Bridge collapse in Baltimore

[Helvellyn]

Is it realistic to expect any bridge to survive being struck by a container ship? Even at low speeds the kinetic energy in those things must be immense.

If the piers themselves wouldn't withstand a collision they should have sufficient protection, especially the ones either side of a shipping channel, this bridge appeared to be lacking any significant protection.

Would you be all that confident that those would stop a large ship? Depending how deep the water is I'd have though that they'd either just get knocked over, or just do a bit of damage to the ship but not necessarily stop it. And they're not covering all angles.

[Helvellyn]

Something that occurred to me is that similar bridges exist in war zones, most obviously the Kerch Strait. If all that was needed to bring it down was to aim a large ship at it, I'd imagine someone would have done just that deliberately in the last few years, yet they haven't. Which suggests the bridge supports there are protected against this, whether deliberate attack or otherwise. It does seem strange that similar protection isn't automatic anywhere where large ships are manoeuvring.

I'd imagine that that bridge is rather carefully monitored, with lots of anti-ship missiles in the vicinity.

Perhaps, but an anti-ship missile would not be able to sink a large ship before it hit the bridge, especially if it was thought to be simply passing under the bridge in the shipping channel. A last minute turn of the ship's wheel 500m-1km before the bridge and a large vessel would be practically impossible to stop. I guess you'd need some mines to rip out the bottom of the ship and even then it might not guarantee stopping it in time. Plus you'd risk blocking the shipping channel.

Missiles would sink any suspicious ships a long way out. It wouldn't rule out a ship that they're happy with being there having being infiltrated, but how easy would it be to do that?

[Helvellyn]

Sounds like the ship got a mayday out and traffic was stopped as a result, so a quick response there probably saved lives.

[Conekicker]

Sounds like the ship got a mayday out and traffic was stopped as a result, so a quick response there probably saved lives.

Pretty sure I've seen a video with a lorry and a couple of cars passing less than 30 seconds before the hit. The roadworkers didn't get away either unfortunately.

[Helvellyn]

Sounds like the ship got a mayday out and traffic was stopped as a result, so a quick response there probably saved lives.

Pretty sure I've seen a video with a lorry and a couple of cars passing less than 30 seconds before the hit. The roadworkers didn't get away either unfortunately.

Ones that started across before it came through.

I'm not diminishing the impact of those who didn't get a chance, but let's not overlook the parts that worked.

[Bryn666]

Is it realistic to expect any bridge to survive being struck by a container ship? Even at low speeds the kinetic energy in those things must be immense.

If the piers themselves wouldn't withstand a collision they should have sufficient protection, especially the ones either side of a shipping channel, this bridge appeared to be lacking any significant protection.

Would you be all that confident that those would stop a large ship? Depending how deep the water is I'd have though that they'd either just get knocked over, or just do a bit of damage to the ship but not necessarily stop it. And they're not covering all angles.

Those concrete islands are designed to deflect rather than stop, so a ship striking them would be bounced away from the critical bridge components somewhat. Have a look at the supports for our major estuary crossings and you can see the remarkable difference between our impact protection design and what was employed here.

I should point out we clearly learned from the Severn Bridge disaster - you'd have hoped the Americans would've learned from the Sunshine Skyway (and the numerous other bridge disasters of a similar type) but hey ho. This is the world people want when they say safety features are meaningless.

[Helvellyn]

I should point out we clearly learned from the Severn Bridge disaster - you'd have hoped the Americans would've learned from the Sunshine Skyway (and the numerous other bridge disasters of a similar type) but hey ho. This is the world people want when they say safety features are meaningless.

There's also a boy who cried wolf effect when it comes to safety features. Get too obsessed with them and real, meaningful ones start getting dismissed along with all the over-reactions and over-caution.

[Bryn666]

I should point out we clearly learned from the Severn Bridge disaster - you'd have hoped the Americans would've learned from the Sunshine Skyway (and the numerous other bridge disasters of a similar type) but hey ho. This is the world people want when they say safety features are meaningless.

There's also a boy who cried wolf effect when it comes to safety features. Get too obsessed with them and real, meaningful ones start getting dismissed along with all the over-reactions and over-caution.

I don't think protecting bridge supports remotely falls into crying wolf territory given how many bridges have collapsed from being hit by passing vessels.

[freebrickproductions]

I should point out we clearly learned from the Severn Bridge disaster - you'd have hoped the Americans would've learned from the Sunshine Skyway (and the numerous other bridge disasters of a similar type) but hey ho. This is the world people want when they say safety features are meaningless.

There's also a boy who cried wolf effect when it comes to safety features. Get too obsessed with them and real, meaningful ones start getting dismissed along with all the over-reactions and over-caution.

I don't think protecting bridge supports remotely falls into crying wolf territory given how many bridges have collapsed from being hit by passing vessels.

It's a pretty major port with large ships passing under that bridge regularly, would work to upgrade the protection around the bridge have affected the size of the shipping channel underneath? I wouldn't be too surprised if any work being done to upgrade the bridge protection was continuously put off to keep the port running until "someday" when they could (afford to) temporarily reduce the size of the shipping channel to allow it to be done, and it's clear that "someday" never came, all the while the sizes of ships continued to increase. The bridge was originally built back in 1977, prior to the Sunshine Skyway collapse in 1980.

No doubt any replacements will feature vastly improved bridge protection. I could also potentially see the port requiring boats to be tugged in from/out past a point on the other side of the bridge, to further try and prevent any disasters like this from happening again.

Apparently two of the workers on the bridge at the time of the strike have been rescued, but a further six (at least) are still unaccounted for, last I saw. Apparently sonar has found what appear to be several vehicles in the water, though divers, last I saw, had yet to be able to reach them. As bad as this whole thing is, it's certainly a major stroke of luck it wasn't worse.

[brummie_rob]

I'm presuming that the VMS signs above the lanes either side of the bridge perhaps showed 'Bridge closed, do not enter' or something, however without a hard closure in place this could have been ignored. The person sat in the DOT control room who got that message onto the gantries in such a short time frame should certainly be congratulated as probably at that time of night usually they are sat round not doing as much and probably easy to have a lapse in concentration.

A tragic event though for the workers, such a shame it coincided with pothole repairs.

[freebrickproductions]

I-895 and I-95 are the next two river crossings in that area, so no doubt traffic on that side of Baltimore will be snarled for a while until the bridge is able to be replaced.

And, unsurprisingly, per the AARoads forum, traffic on the south side of Baltimore is noticeably worse than usual this afternoon after the bridge collapsed.

[Enceladus]

A horrific incident and a very dramatic and rapid collapse of the bridge which was caught on camera footage - and thank heavens that the ship collided with the bridge pier in the wee hours as opposed to rush hour when the bridge would have been full of commuter traffic.

Quick action closing the bridge to traffic as soon as the ship hit. This most definitely saved lives.

We are all aware of the deteriorating state of US transport infrastructure including bridges over the past 25 or so years and the safety implications - but looking at the Scott Key bridge, it seemed to be a rather typical metal "cage" design very common in the USA.

Could this type of bridge design itself - presumably quick to build and cheaper - be inherently unsafe, structural deterioration due to age notwithstanding?

[Big L]

BBC reporting this morning the search for survivors has been called off. There is no chance of surviving in the water for 24 hours, especially in what is effectively the North Atlantic.

[KeithW]

The ship involved, the MV Dali, has a mass of around 116,000 tons, lots of luck designing a bridge that can withstand that sort of impact. This is why really big bridges go for long spans, ideally ships would be towed under it or at least have a tug on standby. That bridge has been in service since 1972 and as its over 1.6 miles long you would have to build a hell of a tunnel to replace it



Perhaps we should reconsider the policy of allowing ships of that size into the port ! A ship that that mass that is not under control is pretty much unstoppable. In 1960 we had a very similar incident with the railway bridge over the Severn.


https://stroudtimes.com/remembering-the ... -disaster/

[roadtester]

…you would have to build a hell of a tunnel to replace it.

I don’t think it will be replaced by a tunnel. Apparently the two parallel North/South interstate routes I-95, I-895) through the area run in tunnels but some traffic - e.g. hazmat - had to go via the bridge (I-695) because it wasn’t permitted to use those other routes. So I think some provision would still have to be made for that.

[Bryn666]

The ship involved, the MV Dali, has a mass of around 116,000 tons, lots of luck designing a bridge that can withstand that sort of impact. This is why really big bridges go for long spans, ideally ships would be towed under it or at least have a tug on standby. That bridge has been in service since 1972 and as its over 1.6 miles long you would have to build a hell of a tunnel to replace it



Perhaps we should reconsider the policy of allowing ships of that size into the port ! A ship that that mass that is not under control is pretty much unstoppable. In 1960 we had a very similar incident with the railway bridge over the Severn.


https://stroudtimes.com/remembering-the ... -disaster/

Plenty of bridges have caissons or similar bulky concrete structures well in advance of critical supports to deflect a boat, damage would still occur but you wouldn't see the entire thing fall into the river in 4 seconds. Have a look at the Humber Bridge piers, they're on artificial concrete islands that would take most of the impact before a vessel hits the main event, we learned this after the Severn Bridge failure.

1.6 miles is not a long distance for a tunnel, but it is not likely to happen there because of the need to shift dangerous loads and the west side of I-695 has a bit of a suburban commuter problem so that's not great either.

Given the Port of Baltimore is only likely to expand further talk of restricting boat sizes is not happening.

[Helvellyn]

Plenty of bridges have caissons or similar bulky concrete structures well in advance of critical supports to deflect a boat, damage would still occur but you wouldn't see the entire thing fall into the river in 4 seconds. Have a look at the Humber Bridge piers, they're on artificial concrete islands that would take most of the impact before a vessel hits the main event, we learned this after the Severn Bridge failure.

Isn't the Humber very shallow there though? Much more practical to build those there. Looking at the photos Keith posted there seems to be something in the water either side of the piers, lines up with them.

[Bryn666]

Plenty of bridges have caissons or similar bulky concrete structures well in advance of critical supports to deflect a boat, damage would still occur but you wouldn't see the entire thing fall into the river in 4 seconds. Have a look at the Humber Bridge piers, they're on artificial concrete islands that would take most of the impact before a vessel hits the main event, we learned this after the Severn Bridge failure.

Isn't the Humber very shallow there though? Much more practical to build those there. Looking at the photos Keith posted there seems to be something in the water either side of the piers, lines up with them.

There were small navigational islands which offered zero impact protection as the vessel managed to drift behind them. The river depth is around 50-80 feet and given there are already bridge piers in that it doesn't strike me as impossible to build additional protection around a critical structure on the approach to a major harbour. You're not looking to stop a massive wayward vessel, you're looking to nudge it away from stuff you don't want it to hit so all this talk of containment is just distraction tactics from engineering failure apologists.

As ever this is human complacency coming back to bite people in the backside - "it'll never happen here" even when there is precedent for it happening in several other places where it couldn't possibly have happened. Engineers need to stop thinking in terms of bottom lines on spreadsheets and work on safe systems design. Given it is reasonably foreseeable a collision could have occurred here mitigation beyond four laughably small navigation islands would've made sense.

[KeithW]

The Russians have sunk old ships and the like to prevent an attack on the Kerch bridge
https://www.politico.eu/article/russia- ... s-says-uk/

In the Baltimore case, it seems that the ship's engines cut out and the ship may well have drifted into the bridge.
Presumably, one approach here would be to require ships to pass under the bridge under tug power, but the main problem is that once the ship has speed then you cannot stop it.

But you can make it change course which is why some ports require tugs to be available. The Tees normally has at least 5 tugs on standby with pilots being required for commercial vessels from the entrance to the river at the South Gare to the locks at the Tees Barrage.
https://www.google.com/maps/@54.5638029 ... &entry=ttu

Before the docks at Stockton were closed the river was navigable for commercial use as far as here.


The only structures that were likely to be hit were the Transporter bridge and Newport Bridge which could be lifted , the Tees Viaduct was built to be high enough to be safe from any vessel but as things happened Stockton Docks were closed at pretty much the same time. As I recall the last time the Newport Bridge was lifted was when the old dock gates were moved down river to be melted down for their scrap value.

[Mark Hewitt]

The Tees normally has at least 5 tugs on standby with pilots being required for commercial vessels from the entrance to the river at the South Gare to the locks at the Tees Barrage.

The vessel was taken out by tugs into the main channel. It was released once there as it would be operating too fast for the tugs. The tugs were still operating when they saw the veseel was in trouble and they attempted to make best speed to assist but didn't get there in time.