Large Container Ship collided with support causing complete collapse of 1.6 mile long bridge. This is a multi-billion dollar accident.
Collapse occured at 1:30 AM. At that hour, on an urban interstate highway, I’d guess about 10 vehicles were on the bridge. The 200 ft drop to the water is not likely survivable.
Maryland: Ship hits Francis Scott Key Bridge causing it to collapse | Fox News
Here’s a video of crossing the bridge in less stressful times.
intercst
Industrial type accident? Or…? How many laws were broken or regulations violated…? Mmm hmm. It “just happened.”
And btw, you’re a civil engineer. My non-engineer observation tells me the bridge came down way too fast for just being bumped by a slow moving boat. Unless that was time lapsed video. Should the bridge have just folded like that?
An article says that the ship lost propulsion and had actually warned MD about the possible collision. I wonder how long before the impact that was. But dang, that is freaky to think about.
I’m not implying "capt dunk or on drugs/no supervision/he’d been caught doing it before " ect that kind of violation. And the Pilot/Captain on duty might not have been aware of anything wrongful. He could have been as much a victim as anybody else. The fault could go pretty deep which is how they like it 'cause it defuses trying to blame anybody.
Or it could very well have been a force majeure.
Reports of the ship catching fire and losing power right before the collision.
Container ships are massive. Even at slow speeds, directly ramming one of the main support piers would result in a catastrophic collapse.
Re: bridge came down too fast
Bridges may very well be designed for weight on one side of pier to counter balance that on otherside. But collapse on oneside can result in domino effect. A good reason to provide extra protection of piers especially near shipping channels.
A video of the ship hitting the bridge has been posted in a few places. You can see the lights go out on the ship, come back on, then go out again.
wrt bridge construction: way back when the earth was young, I took a class in static structural analysis. I could calculate the load in every member of a truss bridge, and whether each member was in tension or compression. Knock out a few members, the others will be overloaded, and down comes the bridge.
Steve
You typically protect the pylons supporting the bridge with big, heavy concrete donuts. But making the donut big enough to absorb the impact from a 100,000 ton ship is very expensive. You can build a bridge with much more redundancy in the structural design, but that costs more money and higher taxes. But that kind of simple arithmetic is much too political to discuss here.
Also, when large ships move around crowded harbors they usually have one or more tug boats attached to both the bow and stern to provide steering in case of propulsion failure. Perhaps Jack Welch-inspired thinking told them the tugs weren’t required in Baltimore?
intercst
My question is based on: They knew when they built the bridge that boats, heavy containers included, would be running under it. It is common and necessary to assume things won’t always go the way we’d like them to. Boat-to-bridge contacts were a possibility. In fact, an inevitability. Hence, they would build for that contingency. Not that the bridge would sustain no damage. Would probably be offline for months, at least, with a big enough impact. The way it came down it seemed like they were just counting the hours till something like this happened.
But… I didn’t post that to belabor a point. It’s about the boat at this point. The OP is an engineer and thought he might have something to say on it.
It’s still about the boat right now (I just woke up from a nap so might need to catch up on events) but there night be more intrigue. The bridge was built in 1977. That was probably back when “They built 'em like they used to.” If it was 10-20 yrs old I’d be more suspicious. I can’t find any info on any previous collisions.
Just saw this in the NYTimes:
{{By Tuesday morning, six construction workers who had been fixing potholes on the Francis Scott Key Bridge remained missing as divers and other emergency workers on boats and helicopters continued to search for them. Two others had been rescued.
Gov. Wes Moore of Maryland called the episode a terrible accident. “We haven’t seen any credible evidence of a terrorist attack,” he said. The bridge is part of Interstate 695.
Initially, officials feared that drivers were submerged in their cars in the Patapsco River. But the warning from the Dali, a Singapore-flagged vessel, gave officials enough time to stop traffic at both ends of the bridge, according to several federal and Maryland officials. }}
That is phenomenal that the ship was able to get the warning out early enough to close the bridge to traffic. Harbor officials were obviously on the ball and not “asleep at the switch” at 1 AM in the early morning.
intercst
Remember the I-35 bridge collapse in Minneapolis? Built in 67, collapsed under rush hour traffic in 2007.
Keep in mind, these bridges are generally built by the lowest bidder. And, in some states, road and bridge maintenance took a back seat to tax cuts for “JCs”. For a while, it became routine to see sheets of plywood hung under bridges in Michigan, to catch the chunks of concrete that fell off, so they would not hit vehicles passing underneath.
Steve
I wonder if this bridge were on the list of “to do’s” with the Infrastructure bill that allocated money to states to repair/construct needed structures…
Pete
Yes, the I-35 bridge in Minneapolis is another example of a cheap light truss bridge with a single point of failure. You can build them stronger and safer, but that costs money and higher taxes and is too political to discuss here.
intercst
Here’s a list of a few -
Key Bridge is not the first bridge collapse in the U.S. from a ship collision | PBS News.
Good summary of contributing causes for the collapse -
Catastrophic accidents are rarely caused by a single point of failure. The added dead load from additional concrete overlay and larger barriers didn’t help.
Thanks for that update. I didn’t recall every hearing just what the exact cause of the failure was. Design flaw. The old “Looks on on paper” trick. Anybody can blow one. New, untested, or even innovative designs for bridges can come a cropper in the real world. A man’s reach should exceed his grasp and all that. But then doesn’t this just bring it back around to inspections? If they’d stayed out in front of things they’d have caught it.
As far as the lowest bidder model: Don’t know if letting contracts to the highest bidder would work any better
It is insane to have a huge heavily laden cargo ship maneuvering without tugboats both within and when leaving or approaching a harbor, as was the case with this disaster. That is what tugs are for!!!
This was grotesque penny wise stupidity, as ship engines can have troubles, especially when getting underway. Ship propulsion is NOT designed for manuevers in constrained spaces with multiple hazards. Baltimore Harbor management (ayyiyiyi! shades of the excellent show The Wire) was being penny wise and pound (catastrophically) foolish.
The collapse of the bridge looked to me exactly as I would expect, not as a direct result of the blow of the ship knocking it all over, but of a chain reaction collapse from the balanced dependence of each part of the structure on the countervailing pressures of the others, the very essence of large cantilever bridges.
d fb
Frank Sobotka learns a lesson how on how things really get done at the Port of Baltimore (NSFW).
About an hour ago I heard someone with experience in this stuff give his observations. I believe he was a former head of the port authority of somewhere. He mentioned those concrete donuts designed to protect the pylons. He referred to them as “dolphins.” At least that’s how it was coming through to me. He said a boat that heavy depending on speed and other factors might have completely over-rode those barriers.
Another case of design flaw? Or “cheaping” on the construction? OR… did they do what they’re there for but they’re not supposed to be the sole means of protection and are only effective with tugs in use and some crisis control protocols being used on the ship to ameliorate any impacts?