EARTHQUAKE ENGINEERING – Base Isolation

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I’m Jim Metzner and this is the Pulse of the Planet. We’re featuring memorable programs from our archives this one from 1994. Engineers are designing a new type of building that they hope will more effectively resist the damage caused by earthquakes.

ambience, Earthquake

We’re listening to time-lapse, underground recordings of an earthquake.

“The method of earthquake protection that we have been working on here is called base isolation. In this approach, the building is separated from the ground, usually by putting some sort of absorption layer between the building and the ground.”

James Kelly is a professor of Civil Engineering at the University of California. He says the building’s absorption layer dissipates much of the energy of an earthquake before it can reach the higher floors.

“There are two kinds of base isolation systems in use at the present time. The one that’s most commonly used uses rubber, and generally natural rubber. The rubber has inherent damping characteristics which allows much of the energy to be absorbed in the rubber layer itself. And the other system uses sliding mechanism. The sliding mechanism is generally teflon against stainless steel. And the mechanism by which this works is that if the shock transmitted from the ground into the structure exceeds a certain level, the building slides on the isolation system. And this tends to reduce the forces transmitted to the structure.”

In light of the recent earthquake in Japan, we followed up this story and learned that thousands of buildings in Japan have used based isolation technology, but according to James Kelly, now a professor emeritus, the Japanese did not use the rubber absorption system on their nuclear power plants.

Celebrating 5000 programs, Pulse of the Planet is made possible by the NSF, I’m Jim Metzner.

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EARTHQUAKE ENGINEERING - Base Isolation

A layer of rubber or sliding steel may help protect buildings from earthquake damage. Could it have made a difference in Japan?
Air Date:04/05/2011
Scientist:
Transcript:

Music

I'm Jim Metzner and this is the Pulse of the Planet. We're featuring memorable programs from our archives this one from 1994. Engineers are designing a new type of building that they hope will more effectively resist the damage caused by earthquakes.

ambience, Earthquake

We're listening to time-lapse, underground recordings of an earthquake.

"The method of earthquake protection that we have been working on here is called base isolation. In this approach, the building is separated from the ground, usually by putting some sort of absorption layer between the building and the ground."

James Kelly is a professor of Civil Engineering at the University of California. He says the building's absorption layer dissipates much of the energy of an earthquake before it can reach the higher floors.

"There are two kinds of base isolation systems in use at the present time. The one that's most commonly used uses rubber, and generally natural rubber. The rubber has inherent damping characteristics which allows much of the energy to be absorbed in the rubber layer itself. And the other system uses sliding mechanism. The sliding mechanism is generally teflon against stainless steel. And the mechanism by which this works is that if the shock transmitted from the ground into the structure exceeds a certain level, the building slides on the isolation system. And this tends to reduce the forces transmitted to the structure."

In light of the recent earthquake in Japan, we followed up this story and learned that thousands of buildings in Japan have used based isolation technology, but according to James Kelly, now a professor emeritus, the Japanese did not use the rubber absorption system on their nuclear power plants.

Celebrating 5000 programs, Pulse of the Planet is made possible by the NSF, I'm Jim Metzner.

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