Baltimore Francis Scott Key Bridge collapse

[tom66]

Looks like a major disaster, with many people in the water, after a ship collided with the bridge structure and the bridge collapsed.

https://bbc.co.uk/news/live/world-us-canada-68663071

Fortunately, fatalities are going to be lower just because of the time at night but multiple vehicles and at least a work crew have gone into the water, so almost certainly several will have died.  It's not clear if anyone on board the ship was injured.

Going to be an expensive day for the marine insurers.   I thought bridges like this were designed to resist the collision of a ship? Is this a design fail?  The bridge is, or was, roughly 50 years old, so it's within the range of time that you'd expect considerations like this to have been made.

[SiliconWizard]

 

[rsjsouza]

What an unfortunate event... The video of the collapse is very impressive - the bridge crumbles as if it was made of paper.

Bridges that collapsed after collisions have happened before and I wouldn't be surprised if negligence or corruption related to its maintenance were critical factors in this case.

[Whales]

That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

[guenthert]

I'm pretty sure that with a massive enough ship sailing fast enough, one could take down any bridge.  I'd think for that reason, there will be limits to what ship and how fast may approach such a bridge.  Were those limits exceeded?

[watchmaker]

What a thing to wake to!  We lived just outside Baltimore for 40 years.  Sad for the victims, sad for the firemen (FIL led the response to a stadium escalator collapse).   Some USN preposition ships there, port does handle mainly cars (that now screws things up).  City/county/state cannot handle the loss of revenue and jobs.

The Mates and Pilots school is also in Balmer ((hon) and this will a classic case study.

Yeah enough mass at any speed will take down a structure with a direct hit.  Which this appears to have been.  Pilot lost his card unless he had a heart attack.

Holy shit!

[Ian.M]

See NOAA chart 12281
The main span's piers were in 30' - 35' of water (+ tidal range), and the channel is dredged to 50'.    They were protected by dolphins either side.   To add enough extra dolphins to 'ship-proof' the bridge would be rather expensive, ballpark estimate on the high side of $100 000 000 USD, just for the dolphins and associated protection works, which is at least double the total annual revenue of the port authority, and a significant fraction of the city's budget which is already forecast to have a $180 000 000 annual deficit for the next decade.

The insurers will pay out (eventually) for the cleanup and a depreciated cost for the bridge, and the city and port authority will have to pick up the rest of the tab unless they can get a federal grant.   Ain't nobody going to be happy, as port fees and local taxes will have to go up.   

@Watchmaker,
 Even if the pilot had a medical issue, unless the ship was found to have suffered a critical systems failure, e.g. loss of both throttle and rudder control, Pilot lost his card FULL STOP, either due to responsibility for the incident or by being medically unfit.  At this point (absent such a failure) the pilot and ships' bridge officers on watch are essentially unemployable in any similar role, probably for the rest of their lives.  'Take an oar and walk inland ...'

[WatchfulEye]

Longer video here. Looks like it shows several episodes of complete electrical failure with the ship drifting.

https://twitter.com/truth68201238/status/1772534441593737582

[tom66]

Yeah, that's terrible.  Looks like the ship pilots would have been able to do nothing about that, and would have been aware of it the whole time...  Makes you wonder if this is going to be down to whomever maintained that engine/power system last.

[soldar]

That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

I think this comment shows a lack of understanding of the scale and proportions of the entire thing. It is pretty much impossible to build that bridge in a way that it could withstand being hit by a mass of, say, 100,000 tons, 150,000 tons etc, going at speed.  And it makes no sense, economic or otherwise.

[vk6zgo]

That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

The Tasman bridge in Hobart was hit by a ship in 1975 & several spans collapsed, with the loss of 12 lives.
The pillars on each side of the navigation channel were designed to take a ship impact, but the others where the ship hit weren't.
The "Lake Illawarra" which brought it down was by today's standards, relatively modest in size.

[iMo]

From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.

[jonpaul]

Possible circidian effect on captian of ship at 01:30?

Impact on commerce at the Baliomore port?

Jon

PS: An old  is dierect desendent of Francis Scott Key, composer of our National Anthem.

[Circlotron]

That brings up an interesting question: are those bridges designed to survive single-ship impacts like that?  We'd hope so, but I wonder if it's actually a requirement.

The Tasman bridge in Hobart was hit by a ship in 1975 & several spans collapsed, with the loss of 12 lives.
The pillars on each side of the navigation channel were designed to take a ship impact, but the others where the ship hit weren't.
The "Lake Illawarra" which brought it down was by today's standards, relatively modest in size.

Remember it well.

[watchmaker]

Mykid (Structural PE) just told me there was a repair crew on the spans.  Fuck.  Coulda been her.

[NiHaoMike]

From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.

Is the ship steer by wire? I would expect that most ships are hydraulically steered and in any case, there would be redundant systems like on aircraft.

[tom66]

From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.

Is the ship steer by wire? I would expect that most ships are hydraulically steered and in any case, there would be redundant systems like on aircraft.

I'm also wondering why they were so close to the bridge pier.  I'd have thought you'd aim for the middle of the bridge and in the event of a power failure you'd just drift through the middle of the bridge.  It looks like they were quite off course and then simultaneously lost power, a bit of a Swiss cheese event.  I know very little about maritime navigation, but it does seem a bit odd that they even ended up in this position in the first place.

[Andy Chee]

From the video above - interesting how fast the ship changed its direction after the first power outage. I would expect the rudders of such a ship will stay in the "last good" direction after the outage.

Is the ship steer by wire? I would expect that most ships are hydraulically steered and in any case, there would be redundant systems like on aircraft.

Remember that in order for the rudder to have any effect, the ship needs to be moving relative to the water, or in other words the ship’s propellers must be providing some thrust.

If the ship is moving at zero speed relative to the water i.e. drifting with the current, the rudder does nothing.

In aircraft terminology, if airspeed is zero the aircraft has stalled.

[Ian.M]

The main span of the bridge was 1100 feet.   MV Dali is approx 160 feet wide, and IRCPS ('COLREGs') Rule 9 states a vessel proceeding along the course of a narrow channel or fairway is obliged to keep "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.", so it would be normal practice under a bridge span wide enough for two vessels to pass, to aim for a point that's considerably off-center. 

The vessel would have been carrying considerable way, and in water much shallower than the beam, would require at least six ships lengths to stop from typical manoeuvring speeds, assuming full astern was available, and there was enough lateral searoom to accommodate the severe slew to one side that is typical of a single screw vessel going hard astern.  If the engine failed, low speed steering would be compromised by the lack of forced water flow over the rudder.

Re: WatchfulEye's video link: The observed thick smoke from the funnel implies the engines were rapidly commanded to full speed, and no pilot or watch officer in their right mind would go full ahead towards a near hazard in restricted waters.   Its likely that the slew into the bridge pier was mostly due to going full astern with  insufficient distance to stop.  Dammed if you do, dammed if you don't.

[NiHaoMike]

The main span of the bridge was 1100 feet.   MV Dali is approx 160 feet wide, and IRCPS ('COLREGs') Rule 9 states a vessel proceeding along the course of a narrow channel or fairway is obliged to keep "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.", so it would be normal practice under a bridge span wide enough for two vessels to pass, to aim for a point that's considerably off-center. 

I wonder if that would get revised to aiming for the center as long as there's no traffic in the other direction, to give more room for error.

[Ian.M]

No, but its common practice to put markers on a bridge span and have a harbour regulation that vessels shall pass between the markers, which effectively has the same result of excluding non-emergency navigation near the piers.

[TimFox]

The last news report I heard on the radio (9:30 CDT on March 26) said that the container ship had suffered a total loss of propulsion.
The ship notified authorities about the possibility of impact, who were able to reduce the number of people at risk on the bridge before the ship hit it.

[guenthert]

The main span of the bridge was 1100 feet.   MV Dali is approx 160 feet wide, and IRCPS ('COLREGs') Rule 9 states a vessel proceeding along the course of a narrow channel or fairway is obliged to keep "as near to the outer limit of the channel or fairway which lies on her starboard side as is safe and practicable.", so it would be normal practice under a bridge span wide enough for two vessels to pass, to aim for a point that's considerably off-center. 

I wonder if that would get revised to aiming for the center as long as there's no traffic in the other direction, to give more room for error.

For the landlubbers: starboard is right side, the ship hit the left pylon.

As far as change of rules is concerned, I could see a demand for ships exceeding a 'safe' size be required to be towed into port by tugs, rather than sailing under own power.

[soldar]

I have sailed my own sailboat on the Chesapeake for quite a few years and know the area well although my main sailing was in the southern part of the Bay.  Lots of stories and memories. I used to love sailing at night.

There can be some strong tidal currents, more so on the southern part, much less so in Baltimore Harbor. I used to know the tides and currents pretty well and use them to my advantage.

As a curiosity, those channels leading up to Baltimore Harbor are marked by "ranges"

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

Leading lights, also known as range lights in the United States, are a pair of light beacons used in navigation to indicate a safe passage for vessels entering a shallow or dangerous channel; they may also be used for position fixing. At night, the lights are a form of leading line that can be used for safe navigation. The beacons consist of two lights that are separated in distance and elevation, so that when they are aligned, with one above the other, they provide a bearing. Range lights are often illuminated day and night.
Two lights are positioned near one another. One, called the front light, is lower than the one behind, which is called the rear light. At night when viewed from a ship, the two lights only become aligned vertically when a vessel is positioned on the correct bearing. 

The span of the bridge is wider but the width of the dredged channel is about 220m (700') so when the ship hit the bridge it was already outside the channel and had hit the bottom which probably slowed it down considerably.

Remember the ship that got stuck in the Suez canal?  Those large container ships are huge!

If the dredged channel is 220 m wide you have 110 m in each direction and if the ship is about 50 m in beam then it only has 30 m clearance on each side. That is about 1/10th of the length of the ship.

In the attached photo I have marked the edges and center of the channel and what width the ship would be taking.

[TimFox]

Edited from an AP news item (11:24 AM CDT) with further details.

BALTIMORE (AP) — A container ship lost power and rammed into a major bridge in Baltimore early Tuesday, causing the span to buckle into the river below and plunging a construction crew and several vehicles into the dangerously cold waters. Rescuers pulled out two people, but six others were missing.

The ship’s crew issued a mayday call moments before the crash took down the Francis Scott Key Bridge, enabling authorities to limit vehicle traffic on the span, Maryland’s governor said.

The ship struck one of the bridge’s supports, causing the structure to collapse like a toy. It tumbled into the water in a matter of seconds — a shocking spectacle that was captured on video and posted on social media. The vessel caught fire, and thick, black smoke billowed out of it.

With the ship barreling toward the bridge at “a very, very rapid speed,” authorities had just enough time to stop cars from coming over the bridge, Maryland Gov. Wes Moore said.