4 ms·

You could try to avoid collisions with barriers, or make the bridge fail differently (only a few spans), or make it tolerant to a single support failing. But yo

You could try to avoid collisions with barriers, or make the bridge fail differently (only a few spans), or make it tolerant to a single support failing. But you need a pretty beefy steel beam to survive a direct hit by... Uh... 200,000t(??) traveling even at a slow jogging pace. (And then it transfers the energy into the rest of the bridge, which will very much not like it). I guess we can be happy failure like this is rare, and that the bridge was not busy: reports indicate 13 cars, and about 7 persons still missing. This could be so much worse. The best way to think about measures is after we know the full chain of events that have lead to this.

bagels 3y ago
Some other bridges have barriers around, but not connecting to the pylons.
- Kye 3y ago
  Those are great for little boats like one of those superyachts. They become dominoes that hit before a boat like this: https://www.vesselfinder.com/?imo=9697428 https://www.vesselfinder.com/?imo=9697428
  - archi42 3y ago
    Absolutely. 116851 long tons deadweight, which the Google info box says includes everything (busy now, so can't check in detail). That's 120,000,000 kg, so a little bit less than I guessed. Now looking at 10km/h or 6.2mi/h or 2.78m/s, that's enough to come up with a big E for E = 1/2 * m * v². The momentum p = m * v is also rather unpleasant. If the momentum was suddenly transferred into my 2,000 kg car (e.g. if the ship hit my car), I could do my work trip in about 1s, though that's only a few times times faster than the ISS (which travels at 7660 m/s). [I'm very busy, so hopefully I didn't forget/add a few 0s by accident. Anyone feel free to correct me if I did.]
    - deleted 3y ago
      [deleted]
TaylorAlexander 3y ago
Right. I am not really thinking of designing pillars that are impossible to knock over. I am thinking of alternative bridge designs where a higher percentage of the total bridge stays up when one pillar is taken out. On this bridge, the main section of the bridge is supported by four spaced pillars, making three main spans there. One of the middle two towers was hit, so this should affect two of the three spans. But it took down all three of them. A span that was supported on both sides by intact towers still came down. That is what I find most surprising here.

bagels 3y ago

Some other bridges have barriers around, but not connecting to the pylons.

Kye 3y ago
Those are great for little boats like one of those superyachts. They become dominoes that hit before a boat like this: https://www.vesselfinder.com/?imo=9697428 https://www.vesselfinder.com/?imo=9697428
- archi42 3y ago
  Absolutely. 116851 long tons deadweight, which the Google info box says includes everything (busy now, so can't check in detail). That's 120,000,000 kg, so a little bit less than I guessed. Now looking at 10km/h or 6.2mi/h or 2.78m/s, that's enough to come up with a big E for E = 1/2 * m * v². The momentum p = m * v is also rather unpleasant. If the momentum was suddenly transferred into my 2,000 kg car (e.g. if the ship hit my car), I could do my work trip in about 1s, though that's only a few times times faster than the ISS (which travels at 7660 m/s). [I'm very busy, so hopefully I didn't forget/add a few 0s by accident. Anyone feel free to correct me if I did.]
  - deleted 3y ago
    [deleted]

TaylorAlexander 3y ago

Right. I am not really thinking of designing pillars that are impossible to knock over. I am thinking of alternative bridge designs where a higher percentage of the total bridge stays up when one pillar is taken out. On this bridge, the main section of the bridge is supported by four spaced pillars, making three main spans there. One of the middle two towers was hit, so this should affect two of the three spans. But it took down all three of them. A span that was supported on both sides by intact towers still came down. That is what I find most surprising here.