Key Bridge collapses into Patapsco River in Baltimore

SamR

Joined Mar 19, 2019
5,078
Best coverage I've seen. Ship had regained power and was backing. Had slowed to 1.5 knots when struck pylons. Fire Dept. and Emergency radio placed 9 vehicles on bridge when it collapsed. You can see the lights of several vehicles on the bridge in some of the video clips.
 

Ian0

Joined Aug 7, 2020
10,217
Comments from a friend who used to be in the merchant navy:
"So far the story of the Singapore flagged "Dali" is not making much sense to me. There is a shortage of facts, and some are counter intuitive to me.
They say the vessel lost power and was going too fast.
Power loss could be the main propulsion system or simply a black out of electrical supply??
If it was electrical, then the emergency generator should have started automatically. The main engine lubricating pump and the steering gear would be routed through the emergency switchboard. This should have permitted an emergency "crash" astern. Travelling through the water fast should not have affected steerage as it is at slow speeds steering is weakest.
Both anchors could have been dropped. This would almost certainly have ripped both windlasses off the fo'castle but might have slowed the vessel.
I am tending to think that physical failure of the rudder or rudder stock might be the problem.
Before every "stand by engines" on entering or leaving port the engines should have been proved ahead and astern. The steering gear should also be tested on both steering pumps and the spare pump made to run too. "
 

SamR

Joined Mar 19, 2019
5,078
Old ship, old gear, happened before to it under a previous owner. They did drop the port anchor and were backing to reduce headway from 8.5 knots to 1.5 when they struck. The Pilot on board is responsible for headway and bearing under his watch. Apparently, they lost complete power including all backups except battery power. Which is very strange but can and does happen.
 

WBahn

Joined Mar 31, 2012
30,286
So about 300 lbs of TNT. Not a very large bomb, but, plastered to the pylon, likely enough to take down a bridge.
It's really not a matter of energy, so much as force and momentum. It's more like a person jumping off of a tall building and landing either on the pavement, or on one of those huge air cushions they use for rescues and stunts. The kinetic energy at impact is identical, but the results are hugely different, since in one case the person is stopped in an inch or so and in the other they are stopped over a distance of many feed. So energy alone simply isn't a useful measure.

You have a ship that is traveling at a certain speed and, in order to stop it in a certain distance, you need to exert a suitable force on it. Obviously, the heavier the ship, the greater the force needed to stop it in that distance. But the real key point is that the shorter the allowed distance, the greater the force.

Then you have the bridge support. There is only so far it can be moved before it fails. That sets a limit on the distance available to stop the ship. I don't know how much deflection that support could tolerate, but I'm guessing it's measured in feet, and not all that many of them. So to stop that big a ship, even going at a slow pace, in a handful of feet, is going to require the bridge support to exert a HUGE lateral force on the ship. I doubt any support made could do that.
 

nsaspook

Joined Aug 27, 2009
13,522
Comments from a friend who used to be in the merchant navy:
"So far the story of the Singapore flagged "Dali" is not making much sense to me. There is a shortage of facts, and some are counter intuitive to me.
They say the vessel lost power and was going too fast.
Power loss could be the main propulsion system or simply a black out of electrical supply??
If it was electrical, then the emergency generator should have started automatically. The main engine lubricating pump and the steering gear would be routed through the emergency switchboard. This should have permitted an emergency "crash" astern. Travelling through the water fast should not have affected steerage as it is at slow speeds steering is weakest.
Both anchors could have been dropped. This would almost certainly have ripped both windlasses off the fo'castle but might have slowed the vessel.
I am tending to think that physical failure of the rudder or rudder stock might be the problem.
Before every "stand by engines" on entering or leaving port the engines should have been proved ahead and astern. The steering gear should also be tested on both steering pumps and the spare pump made to run too. "
I had the sad experience of being on a ship that was infamous for losing power at bad times because of old and poor equipment. The rudder is on a feedback system that can easily go full R/L on loss of power that takes time to correct once the heading has changed because you need to steer out of the bad course with power (slowing alters course too). The emergency generation system takes time to spin up, warmup, stabilize and switch over.
The supply ships hated us.


These guys on that container ship Imo tried their best and called it in correctly as a mayday when they lost it. It sucks when you're powerless to stop something.
 
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joeyd999

Joined Jun 6, 2011
5,389
The kinetic energy at impact is identical, but the results are hugely different, since in one case the person is stopped in an inch or so and in the other they are stopped over a distance of many feed. So energy alone simply isn't a useful measure.
Maybe they need to design crumple-zones into the freighters' bows.

(This is kinda a joke.)
 

WBahn

Joined Mar 31, 2012
30,286
Just heard a report that they are talking about two months to get the port back open.

Color me skeptical.

We've seen several instances in the last few years where we are told it will take months or even over a year to get a major bridge rebuilt and open to traffic -- and then it is open in a couple weeks. Amazing what motivation can accomplish.

In this case, they don't have to build anything -- just demo that part of the bridge that is in the channel and remove (or further demo) any portions that are sticking up high enough to be a hazard to ships. I don't know if the channel is wide enough to normally allow two-way traffic, or if it is just a single lane under the bridge (based on the photos I've seen, I'm guessing it's single lane). If two lanes, you only have to get one lane open in order to get the port operating.

Frankly, if they really want to get the port open, I'm guessing they could do it in a week once they get the go-ahead from the investigators -- and they can be assembling the teams and materials needed to do the job (as well as be planning it) right now.

Then another report said it will be five to ten years to rebuild the bridge. Yet earlier, when they were trying to make the point about how major a structure the bridge is, they had said that it took "nearly three years to build", though I wouldn't be surprised if that is incorrect as so much reporting of fairly easily determined facts shows. But it should take considerably less time to rebuild the bridge than it took to build the original bridge since most of the groundwork is already in place -- both approaches are intact and none of earthmoving that was originally done has to be redone. They need to inspect the foundations of the supports, but there's a good chance they can be reused (unless they decide to make changes to the new bridge to update it for current and foreseen needs, which is pretty likely).

On another note, I'm getting a chuckle out of all the reports telling us that the sonar surveys are detecting cars in the water. Uh... hello. You can see cars on the bridge as it collapses; just where did they think those cars went? The real news would be if they couldn't detect any cars in the water (and just imagine the alien-conspiracy stories that would prompt!).
 

nsaspook

Joined Aug 27, 2009
13,522
Two months easy if they have the explosive shaped charges to slice those trusses into liftable chunks and dredge the channel to clear it. Make it profitable to be quick and safe
 
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SamR

Joined Mar 19, 2019
5,078
Latest report I saw FWIW said they would have the port open in several days and that was from the Ports Authority folks. Kinetic Energy is energy whether small and fast or massive and slow it all adds up and thousands of tons at 1.5 knots isn't anything to ignore as you can see.
 

WBahn

Joined Mar 31, 2012
30,286
Latest report I saw FWIW said they would have the port open in several days and that was from the Ports Authority folks. Kinetic Energy is energy whether small and fast or massive and slow it all adds up and thousands of tons at 1.5 knots isn't anything to ignore as you can see.
Again, energy isn't the main factor here. Things bend and break because of force. Consider an aircraft landing on a carrier deck. The cable plays out and slows the aircraft over a distance of about a hundred yards. What happens if that cable was tensioned so that it would bring it to a stop in ten yards? Answer -- things break. But it's the same energy being dissipated in both cases.
 

SamR

Joined Mar 19, 2019
5,078
A few hundreds of thousands of tons will move a bridge span off of its abutments even at 1.5 knots apparently. LOL now they are screaming around here about "What if it happens at Port Savannah or Port Brunswick Georgia?" Nothing better to pontificate about on the news on a slow night I guess... Yesterday I was watching the bridge into Crimea from Russia being bombed by the Ukranian Air Force. Actually, it was a convoy of Russian military trucks on the bridge and each time you could see the pressure wave from the bomb exploding. Not sure how much was from the munitions dropped and how much was from the munitions in the trucks exploding but it was putting out some impressive pressure waves and the bridge was surprisingly looking like it was withstanding it pretty well. Although news reports were coming out that the bridge had been destroyed it sure didn't look like it. Roadway and siderails appeared to be intact and still on their supports. Both road and rail lines. It may have been shattered, but it was still upright and standing.
 

WBahn

Joined Mar 31, 2012
30,286
A few hundreds of thousands of tons will move a bridge span off of its abutments even at 1.5 knots apparently. LOL now they are screaming around here about "What if it happens at Port Savannah or Port Brunswick Georgia?" Nothing better to pontificate about on the news on a slow night I guess... Yesterday I was watching the bridge into Crimea from Russia being bombed by the Ukranian Air Force. Actually, it was a convoy of Russian military trucks on the bridge and each time you could see the pressure wave from the bomb exploding. Not sure how much was from the munitions dropped and how much was from the munitions in the trucks exploding but it was putting out some impressive pressure waves and the bridge was surprisingly looking like it was withstanding it pretty well. Although news reports were coming out that the bridge had been destroyed it sure didn't look like it. Roadway and siderails appeared to be intact and still on their supports. Both road and rail lines. It may have been shattered, but it was still upright and standing.
A number of people, both officials and guy-on-the-street, were all worked about about why the bridge couldn't withstand this or concerned about it happening again. Just the usual ill-informed echo chamber at work.

As for the Crimean bridge -- is this something new? I haven't seen any reporting about a new attack on it. I'm only aware of two attacks on it -- one back in late 2022 (Oct???) with a truck bomb and one last summer with kamikaze drones. If this is something new, could you post a link to something?
 

Lo_volt

Joined Apr 3, 2014
322
A few hundreds of thousands of tons will move a bridge span off of its abutments even at 1.5 knots apparently. LOL now they are screaming around here about "What if it happens at Port Savannah or Port Brunswick Georgia?" Nothing better to pontificate about on the news on a slow night I guess... Yesterday I was watching the bridge into Crimea from Russia being bombed by the Ukranian Air Force. Actually, it was a convoy of Russian military trucks on the bridge and each time you could see the pressure wave from the bomb exploding. Not sure how much was from the munitions dropped and how much was from the munitions in the trucks exploding but it was putting out some impressive pressure waves and the bridge was surprisingly looking like it was withstanding it pretty well. Although news reports were coming out that the bridge had been destroyed it sure didn't look like it. Roadway and siderails appeared to be intact and still on their supports. Both road and rail lines. It may have been shattered, but it was still upright and standing.
Was this the Kerch bridge or the Antonovsky bridge in Kherson?
 

BobTPH

Joined Jun 5, 2013
9,238
Just heard a report that they are talking about two months to get the port back open.

Color me skeptical.

We've seen several instances in the last few years where we are told it will take months or even over a year to get a major bridge rebuilt and open to traffic -- and then it is open in a couple weeks. Amazing what motivation can accomplish
Agree, I would take an even bet at 3 weeks.
 
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