Baltimore Bridge Collision and Collapse

[jderimig]

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

No way they are going to rename the bridge after the author of the national anthem and a slave owner.

 

[jsdemar]

No way they are going to rename the bridge after the author of the national anthem and a slave owner.

They should name it after Louis Armstrong who popularized the song "Hello Dali". ;-)

"It's nice to have you back where you belong!"

 

[Greg Furtman]

We know what happened and the result. I'm eagerly awaiting the NTSB report on why it happed. What caused loss of power and lack of steerage. I wonder how long before we find out?

 

[bjphoenix]

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

Big, REALLY BIG.

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.

It's obviously not impossible, impractical is another question. I wonder how they did those calculations- if you assume that a solid object with some velocity meets another solid object then the impact force is infinite. You have to assume some movement of one or both objects so the average impulse counteracts the inertia. I don't think a big dolphin moves very much, despite the post above, so the ship has to deform on impact.

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.

Some of the bridge examples given to show bridges that did have protective structures show fairly large dolphins. However they mostly seem to be in line with the bridge support so it is questionable if they would protect against a ship moving at a diagonal. People who know about ship dynamics know more about this than I do, I just work on buildings.

 

[jderimig]

I wonder what would be cheaper.

Installing dolphins to protect the piers from 100-200 ton container ships, OR,
Building another bridge 100 ft or so parallel as a backup.

 

[Art Upton]

The Ships underwater part of the bow is stopped aground in the Mud bank, that is what stopped the ship.

 

[boatgeek]

We know what happened and the result. I'm eagerly awaiting the NTSB report on why it happed. What caused loss of power and lack of steerage. I wonder how long before we find out?

I would guess that NTSB will issue a preliminary set of facts in 1-4 weeks. That will answer a lot of questions.

 

[jderimig]

The Ships underwater part of the bow is stopped aground in the Mud bank, that is what stopped the ship.

Is that the solution then...???

 

[Art Upton]

Is that the solution then...???

Didn't this ship hit or slam into a bank or wall just a few years ago in another country ?

 

[rcktnut]

Any ideas on the type of replacement it's going to be? I'm going to go with a suspension or cable-stayed. Anyone of these will allow for a much bigger span. I don't believe they will keep the 50 year old approaches with a new bridge.

 

[NTP2]

Any ideas on the type of replacement it's going to be?

The bridge that can be built the fastest, our friend the mayor of Baltimore has an economy to save!! And no time for architects!

 

[Capt. Eric]

Any ideas on the type of replacement it's going to be? I'm going to go with a suspension or cable-stayed. Anyone of these will allow for a much bigger span. I don't believe they will keep the 50 year old approaches with a new bridge.

They might put up a similar bridge, but make it higher since ships are getting bigger and higher. They might try to use the existing pillar foundations to save time, so I'd be surprised if the bridge is dramatically different, unless those foundations are not in good shape. But I'm not in the room, so just guessing.

 

[boatgeek]

Any ideas on the type of replacement it's going to be? I'm going to go with a suspension or cable-stayed. Anyone of these will allow for a much bigger span. I don't believe they will keep the 50 year old approaches with a new bridge.

Depends how fast they want it. If the political pressure is there to get it done faster, they’ll replace it more or less with the same bridge. If it’s more important to get more capacity, they’ll do something fancier. It may also depend on the condition of the foundations. If they have to replace all the foundations anyway, they’ll probably go fancy.

(Edit: ninja’d!)

 

[Dotini]

Any ideas on the type of replacement it's going to be?

I've been wondering about which design might allow for the highest net rate of port traffic while the bridge is under construction?

 

[cbrarick]

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.

the Dali's abrupt stop is fairly easily explained. When it hit the pier, a large and heavy chunk of I-691 came crashing down on the bow, driving it into the mud. That's what stopped it so suddenly. Ask any mariner that has ever hit a shoal how quickly you stop.

Yes, I'm sure you could build such a dolphin that would stop the largest ship that could ever enter the Baltimore Harbor. However, the real que3stion is, after such massive structure is built, will that ship be able to squeeze between said dolphins? or will they narrow up the shipping channel so much that only a canoe can fit between them????

 

[NTP2]

Only a canoe can fit between them????

To quote the mayor of Baltimore speaking to the BBC “these things aren’t your kayak”

 

[MClark]

Feds said they will pay whatever it costs.
Bridge will be the most expensive and take as long as possible.
Billions flowing around for a decade will stick to "the right fingers."

 

[Bravo52]

Feds said they will pay whatever it costs.
Bridge will be the most expensive and take as long as possible.
Billions flowing around for a decade will stick to "the right fingers."

My guess is they will walk that back. More likely, they will provide funding in the form of a loan or grants if specific criteria are met. Additionally, the insurer will foot some of the bill. That road/bridge was "private" (meaning state) in a sense that it was a Maryland toll road so that murkys the water, so to speak. Not a "national highway". Aside from the political pandering during an election year, there are good "national interest" reasons to facilitate the rebuilding of the bridge or at least clearing the harbor. However, the "we'll pay for it" isn't as simple as politicians want it to be.

Another interesting topic is the ship was insured for roughly $2-3B. It is said the estimate is the bridge alone may cost $1.5-2B, plus current inflation of about 25%....so as much as ~$2.5B. Seems like that would be within the insurer's boggy...UNTIL... you hear about the 1851 maritime law that could limit the ship's owner's liability to the value of the ship after the crash. It was the same law used by the owners of the Titanic in limiting liability. It is the "The Limitation of Liability Act of 1851" (a US law of all things!) but it is now known as the "Titanic Law".

The one thing for sure is the bridge will be rebuilt long before all the legal wrangling is complete.

 

[jderimig]

Cost to rebuild bridge will be less than most of the new NFL stadiums that taxpayers pick up. And they are used less than a dozen times per year. Bridge cost is peanuts in the grand scheme of things.

 

[cvanc]

The one thing for sure is the bridge will be rebuilt long before all the legal wrangling is complete.

This.

 

[NTP2]

Cost to rebuild bridge will be less than most of the new NFL stadiums that taxpayers pick up. And they are used less than a dozen times per year. Bridge cost is peanuts in the grand scheme of things.

Don’t get me started…

 

[cwbullet]

Building another bridge 100 ft

my guess is the bridge will be more expensive.

 

[boatgeek]

Cost to rebuild bridge will be less than most of the new NFL stadiums that taxpayers pick up. And they are used less than a dozen times per year. Bridge cost is peanuts in the grand scheme of things.

There’s class of politicians who are against blank checks for disaster recovery until the disaster happens in their district. Most people call them hypocrites.

 

[rcktnut]

There’s class of politicians who are against blank checks for disaster recovery until the disaster happens in their district.

............. or they are getting new infrastructure because of a bill they voted down and then bragging about how wonderful it is.

 

[jderimig]

There’s class of politicians who are against blank checks for disaster recovery until the disaster happens in their district. Most people call them hypocrites.

There should not be blank checks for anything. There should be appropriate checks.

This was a spectacular bridge collapse for sure. But there have been several bridge collapses with similar rebuild costs. Again my opinion is the rebuild costs are insignificant in the scheme of things.

 

[Capt. Eric]

There should not be blank checks for anything. There should be appropriate checks.

This was a spectacular bridge collapse for sure. But there have been several bridge collapses with similar rebuild costs. Again my opinion is the rebuild costs are insignificant in the scheme of things.

They don't write blank checks, they write blank promises. Someone else has to issue the checks to fulfill those promises. That someone else are taxpayers who don't buy houses on cliffs, alongside rivers, on the beaches, etc.
(For those in Tornado alley... well, all I can say is "sorry. It's not your fault." and give you a check. But I do hope you're insured so you don't need my check.)

(Now comes the inevitable onslaught from those who lost everything, through no fault of their own, and needed the help. For the record, I'm ok with their checks too, but can't list every possible disaster event.)

 

[boatgeek]

There should not be blank checks for anything. There should be appropriate checks.

This was a spectacular bridge collapse for sure. But there have been several bridge collapses with similar rebuild costs. Again my opinion is the rebuild costs are insignificant in the scheme of things.

That's entirely fair. I think that there will be downward pressure on price since the cost of delays is likely higher than the desire for fancy. But we'll see. And I don't think that there will be any truly blank checks. After all, funding eventually has to get through Congress. I'm guessing it will be attached to a hurricane relief bill in early fall. I'm also guessing that there will be cost-sharing with the state.

I caught a lot of flak back in my school district advocacy days for saying that newly built schools should get one nice/cool/expensive feature and the rest should be slightly nicer than Soviet-style. Budgets were just too constrained for every school to get five expensive features in the design.

 

[jsdemar]

If this were in the WWII era, the channel would be open by now.
(By Dad was a Navy SeaBee in the Pacific).

 

[wsume99]

One aspect of the rebuild that bothers me is there appears to be limited liability placed upon the company that caused the disaster. Whether that be direct liability or through their insurance which also has limited liability. I'm a big fan of individual responsibility and if corporations are considered individuals in many situations then they should be held fully liable for the effects of their actions when an accident happens. Let the feds issue loans to not delay the rebuild but eventually hold those responsible fully liable and extract every dollar possible out of them. Probably won't cover the full cost of the accident and rebuild but at least they are bearing as much responsibility possible. If it bankrupts the company then so be it.

 

[Spacedog49Krell]

The two electrical line towers at the edge of the main channel had dolphins or other barrier type installed years later. The Dali was dragging its port anchor before the collision.

The engineering question I have is "Why all four of the concrete legs of the bridge support broke at the same height above the pier base?"