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Baltimore bridge collapses into river after being hit by cargo ship
(www.theguardian.com)
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this post was submitted on 26 Mar 2024
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The investigation report is going to be interesting. While bridges can only take so much punishment, they are usually designed to survive some collisions with their pylons. I wonder what the state of the bridge was, prior to the collapse. If it's anything like the rest of the infrastructure in the US, it was probably not good. Though, this may also be a case that the designers in the 70's planned for a collision with a cargo vessel of the times, which were tiny bath tub boats compared to the super container ships we have now. The Dali was built in 2015 she is a 300m ship capable of carrying 116851 tons. That's a lot of mass for the pylon and it's barriers to stop.
I'm pretty sure no bridge is designed to survive a collision with a large cargo ship, even a brand new one. It would balloon the cost so much nobody would be willing to pay it.
New bridges are built with protections such as pylons to prevent ships from even getting close to bumping into the bridge after the sunshine skyway bridge collapse of 1980.
In this case I'm not sure it would have mattered. This wasn't a bump or a glancing blow. There's not much which will deflect or absorb that much energy head on.
I disagree, the geometry of protection dolphins use would deflect the ship enough to change its trajectory towards the walls of the channel bed where the ship would run aground before striking the bridge even from a head on collision.
What is a geometry protection dolphin?
They are concrete or wooden structures that are piled deep into the ground like fondation foundation pylons on skyscrapers. The geometry part I was just referring to how they are angled in such a way it ricochets the ship away from the structure it's protecting or towards the channel.
So why on earth didn't the bridge have these?
If I had to speculate? Cost savings... The bridge already had a history of cost reductions such as originally being built with a shared approach way which vastly increased the risk of head on collisions.
So in their effort to save money, they got 6 people killed and now have to spend presumably much more on a whole new bridge...
Possibly but you have to keep in mind this bridge was designed in the late 60s when a lot of the safety regulations that were written in blood hadn't happened yet. The Florida state sunshine skyway bridge collapse wouldn't happen for over a decade after the Francis Scott Key bridge opened.
A. It did, just only a few and the investigation will probably reveal not enough based on giant ships these days.
B. It was built before the Sunshine bridge collapse in 1980 so before the standards were updated.
I believe it refers to this: https://en.m.wikipedia.org/wiki/Dolphin_(structure)
This makes a lot of sense, thanks for the insight!
I suspect there'll be a lot of places taking a good long look at their current chunks of concrete they put around bridge supports and wondering how they'd stand up to the monstrous ships that are now the norm.
This kind of incident may not happen often but it does happen.
I imagine a lot of places may wonder about this and then kick that can down the road until someone does actually collide with their bridge.
!remindme 40 years.
A bridge is quite different to a pylon though.
Literally a block of concrete embedded in the sea floor.
https://www.fhwa.dot.gov/bridge/inspection/
I think you can look up certain characteristics such as this here, I’ve done it before and exported data into Excel when I was looking into something else. If this isn’t the specific site I apologize, I’m on mobile, but it is publicly available.
Edit: these links may be better:
https://www.fhwa.dot.gov/bridge/nbi/element.cfm
https://catalog.data.gov/dataset/national-bridge-inventory-system-nbi
https://infobridge.fhwa.dot.gov/Data
https://geodata.bts.gov/datasets/5e58970e89934e818f38772859addf43_0/explore
It's* no tits
This is the absolute dumbest shit I’ve seen in a while. And it’s said so confidently, kind of amazing.
Why do you say that?
This structure was hit head on by a laden container ship. Container ships weigh between 50,000 and 200,000 tons depending on size and cargo. There is not a structure capable of being created by man which could sustain that amount of force, head on, and retain its structural integrity.
Buncha armchair idiots think they know more about bridge construction than civil engineers. Gods, this place is just more and more like Reddit by the minute.
Kinda crazy how those same construction and civil engineers are going to be investigating if the normal means of protection for this very foreseeable event was done correctly, because we design things to avoid these head on collisions:
https://wjla.com/features/i-team/questions-investigators-will-be-asking-about-francis-scott-key-bridge-collapse-baltimore-container-ship-collision-port-engineering-economy-shipping-hub
Also, not for nothing but even if they find out the dolphins in place were sufficient based on prior standards...this event will likely update the standards, same as the sun bridge in the 80s. Regulations and best practices are written in blood.
People always forget that deflection exists. I don't know why that guy is hung up on stopping the ship instead of just nudging it forcefully. If we can figure out a way to deflect explosions and sabot rounds, we can deflect a ship.
Yeah also just the basic concept of sacrificial parts and things designed to wear. The derailleur hanger on your bike, crumple zones in cars, plastic gears in your KitchenAid mixer - lots of engineering practices are designed around shunting failure to a particular piece or in a particular way, to avoid otherwise catastrophic or very expensive damage.
Oh my god! No way! They’re going to investigate and learn from a rare event! That’s shocking!
We study things all the time. Your extrapolation that an investigation means something was preventable is evidence that your higher brain function has been damaged.
You: "There is not a structure capable of being created by man which could sustain that amount of force, head on, and retain its structural integrity.
Actual engineers in the linked article: literally describe how to build secondary structures to deal with giant ships and prevent head on collisions on bridges.
I know you stopped responding but I'm piling on because I'm apparently in an impish mood:
From: https://www.washingtonpost.com/dc-md-va/2024/03/26/how-key-bridge-collapsed-baltimore/
It takes a pretty special kind of small mindedness to think that this accident will be uninteresting to engineers because container ships are simply too heavy to consider building against.
The amount of force needed to deflect a large object is much smaller than to stop it. In fact, if done over a large enough distance, a tiny amount of force is sufficient.
Need an example? Imagine your big brother is skating down a slope. Could you block him, head on? Probably not. But what if your sister, who was skating next to him, were to slightly steer him out of the way so that he doesn’t hit you?
As an alternative, you can also slow him down over a long distance, requiring the same(?) force but applied in a smaller amount, longer.
Because of a contradictory ass like yourself.