The video posted above by DavidNRockies says that the ship should have a backup diesel generator, and such generators are required to restore electrical power in less than 45 seconds. But there was 58 seconds between the first loss of power and the lights coming back on, so it’s not clear if the backup generator was too slow to restore power, or if it didn’t work at all and it was the main generators that restored power, or something else happened.
Some speculation in this post above.
There are 2 backup generators for the 2 primary generators. I would think the pucker factor of losing the propulsion engine would put the focus on the generators. That’s assuming they are the power source behind the rudder system.
A lot happening on a city-sized ship in a short period of time.
So, lemme see: steel that’s been subject to tremendous stresses, steel that’s spent however long submerged in seawater… Yeh, what could possibly go wrong?
Indeed.
Plus 50 years of weathering and general wear & tear in a marine environment (which the design should have factored in so that it didn’t compromise the structure but) wouldn’t have improved the quality of the components.
On what basis would it be faster (ignoring whether safer or cheaper) to salvage the trusses, reforge and then reinstall them rather than using new steel beams? The US is short on steel?
The value of the salvaged steel will defray some costs but it will be less than the cost of the clean-up, let alone the rebuild.
Replacement with a new truss bridge would work, as indeed it has for 50 years, but methinks that the replacement design won’t be like for like.
For sure there’ll be a helluva more robust protection for the bridge piers. That alone needs to be designed and built co-extensive with the design and build of the new bridge. Not to mention, as has been suggested somewhere up there in this thread, consideration of widening the span and/or dredging the channel.
Conversely, even with enhanced pier footings and broader shipping channel, were the Scott Key II bridge to be built as a truss bridge using recycled I-beams from the original … do you reckon people would be confident driving over it?
Reasonably or not, I wouldn’t be. I suspect the new bridge is going to look different from the destroyed one, in part just to assuage such irrational but inevitable fears.
So we are just assuming that he meant just bending the steel back into place or something then dragging him for it?
Musk has been working with steel for decades. He’s not stupid. There may be *some non-structural areas where steel might be reused, but I’d guess he’s talking about using it for scrap and smelting it.
The steel supply chain isn’t in great shape right now, and sourcing all the fresh steel might take time and cost a lot of money. So he may just be suggesting re-smelting and reusing the bridge steel.
You wouldn’t use this stuff as rebar.
As casing for the expanded piers of the new bridge, maybe.
The civil engineers would still prefer to use new steel.
Steel at that level of abstraction is fungible. Of course the salvage will end up smelted, because no one throws away that much steel (unless it’s battleship-shaped and someone scrapes up the funding for yet another museum ship). But it’s not going to be relevant to the speed at which this bridge is replaced. One bridge, even a big one, is but a blip on the global steel market.
It’s really difficult to see any reading of that tweet besides Elon thinking you can just crane the old spans back up into place. 3 to 6 months is a ludicrously short period of time for anything else. Building the bridge the first time round appears to have taken 5 years. Rebuilding an identical bridge if you had all the steel at hand would be a bit faster because the footings could be re-used, but not 3-6 months territory.
Of course the idea of using a giant crane to lift the old spans up into place is beyond lunacy from a structural engineering perspective, but I don’t see any other plausible reading of the tweet.
Also of course, rebuilding the bridge to the same plan is also beyond lunacy. Bridge engineering has advanced a teeny tiny bit in the past 50 years. I’d expect a much longer main span, probably cable-stay construction, as a preferred replacement. Has any large continuous truss bridge been built in the last 20 years?
I can’t find any site that says whether the Patapsco River is salt water or fresh at that point, but even if it’s freshwater, being submerged in water is not gonna do that steel any good.
Musk is an idiot but that’s nothing new.
“the Baltimore Harbor estuary, is located on the west side of the Chesapeake Bay. The Harbor estuary is the 15-mile tidal region of the lower Patapsco River.”
So depending on the tide, it would range from somewhat fresh to sea-briny.
What does recycled even mean in this context? Could they literally find some unbent beam, remove the rivets and separate it from the bridge then use that same beam in a new construction (assuming it is the perfect length and strength to fit a new design)? IANAEngineer but I would be very surprised if that was possible or even practical. Also, I’d think most of those beams are damaged to some degree by the collapse (twisted/bent not to mention soaking in brackish water). So, even if it were possible to salvage some beams for re-use ISTM they’d still need loads of new beams anyway.
To me, the only recycling the bridge gets is cutting it into pieces and selling it for scrap to be melted and made into new beams.
How about, “Gee, maybe I can con the government to giving me a butt-load of money to fuck around with and waste, being I’m the Smartest Man In The World! People fall for my bullshit all the time, why not this time?”
And US steel production is currently quite robust (apparently it never recovered from the 1980s, but it’s certainly recovered from recent perturbations)
The video below explores the myriad problems surrounding liability for this accident. It is very complex and very weird to people not in the business. I can’t cover it all, you’ll have to watch the 25 minute video but here is one example.
In maritime law the people who have cargo on the ship share in the liability. The reasoning being that the ship would not have been there and involved in an accident if it were not carrying your cargo. This would be akin to you getting in a taxi (or Uber/Lyft) and the taxi driver getting in an accident. The insurance company would lay some liability on you since the driver would never have been in that place and time were they not driving you. Madness but apparently this is normal in maritime law.
Or if a ship sinks (this one didn’t) they can’t be sued for the value of the cargo since the cargo only has value when it gets to port. Since it never got to port the cargo value is zero.
P.S. Anyone know how much steel was in the FSK bridge?
Not long enough to figure out how to stop it from rusting when it gets wet, which it turns out is kind of important when it comes to bridges.
It’s the only way what he said makes any sense at all. He specifically said to “reuse” the steel and gives a very short time span. Re-smelting the steel would take longer than even using new steel. Both versions are ridiculous, but at least the rebending would mean he wasn’t completely pulling the time out of his ass.
I’m sure he knows a bit about steel, but it seems he knows just enough to confidently say something dumb. He has a history of this with disaster situations. And he’s used to others figuring out the details for him. He likely was just basing his idea on his own experiences as the guy telling the experts what to do.
Do note that he got these same objections when he made the tweet. He is free to come up with an explanation of what he meant. No need for any of us to come up with one for him.