11 ms·

Most bridges nowadays (say last century) depend on a careful balance of forces that are transferred through a chain of members in tension and compression. When

• rkagerer 3y ago
  Many homes also incorporate lightweight trusses that can fail in a similar fashion. They pose a unique risk for firefighters, which is why New York went so far as to require warnings be posted outside such structures: https://www.finehomebuilding.com/2015/01/28/new-york-now-requires-truss-warning-on-buildings https://www.finehomebuilding.com/2015/01/28/new-york-now-req...
• armchairdweller 3y ago
  Thanks! So why are huge—ass container ships allowed to navigate underneath fragile public bridges with single points of failure? The not unlikely worst case is that the ship is out of control for some reason…
  • oliviabenson 3y ago
    We notice these type of accidents because they’re so rare. 5k+ people die each year because of large trucks on the road, by comparison, boats and bridges are very safe — that’s why it’s allowed.
    • 3seashells 3y ago
      [dead]
  • bombcar 3y ago
    Because bridges over harbors are quite common an incidents like this are rare.
    • mcv 3y ago
      The Dutch ports of both Amsterdam and Rotterdam have no bridges at all. It's all tunnels. I think that's the best way to go; the least chance of conflict between road and water traffic.
      • keenmaster 3y ago
        Often in America the government waits for something to fail miserably before engaging in a high effort high cost activity that requires a lot of coordination and public buy-in.
        • FrustratedMonky 3y ago
          Wow. Random ship hits a bridge. Shakes fist at sky "the government".
          • Muromec 3y ago
            But that's what you do with random events -- create policies to prevent them from happening, lowering the incidence rate and minimizing damage once it occurs. Which is exactly what government and laws are all about.
            • FrustratedMonky 3y ago
              That is a generous reading of the parent comment. It sounded much more like a common trope, "the do-nothing government just lets things fail, doesn't take action until something fails".
          • etempleton 3y ago
            The amount of arm chair quarterbacking here is astounding. Reddit has a more nuanced conversation than HN right now. A bridge got hit by a container ship at speed and folks here are talking about this like the bridge was not up to standard, or why there was a bridge there at all when they know nothing about the locale. I am not a structural engineer, but I am going to go ahead and guess that not much would still be standing from a direct hit from a container ship. And from observation bridges like this exist all over the world and don’t regularly get struck by container ships. It was a freak accident. If we want to point fingers or question things, perhaps if anything the question is why the container ship lost power repeatedly? Was this a known issue before leaving port?
  • mvdtnz 3y ago
    Not unlikely? Can you point us to all the other times this has happened? You must know of several given your knowledge of how obviously likely this is.
    • rpeden 3y ago
      It's not especially common, but the Sunshine Skyway Bridge in Tampa Bay is a famous example. Similar circumstances - it collapsed after being hit by a ship.
      • 3seashells 3y ago
        [dead]
      • pirate787 3y ago
        The replacement bridge in Tampa famously added "dolphins" which are bumpers in the water to protect the bridge pylons.
      • ZanyProgrammer 3y ago
        that collapsed almost 40 years ago, which really emphasizes it's flat out uncommon, no "buts" needed.
    • SonOfLilit 3y ago
      Downvoted for unkindness towards internet stranger.
    • armchairdweller 3y ago
      When has "nothing will happen as long as we can carefully navigate our massive vessels around these critical pillars" ever been a trustable safety measure? Over the long term shit like this will happen if it the possibility that it happens is not excluded by other measures. This is a public bridge 5 years in the making and who knows how long in planning, and people have been extremely lucky that it collapsed at 3am and not in the middle of the day. It doesn't matter at all how unlikely this is in a given time frame if the impact if it happens at any point in time is catastrophic.
  • rpeden 3y ago
    Because the Port of Baltimore is a very major port, and not allowing ships under it really isn't an option. Vertical clearance for ship traffic might have been the reason this kind of bridge was built in the first place. Otherwise, something lower and more causeway-like might have been sufficient.
    • mcv 3y ago
      If it's a very major port, they can afford to make it a tunnel.
      • c5karl 3y ago
        The Patapsco is much wider here than at the locations of the two tunnels. It would have been a much bigger and more expensive project to build a tunnel that long.
      • adestefan 3y ago
        There already are two tunnels for I-95 and I-895 under the port.
        • mcv 3y ago
          Then why is this one a bridge? Why not go all the way and make this a tunnel too?
          • xav0989 3y ago
            Mostly to have a hazmat route around the city (HAZMAT trucks aren’t allowed in the tunnels) and because bridges are cheaper than tunnels. They needed a third crossing because the traffic warranted it.
            • mcv 3y ago
              > Mostly to have a hazmat route around the city (HAZMAT trucks aren’t allowed in the tunnels) That is a very interesting point I hadn't considered at all. Price is an obvious point, but I hadn't considered hazmat. It does make me wonder how hazmat traffic is handled around Amsterdam. I think they are allowed in some tunnels here.
  • 317070 3y ago
    If bridges and container ships indeed do not go together (something I don't necessarily agree with), you probably want to take away the public bridge and continue to let ships go by. This is economically speaking for the area. Car traffic is just not very efficient in the comparison between the two. Edit: of course there are a ton of other solutions here as well. I am disagreeing with the parent that it is the cars which should get to stay and the container ships which have to move.
    • mcv 3y ago
      You can have smaller container ships. Or have the port outside the bridge. Or indeed replace the bridge with a tunnel, or a better bridge. Amsterdam has no bridges at all crossing the IJ on the west side (where sea-going ships come from) and only a single bridge on the east side (though there's often talk of adding another). Everything is tunnels. Rotterdam has bridges (including the famous Erasmusbrug), but only east of the port area. To the west, everything is tunnels. And the largest ships don't even come close to the city center, but dock at the Maasvlakte out at sea. For both cities, ports have constantly moved closer to the sea.
      • ThrustVectoring 3y ago
        You don't even need to run it as a tunnel the entire way through - Chesapeake Bay has vehicular traffic routed through a combination bridge/tunnel, using tunnels to span the two major shipping channels crossed by the complex.
        • mcv 3y ago
          The A10 ring in Amsterdam does the same on the east side. The west is all tunnel, the east is half tunnel half bridge.
      • palmfacehn 3y ago
        Baltimore has been in a steady state of decline as long as I can recall. Industry has constantly moved away. https://foxbaltimore.com/news/local/as-residents-leave-baltimore-named-among-top-15-shrinking-us-cities https://foxbaltimore.com/news/local/as-residents-leave-balti... >“There’s a lot of people staying [in those cities] and we want to be sure they’re not left with an excess of infrastructure that’s impossible to maintain,” he said. “So what do we do about it?”
  • LargoLasskhyfv 3y ago
    > out of control for some reason... I think the whole ship went dark for a moment. That may have had an impact on the rudder, and then some strong current and/or wind, pushing it sideways. Couldn't see tug-boats.
    • dgritsko 3y ago
      Was watching CNN around 6AM EDT, they had a reporter on scene who mentioned wind "whipping across" the harbor. This was in reference to the potential survivability of the freezing cold water, but it seems likely it could have been a factor in pushing the ship off course as well.
  • layer8 3y ago
    To be able to reach the port. You could argue that such bridges shouldn’t be built in front of ports, but the public also doesn’t like having to drive long detours, and the likelihood of an incident like this one is very low.
• roenxi 3y ago
  It is worth observing that this bridge seems to have 2 pylons and one of them collapsed. The failure seems comprehensible after that - you can see in the video how the balances came apart, there is nothing to hold the left side up so it falls and then remainder of the bridge tried to rotate around the remaining pylon and failed.
  • mcv 3y ago
    It's no surprise that the entire bridge collapses after a pylon collapses. What surprises me is that the pylon collapses. I'd expect those to be extremely solid, with tons of padding. But with ships getting bigger and bigger, I guess there's a limit to what you can account for.
    • xienze 3y ago
      Ships are hundreds of thousands of tons in weight and the momentum acts as a force multiplier. Plus it hit the pylon dead center, which is the worst case scenario. It’s not terribly surprising. I think there’s also an underlying expectation that any competent ship captain would at least be able to see that they’re on a collision course with the pylon well ahead of time and be able to compensate. Which obviously didn’t happen in this case.
      • ponector 3y ago
        There is another video where we can see two power outage occurred. Ship was uncontrollable but with enormous amount of inertia. I'm sure captain tried to do anything he can to avoid collision.
      • TheHypnotist 3y ago
        The trajectory of the ship seemed near perfect right up until just before the bridge where I suspect it experience it's mechanical issue.
        • KineticLensman 3y ago
• HlessClaudesman 3y ago
  On a long enough timeline we all get rammed by a container ship. I would be interested to know some calculations with factors like: expected bridge lifetime, chance of being rammed per year, cost of making supports strong enough plus an extra safety margin to survive maximum ramming force, cost of having major commercial shipping route unusable for an extended period.
  • Retric 3y ago
    Bridges only last for roughly 50 years. Considering such collisions are rare enough to make the news as a memorable event you can workout for yourself that the odds are quite low over a bridges lifespan. They are designed to withstand smaller boat impacts because they occur relatively frequently, but cost vs benefit on rare events that are difficult to mitigate is quite different.
    • yosame 3y ago
      Do you mean 50 years without maintenance? I would be shocked if major bridges weren't designed to last indefinitely.
      • mango7283 3y ago
        I can think of at least 5 famous bridges that are way older than 50 years...
        • Retric 3y ago
          Sure, and there's 100's of thousands of replaced bridges that don't immediately spring to mind. Though to be clear designed to last 50 years isn't the same as saying it will only last exactly 50 years, or that theirs nothing you can do to extend a bridges lifespan if it's replacement is running a little late.
        • bee_rider 3y ago
          If it is a famous bridge, it seems possible that they’ve done some special extra maintenance, replace more wear-and-tear bits that would normally fail. Eventually you probably get the tourist attraction of Theseus.
• ithkuil 3y ago
  “Any idiot can build a bridge that stands, but it takes an engineer to build a bridge that barely stands.” And in practice only bridges that "barely" stand are economically viable
  • kwhitefoot 3y ago
    > only bridges that "barely" stand are economically viable That really depends on what is counted as part of the economy and who is doing the valuing.
    • bbor 3y ago
      I’m a huge “it’s capitalism’s fault” person, but this one feels mostly inevitable. Bridges are wonders of engineering that require this delicate balance, and I don’t think “just build em the old way” is an option. It’s not just price, it’s strength (for non-container-ship events…), span, height, construction time, etc. Obviously I’m in no place to evaluate the specifics of this bridge, and as someone from the SF Bay Area I know allll about corporate corruption fucking up expensive brand new bridges, but I feel like you’re yelling at the moon a bit here. Apologies if I misunderstood though!
    • ithkuil 3y ago
      well, "economically viable" doesn't necessarily mean scraping the bottom. For example the great pyramids of giza are very solidly built. You certainly don't expect that level of build for every commercial or residential building out there. Now, on the other end of the spectrum you can have buildings that can collapse on minor earthquakes. There is a balance somewhere in the middle.
• FrustratedMonky 3y ago
  Yes, and it looks like it did take out an entire section. So it isn't like the ship just 'nicked' it and bent a few members. An entire support was taken out.
• jalk 3y ago
  Which is why many bridges have stuctures around the pillars to avoid the direct collisions