The Future of Earthquake proof buildings.
|An Earthquake Effected Area|
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 your 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 insulators 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, onegroup 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 burythat 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 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 nano-tubes. 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 microprocessor 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 about earthquake invisibility cloaks. Here, you have a series of plastic 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 deformation 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 centimetres 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 courses 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.