Baltimore's Francis Scott Key Bridge Collapses after Ship Strike

[berkeman]

It's probably upthread somewhere, but when do we expect a preliminary report on the cause? It should not be rocket science with access to the ship and crew IMO...

 

[Vanadium 50]

It's been over 6 months since the F-35 crash in South Carolina and still no report. I expect this to happen "with all government speed".

 

[Flyboy]

It's probably upthread somewhere, but when do we expect a preliminary report on the cause? It should not be rocket science with access to the ship and crew IMO...

Preliminary report will probably be at least a month after they finish reopening the channel, if I had to place a bet.

This usually happens when there is a common point of failure taking down the allegedly redundant systems. For example, one thing that could take down all the diesels at the same time would be a fuel problem. There are probably others.

This is why you are hearing some pushback from me on the idea "we need more redundancy!". If the failure was a common element of all the redundant systems, adding more redundancy does not help.

Also, things always seem like better ideas when someone else bears the cost. Let's imagine this was a fuel problem, and occurred when the fuel was being switched over (or prepared to be switched over - it seems a little early for the switch). Cargo ships carry two kinds of fuel - expensive, low-sulfur fuel for use inb harbor, and cheaper, regular fuel for everywhere else. This sounds like a good idea to the general populace "Less pollution, and the shipping companies are the ones who have to pay for it." Until a bridghe goes down. I am not saying this is what did happen, merely what could happen.

Yeah, redundancy would not have fixed a low likelihood failure.

That said, I recall hearing that the ship had been facing electrical issues in port the previous few days, and from my understanding, they use electric pumps to provide all the auxiliary services, from hydraulic pressure to fuel pumps to, well, pretty much everything. If you trip your entire electrical system offline, everything would go out. I really don’t know enough to hazard a guess as to what exactly could have caused that, as I have exactly zero experience with maritime/shipborne electrical systems, but it sounds like possibly a main bus short? They appeared to try and start a backup generator and briefly succeeded, but then it went dark for good.

Shrugs

I’ll wait for more information. Feels like we the public are trying to put together a jigsaw puzzle with missing pieces and a partial reference picture.

 

[Vanadium 50]

My marine engineering experience is limited to steam turbines, but the electrical distribution is a complex thing. I do have some experience with cryogenic plants, and based on that, if they were repairing a problem in harbor, I'd be looking at a configuration change.

The way thing happen is you make N changes to figure out what's broken, find it, fix it, and intend to bring everything back to normal, but for whatever reason, undo only N-1 changes. This is human nature. Checklists and such reduce this, but it's hard to eliminate completely.

Could that have happened here? Absolutely. Did it happen? No idea. We'll know in a few months, I hope.

 

[Astronuc]

It's probably upthread somewhere, but when do we expect a preliminary report on the cause? It should not be rocket science with access to the ship and crew IMO...

Eventually, one will find a report here - https://www.ntsb.gov/investigations/Pages/DCA24MM031.aspx

It could be a year out from the event for a report - or longer.

One can see the time of an event and the accident report for various types of transportation mishaps here
https://www.ntsb.gov/investigations/AccidentReports/Pages/Reports.aspx

https://apnews.com/article/baltimore-bridge-collapse-investigation-85bd81d1dfefc6efc5bc9a2e22d6999a

BALTIMORE (AP) — During the initial stages of a federal probe into the deadly collapse of Baltimore’s Francis Scott Key Bridge, investigators are focusing on the electrical power system of the massive container ship that veered off course.

Jennifer Homendy, chair of the National Transportation Safety Board, said her agency is gathering data with assistance from Hyundai, the manufacturer of equipment in the ship’s engine room. Testifying before a U.S. Senate committee Wednesday morning, she said investigators have also requested assistance to examine its circuit breakers.

“That is where our focus is right now in this investigation,” she said. “Of course, that’s preliminary. It could take different roads, different paths as we continue this investigation.”

Homendy said they’ve zeroed in on the electrical system. The ship experienced power issues moments before the crash, as evidenced in videos showing its lights going out and coming back on.

 

[Baluncore]

The collision occurred about 1 hour before low water. The tidal outflow in the channel would have been strong at that time, before meeting the incoming tide. The bay has a large surface area, so the small, just over one-foot tidal variation, could be quite important.

Does anyone have an estimate of the down-channel current at that time.

In order to maintain steerage way, the vessel would need to exceed the tidal current, which would increase the ground speed. Even if the vessel had stopped, dead in the water, it would still have been moving downstream at the speed of the tidal outflow.

 

[gleem]

Does anyone have an estimate of the down-channel current at that time.

I've tried hard but could not find any data near the Key bridge. However, the tides in the Bay East of the bridge at that date and time are estimated to be about 0.6 kt southward.

However, I found out that the wind speed at the Key Bridge from a NOAA website was about 11 Kts SSE. at the time of the collision.

 

[gleem]

I found some interesting info on the tides in the Chesapeake Bay. The Bays being an estuary has fresh water coming in at one end and seawater coming in at the other and being 200 miles long has currents coming and going at the same time the water will slosh back and forth. But more importantly, is effectively is the north and south winds along the bay.

This seminar discusses the effect of wind on the tides and currents. Chesapeake Bay101,

 

[Astronuc]

FBI opens criminal investigation into Baltimore bridge collapse, AP source says​

https://apnews.com/article/baltimor...vestiagation-58188d524035c756872603055f309c78

The FBI is conducting a criminal investigation into the deadly collapse of Baltimore’s Francis Scott Key Bridge that is focused on the circumstances leading up to it and whether all federal laws were followed, according to someone familiar with the matter.

The person was not authorized to discuss details of the investigation publicly and spoke on the condition of anonymity to The Associated Press.

FBI agents were aboard the cargo ship Dali on Monday conducting court-authorized law enforcement activity, the agency said in a statement. It didn’t elaborate and said it wouldn’t comment further on the investigation, which was first reported by The Washington Post.

Meanwhile, Mayor Brandon Scott on Monday announced a partnership with two law firms to “launch legal action to hold the wrongdoers responsible” and mitigate harm to the people of Baltimore.

 

[Astronuc]

The biggest Key Bridge section yet was pulled from the Patapsco River this weekend.​

https://news.yahoo.com/biggest-key-bridge-section-yet-003300881.html

The approximately 450-ton section of truss sat Monday morning at a processing yard at Tradepoint Atlantic in Baltimore County, where orange sparks flew as workers sawed at the steel. Minutes later, a clawlike pair of shears attached to an excavator tugged on a weakened steel member, folding an entire triangular section of truss onto the ground.

Officials estimate that a total of 50,000 short tons of debris are sitting in the Patapsco River, blocking access to the shipping channel that leads to the Port of Baltimore. The debris is steadily coming ashore in Sparrows Point, and once it’s cut down, it will be sent to local recycling companies.

The ship has power, but the bow thruster isn’t operational, Farrell said. The crash severed electrical wiring tied to the bow thruster, a propeller-shaped system that helps maneuver the ship at lower speeds, and crews are hoping to bring the thruster back online.

Meanwhile, Federal authorities are investigating problems with the ship, including problems with the electrical system while in port. Apparently, they were not addressed satisfactorily prior to the ship leaving the dock.


Regarding the Chesapeake 1000.
https://www.donjon.com/ches1000.htm
https://en.wikipedia.org/wiki/Chesapeake_1000

 

[Vanadium 50]

Apparently, they [electrical problems ] were not addressed satisfactorily prior to the ship leaving the dock.

Ya think?

 

[Tom.G]

Shortly after the bridge crash, I stumbled across a report that the electrical problems whle still in port were caused by power being supplied to too many refrigerated containers. The electrical load was re-distributed several time to stop tripping the circuit breakers.

I was not aware that refrigerated containers were electrically driven.

I also have not been able to find the report again, so please take the above with a bit of scepticism.

 

[jedishrfu]

I found this news reference that mentions that theory

https://www.wcnc.com/article/news/n...apse/507-02e9a160-2ab6-463c-99ce-08f9862d9e45

 

[Frabjous]

On standards
https://www.washingtonpost.com/dc-md-va/2024/04/18/baltimore-bridge-safety-standards/

 

[gmax137]

I was not aware that refrigerated containers were electrically driven.

How else?

 

[Astronuc]

BALTIMORE (AP) — The owner of the massive container ship Dali, which caused the deadly collapse of Baltimore’s Francis Scott Key Bridge last month, has initiated a process requiring owners of the cargo on board to cover some of the salvage costs.

The ship’s owner, Singapore-based Grace Ocean Private Ltd., made what’s known in maritime law as a “general average” declaration, which allows a third-party adjuster to determine what each stakeholder should contribute, according to company spokesperson Darrell Wilson.

https://news.yahoo.com/finance/news/owner-ship-baltimore-bridge-collapse-164820493.html

 

[Vanadium 50]

A general average works like this. If your ship is carrying $800 in bananas and $200 in bowling balls, and the bowling balls need to be pitched over the side, the banana shipper pays the bowling ball shipper (through a maze of lawyers and 3rd parties) $160. Everybody loses 20%.

So far as I know, the cargo owners share no liability for any of the damages.

 

[Baluncore]

https://en.wikipedia.org/wiki/Marine_insurance#General_averages

 

[Astronuc]

The Dali, the container ship that left the Port of Baltimore in the early hours of March 26, before crashing into the Francis Scott Key Bridge, toppling a portion of it, set sail despite its "unseaworthy" conditions, according to a Monday court filing from the City of Baltimore.

In the court document, the city argues that the ship's parent company, Grace Ocean Private Ltd., should be held liable for crashing into the Key Bridge. The filing was in response to Grace Ocean Private Ltd.'s request to limit their liability in damages they have to pay.

In previous filings, GOPL has argued that it shouldn't be held liable for the crash that left six construction workers dead and a length of the bridge wiped out.

https://news.yahoo.com/city-baltimore-claims-court-filing-035530157.html

Meanwhile, slow progress in reopening the port.

https://news.yahoo.com/crews-open-third-temporary-channel-131216716.html

 

[sophiecentaur]

Those lawyers are all rubbing their hands together in anticipation of money money money. It's a win win for those guys.

 

[Astronuc]

US-required bridge inspections don’t test for ship strike. Then, one hit the Key Bridge
https://www.yahoo.com/news/us-required-bridge-inspections-don-194200805.html

Bridge inspections are typically completed by the bridge owner or one of its contractors, then the owner provides the data to the federal government. The Key Bridge’s 2021 inspection is the most recent included in the Federal Highway Administration’s National Bridge Inventory.

Although protection from a ship strike is considered when any bridge is constructed today, there are no federal statutes, regulations or policies that require existing bridges be evaluated for the possibility of a vessel collision. Whether to do so is left to the judgment of each bridge’s owner, the Federal Highway Administration told The Baltimore Sun.

The bridges’ owner is the Maryland Transportation Authority

The authority said that “with the Key Bridge incident in mind, there has been a renewed focus on pier protection” of its bridges and it will consider any recommendations made by the NTSB.

But that agency’s final report could take up to two years. NTSB Chair Jennifer Homendy told members of Congress earlier this month that evaluating “pier protection” is something that bridge owners can do now.

Tugboats have not been required to assist ships under the Key Bridge. And although the bridge’s “pier abutment protection” received high marks during its 2021 inspection, that rating determined merely the “condition” of the protective system — not its strength. It’s similar to inspecting an original Ford Fiesta; despite not having an airbag, its existing safety features could be in working condition, even if they’d be considered inadequate for today’s world.

The Key Bridge had four small concrete “dolphins” — artificial islands meant to deflect vessels from bridge supports — along its channel as buffers for its two biggest support columns. They paled in comparison to protective systems of modern bridges. Auburn University engineer Andrzej Nowak likened them to “kids’ toys.”

 

[Vanadium 50]

US-required bridge inspections don’t test for ship strike.

How could they, realistically?

Lots of forces on a bridge. Lots of kinetic energy in a ship. A bunch of hooring and hollering by politicians and talking heads won't change that.

 

[berkeman]

US-required bridge inspections don’t test for ship strike.

How could they, realistically?

Well, to get good data they could conduct such inspections in the dark, with no prior notice, with the ship's light blacked out...

Oh wait.

 

[sophiecentaur]

How could they, realistically?

They can't but each disaster corresponds to relevant data. The Hindenberg, on its own, put the mockers on H filled airships. This bridge disaster could have been much worse, but for the actions of the road traffic controllers.
As a spectacle, it certainly did the job of putting a huge dot on the graph. I hope the families of the unfortunate workers who died in the incident will be compensated very adequately.
There is plenty of data about all safety matters that's only available from bitter experience when qccidents happen. But there are Mayors of Amity around every corner. That face should be posted in all committee rooms.

 

[Rive]

How could they, realistically?

Well, not really a testing, but you can assess the protection of pillars by sonar data about the cross section (compared to the plans).

 

[Vanadium 50]

Let's turn it around. Suppose I can make bridges twice as unlikely to fail by increasing the cost by a factor of 10. Should I?

Might it not make more sense to build more bridges to increase redundancy rather than fewer but stronger bridges?

I don't know the exact number, but there are ~1500 bridges at least that long in the US. When was the last collapse? 2007 and I-35W? So we are talking a MTBF of something like 20,000 years.

To me, this sounds pretty good. Spending a lot of energy trying to get this to 30,000 or 50,000 seems tough. If you want to argue "nothing is more important than safety", by making drivers take the long way, you are causing more automobile fatalities. These are less dramatic and seldom make the news, but that doesn't mean they aren't real. The optimum point may be more, cheaper bridges.

 

[Vanadium 50]

To extend:

Say a bridge carried 10M cars per year, and saves 5 miles per trip. So that's 1T miles saved per bridge. Taking a car fatality rate of 1 per 100M miles, that means a bridge will save 10,000 lives. If you say typically there are ~10 fatalities per bridge failure, that's still 1000x better.

To me that says that the winning proposition is more bridges, not fewer but safer bridges.

 

[nsaspook]

How could they, realistically?

Lots of forces on a bridge. Lots of kinetic energy in a ship. A bunch of hooring and hollering by politicians and talking heads won't change that.

+1
Look at the relative size of ships and the bridge.

The ship coming through the new channel is not exactly a small boat, yet it is completely dwarfed by the Dali.

 

[jack action]

Say a bridge carried 10M cars per year, and saves 5 miles per trip. So that's 1T miles saved per bridge. Taking a car fatality rate of 1 per 100M miles, that means a bridge will save 10,000 lives. If you say typically there are ~10 fatalities per bridge failure, that's still 1000x better.

That only works if people do end up doing 5 miles less overall. This is what hurts this type of theory: people just do the same amount of mileage, just going somewhere else. Worst of all, easier access to the infrastructure usually just lengthens the commute for most people - because they choose to drive the same amount of time - and they end up driving longer distances.

There is no way a bridge will save 10,000 lives.

 

[phinds]

There is no way a bridge will save 10,000 lives.

 

[Vanadium 50]

There is no way a bridge will save 10,000 lives.

It will over a 20,000 year MTBF. That's 2 lives/year/bridge. To me, that sounds about right. If you like, take an order of magnitude off if you like - doesn't change the conclusions.

You are correct that people have already decided what is an acceptable risk. In the US, it;s about 40,000 fatalities per year. (And my estimate is that without bridges it would be 43,000) The number killed in suspension bridge failures is about 1. Perhaps 2. "Heavens to Betsy! Something must be done!"

 

[Frabjous]

If I understand this correctly
https://conference-service.com/pianc-panama/documents/agenda/data/full_papers/full_paper_46.pdf
the US standard for annual frequency of collapse for critical bridges is 0.0001

 

[Vanadium 50]

the US standard for annual frequency of collapse for critical bridges is 0.0001

Or 1/10,000. My estimate was 1/20,000. (We may define "major bridge differently.)

They claim 35 losses worldwide in 55 years. If the US is 10% of the total, that's a MTBF of 24000 years. If instead its 20%, it's 12000 years.

 

[Rive]

That's 2 lives/year/bridge.

I don't really understand that why 'bridge safety' went down only this way, but I think the money lost on this single accident would be a far more fitting explanation for what's expected to follow than the six (?) casualty.

 

[Vanadium 50]

No objection to that, but if you take the cost of replacing a bridge and spread it around to all the bridges, its $100,000/year. That doesn;t buy you much safety. Heck, it doesn't even buy you much in the way of drawings.

I suspect - but do not know - that a purely economic optimization will lead you to more, but flimsier, bridges.

 

[Rive]

I think as safety, for cases like this we are talking about a pile of gravel dumped around the pillars. Or something like that.
And only for cases where big ships are expected. I can imagine they'll just leave the most alone.
Not like a new layer of containment for an NPP or anything. Just a big pile of gravel dumped at the right place.

 

[Astronuc]

How could they, realistically?

Lots of forces on a bridge. Lots of kinetic energy in a ship. A bunch of hooring and hollering by politicians and talking heads won't change that.

Impact/collision analysis, which is feasible. One can do 'what if' scenarios, and follow with probabilistic risk assessment, as well as a cost benefit analysis. One might decide to spend $50 to 100 million to protect a bridge that would require $5 billion to replace (and protect).

An informed risk assessment requires one to acknowledge that risks to change, e.g., with increase in ship size (and mass), such that old analyses from say 50 years ago may not adequately reflect the current risk. Also, part of the risk also involves the frequency in which ships have power and/or navigation/steering failures. It may be less expensive to require ships to ensure their power and navigation systems are fully functional, with appropriate, backup before leaving port. Or perhaps require tugboats must accompany large ships, or ships deemed to have problems prior to passing critical infrastructure.

 

[Rive]

It may be less expensive to require ships to ensure...

Given the number of ships actually it may be more expensive, but with somebody else paying the bill, and that matters

 

[gleem]

Given the number of ships actually it may be more expensive, but with somebody else paying the bill, and that matters

Ultimately the consumer pays the bill either through taxes or by passing through the increased corporate operating expenses.

 

[Flyboy]

I think that people ate trying to generalize a solution to very situationally specific issues. Every bridge is different, from construction to traffic to risks, and no one solution will satisfy every problem.

In this particular case, the electrical problems should have been sorted out before departure. But that’s with the benefit of hindsight and an armchair to speculate from

 

[Nik_2213]

The converse of this event would seem to be protection of Arctic drill-ships from ice-bergs.
IIRC, following fraught learning curve, a 'layered' approach proved necessary.

For 'harbour' bridges, and such as Thames Barrage, stopping any sizeable incoming 'cold' just needs too much infrastructure / mass. Such would require a non-trivial island, retro-fit potentially narrowing shipping channel and raising the risk of lesser, but channel-blocking collisions...

IIRC, by analogy with freeway edge / motorway median barriers that progressively deform to dissipate energy, re-direct / significantly mitigate impactors, bridge piers etc need outer frangible bollards, middle stronger bollards and inner 'hard place'. Traversing these obstacles dissipates enough energy to swing arrivals from wrecking radial to survivable lateral...

Okay, yes, Titanic would have probably survived t-boning that berg, where-as the lonnng flank scrape popped enough flank plates to take them down. But we want the bridge pier to endure...

 

[Baluncore]

The vast majority of the Key bridge was protected by shallow water, where a vessel of sufficient size could not approach the support columns. There were only the diagonal approaches from the main channel left open to a sufficiently large vessel. (It could be said that the Suez Canal banks were well protected from the Ever Given, by the shallower water at the edge of the canal).

The bridge was "probed" on a daily basis over many years, as part of an unintentional Monte Carlo experiment to find weak points in the defences. It was not until a vessel of sufficient size became available, that the vulnerability was identified by destructive testing.

I would be interested to know how the main channel depth was increased over time by dredging, to allow progressively larger vessels to pass. It seems the mindset of increasing channel depth and capacity, opposed the progressive buildup of parallel protection structure, or banks on either side, that would have narrowed the main channel.

The other issue here is the progressive domino failure of the entire support truss. The majority of the investment could have been protected by having a structure that could suffer only partial collapse. It seems to me that the large size of the truss members, precluded redundancy, in the support structure of the main spans.

 

[Swamp Thing]

 

[Borg]

I think that they've been waiting until they recovered the last body - which was recovered this week.

 

[Hornbein]

 

[Borg]

Explosive charges are scheduled to be set off at 5pm EST today in just under an hour.

Live view here:

 

[Borg]

The video seems to not be live since it did go off at 5 but the video still shows it not exploded 10 minutes later.

 

[nsaspook]

 

[Astronuc]

Cargo ship that caused Baltimore bridge collapse had power blackout hours before leaving port
https://apnews.com/article/baltimor...-report-ntsb-b6d4797441350823adb7721164848c04

According to the preliminary report, at 1:25 a.m. on March 26, when the Dali was a little over half a mile away from the bridge, a primary electrical breaker that fed most of the ship’s equipment and lighting unexpectedly tripped, causing the ship to lose electrical power and experience a blackout. The main propulsion diesel engine shut down after the pumps lost electrical power. The ship’s crew was able to restore power, then called for an assist from tug boats and the senior pilot ordered the ship’s anchor to be dropped.

A second blackout then occurred and a marine radio call was made to warn waterborne traffic. The ship then struck a main support pier on the bridge, causing it to collapse within seconds.

 

[DaveE]

NTSB preliminary report is out. Lots of information in this video, but no ultimate answer to why. Apparently an issue with electrical distribution, not engines or generators.