502
Video: Baltimore bridge struck by boat and collapses (streamable.com)
submitted 2 years ago* (last edited 2 years ago) by to c/news@lemmy.world
92 comments fedilink hide all child comments
 

Here is a link to another post with an article.

https://lemmy.world/post/13553444

you are viewing a single comment's thread
view the rest of the comments
[–] 15 points 2 years ago* (last edited 2 years ago) (7 children)

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.

  • permalink
  • fedilink
  • source
  • hideshow 14 child comments
    •
  • [–] 49 points 2 years ago (2 children)

    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.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 4 child comments
    •
  • [–] 33 points 2 years ago (1 child)

    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.)

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 19 points 2 years ago

    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

  • permalink
  • fedilink
  • source
  • parent
  • [–] 5 points 2 years ago

    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.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 5 points 2 years ago (1 child)

    Baltimore Truthers, already?

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [–] 23 points 2 years ago (3 children)

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

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 6 child comments
    •
  • [–] 21 points 2 years ago (1 child)

    A container ship like that weighs more than the bridge tower it hit.

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 2 child comments
    •
  • [+] -5 points 2 years ago (4 children)
    [deleted]
  • permalink
  • fedilink
  • source
  • parent
  • hideshow 8 child comments
    •
  • [–] 26 points 2 years ago (2 children)

    "Bump" is a galactically humble description of a collision with a container ship weighing nearly 200 million pounds.

    To illustrate this more cleanly, the momentum of a loaded Boeing 787 flying near top speed is 17,760,000 N.s. For this ship going at just 10 km/h, the momentum is about 260,600,000 N.s. In other words, the bridge would need to be able to sustain the equivalent of 14 9/11 attacks, simultaneously.

    The way to tolerate incidents like this is to add multiple points of isolated failure so that even if one point is catastrophically destroyed, only a portion of the bridge goes down while the rest remains intact. I don't think there are many, if any, structures on the planet that can withstand that much force

  • permalink
  • fedilink
  • source
  • parent
  • hideshow 4 child comments
    •
  • [–] 12 points 2 years ago

    This right here. You'd need a frankly ridiculous amount of solid stainless steel to build pylons for seaway protection, and that's for low speed impacts.

    Kinetic energy increases with the square of velocity!

    I'm not a sailor it anything, but I suppose requiring tugboats for all harbor travel of shops over a gross weight might be a good thing. Makes more jobs, at least.

  • permalink
  • fedilink
  • source
  • parent
  • [–] 2 points 2 years ago

    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.

  • permalink
  • fedilink
  • source
  • parent