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Bridge collapse in the US


kevinlms

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8 minutes ago, melmerby said:

They are the same side the ship collided with , they are on the Baltimore side and the "islands", actually look rather flimsy.

This is a Ggogle Earth view, from the road about the position of the struck pylon, Baltimore is the distance:

image.png.0b21d5d8b65e45b9d290fe1811a2932f.png

Ship on the right heading for the main span.

 

Interestingly Baltimore is about 150 miles from the sea!

Apologies, it was a breaking event as I was getting on with my daily routine so can only comment on what I was fed.

An awful state of affairs for sure, I wasn't trying to inject any unnecessary debate, merely seeking more learned discourse.

 

C6T.

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6 minutes ago, Classsix T said:

Apologies, it was a breaking event as I was getting on with my daily routine so can only comment on what I was fed.

An awful state of affairs for sure, I wasn't trying to inject any unnecessary debate, merely seeking more learned discourse.

 

C6T.

They've only been there 3 years.

 

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1 hour ago, kevinlms said:

Absolute maximum revs, maybe?

 

1 hour ago, melmerby said:

It's also belching black smoke out of the stern end as if something serious had happened.

Apparently a single screw ship and the smoke is off the stacks,i guess engines in full reverse as they knew it was heading for bridge as the ship called in emergency first,it would seem its had electrical issue all the time in port with overloads tripping........

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7 hours ago, Night Train said:

Some good footage of the aftermath from the NTSB.

 

 

I expect various figures within the insurance industry will be stocking up on industrial grade vaseline in preparation for the financial rogering they are about to receive.

The suggestion (from an Actuary I was talking to yesterday) is this could be a bigger total loss than the Costa Concordia. If so it could be the largest marine-linked loss on record.

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It wouldn't matter a jot if the ship was out of control, but does anyone else agree that the way the containers are stacked it's difficult (impossible?) to see the bow from the bridge?

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The aim of ship designers and IMO regulations is sight of the sea forward of the ship, not the bow, which is why the wheelhouse (and accompanying superstructure) was moved forward on container ships.

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Presumably there is now a queue of ships waiting to use or leave the harbour. At least the ones outside have the possibility to find an alternative.

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It will be interesting to read the enquiry report, into what actually happened and why, rather than speculation and conjecture in the news and social media.

Edited by fulton
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4 minutes ago, fulton said:

It will be interesting to read the enquiry report, into what actually happened and why, rather than speculation and conjecture in the news and social media.

I don't think that there is much doubt that the ship hit the bridge, causing it to collapse. Video showing all the lights going out, indicates something seriously wrong occurred on boad.

 

Somehow, parts of the bridge will need to be removed fairly quickly, to reopen the Port of Baltimore.

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28 minutes ago, kevinlms said:

Somehow, parts of the bridge will need to be removed fairly quickly, to reopen the Port of Baltimore.

And the vehicles that fell in with the bridge collapse, complete with their occupants.

Nothing will be moving for some time.

 

Baltimore is apparently the No1 port for US vehicle exports, although 9th biggest overall in the US.

 

 

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The Dartford Crossing (QE2) bridge piers look to have substantial protection.  
 

IMG_0218.jpeg.25c727b77d8bd1576bdbacc1a4cee33d.jpeg

 

They are also close to the river bank so may be in shallower water than the main navigable channel.

 

Cheers

 

Darius

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5 minutes ago, Darius43 said:

The Dartford Crossing (QE2) bridge piers look to have substantial protection.  
 

IMG_0218.jpeg.25c727b77d8bd1576bdbacc1a4cee33d.jpeg

 

They are also close to the river bank so may be in shallower water than the main navigable channel.

 

Cheers

 

Darius

The piers are also made of concrete. I noticed on the bridge that collapsed that the concrete sections remained intact and only the steel girder section collapsed.

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8 minutes ago, PhilJ W said:

The piers are also made of concrete. I noticed on the bridge that collapsed that the concrete sections remained intact and only the steel girder section collapsed.


The concrete pier of the Baltimore bridge was the part struck by the ship and it collapsed causing loss of support to the steel bridge structure and its subsequent progressive collapse.

 

In the still from the NTSB footage below you can see parts of the collapsed reinforced concrete pier structure to one side and actually on top of the bow of the ship.

 

IMG_0220.jpeg.d0cf4d2d319f1315faeb8fd1c33f8f28.jpeg

 

Darius

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When fully laden, Dali would have had a mass of around 115,000,000 kg. It was moving at 8 knots, roughly 4 metres per second. 

Its kinetic energy dissipated in the collision (calculated using 0.5mV^2) would therefore have been nearly 1 TeraJoule. Equivalent to exploding 200 tons of TNT.

It would have taken some stopping, and considering the sheer amount of energy and the shape of the bow, I suspect that any realistic pier protection wouldn't have stopped it before the bow hit the pier itself.

 

 

Edited by Mol_PMB
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10 minutes ago, PhilJ W said:

I was talking of the ramps leading up to the section that collapsed.


Actually a stretch of the ramps also collapsed.

 

IMG_0221.jpeg.d476ac0e56670acc9b8a83a60c8d8f08.jpeg


Graphic courtesy of today’s Guardian.

 

Darius

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12 hours ago, Classsix T said:

I'd not debate you on that Ian, but aren't one-offs why we have risk assessment, fail safe and worst case scenario consultation?

I am aware that since Piper Alpha that whole area of study has mushroomed into a necessary part of the project development paperchase. Indeed ISTR having discussions with a senior chap from Arthur D Little more than 30 years ago, downstream from the Clapham Accident. But I am not clear at what point in the last 47 years the likelihood of yesterday's disaster might have been considered significant enough for study, still less the justification for the huge investment needed for real mitigation. 

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51 minutes ago, meil said:

Whilst everyone is talking about the ship what about the protection to the bridge piers? This type of accident was clearly foreseeable during the design phase of the bridge yet it would appear (and I can't see any) that no, or totally inadequate, pier protection was provided.

 

Quite frankly this comes as no surprise having worked with a number of USA civil engineers during my career. They seem to have an inability to foresee such scenarios.

But the same thing has occurred in railway accidents, where supporting pillars got knocked out, usually with very nasty results.

 

Here's a couple of examples.

 

https://en.wikipedia.org/wiki/Granville_rail_disaster

 

https://en.wikipedia.org/wiki/Lewisham_rail_crash

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Posted (edited)
11 minutes ago, Mol_PMB said:

When fully laden, Dali would have had a mass of around 115,000,000 kg. It was moving at 8 knots, roughly 4 metres per second. 

Its kinetic energy dissipated in the collision (calculated using 0.5mV^2) would therefore have been nearly 1 TeraJoule. Equivalent to exploding 200 tons of TNT.

It would have taken some stopping, and considering the sheer amount of energy and the shape of the bow, I suspect that any realistic pier protection wouldn't have stopped it before the bow hit the pier itself.

 

 


200 tons of TNT detonating does impart the energy a bit faster than a ship impact.  
 

The key parameter is the “impulse” which essentially is how quickly the energy is imparted into whatever is receiving it.

 

For example, I could give you a push on the arm or a punch.  Both impart the same energy but the push is slower and the punch much faster.  The punch hurts…

 

Darius

Edited by Darius43
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Posted (edited)

IMG_0219.jpeg.7600a8362af946cea0bf50c19c5bd4de.jpeg

 

Concrete dolphin protection to the piers of the first Forth Road Bridge. 
 

They don’t need to absorb all the energy of a ship impact as some of it goes into buckling the ship’s hull and some in deflecting it’s trajectory.

 

Darius

Edited by Darius43
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