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Baltimore's Key Bridge struck by cargo ship, collapses

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Re: Baltimore's Key Bridge struck by cargo ship, collapses

#531

Post by callalex »

myself248 wrote: post #490
mixedmath wrote: post #290

Earlier quoted context omitted.

I'm not sure if I would expect any bridge to survive being struck by an enormous container ship.

A lot of bridges have their pilings set on mini islands, terrifically reinforced piles of stone and concrete that extend for quite some distance around the actual support. I don't know why some are built without that, it always weirds me out seeing the spindly legs going straight into the water, and this is why. Edit to add: Check out Fort Carroll, precisely such an artificial island just a few hundred yards away in…

Civil engineering is very complex and doesn’t go off of feelings. I’m sure the type of soil and rock that the bridge is built on inform such decisions.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#532

Post by munificent »

OJFord wrote: post #497
paddy_m wrote: post #438

Youtube tracking analysis from a knowledgeable mariner. He says that at about 1:24 AM the ship loses power (from video feed) while traveling 8.5 knots. at 1:25.30 power is restored. at 12:25.59 the ship shows smoke. The ship has already drifted in the channel. It is believed that at this time the ship applied full reverse power as evidenced by the black smoke. (My analysis: the ship drifted but hasn't turned in the c…

Apparently (this is just via someone on Reddit who supposedly heard/read it somewhere) the ship mayday'd on losing power hoping the bridge could be cleared. But why not (or did it?) also just blast its horn repeatedly, drawing attention so people on or near the bridge would notice it and realise something was wrong and perhaps even where it was headed? I'm sure it's not allowed generally and not the protocol and what…

> But why not (or did it?) also just blast its horn repeatedly,

Hard to blow your electrically driven horn when you've lost power.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#533

Post by mikeyouse »

throwanem wrote: post #436
mikeyouse wrote: post #414

Earlier quoted context omitted.

In Philly, they sacrificed some of the road underneath it and narrowed the traffic lanes over the bridge to enable a very quick, albeit temporary repair. There’s no such option for a span of this length over a river — this is a decade long project that could potentially be sped up to be a years long one.

Sure, 5-10 years makes sense especially considering it took 5 years to build last time. But GP's formulation seemed to suggest a considerably longer expectation, and that's more what I was wondering about.

I took it to mean considerably longer in relation to the bridge in Philly -- which of course it will be since that overpass reopened in ~2 weeks.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#534

Post by semi-extrinsic »

hgfghj wrote: post #521
bastardoperator wrote: post #494

Earlier quoted context omitted.

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

That ship had a 10,000 TEU capacity and was actually hauling a little under 5,000 TEUs. An empty container weighs a little over 5,000lbs, and a full one can be up to 67,000lbs. If you do the math, you find that it’s just an astronomical amount of momentum, and there’s no effective defense for a bridge that needs support in more than 30 or so feet of water.

Throwback to the scene in The Day After Tomorrow where the cargo ship comes to an almost instant halt after impacting a bus wreck under water. For some reason it managed to stand out as ridiculous even in that movie.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#535

Post by jcranmer »

JohnMakin wrote: post #525
divbzero wrote: post #509

Earlier quoted context omitted.

Glad to hear your dad made it across safely. According to current reports, the Maryland Transportation Authority Police responded to the ship’s “mayday” and stopped traffic in the minutes before the catastrophe, but 6 construction workers are still unaccounted for. https://www.baltimoresun.com/2024/03/26/key-bridge-collapses...

They keep reporting this, and maybe it was because the video was sped up, but it looked like there was still traffic going across until very close to the collision

The last car crossing that I can see clears the span about 1:28:06; the bridge collapses about 1:28:48. That's about 40 seconds of gap between the traffic and the collapse.

I haven't timed how frequently cars are coming, but it seems to be about every 30 seconds or so, which--combined with the time it takes to cross the bridge--is evidence that a bridge closure was effected just before the bridge collapse.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#536

Post by OJFord »

munificent wrote: post #532
OJFord wrote: post #497

Earlier quoted context omitted.

Apparently (this is just via someone on Reddit who supposedly heard/read it somewhere) the ship mayday'd on losing power hoping the bridge could be cleared. But why not (or did it?) also just blast its horn repeatedly, drawing attention so people on or near the bridge would notice it and realise something was wrong and perhaps even where it was headed? I'm sure it's not allowed generally and not the protocol and what…

> But why not (or did it?) also just blast its horn repeatedly, Hard to blow your electrically driven horn when you've lost power.

I suppose I assumed it was compressed air, that once you had a 'full' (at pressure) tank, you could do a certain amount of blowing even without power. But fair point, I don't really know how they work, and if they are actively electric I certainly didn't know that and obviously that wouldn't have worked and so there's the answer.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#537

Post by Systemling0815 »

divbzero wrote: post #509
ajdude wrote: post #481

Earlier quoted context omitted.

I was incredibly worried about my dad, he's a truck driver and drove that bridge just an hour prior to this happening. I'm hearing there were at least 20 cars and a truck on the bridge, plus construction workers, at the time; my heart goes out to those families

Glad to hear your dad made it across safely. According to current reports, the Maryland Transportation Authority Police responded to the ship’s “mayday” and stopped traffic in the minutes before the catastrophe, but 6 construction workers are still unaccounted for. https://www.baltimoresun.com/2024/03/26/key-bridge-collapses...

[dead]

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#538

Post by JumpCrisscross »

hgfghj wrote: post #521
bastardoperator wrote: post #494

Earlier quoted context omitted.

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

That ship had a 10,000 TEU capacity and was actually hauling a little under 5,000 TEUs. An empty container weighs a little over 5,000lbs, and a full one can be up to 67,000lbs. If you do the math, you find that it’s just an astronomical amount of momentum, and there’s no effective defense for a bridge that needs support in more than 30 or so feet of water.

> there’s no effective defense for a bridge that needs support in more than 30 or so feet of water

You deflect it. Failing at that, you direct the force into destroying the ship.

Of course, the best solution is no in-water pylons. But that isn’t always feasible.

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#539

Post by samstave »

bastardoperator wrote: post #494
paddy_m wrote: post #438

Youtube tracking analysis from a knowledgeable mariner. He says that at about 1:24 AM the ship loses power (from video feed) while traveling 8.5 knots. at 1:25.30 power is restored. at 12:25.59 the ship shows smoke. The ship has already drifted in the channel. It is believed that at this time the ship applied full reverse power as evidenced by the black smoke. (My analysis: the ship drifted but hasn't turned in the c…

The video is surreal, it looks like it barely bumps the bridge and 2 seconds later the entire thing is gone. I don't know what I was expecting, the bridge just looked extremely fragile, makes me wonder what other bridges are at risk of an event like this.

[flagged]

Re: Baltimore's Key Bridge struck by cargo ship, collapses

#540

Post by peteradio »

semi-extrinsic wrote: post #534
hgfghj wrote: post #521

Earlier quoted context omitted.

That ship had a 10,000 TEU capacity and was actually hauling a little under 5,000 TEUs. An empty container weighs a little over 5,000lbs, and a full one can be up to 67,000lbs. If you do the math, you find that it’s just an astronomical amount of momentum, and there’s no effective defense for a bridge that needs support in more than 30 or so feet of water.

Throwback to the scene in The Day After Tomorrow where the cargo ship comes to an almost instant halt after impacting a bus wreck under water. For some reason it managed to stand out as ridiculous even in that movie.

Somebody should do a side-by-side of that scene with this threads scene in gif.
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