5 ms·

At least in the links with the video now you can see that the container ship directly hits one of the two main (and in the central area only) pillars completely

At least in the links with the video now you can see that the container ship directly hits one of the two main (and in the central area only) pillars completely collapsing it. No matter(1) the engineering there is no pretty much way to not lose the whole large middle area and left area leading to the destroyed pillar in that situation. Such a collapse crates so much force (tension vibrations etc.) so that the collapse of the section right of the right pillar is not unreasonable. The only question is if the impact should have made the pillar collapse. But a loaded container ship is ... absurdly massive I mean they are like multiple high raise building (but not sky scrapers) standing squished together side by side. So the force it can apply is huge and if cargo moving in it there will be force applied to whatever it crashes into even after the initial impact. And looking at the waves caused by impact with the base it was at least 8m high I think (depending on the container ship). So that wasn't a "slow moving" impact. And even slow moving impacts with container ships can tear apart a solid jetty. So while the US has issues with infrastructure maintenance idk. if anything but building a many pillar bridge would have made any difference. And building a many pillar bridge might not be very viable depending on the under water landscape and water use under the main area. EDIT: Looking at pictures with daylight where you can try to estimate the high of the ship using containers I would say the waves where handwavingly 4 containers high so ~9.5m and it also looks like the ship might have embedded half of the pillars fundament into/under itself (but it's a bit hard to tell to the angle of the picture). I think if that's the case probably the huge majority of bridge pillars of past and presence would have collapsed.

JohnBooty 3y ago
It certainly does not seem reasonable to design a bridge pillar to withstand a direct impact from a massive cargo ship. But I guess I thought that maybe there was... typically some kind of earthen buffer around the pillar to prevent such an impact? That's probably impractical too, I guess. I guess I just didn't realize ~$1bn bridges were one fluky ship accident away from total collapse at any given time. I think maybe I prefer my previous state of ignorance, to be quite honest....
- hgomersall 3y ago
  An earth buffer is just a bigger pier.
- kamaal 3y ago
  >>But I guess I thought that maybe there was... typically some kind of earthen buffer around the pillar to prevent such an impact? It does look reasonable to have such a buffer. But any preventive measure will have limits as what and how serious an impact it can deal with. In this case the ship this massive is something that is carrying ridiculous inertia, and its highly unlikely even a buffer could stop such an impact. I think at some point you are better off solving these issues with more regulation(smaller ships)? Instead of treating this as a engineering problem.
  - unsupp0rted 3y ago
    It wouldn't take as much of a buffer to redirect the ship at an angle away from the pillar, would it?
    - kergonath 3y ago
      I think this would be even harder. Whilst the ship has a lot of kinetic energy that needs to get dissipated, it also has a huge momentum that needs to be partly overcome to redirect it. You’d also need a material with enough structural strength to turn the ship. Materials that can crumple or deform (like huge concrete blocks or earthworks) are great at dissipating energy, but they aren’t great at deflecting things.
  - mannykannot 3y ago
    > But any preventive measure will have limits as what and how serious an impact it can deal with. The recent grounding of a large container ship in Baltimore's harbor channel demonstrates that a sufficiently massive berm will stop any ship. What's needed is the will to do something about low-probability but catastrophic events (though large-ship collisions, groundings and fortuitously harmless steering failures are frequent enough that this should not have been dismissed as a low-probability event.) https://www.cnn.com/2022/03/16/business/evergreen-container-ship-grounded/index.html https://www.cnn.com/2022/03/16/business/evergreen-container-... In this case, the nearby towers supporting transmission lines across the channel seem to be better-protected against ship collisions than the piers of the bridge. https://images.app.goo.gl/J6vTeDW5xjysbdjr9 https://images.app.goo.gl/J6vTeDW5xjysbdjr9
onetimeuse92304 3y ago
> So that wasn't a "slow moving" impact Exactly. It is only the scale and the viewing angle that makes it seem slow moving.
xoa 3y ago
Just to put some numbers on this: The MV Dali (IMO#9697428) is a little over 95000 GT, or ballpark-ish probably around 114000 tons loaded (and it seems to have been loaded, which would make sense on departure). If it was going even 5kn (2.6 m/s) that'd be about 300 million newton-seconds, or about 3.3 times the momentum of a large jumbo jet like a 747 shortly at cruising speed (around 560 mph). It'd still have the same momentum as said jet if it was going just 1.5kn. The ship of course is enormously more stoutly built and the force is going to be transmitted far more directly into whatever it hits vs into explosions driving mass elsewhere. I've read that both on water and in space for that matter enormously massive objects moving very slowly messes with human perception and "common sense", it "feels like" something moving along smoothly and slowly should be stoppable or come to a stop. Enormous momentum and forces can be terrifying things.
- KineticLensman 3y ago
  > enormously massive objects moving very slowly messes with human perception and "common sense" Yes, hence warnings to amateur boat users (e.g. on a canal boat) not to try to stop a collision with the bank using your arms or legs. [Edit] Boats can also do things that are unintuitive if you are used to driving a car. E.g. turning round the centre of gravity when you steer rather than following the front wheels.
  - smogcutter 3y ago
    In the black powder era of warfare, soldiers were given similar warnings about “slowly” rolling cannonballs. People would think they could stop them like soccer balls, and lose a foot.
  - bmelton 3y ago
    There are similar warnings for sailing vessels, but because the standing rigging of the ship is usually kept in high enough tension that putting your hands on a pilon to stop a collision might leave your hands vulnerable to being cut off by a mainsail's shrouds.
    - 3y ago
zeteo 3y ago
You don't need to build the bridge to an absurd strength, but it may have been insufficiently marked as a navigational hazard. Something like a few well-lit pillars 500 feet upstream in the water would have given the ship plenty of warning to change course, since a vessel travelling at 5 knots takes about a minute to go 500 feet. The total bridge length is on the order of 10,000 feet, so widening the safe area around the pillars to 500 feet would not be a significant impediment to navigation.
- ToucanLoucan 3y ago
  I've seen close-up video where you can see the ship losing electrical power twice for not-insubstantial times as it approaches the column. I suspect that was a much larger factor in the collision than anything the crew may or may not have done. Warning time doesn't mean shit if you can't steer.
  - nytesky 3y ago
    https://twitter.com/ChaudharyParvez/status/1772538539495809075 https://twitter.com/ChaudharyParvez/status/17725385394958090... Posted video of power loss. Also black smoke coming out rear — is that normal? Any clue of what onboard crisis they were dealing with?
    - kossTKR 3y ago
      It seems traffic has stopped in the last moments before the hit? Also looks like it's emergency vehicles in standstill that are falling, i can't discern any moving cars at collapse?
      - ToucanLoucan 3y ago
        I heard through the grape vine they were able to halt traffic across the bridge at the last minute. Only people actually on it when it fell were construction workers who were filling potholes at the time.
      - vcg3rd 3y ago
bmitc 3y ago
I mean, yes, everybody is pointing out about the mass of the container ship, but that's actually to the point of the above question and my question. Because the ship's size and weight are obvious. Were ships this size regularly passing by or under this bridge such that this scenario was effectively bound to happen given a ship failure and/or pilot error? That's my question. I'm not familiar with port activities, so it seems weird to have basically no secondary protection for that bridge with container ships of that size operating so close that they can hit it mere minutes after some failure. Watching this video (https://www.youtube.com/watch?v=qJNRRdha1Xk https://www.youtube.com/watch?v=qJNRRdha1Xk) shows that the ship was incredibly close to the bridge in the first place, even prior to the supposed failure. It's a bit bewildering to me, with my current knowledge, that this scenario wasn't envisioned prior.
- shaboinkin 3y ago
  That was my thought. The supports look like toothpicks relative to the ships that routinely pass through. I don't know enough about the forces involved here, but I'd like to think when they rebuild, they will add some sort of deflection capabilities around the supports that ships must past in between. But again, I don't know what that would take to deflect a massive ship like this. In hindsight, the bridge looks terribly exposed given the persistent risk of ships passing through.

JohnBooty 3y ago

It certainly does not seem reasonable to design a bridge pillar to withstand a direct impact from a massive cargo ship. But I guess I thought that maybe there was... typically some kind of earthen buffer around the pillar to prevent such an impact? That's probably impractical too, I guess. I guess I just didn't realize ~$1bn bridges were one fluky ship accident away from total collapse at any given time. I think maybe I prefer my previous state of ignorance, to be quite honest....

hgomersall 3y ago
An earth buffer is just a bigger pier.
kamaal 3y ago
>>But I guess I thought that maybe there was... typically some kind of earthen buffer around the pillar to prevent such an impact? It does look reasonable to have such a buffer. But any preventive measure will have limits as what and how serious an impact it can deal with. In this case the ship this massive is something that is carrying ridiculous inertia, and its highly unlikely even a buffer could stop such an impact. I think at some point you are better off solving these issues with more regulation(smaller ships)? Instead of treating this as a engineering problem.
- unsupp0rted 3y ago
  It wouldn't take as much of a buffer to redirect the ship at an angle away from the pillar, would it?
  - kergonath 3y ago
    I think this would be even harder. Whilst the ship has a lot of kinetic energy that needs to get dissipated, it also has a huge momentum that needs to be partly overcome to redirect it. You’d also need a material with enough structural strength to turn the ship. Materials that can crumple or deform (like huge concrete blocks or earthworks) are great at dissipating energy, but they aren’t great at deflecting things.
- mannykannot 3y ago
  > But any preventive measure will have limits as what and how serious an impact it can deal with. The recent grounding of a large container ship in Baltimore's harbor channel demonstrates that a sufficiently massive berm will stop any ship. What's needed is the will to do something about low-probability but catastrophic events (though large-ship collisions, groundings and fortuitously harmless steering failures are frequent enough that this should not have been dismissed as a low-probability event.) https://www.cnn.com/2022/03/16/business/evergreen-container-ship-grounded/index.html https://www.cnn.com/2022/03/16/business/evergreen-container-... In this case, the nearby towers supporting transmission lines across the channel seem to be better-protected against ship collisions than the piers of the bridge. https://images.app.goo.gl/J6vTeDW5xjysbdjr9 https://images.app.goo.gl/J6vTeDW5xjysbdjr9

onetimeuse92304 3y ago

> So that wasn't a "slow moving" impact Exactly. It is only the scale and the viewing angle that makes it seem slow moving.

xoa 3y ago

Just to put some numbers on this: The MV Dali (IMO#9697428) is a little over 95000 GT, or ballpark-ish probably around 114000 tons loaded (and it seems to have been loaded, which would make sense on departure). If it was going even 5kn (2.6 m/s) that'd be about 300 million newton-seconds, or about 3.3 times the momentum of a large jumbo jet like a 747 shortly at cruising speed (around 560 mph). It'd still have the same momentum as said jet if it was going just 1.5kn. The ship of course is enormously more stoutly built and the force is going to be transmitted far more directly into whatever it hits vs into explosions driving mass elsewhere. I've read that both on water and in space for that matter enormously massive objects moving very slowly messes with human perception and "common sense", it "feels like" something moving along smoothly and slowly should be stoppable or come to a stop. Enormous momentum and forces can be terrifying things.

KineticLensman 3y ago
> enormously massive objects moving very slowly messes with human perception and "common sense" Yes, hence warnings to amateur boat users (e.g. on a canal boat) not to try to stop a collision with the bank using your arms or legs. [Edit] Boats can also do things that are unintuitive if you are used to driving a car. E.g. turning round the centre of gravity when you steer rather than following the front wheels.
- smogcutter 3y ago
  In the black powder era of warfare, soldiers were given similar warnings about “slowly” rolling cannonballs. People would think they could stop them like soccer balls, and lose a foot.
- bmelton 3y ago
  There are similar warnings for sailing vessels, but because the standing rigging of the ship is usually kept in high enough tension that putting your hands on a pilon to stop a collision might leave your hands vulnerable to being cut off by a mainsail's shrouds.
  - 3y ago

zeteo 3y ago

You don't need to build the bridge to an absurd strength, but it may have been insufficiently marked as a navigational hazard. Something like a few well-lit pillars 500 feet upstream in the water would have given the ship plenty of warning to change course, since a vessel travelling at 5 knots takes about a minute to go 500 feet. The total bridge length is on the order of 10,000 feet, so widening the safe area around the pillars to 500 feet would not be a significant impediment to navigation.

ToucanLoucan 3y ago
I've seen close-up video where you can see the ship losing electrical power twice for not-insubstantial times as it approaches the column. I suspect that was a much larger factor in the collision than anything the crew may or may not have done. Warning time doesn't mean shit if you can't steer.
- nytesky 3y ago
  https://twitter.com/ChaudharyParvez/status/1772538539495809075 https://twitter.com/ChaudharyParvez/status/17725385394958090... Posted video of power loss. Also black smoke coming out rear — is that normal? Any clue of what onboard crisis they were dealing with?
  - kossTKR 3y ago
    It seems traffic has stopped in the last moments before the hit? Also looks like it's emergency vehicles in standstill that are falling, i can't discern any moving cars at collapse?
    - ToucanLoucan 3y ago
      I heard through the grape vine they were able to halt traffic across the bridge at the last minute. Only people actually on it when it fell were construction workers who were filling potholes at the time.
    - vcg3rd 3y ago

bmitc 3y ago

I mean, yes, everybody is pointing out about the mass of the container ship, but that's actually to the point of the above question and my question. Because the ship's size and weight are obvious. Were ships this size regularly passing by or under this bridge such that this scenario was effectively bound to happen given a ship failure and/or pilot error? That's my question. I'm not familiar with port activities, so it seems weird to have basically no secondary protection for that bridge with container ships of that size operating so close that they can hit it mere minutes after some failure. Watching this video (https://www.youtube.com/watch?v=qJNRRdha1Xk https://www.youtube.com/watch?v=qJNRRdha1Xk) shows that the ship was incredibly close to the bridge in the first place, even prior to the supposed failure. It's a bit bewildering to me, with my current knowledge, that this scenario wasn't envisioned prior.

shaboinkin 3y ago
That was my thought. The supports look like toothpicks relative to the ships that routinely pass through. I don't know enough about the forces involved here, but I'd like to think when they rebuild, they will add some sort of deflection capabilities around the supports that ships must past in between. But again, I don't know what that would take to deflect a massive ship like this. In hindsight, the bridge looks terribly exposed given the persistent risk of ships passing through.