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[ INTRO ]
Nature has an entire suite of disasters at its disposal, and some are more difficult
to predict than others.
Like earthquakes.
Earthquakes are basically impossible to predict with any real certainty,
so populations living on or near fault lines are constantly on the lookout for the next
big one.
Still, it’s not like we’re not twiddling our thumbs, just waiting for it to strike.
Engineers have already developed some pretty amazing inventions that help protect buildings
during ‘quakes, and they’re working on more.
Here’s what they have in their arsenal now, along with a sneak peek of what’s on the
horizon.
Today, there are a few main ways we try and protect buildings from earthquakes.
One is to keep buildings from shaking side to side as much as possible,
and that can be done in several ways.
Many huge skyscrapers utilize massive swinging balls, a.k.a. tuned mass dampers.
They’re large pendulums placed high inside buildings, and they sway in response to any
movements the building makes.
That counteracts whatever is happening outside.
The most famous building with one of these is probably Taipei one-oh-one in Taiwan.
For shorter buildings, engineers often choose a different route:
They isolate the base of the building from the ground using a system of rubber and lead
that serves as a shock absorber.
A major airport in Turkey uses this method,
and it’s one of the largest seismically isolated buildings in the world.
It uses three hundred separate isolators that can reduce the side to side ‘umph’ the
earthquake puts on it by eighty percent.
Which is impressive.
Still, while tuned mass dampers and shock absorbers are great, they’re not perfect.
So engineers are also exploring new options to really step up their game.
Some of this research builds off of existing ideas.
For example, in two thousand fifteen, one group proposed a new system called vibrating
barrier,
which is like a super-strong version of a regular shock absorber.
You start with a weight held in place by springs.
Then, you stick it all in a box, and bury that box near a building’s foundation.
When an earthquake comes along, the weight gets jostled around,
and in doing so absorbs the vibrational energy that would otherwise hit the building.
This kind of tech would be perfect for buildings you can’t modify,
like historical landmarks.
But it isn’t ready to go primetime yet.
You still have to calibrate the system to absorb a certain frequency, which is specific
to each building.
That’s because, depending on a building’s mass and what it’s made of,
there are going to be some frequencies that make it vibrate more than others.
So, you’d need to use springs of a specific stiffness.
More massive buildings will also need more massive dampers.
Still, models suggest this could do a lot of good: Some experiments report that this
system could reduce the amount of acceleration a building is subjected to almost ninety percent.
Also, they could protect multiple buildings at once!
So they’re totally worth researching further.
Of course, there are a thousand ways to solve a problem, so other teams have approached
this earthquake challenge a little differently.
For example, one major field of research involves investigating how to strengthen the buildings
themselves.
Some of that involves using fancy new construction ingredients, like carbon nanotubes.
But there’s another way to go about it, too.
Like, in twenty eighteen, one team at Purdue announced that they had been 3D-printing cement
paste into specific shapes and patterns to improve the concrete’s response to earthquakes.
They’re calling these patterns “architectures”, and they’re capable of carefully directing
pressure that could induce cracks.
So, even though damage does happen to the structure, the /overall/ damage is minimized.
What’s really cool, though, is that these architectures are inspired by nature
— specifically, by the shells of arthropods.
For example, the mantis shrimp has a giant claw to smash prey at a blinding speed.
To avoid having this claw develop one huge crack,
it’s structured in such a way that microcracks form in a specific helical pattern that distributes
the pressure over a larger area.
That makes the claw less brittle overall.
And now, those helical patterns are being used in construction.
Admittedly, this research is pretty new, so it’s going to take some time to figure out
exactly if and/or how it can be incorporated into future buildings.
But it’s pretty awesome that our solution to a natural disaster could come from nature
itself.
Now, vibrating barriers and nature-inspired materials are cool,
but they might seem pretty standard in the engineering world.
So if you’ve been holding out for a really weird, wonderful example…
we have one of those for you, too.
I’m talking earthquake invisibility cloaks.
Here, you have a series of vplastic rings built into the foundation of your building
of choice.
Each ring has its own specific stiffness and elasticity to absorb a certain frequency of
wave.
When an earthquake hits, the rings deform and deflect some of the ‘quake’s energy
along themselves,
moving that energy around the building so that the people inside never feel a thing.
Basically, the building becomes “invisible” to earthquakes.
I mean, this isn’t great news for the next building over if it doesn’t have its own
protection,
but I guess this technology lives in a world where it does.
The more rings you have, the more frequencies you can cover.
And you don’t necessarily need a hundred of them, either —
you just need enough to take care of the most abundant frequencies, and the ones the building
is most sensitive to.
Also, as a huge bonus, these rings don’t have to be massive.
For a ten meter-wide building, each ring would only have to be about ten centimeters thick.
This technology started getting attention around two thousand nine, though, so there
are obviously a few things to work out before it starts popping up in the real world.
But like the other developments we’ve talked about, it is really promising.
At the end of the day, the Earth isn’t going to stop throwing earthquakes at us.
But these kinds of innovations mean that, maybe one day, we won’t have to worry too
much about the next big one.
Earthquakes aren’t the only challenge engineers have to tackle, though.
Their work involves everything from traffic to suspension bridges —
and if you want to learn more about those fields, you can check out the Infrastructure
chapter in the Physics of the Everyday course from Brilliant.
It even has a whole section about skyscrapers.
One thing I learned was that many skyscrapers have a center of mass that’s below the surface.
That helps stop them from falling over, and it’s cool to think about.
This course has plenty of other facts, diagrams, and interactive quizzes, too,
so whether you want to learn about skyscrapers or airplanes, there’s probably something
there for you.
Also, if you download Brilliant’s iOS app, you can get their courses offline!
To learn more, you can head over to Brilliant.org/SciShow.
And if you want to get yourself an annual Premium subscription, the first 200 people
to sign up at that link will get 20% off!
[ outro ]