Baltimore Bridge collapse after ship collision 125

[Tomfh]

https://amp.9news.com.au/article/b73620ea-64ab-4253-8cb0-37102418fcab

 

[3DDave]

The reasons for the attack don't matter when the way to avoid what was known to be a problem from previous hijackings and non-flight crew in the cockpit was clear.

Nice bit of strawmanning, but utterly irrelevant to doing a risk analysis.

 

[Murph 9000]

I don't really see most bridges being able to survive such collisions undamaged; the Bay Bridge doesn't have much protection against a ship that masses 10x+ the mass of the supports. The only protection is really how much redundancy is built into the bridge itself.

Curiously, the extremely similar Forth Road Bridge was upgraded in 1999 with a series of linked cofferdam cells filled with rock and capped with concrete. There's considerably less ship traffic on the Forth than in the SF Bay. Most of the traffic is much smaller, with the exception of the occasional aircraft carrier. The steelwork of the towers was considered non-redundant and vulnerable to impact from a ship in a 1995 report; I don't see any additional redundancy in the main towers of the Bay Bridge.

 

[RustyNCrusty]

How will they cut the bridge elements? Given the loads on the structural elements this would appear to be very hazardous particularly near the bow of the boat. It's hard to imagine this would be done using torches due to the possible reactions of the structural elements on being cut. Would this be done using using a thermal material like a linear thermite charge to do the cutting?

 

[dik]

or, how much care is taken to prevent the accident in the first place.

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[3DDave]

I love the Firth of Forth bridge in the background. I believe its predecessor was the subject of "Engineers of Dreams".

The caps on the Forth Road suspension bridge do not appear to provide enough distance for the overhang of a ship.

The engineering question is what is the expected cost vs the expected benefit.

 

[RoopinderTara]

phamENG: Can I quote you in an article?

If you really think somebody could have monitored tides, currents, and winds along with aligning schedules just so and then be such an amazing ship handler as to line it up perfectly 5 minutes out and then cut power to the entire ship at just the right moment to make it turn and hit at the perfect angle...you're off your rocker.

Roopinder Tara
Director of Content
ENGINEERING.com

 

[TugboatEng]

They can saw it with a chain. See *Golden Ray" for an example.

Explosives is option 2.

 

[Jeff Ostroff]

They have construction vehicles that have giant metal snips on the end, they can very easily check through that, and they will cut off sections of the truss with this, and lower them with a crane down to a barge for easy floating away.

 

[KevinK2]

The next step in clearing the channel is clearing the bridge structure from the bow of the ship. The plan is to cut the structure into sections, reducing weight to allow the floating cranes to begin. Too dangerous for workers to do the cutting, as the structure is likely stressed as it straddles the bow and would move when cut. Proper path is to set ignition charges (C4?) at strategic parts of the frame, with remote detontion.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[KevinK2]

Jeff Ostroff (Electrical): Before giant snips could be used, a stable floating platform would be needed. Like the crane barges, the platform would need to be stabilized using at least six, tensioned anchors to the waterway bottom. But the structural clutter prevents that from happening now, delaying use of the cranes.


Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[Nukeman948]

We are not yet at a point where we are just chopping up scrap for the recyclers. Cutting steel trusses with any method must be done very carefully and with consideration for where those pieces that are under tremendous tension may land. The survey crews were already there on the first day to map out the exact location of the 24" gas main that parallels the bridge. They will not be using explosives or giant metal snips without doing a bit of homework on the potential for making the situation worse or endangering the people that are doing the work.

https://gcaptain.com/dali-salvage-baltimore-gas-pipeline/

[sub]
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[Murph 9000]

The caps on the Forth Road suspension bridge do not appear to provide enough distance for the overhang of a ship.

They are adequate for the typical ships which go upstream of the bridges, designed in the late 1990s and the shipping traffic hasn't significantly changed since then. The original bridge piers were considered strong enough for ship impact, with the upgraded defences being specifically for the expected overhang of ships using the river. The ports upstream are quite small, compared to the massive container ports elsewhere, and the river channel is relatively narrow and shallow. The exception is the Queen Elizabeth class carriers, but they are maneuvering slowly at that point and have tugs to assist them.

 

[KevinK2]

The benefit of an explosive approach is workers can detonate it from a safe distance, vs trying to support workers while they manually cut the steel components. I assume there is a lot of experience regarding charge sizeing and safe distances, based on taking down buildings, tall antennas, etc. Lesser of a couple evils.

Kevin Kelleher, P.E. (retired)
Internal Mechanical Eng'g Consultant
DuPont ESD Specialists

 

[Retiredat46]

A few minutes ago I saw a live shot on CNN where someone was using a cutting torch on part of the bridge truss that's away from the ship.

 

[Murph 9000]

CDI have plenty of experience using shaped charges to chop up steel truss bridges into little pieces.

 

[JohnRBaker]

The cutting torches could simply be where they're selectively weakening the structure so as to facilitate the eventual demolition using shaped charges. There are salvage/demolition companies with that expertise, to say nothing of the Corp of Engineers.

John R. Baker, P.E. (ret)
Irvine, CA
Siemens PLM:

The secret of life is not finding someone to live with
It's finding someone you can't live without

 

[lexpatrie]

I'm not caught up, but I did find what I was looking for, it wasn't a tug captain, it was a harbour captain, I didn't quite remember it. But they did blame him for quite a while.

https://www.latimes.com/archives/la-xpm-2002-sep-09-me-lerro9-story.html

 

[waross]

I used to drink coffee every afternoon with a retired demolition contractor.
He described removing a collapsed bridge that was blocking a major waterway.
Divers placed shaped charges on the structure..
After the first set of charges were detonated they got a frantic visit from the operators of a nearby underground mine.
Subsequent charges and detonations were coordinated with the mine operators.


--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[Alistair_Heaton]

Seems the crazy Dane that I know, and was doing the Suez grounding is on the job with SMIT.

Seems there is a HP gas line under it all.

 

[FacEngrPE]

OFFICIAL SITE FOR INFORMATION REGARDING THE FRANCIS SCOTT KEY BRIDGE RESPONSE LINK

Demolition started Saturday
A large diameter high pressure gas transmission line (BG&E) was found to be very close to or underneath of the grounded ship, this has delayed attempts to Salvage the MV Dali

Baltimore Bridge Collapse 2024 Live | Baltimore Bridge Operations | Baltimore Bridge News LIVE |N18L CNN-News18 LINK to live video

Crews work to lift Baltimore bridge debris; officials eye temporary channel around collapse site WTVR CBS 6 LINK to video

Salvage at the Baltimore collapse site of the Francis Scott Key Bridge is well underway.
Minorcan Mullet LINK to video

Demolition Work Begins On The Francis Scott Key Bridge
John Konrad (gCaptain)
March 30, 2024

https://gcaptain.com/demolition-work-begins-francis-scott-key-bridge/