Baltimore Bridge

[Werewolf]

Your regular reminder that Elon Musk is an idiot.

https://twitter.com/x/status/1774117439208329583

It does however potentially explain a fair bit about the build quality of his cars

I can't imagine any actual qualified engineer even entertaining the idea unless there was no other option to ever build something else.
Besides anything else that isn't visible to the naked eye, there is going to be a lot of that metal that is bent and is going to be faster to replace than try and fit back together.

I also suspect any replacement is going to be a design that isn't "single point of failure", and will be built to current standards, not the standards of the 1960's.

 

[Sankari]

It does however potentially explain a fair bit about the build quality of his cars

...and his rockets.

I can't imagine any actual qualified engineer even entertaining the idea unless there was no other option to ever build something else.
Besides anything else that isn't visible to the naked eye, there is going to be a lot of that metal that is bent and is going to be faster to replace than try and fit back together.

I also suspect any replacement is going to be a design that isn't "single point of failure", and will be built to current standards, not the standards of the 1960's.

The craziest part—even worse than the moronic suggestion that they should re-use metal already weakened by the collision—is that he and others are suggesting the bridge should be repaired, instead of being scrapped entirely and replaced with a superior design.

What Baltimore needs is not a repaired 1970s bridge, but a 2020s bridge built to the latest standards, with modern marine traffic in mind.

 

[Jokester]

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.

My dad is ex merchant navy and he was saying they should have had tugs taking this out of port, but it will likely have come down to cost and inadequate risk assessments.

 

[dowie]

Doesn't make sense to reuse - like in theory *some* might be able to after inspection - but that in itself adds time and isn't very good PR-wise.

More to the point though you'd still need many new ones to be built and would they even be trying to replicate the same design - probably not. Ergo would they even make sense for the new design given they were made for the requirements of the old one. (Presumably, they may want to take the opportunity to build a bigger, taller bridge ergo it's pointless!)

Certainly trying to get a replacement built quicker is worthwhile and there perhaps are inefficiencies to address but that re-using the steel idea seems very sus.

 

[Terminal_Boy]

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.

I wondered as I’ve seen videos of ships capsizing them if the bridge crew screw up.

 

[Dis86]

I wondered as I’ve seen videos of ships capsizing them if the bridge crew screw up.

They tend to have very low freeboard and relatively shallow draught. Quite easy to upset one!

 

[Dis86]

My dad is ex merchant navy and he was saying they should have had tugs taking this out of port, but it will likely have come down to cost and inadequate risk assessments.

It depends. If they crew have significant experience of the port they might be allowed to take it out themselves. We certainly don't use the tugs for everything although most decent sized vessels will have one of our pilots on board.

 

[Jokester]

It depends. If they crew have significant experience of the port they might be allowed to take it out themselves. We certainly don't use the tugs for everything although most decent sized vessels will have one of our pilots on board.

It less about experience and more about preventing major accidents. It seems incredible that nobody picked up they were shifting 100,000+ ton ships metres away from critical infrastructure that didn't also have any kind of protection for collision.

 

[Dis86]

It less about experience and more about preventing major accidents. It seems incredible that nobody picked up they were shifting 100,000+ ton ships metres away from critical infrastructure that didn't also have any kind of protection for collision.

Oh I agree. There are a lot of factors that will go in to the decisions, for us the main one is the depth of the channel and it remaining navigable.
I imagine with the width of the river there that's not an issue so they should rightfully then consider obstacles. Margins on container shipping are fairly tight so I do wonder if cost is one of the issues here.

 

[DB_SamX]

It does however potentially explain a fair bit about the build quality of his cars

I can't imagine any actual qualified engineer even entertaining the idea unless there was no other option to ever build something else.
Besides anything else that isn't visible to the naked eye, there is going to be a lot of that metal that is bent and is going to be faster to replace than try and fit back together.

I also suspect any replacement is going to be a design that isn't "single point of failure", and will be built to current standards, not the standards of the 1960's.

There is currently a big push in the industry to reuse existing/old steelwork, as long as not damaged. "circular economy". Lots of guides have been published to help engineers assess their capacity, and website to buy/sell old steel. So it wouldn't surprise me to potentially reuse whatever steel ie still intact/decent condition. It will save a lot of embodied carbon.

 

[scarps]

My dad is ex merchant navy and he was saying they should have had tugs taking this out of port, but it will likely have come down to cost and inadequate risk assessments.

The tugs had already taken it as far as they take any other similar sized ship at that port. It did say though they can go further but like you say, they don't to save costs.

 

[aVdub]

There is currently a big push in the industry to reuse existing/old steelwork, as long as not damaged. "circular economy". Lots of guides have been published to help engineers assess their capacity, and website to buy/sell old steel. So it wouldn't surprise me to potentially reuse whatever steel ie still intact/decent condition. It will eave a lot of embodied carbon.

If it was good enough for the USS New York, then it would be good enough to rework for the bridge imo.

There's reworked steel everywhere.

 

[Chuk_Chuk]

There is currently a big push in the industry to reuse existing/old steelwork, as long as not damaged. "circular economy". Lots of guides have been published to help engineers assess their capacity, and website to buy/sell old steel. So it wouldn't surprise me to potentially reuse whatever steel ie still intact/decent condition. It will save a lot of embodied carbon.

What does reuse mean in this context?

Do you mean fishing out the bits truss work giving it an inspection and maybe a protective coat before using it on a new project? Or is there more involved?

 

[Hagar]

I would say not reuse but definitely remake. Steel is crystalline and over a long life will form hairline cracking only visible under a microscope. Remanufacture and rolling will make new steel however I would not design a steel truss to replace this bridge but a cable stayed superstructure providing longer spans in reinforced concrete with much improved protection within the river.

 

[mrk]

That Elon tweet is so on-brand, surprised he doesn't just delete tweets that prove him to be a bit silly at this point

Remember this bridge was something like 1.5 miles long? Modern times require modern bridges.

 

[keyser van someone]

What kind of bridge would be able to withstand a direct hit from a ship that size? How much kinetic energy would the structure have to stop - not just slow down, but instantly stop?

Jonathan V. Last (@jvlast) on Threads

I've been trying to figure out an f=ma equivalent of the container ship bridge collision to give people a sense of scale. If something weight 93,000 tons is moving at, say, 2mph, and collides to a near-immediate stop, what is kind of event is that like, physics nerds?

www.threads.net

"It’s like getting hit by ~5200 bananas going at Mach 1" lol

 

[mrk]

What kind of bridge would be able to withstand a direct hit from a ship that size? How much kinetic energy would the structure have to stop - not just slow down, but instantly stop?

"Our lowest estimate of how much force it would take to slow the Dali, if it were fully loaded, is around 12 million newtons, about a third of the force it took to launch the Saturn V rocket for the Apollo moon missions.

And our higher-end estimates, reviewed by several civil engineering experts, suggest it is realistic to put the force of the impact with the pier at upward of 100 million newtons.

“It’s at a scale of more energy than you can really get your mind around,” said Ben Schafer, a professor of civil and systems engineering at Johns Hopkins."

Force of Ship Impact Was on the Scale of a Rocket Launch

A Times analysis used preliminary data to estimate the force of the impact on the Baltimore bridge. It involved “more energy than you can really get your mind around,” an expert said.

www.nytimes.com

I think the short answer really is not many bridges, old or new lol.

 

[Blackjack Davy]

Which is why according to an expert these days they would build an earth rampart for want of a better word around the bridge support to absorb the energy of the impact before it hit the structure, when it was built the average ship size was around 44,000 tons these days its nearer 300,000 tons, a massive difference in kinetic energy

 

[Dis86]

What kind of bridge would be able to withstand a direct hit from a ship that size? How much kinetic energy would the structure have to stop - not just slow down, but instantly stop?

Jonathan V. Last (@jvlast) on Threads

I've been trying to figure out an f=ma equivalent of the container ship bridge collision to give people a sense of scale. If something weight 93,000 tons is moving at, say, 2mph, and collides to a near-immediate stop, what is kind of event is that like, physics nerds?

www.threads.net

"It’s like getting hit by ~5200 bananas going at Mach 1" lol

Mach1 banana sounds like a good forum name

 

[dowie]

What kind of bridge would be able to withstand a direct hit from a ship that size? How much kinetic energy would the structure have to stop - not just slow down, but instantly stop?
[...]

"It’s like getting hit by ~5200 bananas going at Mach 1" lol

Yup, it's an insane amount of force, as Werewolf pointed out earlier in the thread. That's why they instead aim to deflect ships away from hitting bridges etc.. rather than stopping them.