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  • DNews is based in grand old San Francisco.

  • Known for it's culture, or counterculture, giant reddish orange bridge, and earthquakes.

  • Earthquakes happen when tectonic plates shift.

  • This sudden burst of energy sends seismic waves shooting in all directions.

  • These waves can violently shake buildings both up and down and side to side with enormous

  • force.

  • It's this forceful shifting that actually causes stress on the buildings to the point

  • of collapse.

  • As we live in an Earthquake prone area, we realize a fundamental truth.

  • Earthquakes don't kill people.

  • Buildings do.

  • So researchers have spent a lot of time wondering how to make buildings safer.

  • When an engineer is first planning a new building they have to take into account where the building

  • will be built.

  • Earthquake guidelines are different in say Kansas than in California.

  • The intensity of forces from Earthquakes varies from place to place.

  • The goal when building in high intensity earthquake areas is to make a building earthquake resistant.

  • Earthquake proof is doable, but extremely expensive.

  • Now, to be consideredEarthquake resistant” a building can suffer damaging, but it can't

  • collapse on the people trying to get out.

  • And there's two main ways to do that, by designing a building so it's stronger or

  • more flexible.

  • One way engineers can make buildings stronger is by reinforcing concrete with steel.

  • But in high risk areas like California, that's often not enough.

  • One of the most effective ways to protect a building from such disasters is to keep

  • them from moving by detaching it from the ground.

  • Base isolation is when engineers design a structure to be built on top of a separate

  • base, instead of attached to a foundation, so that when an earthquake hits, the base

  • moves, but the building only ways slightly.

  • For instance San Francisco's City Hall was retrofitted with a base isolation system.

  • And this concept isn't new.

  • We see these examples as early as the 4th century.

  • They utilized isolation bases made of smooth rocks that could slide against each other.

  • In modern times these bases are usually made out of a combination of a flexible material

  • like rubber and steel.

  • The rubber also acts like a shock absorber.

  • But a cool piece of shocking tech comes Taiwan.

  • The supertall skyscraper, Taipei 101, combats earthquakes with a giant 728 ton ball.

  • Well it's technically called a “tuned mass damperbut it's basically a giant

  • ball that's suspended near the top of the building.

  • If the building sways because of an earthquake or a typhoon, the damper swings in the opposite

  • direction.

  • During a particularly strong gust in 2015, the ball in Taipei 101, swung a meter from

  • it's center position.

  • And technology is getting even more advanced.

  • According to one study published in the journal Applied Physics Letters researchers are working

  • on a way to make a building invisible to shock waves using a shield.

  • This shield of concrete and plastic buried at least 3 feet down, looks like two rainbows

  • surrounding the building with a gap between them.

  • Each strip, orcoloris more stiff the farther out they are from the core.

  • The waves have an easier time traveling through a stiff and hard layer.

  • So the waves, once they hit a softer layer, deflect and head back to the easier path.

  • The way these plates curve, essentially channels the shock waves around the building.

  • As they move around the building they hit a gap in the plate which allows some of the

  • force to dissipate.

  • So the plate kind of hides the building from the Earthquake.

  • Like an invisibility cloak for earthquakes!

  • When earthquakes hit, their intensity is measured in a point system called the richter scale.

  • Trace takes a look at the different ways seismologists measure earthquakes and what do these ratings

  • mean in this episode right here.

  • Have you lived through an earthquake?

  • Tell me your experience down in the comments below

DNews is based in grand old San Francisco.


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How We Design Buildings To Survive Earthquakes

  • 7 1
    joey joey に公開 2021 年 04 月 26 日