USA has thousands of bridges and it looks these rae hit regularly as per below:
At least 6,000 times in the past 22 years – an average of more than five times a week – crews on board massive cargo ships, oil tankers, container barges and even cruise vessels have reported what befell the Dali: a loss of power, loss of propulsion, loss of steering, or some combination of the three,
Baltimore bridge disaster was rare; the conditions behind it are not (usatoday.com)
From the linked article:
Is this a true representation of where the remnants of the bridge landed on the M/V Dali, or is it an “optical illusion” caused by the aspect of the photo?
Optical illusion. See the water btw this thng on the photo and Dali 
In open water, yes. In a channel you have to take into account the bank effect. Bank effect can be confusing, depending on channel configuration, and it can easily overpower weak rudder power due to a stopped propeller. From looking at AIS replays it appears that the Dali was slightly to right of the centerline as she approached the Curtis Bay Channel. That would cause the helmsman to be using a little bit of right rudder since the tendency of the ship would be to pull a bit to port. A pilot would often order 5-10 right and leave it there instead of giving a lot of back and forth rudder orders. A helmsman unfamiliar with bank effect would probably go back and forth from midships to 10 or 20 right expecting the ship to go straight at midships... which it would at sea where he has most of his experience. My experience is that helmsmen are not trained in bank effects.
As the outline of the ship enters the opening of the Curtis Bay Channel that pull to left disappears due to the new deeper water on the ship's starboard side. If power to the rudder is lost at this moment or if the helmsman (generally unaware of the change in water depth around the ship) leaves right rudder on (or both) the ship will begin to turn to starboard because the direction/effect of the bank effect has reversed. The ship's tendency is to seek equal pressure on both sides of the bow. So now she wants to go to starboard because of the wider area of deep water. With this sudden change in bank effect the average helmsman might be slow to begin using left rudder because for the last mile or more she has been using right rudder to maintain course.
I am speaking from my experience on the Houston Ship channel in the vicinity of the Bayport channel and the junction of the HSC with the San Jacinto River.
This is speculation that can only be cleared up by examination of recorded rudder angles and comparing them to ship's position and timelines of power outages - info that I do not have access to. I just wanted to clarify that it is possible for bank effect to overwhelm the reduced effect of the rudder at that speed.
Epistemic accidents, by contrast, are unavoidable because engineers necessarily build technologies around fallible theories, judgements and assumptions.
Can we say , wHat is contained in this pub applies also to M/V Dali EVENT??
Spowiednick
This is some high flown serious stuff - like marine steel grade SH 1T. Big words that need to look up one of these days. I don’t think it applies. If the blackout damaged the steering gear like we think it did, regulations and thus rules and thus standards need to be revised for more a more robust spec and FAT tests and periodic demos to Class.
If I read that right it is saying that it is impossible to accurately assess failure modes in complex situations.
I would argue that is probably correct, BUT that does not relieve the effort of trying.
I would like to see the risk analysis of this bridge, what assumptions were made, and what its review schedule is. I would also like to see the Port of Baltimore procedure for controlling which ships may or may not be authorized to enter the port.
My current ASSUMPTION is that if there was an original analysis the assumptions did not include a ship of this size or the potential death of hundreds if the failure occurred during rush hour.
Apparently someone has done such an analysis on the Delaware Twin Bridges as that dolphin contract was already let and started before the Key disaster.
So a 3500teu container ship, around 230m long and 40k plus displacement travelling at 8kts hitting the bridge buttress head on would not have brought down the bridge
Really
Sorry read it wrong a 3000teu container ship would be around 200 to 210m long.
Still…
Remember the Tampa bridge had not yet been knocked over. Someone decided that protecting the bridge was just not worth the money. That someone is long gone, either retired or dead. For their professional lifetime they were correct.
No one did shit to protect the Bay Bridges just around the corner either.
Sounds like someone really screwed the pooch to me.
But hey ho
have read the following:
“As for the culpability of Port of Baltimore and State authorities, the problem of ‘collapsible on one ship strike’ bridges in the US is reportedly well documented and runs to thousands. Also reported that other ports in same region had already accomplished or were planning installation of bridge support protection for similar bridges. No announcements yet seen as to what Port of Baltimore’s plans were but it seems impossible they were not aware of the high level of risk. As such, owner’s/P&I lawyers may well plead Port of Baltimore/State contributory negligence as a part of their civil claims defence.”
Must say, if I was a lawyer, that would have occurred to me.
I see a lot of " get those foreign bastard’s who knocked down our bridge to pay" in the comments on social media and in the press.
Just saying
They were well aware of the risk and conducted a cost analysis into improving the pylon protection. The analysis was shelved owing to the projected cost. This followed a previous allision with the bridge by a smaller container vessel.
Looks like combined brainstorming here is bringing more and more interesting items into the light. Thank You.
I am hypothesising here although one would assume that, contained within that analysis, would be a professional engineering opinion on the consequences of pylon allision by modern day larger vessels. This would be a means of qualifying the high projected cost.
The question to be asked is what other measures were considered/analysed to mitigate this significant risk.
I’ve dealt with the lawsuit-part of allisions over the years. Small stuff. Broken pilings. Dodgy docks falling over when you toss a mooring line on them. Certainly, less than a mil in damages.
The one thing I’ve learned is this: it’s not like car damage. Cars depreciate. But for some reason there are no such things as old pilings. There are no such things as rotten docks with bad repairs. Every piling you break, even if it’s a 100-years old and more worms than wood, is brand new once the lawyers start haggling.
The dock that creaks when a fat seagull lands on it, and had its opening-day ribbon cut by Julius Caesar, is as fresh as a daisy as soon as you hit it.
Your ship didn’t break the past. It bought the present. The present cost of replacing the past.
It will be interesting to see if this maritime rule-of-thumb pertains to bridges.
From NPR’s Nell Greehfield Boyce.
“ GREENFIELDBOYCE: Well, it was built back in the 1970s, and it was built before the terrible Sunshine Skyway accident in Florida. That was in 1980, and that disaster brought a lot of attention to the need to protect bridges from ship strikes. Interestingly, though, a few months after that Florida accident, a cargo ship actually ran into the Key Bridge in Baltimore, and back then, its protective measures worked. There was this concrete structure around the bridge support that was destroyed, but the bridge itself was unharmed. And that was seen as a success story. But that was a long time ago, decades ago, and in general, cargo ships weren’t nearly as big as they are today. And it seems that in this case, this huge cargo ship overwhelmed whatever protection system the Key Bridge had around its supports.”
NPR asked the Maryland Transportation Authority whether a threat assessment had been conducted for the Key Bridge and whether the agency had invested in enhancing the dolphins’ structures since they were built in the 70s. The agency did not respond.
Every year, the Maryland Department of Transportation conducts a report that evaluates the state’s transportation infrastructure and determines its priorities for investment. Repairs to the bridge were suggested in 2017, that year’s annual report states, and satellite imagery indicates two transmission towers were constructed between 2019 and 2022, on the side of the bridge closer to Baltimore city. But nautical charts show the current sizes of the dolphins are similar to their original 1978 dimensions — the four don’t appear to have been significantly enlarged since then.
Leon, the professor of structural engineering at Virginia Tech, said states face tough choices when it comes to spending on infrastructure.
“They have lacked resources for many years,” he said. “And so they tend to take care of what they think are the more urgent problems.”
But putting off this kind of investment can have dangerous consequences, he said.
“Unfortunately, we have taken things for granted for too long. We haven’t done the appropriate maintenance, the appropriate upgrading,” remarked Leon. "And so this is the result of that."https://www.washingtonpost.com/dc-md-va/2024/03/29/baltimore-bridge-collapse-inspections-minneapolis-tampa/
