Viewing 40 posts - 41 through 80 (of 164 total)
  • Baltimore bridge collapse
  • robola
    Full Member

    I am slightly surprised that they don’t negotiate that bridge with tugboats for a ship that size. Suppose it would slow down passage too much.

    frankconway
    Full Member

    I hope the rescuers get everyone safely out of the water but that’s unlikely.

    There is nothing unusual about the bridge design; comments about ‘flimsy supports’ lack engineering credibility.

    As for pier protection, can anyone provide examples on bridges which span major shipping channels?

    The span between the central piers is 1150′ and the ship had a maximum width of 150′ so it was about 500′ off the centre line.

    I’m calling either human error and/or technical failure.

    Someone on the deck must have seen they were way off-line in a shipping channel. Was there no ship-to-shore radio messaging warning of an imminent collision?

    sharkbait
    Free Member

    I’m surprised it didn’t ground before it hit the pillar.

    Or hit the ‘protective island in the middle of the other span (plus there seems to be a large pillar in the water in line with the bridge pillar).

    Edit: ignore that….. the island was quite a distance away.

    sharkbait
    Free Member

    Was there no ship-to-shore radio messaging warning of an imminent collision?

    Very likely between the ship and the harbour authorities but only when it was too late, and I guess the latter would then have to get the police to close the bridge which would have taken time.

    gobuchul
    Free Member

    It’s a narrow channel, the ship wasn’t “way off course”.

    It only took seconds for the ship to drift out of the channel when power was lost.

    frankconway
    Full Member

    I didn’t say ‘ way off course’.

    My wording was ‘way off-line’; there is a difference.

    I stand by my comments.

    multi21
    Free Member

    This pic really highlights the scale of what happened

    gobuchul
    Free Member

    “I didn’t say ‘ way off course’.

    My wording was ‘way off-line’; there is a difference.

    I stand by my comments.”

    They weren’t way off-line before the blackout, you can see their track on Marine Traffic.

    Once they lost power they would of known they were heading off track, the radars and nav systems are some of the last things to go but they wouldn’t of had enough power to operate the rudder. Not a lot they could of done apart from drop an anchor.

    scruff9252
    Full Member

    As for pier protection, can anyone provide examples on bridges which span major shipping channels?

    forth road bridge;

    https://www.transport.gov.scot/media/49232/record-of-determination-a90-forth-road-bridge-cathodic-protection.pdf

    tay road bridge;

    https://www.tayroadbridge.co.uk/about/history/past-projects

    and I’m pretty sure there is comparable protection on both the Severn bridge and the Dartford crossing too.

    Cougar
    Full Member

    From elsewhere on the Internet:

    “the ship lost power twice, officials are speculating a fire on board.”

    This is, of course, completely unconfirmed.

    sharkbait
    Free Member

    Someone on the deck must have seen they were way off-line in a shipping channel

    They weren’t…. and then they were, but were basically powerless to do anything about it.

    (also they wouldn’t go through the middle of the span as they need to leave the Fort Carroll island to port so would probably already be on a course closer to the starboard pier)

    squirrelking
    Free Member

    Holy shit.

    I won’t speculate on the cause, there are plenty of seemingly innocuous things that can shut down an engine but if you’re blacked out you’re at the mercy of the currents. Looks like a genuine case of wrong time and place.

    I’m more concerned about the folk on the bridge tbh.

    honourablegeorge
    Full Member

    frankconway

    There is nothing unusual about the bridge design; comments about ‘flimsy supports’ lack engineering credibility.

    Yeah, there’s “flimsy” and there’s “collapsed when hit by several million tons of ship”

    nickc
    Full Member

    I’m looking forward to the  the whole “Today I am expert in (but not limited to) Harbour piloting, maritime navigation, and multi-span bridge engineering” vibe that this thread will descend into in short order. Don’t let me down.

    gobuchul
    Free Member

    I can claim 2 of those.

    paddy0091
    Free Member

    can’t believe someone just got themselves out of the water and refused help.

    Fingers crossed for others, but at 9deg it’s sadly unlikely there will be any further survivors.

    Horrible all round.

    gobuchul
    Free Member

    It will be a massive task to even recover the bodies.

    thisisnotaspoon
    Free Member

    As for pier protection, can anyone provide examples on bridges which span major shipping channels?

    Forth yes, is there a major port on the Tay upriver of the bridge? It’d be interesting to see what calculation they used to size them because I wonder how feasible it would be to stop a container ship that size. Because if you made it strong enough then the ship sinks and you end up with even worse disruption as/if it blocks the channel anyway.

    And from watching American politics, infrastructure funding seems very disjointed with projects being added as amendments to other legislation to get votes.

    gobuchul
    Free Member

    Øresund Bridge

    convert
    Full Member

    It will be a massive task to even recover the bodies.

    Possibly considered a bit distasteful at this point so close to the event but I’d say basically impossible unless they get very lucky. And possibly worse – given the time pressure they will be under to get the wreckage of the bridge clear and the shipping lane reopened , the chance of the ‘final resting place’ being given any sort of respect is slim to none. Bodies might be ‘recovered’ amid the clearing maybe but I’d sure as hell not want to be present as a family member when it happened.

    squirrelking
    Free Member

    Because if you made it strong enough then the ship sinks and you end up with even worse disruption as/if it blocks the channel anyway.

    Not necessarily, ships can t-bone each other and still sail themselves to dry dock.

    And I’m not sure about worse disruption, in case you missed it there’s an entire bridge blocking the channel.

    gobuchul
    Free Member

    The main navigation channel is pretty narrow.

    It shouldn’t take too long to open that back up, however, if that would be enough to make be considered safe enough to use, with all the other stuff going on, is another question.

    It’s going to be an interesting job getting the ship free of the wreckage before you even start clearing the channel.

    seriousrikk
    Full Member

    I wonder how feasible it would be to stop a container ship that size

    The islands they build are rarely put together to flat out stop a ship of that size, and indeed if there were a direct collision it would still be pretty bad I’m sure. But they do try and build them strong enough that they can deflect such a vessel and leave the structure largely in tact.

    How often they actually get put to the test though, I don’t know…

    Cougar
    Full Member

    I’m looking forward to the the whole “Today I am expert in (but not limited to) Harbour piloting, maritime navigation, and multi-span bridge engineering” vibe that this thread will descend into in short order. Don’t let me down.

    In that case I’d recommend IFLS’s feeds on Facebook. We’re going to need more Bacofoil.

    somafunk
    Full Member

    Christ, those poor folk seeing that coming towards them on the bridge, and I feel for the pilots who will be native to the water, know the route/tidal currents extremely well and do this job many times a week – must surely be a propulsion/engine/rudder failure.

    thisisnotaspoon
    Free Member

    Not necessarily, ships can t-bone each other and still sail themselves to dry dock.

    In engineering terms “not necessarily” gets into the realms of business cases though. Civils isn’t my area but I imagine it goes something similar to my industry:

    New stuff is built to codes, standards and best available technology / best industry practice.

    Old stuff remains as it is unless either there’s a mandatory (not necessarily legislative, might jus t be forced by insurance, or your safety case is no longer valid as you stated that something never happens) change required e.g. after Buncefield I was busy for years re-designing the instrumentation on storage tanks. Or someone develops a business case that says £.. million will save you x*£..million on a 1 in <x chance.

    In this case I’m guessing someone figures the risk of a collision was low enough.

    Selling preventative engineering is hard work, a few tens of millions on this would not have won any votes compared to building a school or fixing potholes.

    And I’m not sure about worse disruption, in case you missed it there’s an entire bridge blocking the channel.

    Yup, but you’d have exactly the same problem (probably harder to solve) if it was a ship sunk in the channel.

    slowoldman
    Full Member

    I can claim 2 of those.

    I can claim 1 but without any knowledge of protecting bridges against ship collisions. It would appear that protection to the Forth bridges was considered well after the original construction, I would imagine due to increases in ship size.

    Because if you made it strong enough then the ship sinks and you end up with even worse disruption as/if it blocks the channel anyway.

    I would go with the ship sinking any day rather than a major bridge collapse. If the protective caissons around bridge piers are well shaped it would only be a glancing blow anyway.

    joshvegas
    Free Member

    “As for pier protection, can anyone provide examples on bridges which span major shipping channels?”

    Um… The cable bridge about 50m away from the bridge that was hit?

    5lab
    Full Member

    there’s cost/benefit on any engineering. Lets say adding some islands big enough to stop a massive container ship costs $1bn per bridge (guessing, obviously). And there’s maybe 1000 bridges that need such protection – thats a trillion dollars – if bridges last 100 years on average, that’s 10bn dollars per year. If 20 people died last night, its terrible, but when was the last time such an event occured? a decade ago? if so the cost of putting protection up would be $5bn per person.

    even if the numbers are way way different what I’m suggesting – $100m to build an island, only 100 bridges worth protecting, one falls over ever year, you’d still be looking at $5mm per person which has got to be only *just* breaking even.

    politecameraaction
    Free Member

    “I can claim 1 but without any knowledge of protecting bridges against ship collisions”

    I can claim all 3 of them.

    piemonster
    Full Member

    Forth yes, is there a major port on the Tay upriver of the bridge?

    Perth, not major in any way. Boats are still big enough you would not want them bumping into any transport bridges.

    joshvegas
    Free Member

    I am fairly sure (because I remember both event) the forth protection was put in in the 90 on privatisation of the rosyth docks. I assume to allow civilian shipping, coincided roughly with the ferry terminal.

    politecameraaction
    Free Member

    “there’s cost/benefit on any engineering.”

    True, but don’t forget about the cost of rebuilding the bridge, the cost of the obstructed maritime channel, and the cost of increased congestion on I95 etc (which in my amateur observations are rammed 20 hours a day).

    dissonance
    Full Member

    you’d still be looking at $5mm per person which has got to be only *just* breaking even.

    Its not just per person though but the additional costs of a)removing the wreckage b)rebuilding it and c)the disruption caused during that time to normal traffic flows in the country.

    thisisnotaspoon
    Free Member

    you’d still be looking at $5mm per person which has got to be only *just* breaking even.

    Obviously we’re not crude enough to actually put a number on it like that. But if you work backwards it’s usually ranked:

    personal injury – £100k lost profit
    on site fatality – £1million
    multiple fatalities or one member of the public – £10 million

    Varies between industries as it’s linked to reputational damage, so nuclear will rank it much higher because 1 death in a nuclear facility is news for the next couple of decades.

    That Tay Bridge project for example was ~£30million in todays money.

    squirrelking
    Free Member

    Yup, but you’d have exactly the same problem (probably harder to solve) if it was a ship sunk in the channel.

    “Not necessarily” was in reply to the notion that it would sink a ship. They’re surprisingly resilient, even loaded up the way that one was.

    but when was the last time such an event occured? a decade ago?

    Barely a month ago when a barge hit the Lixinsha Bridge in Guangzhou.

    slowoldman
    Full Member

    So it appears there was an international symposium on ship collisions in 1998

    Ship Collision Analysis

    gobuchul
    Free Member

    Ships and barges hit bridges all the time.

    But usually it’s the vessel that’s smaller or a similar size to the bridge.

    This one was the other way around and a very long bridge to boot.

    honourablegeorge
    Full Member

    When I was a kid of about six, my uncle took me in his delivery truck for the day, drove me all around various neighbouring towns delivering dairy stuff. We stopped at a bridge, and he knew the chap who controlled the bridge, I got to go in the control room and pull the red lever to open the bridge. We opened it fully, and then waved through an American tourist who was piloting his beautiful glass-cabined river cruiser. And we all watched in amazement as he slowly steered it straight into the bridge and smashed it to bits, taking out pretty much the entire above deck area of the boat. So I think I can consider myself an authority here.

    martinhutch
    Full Member

    There is a trade off we make between convenience, cheapness and safety. Occasional interactions between critical infrastructure and mahoosive ships are the price of our demand for vast amounts of stuff to be brought almost into the heart of a city. I don’t know if they could have done more to protect the piers, or used tugs more often for these vessels, but there is likely to be a financial consideration for both options.

Viewing 40 posts - 41 through 80 (of 164 total)

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