Baltimore Bridge

[Hagar]

I said “just as hard if not harder”. The harder bit was in reference to extreme conditions were you’re expecting to absorb a significant amount of kinetic energy but must transfer the kinetic energy back to the ship to change its velocity so that you can “deflect the ship” or whatever you actually meant by that statement.


Now then Do the question I asked. Go on since it’s just basic physics you should be able to easily do the maths to calculate the component velocity of the ship at different approach angles and frontal collision points. It’s just trigonometry. We need to make sure the barriers work in all conditions right?

Also please explain how you’re going to control the point of impact of the ship to ensure you only get the shallow graze angles you are talking about and not any of the worst case conditions where you have to absorb significant amount of kinetic energy.

After you can explain how you’re going to build your barrier to not plastically deform (or how the ships hull won’t just plastically deform) under the immense kinetic energy load and how it will remain rigid enough to allow for this “deflection” you are talking about?

Which is completely wrong as already explained - you're still conserving some momentum in the direction perpendicular to the bridge if you're deflecting the ship vs bringing it to a compete halt.

That it can be a "significant amount" of kinetic energy doesn't matter, it's still going to be an even more significant amount and thus even harder if you want to halt the thing!



I don't need to explain that at all, these things already exist. Nor did I claim that a ship wouldn't deform or would be deflected in every scenario. It's your claim that deflecting a ship is as hard or harder than brining it to an immediate halt that is falty here.

I think you two need to get a slide rule, or a room.


It is possible to provide large enough fenders on piled dolphin structures to berth and moor these ships travelling at several metres per second, it is therefore feasible to provide several of these structures to protect a critical bridge structure from impact.accepting thst some damage may occur on both the vessel and the protection structure.

Several lines of 3000mm diameter steel piles driven deep into the sea bed with a thick concrete deck sounds about right with some of the piles as rakers.

 

[imtoooldforthis]

According to MAGA voters, if America didn't send old weapons to Ukraine then this Singaporean ship would not have lost power and gone straight into a bridge support

So far today I’ve read that this happened because of DEI (Baltimore mayor is black), Israel, China and of course “Biden and the woke mob” lol.

Their ability to wedge dunce tier culture war nonsense into everything is remarkable

 

[Chuk_Chuk]

I think you two need to get a slide rule, or a room.


It is possible to provide large enough fenders on piled dolphin structures to berth and moor these ships travelling at several metres per second, it is therefore feasible to provide several of these structures to protect a critical bridge structure from impact.accepting thst some damage may occur on both the vessel and the protection structure.

Several lines of 3000mm diameter steel piles driven deep into the sea bed with a thick concrete deck sounds about right with some of the piles as rakers.

Dowie has got my point already. At this point I’m giving him fetch quests since he wants to pointlessly argue.

 

[dowie]

Dowie has got my point already. At this point I’m giving him fetch quests since he wants to pointlessly argue.

You were wrong and can't admit it but I don't think there is much to carry on with here.

 

[Thekwango]

and another thread begins to disappear down the dowie hole......yay

 

[Dis86]

What if the tug loses power like the ship did?

Not saying its a bad idea, it is sensible, how do you mitigate against all possible scenarios.

Something I've also encountered, we had a standby tug.

 

[plasmahal]

Something I've also encountered, we had a standby tug.

Is that the same as having a very keen side piece?

 

[DB_SamX]

From the Institution of Structural Engineers:

Spoiler: Click to expans

IStructE believes that ongoing risk assessment of structures is critical. Investigators will review the pier design and changes to vessel impact protection devices to determine potential shortfalls in risk management.

Bridge expert Ian Firth, independent consultant, IStructE’s past-President and a Fellow comments as follows:

“It is almost impossible to design a bridge pier to withstand this kind of impact. Therefore, we tend to design impact protection measures to prevent it from happening instead."

“Dolphins or other vessel impact protection devices in the water are commonplace since the Sunshine Skyway collapse in 1980. But this bridge was built in the 1970’s, so the design would not have incorporated these devices at that time. The fact that a vessel can veer off course and hit the pier is the reason to design vessel impact protection systems so that a large vessel cannot hit the critical bridge support."

“The footage shows there are small dolphins, (the small round objects visible in the film), each side of the bridge piers - these have not prevented the vessel hitting the pier.

“A new bridge design would probably be a cable stayed bridge with a much larger span, moving the supports well away from the navigation channel and into shallower water.”

IStructE also considers that a full investigation will have to address many aspects of why this happened, asking questions such as:

1. There are navigational rules for ships, why was this vessel out of its channel?
2. Bridge piers are normally protected from impact, so what exactly was the pier design?
3. Are the codes and regulations sufficient for today’s increasingly larger cargo ships?
4. Are further measures required to ensure this does not happen again?

Interestingly I was interviewing candidates this morning on behalf Institution of Civil Engineers, for them to join as Chartered Members, and one of them is a long-span bridge designer. The bridge he focussed his presentation on was a cable stayed bridge with a much larger span indeed, with the supports being away from the sides of the river it was crossing (not just to avoid collisions though).

 

[Disco_P]

I think your a little out there....

Just a smidge, shoulda said the largest container ship in the world was 29,000 tonnes

 

[Disco_P]

From the Institution of Structural Engineers:

Spoiler: Click to expans

IStructE believes that ongoing risk assessment of structures is critical. Investigators will review the pier design and changes to vessel impact protection devices to determine potential shortfalls in risk management.

Bridge expert Ian Firth, independent consultant, IStructE’s past-President and a Fellow comments as follows:

“It is almost impossible to design a bridge pier to withstand this kind of impact. Therefore, we tend to design impact protection measures to prevent it from happening instead."

“Dolphins or other vessel impact protection devices in the water are commonplace since the Sunshine Skyway collapse in 1980. But this bridge was built in the 1970’s, so the design would not have incorporated these devices at that time. The fact that a vessel can veer off course and hit the pier is the reason to design vessel impact protection systems so that a large vessel cannot hit the critical bridge support."

“The footage shows there are small dolphins, (the small round objects visible in the film), each side of the bridge piers - these have not prevented the vessel hitting the pier.

“A new bridge design would probably be a cable stayed bridge with a much larger span, moving the supports well away from the navigation channel and into shallower water.”

IStructE also considers that a full investigation will have to address many aspects of why this happened, asking questions such as:

1. There are navigational rules for ships, why was this vessel out of its channel?
2. Bridge piers are normally protected from impact, so what exactly was the pier design?
3. Are the codes and regulations sufficient for today’s increasingly larger cargo ships?
4. Are further measures required to ensure this does not happen again?

Interestingly I was interviewing candidates this morning on behalf Institution of Civil Engineers, for them to join as Chartered Members, and one of them is a long-span bridge designer. The bridge he focussed his presentation on was a cable stayed bridge with a much larger span indeed, with the supports being away from the sides of the river it was crossing (not just to avoid collisions though).

So you're one of the lovely folk I get to chat to in a couple years time...

 

[dowie]

From the Institution of Structural Engineers:

[...]
Bridge expert Ian Firth, independent consultant, IStructE’s past-President and a Fellow comments as follows:

“It is almost impossible to design a bridge pier to withstand this kind of impact. Therefore, we tend to design impact protection measures to prevent it from happening instead."

“Dolphins or other vessel impact protection devices in the water are commonplace since the Sunshine Skyway collapse in 1980. But this bridge was built in the 1970’s, so the design would not have incorporated these devices at that time.

Echos what this Engineer says too:

expert reaction to Baltimore bridge collapse | Science Media Centre

www.sciencemediacentre.org

“I would have expected to see a system of ‘dolphins’ and/or fendering, adequately secured into the river bed. Such a system would be aligned on both sides of each main pier with the purpose of deflecting errant vessels from collision with the piers. Collision protection would generally be designed to resist glancing or sideways impact forces, much less than from head-on impacts. Other measures would comprise warning systems including navigation lights etc.

Need to deflect vessels away from colliding with the bridge.

 

[200sols]

and another thread begins to disappear down the dowie hole......yay

Actually think he raises some good points, the other poster is just being deliberately condescending.

 

[Uther]

Build a tunnel.

They''ll never build a tunnel big enough for a ship like that silly.

 

[Chuk_Chuk]

Actually think he raises some good points, the other poster is just being deliberately condescending.

i am going to be condescending when someone ignores what I wrote in my post then repeats it back to me like they just discovered it, yet somehow believe I’m not going to notice.

The dowie hole is just subtle strawmen to maintain the argument.

 

[BowdonUK]

It didn't did it? The centre section collapsed. A lot of the bridge is still intact.

There were at least 2 sections that collapsed in the centre, split by supports. One section collapsed directly because the support had been hit. But when that went down it pulled another support down, which took down the other section.

It shows the section support collapse in that video.

 

[Terminal_Boy]

Something I've also encountered, we had a standby tug.

Am I right in thinking that tugs, while extremely powerful, aren’t very fast by large ship standards?

 

[Dis86]

Am I right in thinking that tugs, while extremely powerful, aren’t very fast by large ship standards?

I think ours only go up to something like 12 knots.
Fairly small units as far as tugs go ( Damen Stan's). If we need bigger boys we call in the likes of Svitzer whose units are both a bit quicker and definitely more powerful.
Even ours have two engines that are basically from a lorry with bigger turbos on...(think they're deutz units on one, volvo pentas on the other). About 1500bhp combined.

 

[Minusorange]

There were at least 2 sections that collapsed in the centre, split by supports. One section collapsed directly because the support had been hit. But when that went down it pulled another support down, which took down the other section.

It shows the section support collapse in that video.

Basically all the bridge part of the bridge collapsed

 

[Harlequin]

 

[dowie]

i am going to be condescending when someone ignores what I wrote in my post then repeats it back to me like they just discovered it, yet somehow believe I’m not going to notice.

The below was in reply to a post about how difficult it would be to stop a ship - I point out that you don't necessarily need to stop it you can deflect it (this should be obvious - it's basic physics, if some momentum is still maintained then that obviously requires less force than bringing it to a complete halt) but you didn't seem to grasp that:

You don't need to stop it you just need to deflect it, various bridges do actually have this sort of protection and in the case of the Baltimore bridge there appear to be some other poles in the water in front of the bridge that are protected, sadly the bridge itself isn't.

I think deflecting would be just as hard if not harder, since you don’t know the direction of travel.

You don't need to know the direction of travel (though you'd have a reasonable idea from both directions) it's still easier (requires less force) than stopping it.

Now let's see what some experts have to say on the matter:

expert reaction to Baltimore bridge collapse | Science Media Centre

www.sciencemediacentre.org

Ian Firth, independent consultant, Fellow and past president of the Institution of Structural Engineers, said:

“It is almost impossible to design a bridge pier to withstand this kind of impact. Therefore, we tend to design impact protection measures to prevent it from happening instead.

“Dolphins or other vessel impact protection devices in the water are commonplace since the Sunshine Skyway collapse in 1980. But this bridge was built in the 1970’s, so the design would not have incorporated these devices at that time. The fact that a vessel can veer off course and hit the pier is the reason to design vessel impact protection systems so that a large vessel cannot hit the critical bridge support.

Alan Hayward FREng CEng FICE FIStructE, retired bridge engineer, said:
[...]
“I would have expected to see a system of ‘dolphins’ and/or fendering, adequately secured into the river bed. Such a system would be aligned on both sides of each main pier with the purpose of deflecting errant vessels from collision with the piers. Collision protection would generally be designed to resist glancing or sideways impact forces, much less than from head-on impacts. Other measures would comprise warning systems including navigation lights etc.

Debate emerges over whether modern protections could have saved Baltimore bridge

A debate has emerged over whether modern safety protections could have saved a Baltimore bridge after it was struck by a cargo ship

abcnews.go.com

Sherif El-Tawil, a University of Michigan engineering professor, said there are several safety measures that “would have made a huge difference” had they been in place Tuesday morning when a cargo ship plowed into the bridge and caused its collapse.

El-Tawil said a fendering system may have softened the 985-foot-long ship's blow. Pilings anchored to the river bottom, known as dolphins, are another measure that could have helped to deflect the container ship Dali.

Why are all these experts talking about "deflecting" the ship, well bringing it to an immediate halt requires a heck of a lot more force for a start as I've already pointed out to you. I thought this should have been apparent but instead, you've claimed I made some straw man argument, you're simply wrong here, in fact you just seem confused here:

I said “just as hard if not harder”. The harder bit was in reference to extreme conditions were you’re expecting to absorb a significant amount of kinetic energy but must transfer the kinetic energy back to the ship to change its velocity so that you can “deflect the ship” or whatever you actually meant by that statement.

Perhaps the expert engineers pointing it out too will help you here and you don't need to engage in this sort of thing...

Dowie has got my point already. At this point I’m giving him fetch quests since he wants to pointlessly argue.

I was pointing out factual information, I wasn't trying to pointlessly argue, my point was relevant to the thread and was answering another poster who (quite correctly) pointed out that stopping a huge ship requires serious amounts of force - ergo it's worth saying you can in fact deflect a ship instead and that is easier.