about the same rate at which your fingernails grow. Assuming this rate continues, scientists project that Los Angeles and San Francisco will be adjacent to one another in approximately 15 million years.
6.The East African Rift System is a 50-60 km (31-37 miles) wide zone of active volcanics and faulting that extends north-south in eastern Africa for more than 3000 km (1864 miles) from Ethiopia in the north to Zambezi in the south. It is a rare example of an active continental rift zone, where a continental plate is attempting to split into two plates which are moving away from one another.
7.The first “pendulum seismoscope” to measure the shaking of the ground during an earthquake was developed in 1751, and it wasn’t until 1855 that faults were recognized as the source of earthquakes.
8.Moonquakes (“earthquakes” on the moon) do occur, but they happen less frequently and have smaller magnitudes than earthquakes on the Earth. It appears they are related to the tidal stresses associated with the varying distance between the Earth and Moon. They also occur at great depth, about halfway between the surface and the center of the moon.
9.Although both are sea waves, a tsunami and a tidal wave are two different unrelated phenomenona. A tidal wave is a shallow water wave caused by the gravitational interactions between the Sun, Moon, and Earth. A tsunami is a sea wave caused by an underwater earthquake or landslide (usually triggered by an earthquake) displacing the ocean water.
10.The hypocenter of an earthquake is the location beneath the earth’s surface where the rupture of the fault begins. The epicenter of an earthquake is the location directly above the hypocenter on the surface of the earth.
11.The world’s greatest land mountain range is the Himalaya-Karakoram. It countains 96 of the world’s 109 peaks of over 7,317m (24,000 ft). The longest range is the Andes of South America which is 7,564km (4700 mi) in length. Both were created bythe movement of tectonic plates.
12.It is estimated that there are 500,000 detectable earthquakes in the world each year. 100,000 of those can be felt, and 100 of them cause damage.
13.It is thought that more damage was done by the resulting fire after the 1906 San Francisco earthquake than by the earthquake itself.
14.A seiche (pronounced SAYSH) is what happens in the swimming pools of Californians during and after an earthquake. It is “an internal wave oscillating in a body of water” or, in other words, it is the sloshing of the water in your swimming pool, or any body of water, caused by the ground shaking in an earthquake. It may continue for a few moments or hours, long after the generating force is gone. A seiche can also be caused by wind or tides.
15.Each year the southern California area has about 10,000 earthquakes. Most of them are so small that they are not felt. Only several hundred are greater than magnitude 3.0, and only about 15-20 are greater than magnitude 4.0. If there is a large earthquake, however, the aftershock sequence will produce many more earthquakes of all magnitudes for many months.
16.The magnitude of an earthquake is a measured value of the earthquake size. The magnitude is the same no matter where you are, or how strong or weak the shaking was in various locations. The intensity of an earthquake is a measure of the shaking created by the earthquake, and this value does vary with location.
17.The Wasatch Range, with its outstanding ski areas, runs North-South through Utah, and like all mountain ranges it was produced by a series of earthquakes. The 386 km (240-mile)-long Wasatch Fault is made up of several segments, each capable of producing up to a M7.5 earthquake. During the past 6,000 years, there has been a M6.5+ about once every 350 years, and it has been about 350 years since the last powerful earthquake, which was on the Nephi segment.
18.There is no such thing as “earthquake weather”. Statistically, there is an equal distribution of earthquakes in cold weather, hot weather, rainy weather, etc. Furthermore, there is no physical way that the weather could affect the forces several miles beneath the surface of the earth. The changes in barometric pressure in the atmosphere are very small compared to the forces in the crust, and the effect of the barometric pressure does not reach beneath the soil.
19.From 1975-1995 there were only four states that did not have any earthquakes. They were: Florida, Iowa, North Dakota, and Wisconsin.
20.The core of the earth was the first internal structural element to be identified. In 1906 R.D. Oldham discovered it from his studies of earthquake records. The inner core is solid, and the outer core is liquid and so does not transmit the shear wave energy released during an earthquake.
21.The swimming pool at the University of Arizona in Tucson lost water from sloshing (seiche) caused by the 1985 M8.1 Michoacan, Mexico earthquake 2000 km (1240 miles) away.
22.Earthquakes occur in the central portion of the United States too! Some very powerful earthquakes occurred along the New Madrid fault in the Mississippi Valley in 1811-1812. Because of the crustal structure in the Central US which efficiently propagates seismic energy, shaking from earthquakes in this part of the country are felt at a much greater distance from the epicenters than similar size quakes in the Western US.
23.Most earthquakes occur at depths of less than 80 km (50 miles) from the Earth’s surface.
24.The San Andreas fault is NOT a single, continuous fault, but rather is actually a fault zone made up of many segments. Movement may occur along any of the many fault segments along the zone at any time. The San Andreas fault system is more that 1300 km (800 miles) long, and in some spots is as much as 16 km (10 miles) deep.
25.The world’s deadliest recorded earthquake occurred in 1556 in central China. It struck a region where most people lived in caves carved from soft rock. These dwellings collapsed during the earthquake, killing an estimated 830,000 people. In 1976 another deadly earthquake struck in Tangshan, China, where more than 250,000 people were killed.
26.Florida and North Dakota have the smallest number of earthquakes in the United States.
27.The deepest earthquakes typically occur at plate boundaries where the Earth”s crust is being subducted into the Earth’s mantle. These occur as deep as 750 km (400 miles) below the surface.
28.Alaska is the most earthquake-prone state and one of the most seismically active regions in the world. Alaska experiences a magnitude 7 earthquake almost every year, and a magnitude 8 or greater earthquake on average every 14 years.
29.The majority of the earthquakes and volcanic eruptions occur along plate boundaries such as the boundary between the Pacific Plate and the North American plate. One of the most active plate boundaries where earthquakes and eruptions are frequent, for example, is around the massive Pacific Plate commonly referred to as the Pacific Ring of Fire.
30.The earliest recorded evidence of an earthquake has been traced back to 1831 BC in the Shandong province of China, but there is a fairly complete record starting in 780 BC during the Zhou Dynasty in China.
31.It was recognized as early as 350 BC by the Greek scientist Aristotle that soft ground shakes more than hard rock in an earthquake.
32.The cause of earthquakes was stated correctly in 1760 by British engineer John Michell, one of the first fathers of seismology, in a memoir where he wrote that earthquakes and the waves of energy that they make are caused by “shifting masses of rock miles below the surface”.
33.In 1663 the European settlers experienced their first earthquake in America.
34.Human beings can detect sounds in the frequency range 20-20,000 Hertz. If a P wave refracts out of the rock surface into the air, and it has a frequency in the audible range, it will be heard as a rumble. Most earthquake waves have a frequency of less than 20 Hz, so the waves themselves are usually not heard. Most of the rumbling noise heard during an earthquake is the building and its contents moving.
35.When the Chilean earthquake occurred in 1960, seismographs recorded seismic waves that traveled all around the Earth. These seismic waves shook the entire earth for many days! This phenomenon is called the free oscillation of the Earth.
36.The interior of Antarctica has icequakes which, although they are much smaller, are perhaps more frequent than earthquakes in Antarctica. The icequakes are similar to earthquakes, but occur within the ice sheet itself instead of the land underneath the ice. Some of our polar observers have told us they can hear the icequakes and see them on the South Pole seismograph station, but they are much too small to be seen on enough stations to obtain a location.