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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

#411

Post by apocalyptic0n3 »

b33j0r wrote: post #208
Retric wrote: post #187

Earlier quoted context omitted.

Bridges only last for roughly 50 years. Considering such collisions are rare enough to make the news as a memorable event you can workout for yourself that the odds are quite low over a bridges lifespan. They are designed to withstand smaller boat impacts because they occur relatively frequently, but cost vs benefit on rare events that are difficult to mitigate is quite different.

Interested in this claim, because it sounds about right, except that I can’t name a bridge constructed in the past 50 years. The bridges we can all name are pushing 100+ right?

There's a massive one being constructed right now - the Gordie Howe International Bridge. It'll be the second bridge (and fourth crossing) between Detroit and Windsor when it opens next year. Although maybe I only know of that one because I grew up in metro Detroit.

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

#412

Post by kube-system »

yread wrote: post #119
taf2 wrote: post #90

It took 5 years to build in the 1970s. It took 5 seconds to destroy

let's see how long will it take to build today

Pittsburgh built the replacement for the collapsed Fern Hollow Bridge in less than 8 months. The one that collapsed took 14 months to build.

https://en.wikipedia.org/wiki/Fern_Hollow_Bridge

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

#413

Post by dragontamer »

mixedmath wrote: post #290
AndrewKemendo wrote: post #287

Earlier quoted context omitted.

I agree. I lived in PG county for years and this is a big deal The 295 bridge collapse a decade ago was similarly shocking U.S. infrastructure is beyond crisis level.

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

The container ship "unluckily" maneuvered between the protective barriers. About 4 more protective barriers would have stopped this collapse.

------

No bridge survives being struck by a container ship. That's why barriers are erected around critical points. There already were barriers, they just weren't complete coverage for some reason. (EDIT: Maybe the older 1970s era design of this particular bridge wouldn't allow more protection to be placed. Obviously this situation calls for a full investigation / lessons learned kind of thing, as part of the new bridge building process)

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

#414

Post by mikeyouse »

throwanem wrote: post #363
rayiner wrote: post #342

This is going to have a huge impact on traffic patterns in the mid Atlantic. The bridge carries 695 (the Baltimore beltway) across the river. Although I95 goes through Baltimore, 695 is one of two major bypass routes that’s a more direct shot from places south of the city to places north of the city (the other being the Baltimore harbor tunnel carrying 895). Unlike the Philadelphia bridge span collapse recently, I do…

> Unlike the Philadelphia bridge span collapse recently, I don’t foresee this bridge being rebuilt anytime soon. How come?

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.

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

#415

Post by theluketaylor »

master_crab wrote: post #364
litenboll wrote: post #348

Earlier quoted context omitted.

I had a summer job once, filling trains with sugar. They weighed about 15kkg per wagon (usually 5-10 wagons per train IIRC). One time the pulling cart broke down and we had to switch it for another, but when we took it off the rails we forgot about the "shoe" that is supposed to go between the rail and one of the wheels so it can't move downhill (it was like 1degree of slope so barely recognizable as a slope). It sta…

Also want to highlight this for another reason. At slow speeds rail and boats suffer from far less “moving” friction than road vehicles. So once off there is very little slowing them down vs cars and trucks that suffer from high rolling friction.

Grady Hillhouse of Practical Engineering recently did a great demo of this. He was able to pull his car in neutral and an empty train car on rails with roughly the same force.

https://www.youtube.com/watch?v=nGhBHrr5CYQ

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

#416

Post by nytesky »

ToucanLoucan wrote: post #347
zeteo wrote: post #337

Earlier quoted context omitted.

You don't need to build the bridge to an absurd strength, but it may have been insufficiently marked as a navigational hazard. Something like a few well-lit pillars 500 feet upstream in the water would have given the ship plenty of warning to change course, since a vessel travelling at 5 knots takes about a minute to go 500 feet. The total bridge length is on the order of 10,000 feet, so widening the safe area around…

I've seen close-up video where you can see the ship losing electrical power twice for not-insubstantial times as it approaches the column. I suspect that was a much larger factor in the collision than anything the crew may or may not have done. Warning time doesn't mean shit if you can't steer.

https://twitter.com/ChaudharyParvez/status/17725385394958090...

Posted video of power loss. Also black smoke coming out rear — is that normal? Any clue of what onboard crisis they were dealing with?

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

#417

Post by mherchel »

_fat_santa wrote: post #390
G0dchi1d wrote: post #388

Every bridge with large cargo ship traffic beneath them should have channels designed to guide the commercial traffic, installed beneath them. Every city with bridges like these should, with state AND federal funding, should begin the process of constructing such "guidance channels" beneath these bridges IMMEDIATELY!!! It should be IMPOSSIBLE for Ships large enough to damage bridges to even be able to come into conta…

The problem is momentum. These ships weigh thousands of tons so something as simple as coming to a stop is difficult. The ship probably knew it would collide with the bridge well in advance but had no way stop of avert the ship due to it's sheer size.

Doesn't have to stop them, just has to redirect them

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

#418

Post by 5555624 »

jsumrall wrote: post #351

The design of the Chesapeake Bay Bridge-Tunnel, specifically the tunnel part, makes a lot of sense now. Imagine a US navy port (Norfolk) being inaccessible if this happened there.

Which is why there's a tunnel -- when Virginia looked at replacing the ferry that ran between the Eastern Shore and Norfolk/Virginia Beach, the US Navy objected to a bridge over fears it could collapse. (An accident, sabotage, etc.) That's also why I64 has a bridge-tunnel design, as well.

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

#419

Post by gregors »

rob74 wrote: post #95
hgomersall wrote: post #85

Earlier quoted context omitted.

I'm not sure how many brand new bridges would stay up after having one of the piers on the main span removed.

The trick is to make sure the piers are not removed. For example, the new Tampa Bay Sunshine Skyway Bridge (rebuilt after a similar disaster): > In addition to a wider shipping lane, the channel would be marked by a 1⁄4 mi (400 m)-long series of large concrete barriers, and the support piers would be protected by massive concrete "dolphins". https://en.wikipedia.org/wiki/Sunshine_Skyway_Bridge#/media/...

Good view of them on Google maps

https://www.google.com/maps/place/Sunshine+Skyway+Bridge/@27...

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

#420

Post by appplication »

gonzo41 wrote: post #120
mkl wrote: post #37

Earlier quoted context omitted.

That's clear in the livestream video too. It's like it was fairly on track then changed to head straight for the pylon. A lot of smoke starts coming out of the funnel at the same time as the course change, and the ship's lights go out before impact.

It appears to have lost power twice before veering into the foundation of the bridge..

How often would a large ship like the is lose power? Seems like terribly poor timing.
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