re: Francis Scott Key Bridge in Baltimore has collapsed - container ship wrecked into it

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Your standalone thread was killed, luckily I had clicked the link and watched the video. Solid breakdown of the events with GPS tracking times (somewhat) to the video.

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When a ship leaves port there is a requirement to start stand-by generators for the duration of the voyage out.
But sometimes there are other issues, a switch board failure, or auto-control issue and you can lose the lot. it has happened to me a few times over the years.
Everything goes off-line and the main engines shut down automatically because they have no feed pumps for fuel, lube oil and air.
The emergency generator will usually start - a small diesel housed on the upper deck usually behind the bridge. It gives enough power for the nav gear and some ventilation, and enough power to enable the engineers to get the rest of the gear back on-line.
That is probably driving the lights we see come back on but not as many as before. The engineers then go round the engine room and control room and manually switch all the gear back on. That can take some time.
But because of the emergency the engineers in this case would have to make a terrible decision to start the main engines immediately to go emergency full astern possibly without supporting pumps and almost certainly with some engine damage.
Black smoke is always a sign of incomplete combustion. the massive pumps that supply air to the engine room would be off-line and so the engines would be gasping for air. The fuel would burn but without enough air hence the black smoke.
in full-astern mode the rudder would be useless.
I really hope the anchor team got off the foredeck before the bridge came down on top of them.

Comment from the video

This is the stupidest junk

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Looks intentional

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Perfectly good explanation above your post by a professional and then you come with this.

(no message)

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Looking at the bridge I am still a little unsure why the furthest right span failed.

To me it looked like with the left pier out, the right span turned into a simple span supported on both sides (one side the remaining pier, and the other the approach).

My guess is the furthest right section of the bridge (where the bridge starts) was never meant to support that kind of shear load when the central span fell, but I do buildings and not bridges.

Any bridge structural guys out there that can help me out?

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First things first, I am not a degreed engineer but Uncle Sam spent a lot of time and money teaching me to produce dynamic bridge failures and to identify and exploit the vulnerabilities that can produce this using the least time, explosives, and manpower. In a nutshell, I was taught to break shite y'all build so basically failure modes is what I see when I look at a bridge.

When the continuous span fails left of the right bearing you are not left with a simple span to the right of the bearing. You are left with a component of a continuous span. If you watch the GIF the moment the lower chord fails on the left side of the right bearing that chord loses all its axial tension and the remaining portion of the span has nothing to hold it and it fails to the right side of the right bearing and just rotates on the bearing into the water.

The engineers could have used far more material and built the individual portions between bearings to function as simple spans but that costs a lot of money and would have been a completely different bridge design (arguably less aesthetic) with three sets of trusses that functioned independently. I have occasionally seen this approach used on rail bridges but they have different loading requirements.

BTW I know I am preaching to the choir so don't take anything as intentional condescension.

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The ship hit the bridge just before the Hawkins Point low tide of 2:13 AM. Little to no tidal movement.. barely creeping out in the same direction as the ship if anything.

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Was curious so looked it up. Hawkins Point low tide occurred approximately one hour after the incident, reported to be 1:30 a.m. Winds at NOAA Fort McHenry station calm and negligible. Wind and tide do not appear to be a contributing factor.





Joining the speculation normal for an OT thread, it is a) absolutely possible for an electrical switchboard malfunction to kill the engine and b) a 250 ton Crane Barge or DP Vessel with same could arrive anywhere from one week to one month from now. My educated guess is more than one will be required, with extensive manned diving demolition crews needed.

There will be significant and time consuming structural analytical engineering work required before they begin removing the bridge sections and container vessel. This is a huge project with only a few companies in the world capable of executing without making a bad situation worse.

God Bless to all affected by this tragic accident.

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I notice them regain power and almost turn out of the way at the end.

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They regained power twice and the black smoke was the vessel attempting to back down but a 1000’ ship traveling at 9 knots isn’t just going to stop and start backing on a dime.

Even if they dropped 8 anchors, that ship wasn’t stopping

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When a ship leaves port there is a requirement to start stand-by generators for the duration of the voyage out

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It depends on the vessel. Some vessels aren’t equipped or set up to run 2 generators at a time. I don’t how this vessel was set up.

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Black smoke is always a sign of incomplete combustion. the massive pumps that supply air to the engine room would be off-line and so the engines would be gasping for air. The fuel would burn but without enough air hence the black smoke. in full-astern mode the rudder would be useless. I really hope the anchor team got off the foredeck before the bridge came down on top of them.

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The black smoke was likely an indication that the vessel was trying to back down

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All this just makes me think how vulnerable this country is.

You wouldn't even have to destroy the infrastructure in total. Just do enough damage to reduce the integrity to the point of inoperability.

Our infrastructure is already crumbling, something like this could kick it over

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I think about this a lot. Could really cripple an entire region if you hit a few bridges, railways, and key power grid targets.