Baltimore Bridge Collision and Collapse

[Capt. Eric]

See @OverTheTop , the ship is huge I mean if you look at those boxes they are the same ones you see on the back of a semi and they are stacked 10 or 15 high…

They are also stacked about 10 high below deck. Not all of them are full, but even empty, a 20ft container weighs 2 tons, a 40ft about 3.5.

 

[Bravo52]

It’s surprisingly deceptive how many containers that ship, or any large container ship can carry. This one in particular had about 4700-5000 containers on it and I read that it was capable of up to 10,000. I’m sure that depends on the size of said containers but, that’s a lot. Apparently, the largest container ship can carry 24,000+ containers…again, depending on the size of the boxes.

For fun, search how many shipping containers are lost at sea…that is surprising.

 

[Capt. Eric]

It’s surprisingly deceptive how many containers that ship, or any large container ship can carry. This one in particular had about 4700-5000 containers on it and I read that it was capable of up to 10,000. I’m sure that depends on the size of said containers but, that’s a lot. Apparently, the largest container ship can carry 24,000+ containers…again, depending on the size of the boxes.

For fun, search how many shipping containers are lost at sea…that is surprising.

When they rate container ship capacity it is in "teu" or "twenty foot equivalent units". Two 20ft boxes = one 40ft box, both at the standard 8ft height. (Seems silly to say that, but you'll see why I do.

Most containers are 20ft or 40ft, with the later being more popular with shippers. So a ship like that will likely have about 75% as 40 footers.

So it's capacity might be 10,000 teu, and that gets reported as that many containers. But since most are 40ft boxes, they only had about 4700 boxes. Makes it sound like they were less than half full, but looking at the pictures, they were almost to capacity.

Also, just to split hairs, containers do come in other sizes. 45, 53, 55 foot long, and 8.5, 9ft high. There are also flat racks, open top, open side, tank, refrigerated, insulated, and various other types for use with different types of cargo. I've even seen containers converted into stalls for carrying horses.

 

[wsume99]

Would it be reasonable to assume that the Port of Baltimore did a risk analysis on the likelihood of an event like this occurring? I'm assuming they would have. I would also assume the results of that assessment had to show the risk of doing nothing was less costly than implementing any sort of protective measure to prevent a bridge collapse such as mandating tugs or installing some sort of physical barrier to prevent contact with the main pier.

I've been on the investigation side of mishaps and normally what we find is the risk was evaluated but because someone didn't like the initial answer the inputs to the analysis were "refined" and magically the final answer says no changes are needed. I have a gut feeling this is the case in this situation.

 

[cbrarick]

Wsum99, I think you have it a little sideways.

Question 1: what's the largest ship that could possibly come into the Baltimore Harbor?
Question 2: Is there any possible method of protecting the bridge from that ship? Don't forget, that ship was 100,000 tons...think of the inertia at 9 knots
Question 3: What is the cost of this protection and is it practical to construct said barrier?

it might have been decided that such barrier was impossible, impractical or far too expensive to construct.

I'm willing to bet that they did the assessment, however. I've sat on the Capital Region Emergency Planning Commission in CT and you'd be surprised what was planned for / evaluated and a "wish list" of projects developed, each of which needed funding......

 

[wsume99]

Wsum99, I think you have it a little sideways.

Question 1: what's the largest ship that could possibly come into the Baltimore Harbor?
Question 2: Is there any possible method of protecting the bridge from that ship? Don't forget, that ship was 100,000 tons...think of the inertia at 9 knots
Question 3: What is the cost of this protection and is it practical to construct said barrier?

it might have been decided that such barrier was impossible, impractical or far too expensive to construct.

I'm willing to bet that they did the assessment, however. I've sat on the Capital Region Emergency Planning Commission in CT and you'd be surprised what was planned for / evaluated and a "wish list" of projects developed, each of which needed funding......

Sideways? If they didn't do a risk assessment then I would say they were negligent. I am pretty confident someone did the assessment. I'd like to see what mitigations they put in place to prevent a collision with the bridge or the logic behind why implementing any protective measure was impractical. I am most interested in their estimation of the probability of a collision happening and how that compares to the realized probability.

 

[NTP2]

logic behind why implementing any protective measure was impractical.

If you can find me a engineer that can design a protective measure that can work for this size ship AND be cost effective, I’ll give you a quarter.

 

[cbrarick]

Oh, man, I'll never get a quarter.

 

[wsume99]

If you can find me a engineer that can design a protective measure that can work for this size ship AND be cost effective, I’ll give you a quarter.

Doesn't need to be a physical barrier. As was discussed earlier in the thread, tug escorts to the bridge may have prevented this.

In terms of a physical barrier, I'd say a redundant sacrificial bridge pier, called a dolphin, about 50 ft in front the the actual bridge pier would have been sufficient. The Dali stopped pretty quickly when it hit the main pier. Found this article discussing the topic. Looks like I'm not way off base asking why a collision protection system was not in place.

 

[cwbullet]

Doesn't need to be a physical barrier. As was discussed earlier in the thread, tug escorts to the bridge may have prevented this.

In terms of a physical barrier, I'd say a redundant sacrificial bridge pier, called a dolphin, about 50 ft in front the the actual bridge pier would have been sufficient. The Dali stopped pretty quickly when it hit the main pier. Found this article discussing the topic. Looks like I'm not way off base asking why a collision protection system was not in place.

I will bet the rebuild has one.

 

[boatgeek]

Sideways? If they didn't do a risk assessment then I would say they were negligent. I am pretty confident someone did the assessment. I'd like to see what mitigations they put in place to prevent a collision with the bridge or the logic behind why implementing any protective measure was impractical. I am most interested in their estimation of the probability of a collision happening and how that compares to the realized probability.

I think you overestimate public agencies’ willingness to look for trouble. I believe this bridge was hit by a ship long ago, and it survived then, partly because the ship was much smaller. When they brought in newer, larger ships, everyone was likely looking at revenue and not doing risk assessments. Is that negligence? Maybe. Is it common? Absolutely.

 

[Capt. Eric]

Risk assessments are useless. Just a feel good paper exercise to make managers feel like they did something. Done many of them because it was required, but none ever did anything to change what we were doing or improve the operation. CYA.

 

[boatgeek]

Risk assessments are useless. Just a feel good paper exercise to make managers feel like they did something. Done many of them because it was required, but none ever did anything to change what we were doing or improve the operation. CYA.

I’ve been involved in a couple of risk assessment for oil industry projects. One was sort of useful, the other far less so. My favorite moment was when they spent more money in billable time talking about whether a particular item was needed than the item itself cost. Great use of time, folks! And that was in the useful one.

 

[Grog6]

They protect a lot of bridges from this; it amazes me this one wasn't, given it's importance. This shut down a major highway and a seaport, for months at a minimum.

 

[rharshberger]

I’ve been involved in a couple of risk assessment for oil industry projects. One was sort of useful, the other far less so. My favorite moment was when they spent more money in billable time talking about whether a particular item was needed than the item itself cost. Great use of time, folks! And that was in the useful one.

Happens all the time where I work at on the other side of the state from you....we buy equipment it never gets used, technology gets better...we buy new equipment to do the job...the old equipment gets "excessed" still new...it took 20 years to build a project that was supposed to take 10.....

 

[jderimig]

Risk assessments are useless. Just a feel good paper exercise to make managers feel like they did something. Done many of them because it was required, but none ever did anything to change what we were doing or improve the operation. CYA.

I think it will be a toss-up whether more billable hours will be spent on a risk assessment or on deciding the name of the new bridge.

 

[wsume99]

As bad as this seems it could have been a lot worse. This would be a very different situation if it happened at 5:00 pm on a weekday. People would not be wondering if this could have been prevented, they would expect it never happens again.

 

[boatgeek]

I think it will be a toss-up whether more billable hours will be spent on a risk assessment or on deciding the name of the new bridge.

Easy. The risk assessment will be more billable hours. The name will be chosen via contest, and they’ll pick the second place entry after “Bridgy McBridgeface.”

 

[Bravo52]

Risk assessments are useless. Just a feel good paper exercise to make managers feel like they did something. Done many of them because it was required, but none ever did anything to change what we were doing or improve the operation. CYA.

I wouldn't say "Risk assessments are useless", what agencies/people chose to do with them maybe. I think it is more likely that a risk assessment was done at some point but it was probably outdated, misapplied or ignored. We may never know as the last thing the Port of Baltimore and State of Maryland will want is something showing up that says; "Hey, look at that! Looks like we knew this might happen!"

 

[Last Ox]

Just my two cents.

I have some experience conning ships under bridges (to be fair, nothing over 20,000 tons). A ship is nothing like a car, bus, or airplane - in how it is powered, turned, or controlled. Many monday morning quarterbacks in the press may as well be asking "Why didn't the train stop? Surely they could see the car stalled on the tracks?" Nothing is as simple or easy as they imagine. Those of us who have been there are more likely to be thinking "There but for the grace of God go I". When things go badly wrong on a large ship, you are playing catch up and often lose.

One thing is clear, few people understand what a maritime pilot is. They do not drive or command the ship. They are local experts and, technically, only advisory. Except in the Panama Canal (or while entering a drydock) ship's company are responsible for controlling the ship. That said, pilots often all but have the con, ships can simply do whatever the pilot says (but if it goes wrong, bear responsibility for whatever mishap may occur). NTSP will sort it out, but I've seen nothing that indicates either the harbor pilots or ship's company did anything wrong and they clearly did some critical things right. Fun fact - maritime pilots are far more likely to die on the job than police officers, getting on and off an ship in open water isn't ever completely (often, even reasonably) safe.

As someone said, the insurance industry will probably have a lot more influence on outcomes than U.S attempts at regulation of foreign flagged shipping, and barring foreign shipping from U.S harbors would mean ending more than 90% of our foreign trade.

I've had a few extended tug escorts, but only on ships with compromised rudders or other control or propulsion problems. Traveling with tugs made up is no bed of roses either, more moving parts is more things to go wrong and no guarantee you can stay out of trouble. Making up or casting off a tug alongside in open ocean is in itself a dangerous evolution.

The bridge had dolphins (visible in photos) but the 4 structures present provided limited protection, and only from a very narrow approach angle. Better protection for bridges is something to look at, but protecting a bridge from a ship that weighs as much as 10-20 loaded freight trains (and doesn't collapse on itself like a derailed train) isn't trivial. The situation reminds me of standards for nuclear power containment structures (which had to be rewritten, but not retroactively, when jumbo jets came on the scene). One of the things we were very aware of fifty years ago is the number of everyday hazards we accept much greater risks for than the worst case scenario fault trees for nuclear power safety. Modern society has trouble treating risks rationally - falling haystacks, for example, kill more people in the US than sharks, rattlesnakes or lightning.

Bottom line is, the ocean is a dangerous place and things sometimes go wrong. Odds are, that will sometimes happen in a bad time and place, and we can usually improve the odds, but never beat them entirely. We can probably do somewhat better than the former Key Bridge in several respects, but nobody necessarily did anything "wrong" and even with extreme measures and investment the risk can't be engineered out entirely.

 

[Cape Byron]

The 100,000 tonne ship hit the bridge fender and it just collapsed/exploded from what I have read. Not many things will stop that sized impact.

 

[Capt. Eric]

View attachment 637753

But a Starship moves much, much faster, so has a great deal more energy if it hits something.

 

[bjphoenix]

I am no expert, but I suspect the bridge itself does not need as much post mortem analysis as, after all, it didn't fail - it was knocked down.

I think they will still do extensive analysis to determine how it failed. The truss was primarily three spans and one question would be why the third span failed, or maybe how close it came to not failing. Some structures are designed these days to better withstand loss of one area and leave the rest standing, as a result of the Oklahoma City bombing.

The 100,000 tonne ship hit the bridge fender and it just collapsed/exploded from what I have read. Not many things will stop that sized impact.

I've seen discussions online about other similar bridges having large dolphins to protect the bridge supports. Designing a dolphin to effectively stop a mass of this size is not trivial. Some of the ones seen at other bridges are fairly large diameter but you can't see that they are also fairly tall and need to be anchored to the sea bed very well.

 

[cbrarick]

I wonder if placing dolphins large enough to do protect the bridge from that ship would make the shipping channel unusable due to the anchorage criteria of the dolphins. The article wsum99 posted actually concluded that there is no practical method of protecting the Key Bridge
when we were looking at bridges in the capital region, there's a high level bridge built in 1938 that is wind rated for only 70 mph. above that it must be inspected by engineers. It's a steel through arch bridge and there's no way to improve it's wind rating. As we started working on hurricane preps, the only solution was to replace it. Problem is that there are native american burial grounds preventing any type of change to it's access. This prevents a side by side replacement as on that side the road curves significantly to avoid the burial grounds. Solution: plan that the bridge is unusable for several months after the hurricane. While this will significantly impact travel (the other crossings are at least 10 miles away) it's the only workable solution. Some things are just unfixable.

 

[les]

I've seen discussions online about other similar bridges having large dolphins to protect the bridge supports.

Just how big are these DOLPHINS that can move a 100,000 ton ship?





And what do you feed them???
Do you get a tsunami from the splash when they land?



sorry if too soon, especially with the loss of life.....

 

[wsume99]

The article wsum99 posted actually concluded that there is no practical method of protecting the Key Bridge

In that article they talked to multiple professors, I think it was three or four. Yes, the last professor mentioned in the article was quoted as saying he did the calculations and it would be impossible to design a dolphin to stop a ship that large. I disagree with that statement. I point to the fact that the Dali stopped when it hit the main pier of the Key Bridge. It actually stopped quite abruptly. So I don't think it's reasonable to say no dolphin could be designed to stop a large ship. Maybe there isn't room to fit it in with all the other shipping channels in the area but that's a logistical issue, not a physics impossibility as many are making it seem.

 

[jderimig]

Easy. The risk assessment will be more billable hours. The name will be chosen via contest, and they’ll pick the second place entry after “Bridgy McBridgeface.”

Naming the bridge will not be that easy. Any contest will need judges. Just like a RA.

 

[rcktnut]

I doubt they are going to retire the name of the bridge.

 

[jsdemar]

To build effective dolphins or other protective structures of the size needed for today's cargo ships, the span over the channel has to be much wider than the Key Bridge was. The pillars holding the span have to be far enough away from the channel to allow the ship to hit the protective structures long before making it to the bridge pillars. This is what likely prevented any plans to update the existing bridge. And will require a whole new design for the next bridge.

 

[boatgeek]

In that article they talked to multiple professors, I think it was three or four. Yes, the last professor mentioned in the article was quoted as saying he did the calculations and it would be impossible to design a dolphin to stop a ship that large. I disagree with that statement. I point to the fact that the Dali stopped when it hit the main pier of the Key Bridge. It actually stopped quite abruptly. So I don't think it's reasonable to say no dolphin could be designed to stop a large ship. Maybe there isn't room to fit it in with all the other shipping channels in the area but that's a logistical issue, not a physics impossibility as many are making it seem.

I haven't looked at the navigational charts in the area, but it's also possible it stopped after running into the mud outside the channel. Running aground is just about the only way to stop a ship quickly.

Naming the bridge will not be that easy. Any contest will need judges. Just like a RA.

The judges will be the US Secretary of Transportation, the MD Secretary of Transportation, and the mayor of Baltimore. They will have some aides who vet the options, but I really only see three, in descending order of probability:
1. Keep the Key Bridge name. It's got tradition in favor of it, and is likely the least controversial. That's worth a lot, especially if the three judges above are from different political parties.
2. The most prominent MD civil rights leader who does not yet have a bridge named after them.
3. The name of one of the workers killed in the collapse. If it had been only one worker killed, or if a state trooper had been killed, this would go up the list. As it is, I only see this happening if there was one worker who died who also demonstrably saved others' lives.