Video: Baltimore bridge struck by boat and collapses

Breezy@lemmy.world to News@lemmy.world – 497 points –
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I feel like the whole thing shouldn't have come down as easy as it did...

Edit: Nevermind, I didn't realize how large this ship actually is.

I don't think integrity after getting a support annihilated by a massive ship is a reasonable design objective. You'd need way more supports and structure, at least doubling the weight and cost of the structure, I'd guess maybe 4x. As far as stress tests go, getting one of your two supports knocked out is an extremely stressing condition.

I learned recently that in engineering there’s a saying that anyone can build a bridge that will stand, but only an engineer can build a bridge that barely stands.

Which seems dark, but bridges are built on budgets while adhering to aesthetic, material, and site/traffic (on, under, and sometimes over) requirements.

And besides, that ship was between 210 to 257 million pounds, traveling at whatever speed it was going. I’m not a physicist, but I recon that’s enough force to knock down a bridge. (As evidenced.)

Even moving very slowly, that's a hell of a lot of force exerted on something designed to take a sideways load caused by, at most, wind.

getting one of your two supports knocked out is an extremely stressing condition.

Bridges need therapists too!

if you ever made a bridge out of toothpicks in school, the lesson is how much force it can hold straight up and down. Something super heavy whacking at its side while also dead on nailing one of the major support structures.... yeah thing crumbled like toothpicks

Baltimore Truthers, already?

I took it as less of "gubment did it" and more "holy shit that bridge seems shoddy as fuck"

The crazy thing is it isn't even the bridge being shoddy. It's terrifyingly simple physics. High mass objects moving slowly and low mass objects moving quickly are both incredibly destructive. I'm not entirely sure how you build safeguards against a collision like that. It would need military grade protection -- assuming even the military has something which could withstand that.

Think of it like this. A bridge is designed to distribute weight and force and stand up. It isn't designed to take a hit like this.

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It's not just that the ship is as big as it is. A ship half it's size could have done it too. Bridges like this are very strong in the way of supporting their deck. But the way they achieve it is by spreading the weight out over a very large area. Interrupt that and the whole thing comes down.

the whole thing shouldn't have come down as easy as it did

Like jet fuel to a steel beam?

(Is it too soon if I was an eyewitness?)

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