Francis Scott Key Bridge Collapses

[Machinebuilder]

Anybody familiar with the bridges over the Ohio River and Mississippi River near Cairo,  IL?  They are near Fort Defiance.

Talk about bridges that will make you draw up a bit!  They are steel truss bridges, I think the Roman's built them. I've crossed them a few times.  They feed my irrational fear of bridge collapse. 

Last time over them the rivers were near historic low levels so the bridges seemed higher.  That stupid little bridge on the Kentucky side before the Ohio River bridge isn't exactly confidence inspiring!

I drove across them last fall.

Those are very narrow bridges, I really puckered with a semi coming towards me

[rusticretreater]

That's one of the positive things that can come out of a disaster like this.  Suddenly, everyone is looking at their bridges and saying we gotta replace that.

The real problem is how to pay for it all.

[Ianab]

The real problem is how to pay for it all

That's for sure. 

We have some dubious bridges around NZ too, but generally in areas with low traffic. The high traffic roads get a bit more spent on them. 

This is the bridge over the Haast River in the Sth Island. It's only one lane, but ~750 metres (almost 2500 ft) long, and it's single lane. 




This is a bridge a few miles North of Haast at Franz Joseph that washed out in bad weather. Luckily they had closed the bridge as the local road crews were worried (correctly) that it could fail. The detour around that bridge was ~12 hours and 1,000 km. As the bridge was a "Bailey" style, (prefab trusses), probably from when an earlier bridge was washed out, they were able to rebuilt it in only 18 days, and that was with some extra rain that slowed work.  

This is what the river usually looks like, with the current bridge, and the rock barrier added at the Nth end where the last failure started. 

https://maps.app.goo.gl/HQE7DCoYtB1Qms2R6

With a few hundred million they could obviously build a better bridge, but the amount of traffic just doesn't justify it. 

[beenthere]

One lane, so the traffic sits and waits for oncoming cars to clear that lane? 

[rusticretreater]

Yep and you hope the light isn't malfunctioning.

After Hurricane Agnes back in the 1970's, the area I was living in got totally washed out.  A 100 year old girder bridge in Occoquan fell, one of the two I-95 bridges over the Occoquan river had its footer washed out and they closed both spans for a bit, and the nearby US 1 two span bridge had one span fall(some fella got off of it just in time and stood there as it fell) and the other crippled.  You could go south, but you had to go west 20 miles to get heading North.

[Ianab]

One lane, so the traffic sits and waits for oncoming cars to clear that lane?

Yup, like I said it's not a high traffic area. 

Yep and you hope the light isn't malfunctioning.

What is this light of which you speak? 

The longer Haast bridge does have a couple of small passing bays on it, that are just wide enough for 2 vehicles to pass, so if 2 cars do end up on it, you can pull in and let the other past. 

There was another one lane bridge up the Coast further, that's also a rail bridge. Not rail AND road, it was Rail OR Road. Trains had right of way. It's since been replaced by a nice new 2 lane structure as it's in a more populated area. The old bridge is still there though

https://maps.app.goo.gl/iVLpcTEgNtLLvTvQ7

[Don P]

We had a couple of those growing up, they were known as "chicken bridge",as in, "Go up to the chicken bridge on the Haw river" and everyone would know where you were talking about.

[Southside]

Heard one of those "experts" say that "we should have enough steel in the US to build the new bridge" ---- that's comforting that we have enough steel for one bridge...

[Ianab]

Heard one of those "experts" say that "we should have enough steel in the US to build the new bridge" ---- that's comforting that we have enough steel for one bridge...

"Just In Time" manufacturing is a thing. Is there enough steel On Hand, or does it have to be ordered / produced / delivered and then made into the bridge parts. Usually a bridge project is years in the planning, so materials get pre-ordered and delivered as needed. 

I'm sure they are in the early stages of planning a new bridge already, but what's the design and material list going to be, and who's going to supply it?  I'm sure it will happen, US is still the 4th largest steel producer in the World, so there is plenty of steel available, just it may not actually have been produced yet. 

[SawyerTed]

Much will depend upon the aesthetics versus pure functionality of the new bridge.   Will it be a work of art, an engineering marvel and visually appealing; OR will the new bridge be a functional and practical construction meant to convey traffic and allow ships to pass?

It's hard to have a masterpiece engineered in a short time.   Innovation takes time.   

[Resonator]

Heard one of those "experts" say that "we should have enough steel in the US to build the new bridge" ---- that's comforting that we have enough steel for one bridge...

Has this "expert" ever even been to a steel mill? Yes they've got the steel, and roll out more hot fresh every day.

Engineering designs, contactor bids, government regulations, beam fabrication at the bridge builder shop, inspections and approvals, shipping the oversize loads, and final construction assembly at the site, that will take time.

[Resonator]

There was another one lane bridge up the Coast further, that's also a rail bridge. Not rail AND road, it was Rail OR Road. Trains had right of way.

Shared train and auto bridges were common in the early 1900's, trains were the primary means of travel and car travel was still in it's early stages. Often there was one lane of road, and one railroad track side by side or a double decker bridge with trains on top and cars underneath. It wasn't until Dwight D. Eisenhower was in office that the modern interstate highway system we have was built. Side note it's original purpose wasn't just for commerce, but as a means of defending the US. Hence the signs for I 40, I 80, etc. are shaped like a shield.

[Magicman]

The original Mississippi River bridge at Vicksburg included both train and automobile/truck traffic.  It was quite narrow and was a special "experience" to cross it with the then steam locomotives.    It still carries the RR traffic and the I20 automobile/truck traffic has it's own newer/wider bridge.

[gspren]

Back when the Key Bridge was built Bethlehem Steel was still in production and quite near to the bridge, it's been shut down for a number of years now. A quick search shows that the mill was officially closed in 2012 although Bethlehem sold it a few years earlier.

[SawyerTed]

Just mulling this over a bit.  Will there be disruption in steel and concrete supply in other areas of the country to prioritize the FS Key bridge replacement?  Will the bridge replacement take priority over other projects, causing delays and supply chain concerns?  

Even the Three Gorges Dam in China impacted concrete supply worldwide.  

It might not be a bad time to have welding certification, concrete experience, crane operator or construction management skills in the region.  Even a captain's license, tug operator, crew etc will be in demand.

There are lots of economic impacts and opportunities for jobs and businesses.

[Magicman]

I suspect that much of the materials and labor will require overtime other than what is normal.

[Ianab]

I can't imagine one bridge construction, even a large one, causing any huge disruption to supplies. There must be 100+ large construction projects going on around the US already. One more wont be the last straw. 

The disruption the closed port will be starting to cause will probably have more and wider effects.  

I see that some big crane barges have been moved in to start clearing the debris, which will be a big job on it's own. 

[Jeff]

If building one bridge, unless it is to Hawaii, disrupts any thing else in this world due to lack of ANY resource, we are already doomed. 

[Southside]

Apparently the ship came to rest right on top of a high pressure natural gas line.  At some point you begin to scratch your head. 

[Bert]

US Steel in Pittsburgh is pending sale to the Japanese. Go Figure. Its big news around these parts. Seems just plain wrong.

[chet]

The historic Portage Lake Lift Bridge in da UP is a 2 deck lift bridge, cars on top and train track on lower deck  

Quoted from the National Historic Civil Engineering Landmark article, 

The Houghton Hancock Bridge, officially known as the Portage Lake Lift Bridge, is the only bridge of its type in Michigan. When completed, it was the heaviest vertical lift span ever constructed. The unique bridge was designed as a double-deck bridge. The lower deck was designed for railroad traffic, and the upper deck was for highway traffic. However, to minimize the disruption of vehicular traffic on the bridge, the lower railroad deck of the lift span was designed to also accommodate vehicular traffic. This allowed the bridge to be raised slightly so that the railroad deck served the highway deck. While this would leave the railroad level of the bridge closed to trains, vehicular traffic could continue to cross the bridge, while allowing boats of intermediate size to pass under the bridge, where they would not have been able to do so if the left span was fully lowered. For large ships, the span could also be fully raised, which would completely stop traffic on the bridge. Today, trains no longer use the bridge, but the lower deck continues to serve as a crossing for snowmobiles in the winter. During the winter, the lift span is fully lowered, enabling snowmobiles to use the lower lift span deck level, while vehicular traffic uses the upper lift span deck level. At all other times of the year, the bridge is raised to the intermediate position, allowing vehicular traffic to use the lower lift span deck level, while closing off the unused lower snowmobile deck level. Today, the bridge does not raise beyond the intermediate level frequently, since large ships do not use the waterway as often. However it does raise beyond the intermediate position occasionally for sail boats.

[Gary_C]

Here is a ships Engineer's explanation for what was going on in the engine room of that ship. (edit: the website has disabled playback on other sites.)
Expert Ships Engineer Reacts to Baltimore Bridge Crash (youtube.com)

Key points of his expert analysis are:

The total time from first lights (power) out till contact with the bridge was under five minutes. During that time the first perhaps 60 seconds were waiting for lights to come back on and determining what went wrong. The heavy black smoke from the stack may indicate the engine room may have shifted engines to full astern. The problem is that twenty foot diameter prop acts like a paddlewheel and begins to pull the stern to port (left) while the bow of that 900+ foot ship drifts to starboard. He suggests that a better course may have been to go full ahead and use the opposite prop rotation to try to swing the bow away from the bridge. He also notes that the bow thrusters are totally ineffective above 3 knots and the ship was traveling at 8 knots but slowed to just under 8 knots before it struck the bridge piers.

Bottom line is the crew may well have done all they could to avoid collision with the bridge.

It was also reported in other places where the ship was fighting with power outages at the dock. One suggestion was there were refrigerated containers on the ship and one or more of those refrigerated unit may have been tripping the breakers at the dock. So it may well be the real cause of the accident was failure to resolve those power outages before departing the dock. Once the ship lost power the first time under way while still maneuvering in the port, it was just an accident waiting to happen.

[beenthere]

Video of cutting the bridge apart. Close-up of the size of the steel to be torched apart. Not "live" as implied, and just some footage that is cycled over and over. But a glimpse at what it is going to take.

[customsawyer]

That is going to be like doing storm clean up in the woods. All kinds of different stresses and pressures on some of that steel.

[Resonator]

That's what they said on the news, difficult for them to tell what beams are under tension or compression. I don't envy the ironworkers with the torch in that personnel basket. Crazy to see in the close up view shipping containers smashed like pop cans under the bridge framework.
The Army Core of Engineers said their plan is to open a smaller lane to get smaller ship traffic in and out of the port, until the main channel is open.