How do the construction employees do it?
In: Engineering
By doing something that sounds kind of counter intuitive. By reinforcing the building, and make it more wobbly.
Basically, when an earth quake hits you want your building to be able to rock and sway a little bit to help absorb the energy from the vibrations. And then because of that you also want your building strong enough to handle that rocking and swaying.
Hard brittle construction (like stone or concrete) can be either directly reinforced with steel, or have additional steel elements placed around it. This is because steel, compared to concrete, if much more elastic and able to bend/twist while returning to its original shape and strength, while trying to bend concrete will permanently crack it.
Then they will also add “Dampening Elements”. You can imagine this as large, strong springs that criss cross along a wall, that all the building moves stretch and contract, helping to keep the building vertical enough that it doesn’t fail, as well as absorbing more energy from the vibrations.
Again this is another example of adding things to a building that allow it to move and absorb the energy, while keeping it from just cracking apart.
Another method is the augment the buildings foundation with a “seismic insulation structure”. Which to explain simple is like putting the whole building on giant springs that act like shock absorbers. These allow the ground to move around under the building but keep the building in roughly the same spot.
These work like the suspension in a car, that allow the tires to move up and down to absorb all the cracks and bumps in the road, while keeping your ride inside the car feeling smooth.
Imagine a house of cards on a table. If you jostle the table sideways, it buckles and collapses. This force is called shear, if you wanted to make the house if cards stay up, you need to make it resist shear forces, by applying something like tape to make it wobble without collapsing.
It’s the same idea on a larger scale. They add in the ability for the building to sway without falling. This can mean making the building sit on giant springs (like car suspension) or on “hinges” of sorts.
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