Soldato
and another thread begins to disappear down the dowie hole......yay
Baltimore Bridge
- Thread starter imtoooldforthis
- Start date
Suspended
Something I've also encountered, we had a standby tug.
Is that the same as having a very keen side piece?
Soldato
From the Institution of Structural Engineers:
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).
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:
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:
- There are navigational rules for ships, why was this vessel out of its channel?
- Bridge piers are normally protected from impact, so what exactly was the pier design?
- Are the codes and regulations sufficient for today’s increasingly larger cargo ships?
- 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).
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Soldato
Just a smidge, shoulda said the largest container ship in the world was 29,000 tonnes
Soldato
So you're one of the lovely folk I get to chat to in a couple years time...
Echos what this Engineer says too:
Need to deflect vessels away from colliding with the bridge.
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Actually think he raises some good points, the other poster is just being deliberately condescending.
Soldato
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.
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Soldato
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 didn't did it? The centre section collapsed. A lot of the bridge is still intact.
It shows the section support collapse in that video.
Soldato
Am I right in thinking that tugs, while extremely powerful, aren’t very fast by large ship standards?
Suspended
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.
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Soldato
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- 25 Nov 2005
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Basically all the bridge part of the bridge collapsed
Soldato
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:
Now let's see what some experts have to say on the matter:
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
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:
Perhaps the expert engineers pointing it out too will help you here and you don't need to engage in this sort of thing...
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.
Man of Honour
Deflection is common practice usually but I guess at the time the bridge was built wasn't considered or omitted? All the bridges in London are built to deflect.
That said should any large vessel hit the deflection structures a full structural inspection of the bridge will have to take place regardless. Many of the ones in London are now monitored with various sensors to monitor movements, stresses and strains over time.
Prevention however is better than cure. In my opinion 2 things failed here. 1 not having a tug boat for such a large vessel in that area with many obstacles, and lack of protection for the structures.
That said should any large vessel hit the deflection structures a full structural inspection of the bridge will have to take place regardless. Many of the ones in London are now monitored with various sensors to monitor movements, stresses and strains over time.
Prevention however is better than cure. In my opinion 2 things failed here. 1 not having a tug boat for such a large vessel in that area with many obstacles, and lack of protection for the structures.
Soldato
$2-10 million spent since 1980 on updated protection, even $50 million would have been money well spent on such a critical structure. Saving billions of lost revenue and rebuild costs. I don't know if there was a health and safety plan looking at credible incidents but it appears lacking.
Also as was evidenced in the twin towers, American civil engineering codes were particularly poor in considering progressive failure modes. Taking out one pier whilst certainly disabling the structure should not bring about the total collapse of the whole deck spans.
London in the upper reaches is not navigable today for such large vessels but any structure below the QEII bridge should be resistant or protected from direct impacts.
So the remaining structure that has the road intact on struts over the river is what?
They're ramp sections with much smaller spans, the actual bridge part i.e the girder structure collapsed entirely.