The Swiss Seismic System

Not Switzerland, as that country is known for its superior engineering*, and they’d probably scoff at this kind of patchwork, but Swiss Cheese. Below you see a beautiful concrete shear wall, essential for taking wind and earthquake loads from one level of a building to the next — helpful for people not dying! — punched through with one big hole and a couple small ones.

Oops, you thought you had a wall, but now you don’t!

Ideally you reinforce these things beforehand vertically, horizontally, and at 45 degrees at each corner (even more ideally you do a finite element analysis — lots of computer modeling and numerical methods to go gaga over — but that’s let’s not let the perfect be the enemy of the good). Here, reinforcing beforehand clearly didn’t happen and the fix was to bolt plates to the wall — the technical term is “band-aids.”

It’s a valiant effort, but if originally you were going to reinforce the opening in three directions, and now you’re only doing it in one, that’s a problem. Presumably, some engineer modeled the above reinforcing situation and decided it was okay, but the point remains that you’re not really replacing the lost capacity of the wall; it’s weaker and going to behave differently. More specifically it’s going to crack through the weakest cross-section — in a line running through all those holes.

Cracking itself isn’t inherently a problem — it dissipates energy in a quake, keeping other parts of the building from collapsing — but now it will happen at lower magnitudes, meaning the building is damaged more easily and has a shorter lifespan. Which is why these holes piss the hell out of me. Buildings cost a huge amount in nonrenewable resources and construction waste is a significant percentage of landfill wastes. They are only useful for a small amount of years (averages I’ve seen thrown around: 50-80). When you weaken the seismic system you take years off the building’s lifespan.

Yet contractors go around drilling like a gang of drunk yahoos prospecting for oil. Afterwards, they send you pictures like the above and ask if it’s okay. Dudes: you already demolished the wall! I guess it’s going to have to be. They explain that their schedule dictated they had to have the hole immediately. Which makes sense. The schedule ($$$) is definitely more important than life safety; definitely more important than the long-term value of the building. Assholes.

*Plus I’m not really sure they have an earthquake problem — they’re pretty far from a plate boundary — and hence might have no need for a seismic system. Normally that would mean I would sneer at the “engineering,” but oh! The bridges!

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