Bridge Collapse

[farmersammm]

The Francis Scott Key bridge was a truss bridge. A truss will fail if just one node fails. There's no redundancy. And, the fact that it was a continuous truss probably made the entire structure fail, while if it had been compact trusses(single units resting on each pier), it might have only failed in one section.

I suppose a lot of it is economics. Stuff is built with the lightest, cheapest, material possible, to make it affordable.

Some kind of engineer, on one of the news shows, said that even the protective barriers around the piers couldn't withstand the direct impact of such a large ship. God only knows what a "sufficient" barrier would cost. And, I guess you have to remember that a lot of our bridges were built before the super ships of today. They didn't foresee the damage that could be caused by something this large.

Truss vs. Beam.....................

We had a similar accident here in this state.

The I-40 bridge near Webber Falls was hit by a barge. NOTE THAT ONLY A SMALL SECTION COLLAPSED. The remainder stayed intact. This is the power of the beam vs. a truss. A beam will fail locally, not globally.

It's more expensive to built this way, but I believe it pays off in the long run.

I'd also venture a guess that if this bridge had been built with today's modern pre stressed concrete, the results would have been worse. I am not a fan of concrete bridges.

[jpump5]

We had a girder bridge collapse in Connecticut without being struck.
(Mianus river, 1980’s) Apparently blocked drains and lack of inspection
led to an expansion joint pin corroding and causing the collapse.

[mrmikey]

When the Mackay Bridge over Halifax Harbour in Nova Scotia was built in 1970 collision with the piers was a concern that was brought up. The rubblestone 'island' around the supports is supposed to prevent any damage from an errant ship hitting them. I 'think' they were done after the oil rig broke lose in the harbour in '82.

[whtbaron]

A sad day for Baltimore...

https://www.theguardian.com/us-news/...e-what-we-know

[acourtjester]

They need to being one of those lifting barges, IE the oil rig movers there to remove the downed bridge parts to clear the channel. This would get some things back to normal. Replacing the bridge is a long time action. They are looking at years of design and contract work before things can get moving again, sadly. We had 2 bridges knocked out from Hurricanes and the drive around was maddening for about a year each.

[NotaVegetarian]

Our prayers are with all the families

[smithdoor]

I agree 👍
Iron workers have the third most dangerous job even in war time.

Dave

Our prayers are with all the families

[smithdoor]

In California they replaced in a year or two.
Here we had bridges down just week and had temp fix. I less that a year a new bridge. Some did take longer but was fast too.

Now just think iron worker that do cutting to remove the old bridge. Great pay all I can say.

Dave

They need to being one of those lifting barges, IE the oil rig movers there to remove the downed bridge parts to clear the channel. This would get some things back to normal. Replacing the bridge is a long time action. They are looking at years of design and contract work before things can get moving again, sadly. We had 2 bridges knocked out from Hurricanes and the drive around was maddening for about a year each.

[vwguy3]

The sad thing is is that a ship of that size would make mince meat out of the "pile island".
There definitely needs to be some sort of barrier but what would it take to stop a ship of that size?

[yooper]

Might be better off putting in a tunnel to replace it ?

[tapwelder]

Newton’s laws of motion. I am sure there are a lot of folks who didn’t know how much distraction a floating vessel could cause.

[John T]

I'd also venture a guess that if this bridge had been built with today's modern pre stressed concrete, the results would have been worse. .

Gotta love a farmer who thinks he is an Engineer....

This bridge was built in the 70's

[whtbaron]

Gotta love a farmer who thinks he is an Engineer....

This bridge was built in the 70's

Been thinking about getting a train...

[12V71]

Been thinking about getting a train...

Easy to drive... no steering wheel needed. Knowing how to work the brakes on downhill grades is kinda helpful.

[smithdoor]

It save taxes for better pay government employees.

Dave

The sad thing is is that a ship of that size would make mince meat out of the "pile island".
There definitely needs to be some sort of barrier but what would it take to stop a ship of that size?

[whtbaron]

Easy to drive... no steering wheel needed. Knowing how to work the brakes on downhill grades is kinda helpful.

And I'll have the headstart to going electric... halfway there...

[BillE.Dee]

Been thinking about getting a train...

joey knows where they park the train that uses the key bridge

[whtbaron]

joey knows where they park the train that uses the key bridge

There's a couple short lines around here too. I'm sure they wouldn't mind if I borrowed their engine for driver's ed...

[smithdoor]

Nothing wrong with eye ball engineers. I see it in all trades.
Most Farmers I know will hire a real engineer in steel .

In old work it was called { THOUGH AND PRAY ENGINEERING }

I see it lot when something (extra large like on base plates or beam).

In my line work it was door opener using a 5 hp motor to open a door. If do calculations a 1/4 to 3/4hp will most you need. By company doing work just use over size.

Dave

FYI The wrost I thing I try to reverse engineer is trailers. They built by the last trailer that fail just use next size larger steel

Gotta love a farmer who thinks he is an Engineer....

This bridge was built in the 70's

[smithdoor]

All the train engineers need to stop and go and still run into things just ask Farmers cows and train needs a cow catcher. Bad drivers.

Dave

Been thinking about getting a train...

[52 Ford]

[BillE.Dee]

very sad.

[duaneb55]

Might be better off putting in a tunnel to replace it ?

CMVs with HazMat couldn't use it.

[farmersammm]

I'd respectfully suggest that John stick to what he knows best, and leave the Farmer Engineering to us'n farmers



https://www.cnbc.com/2024/03/28/balt...-collapse.html





https://www.msn.com/en-us/news/us/wh...ce/ar-BB1kz6Eh


This stuff isn't rocket science. The strength of a truss comes from the node connections, which if they fail, can render the entire truss useless. It's a fragile system. I believe there are ways to insure some redundancy, but it's over my pay grade............I just feed cows, slop the hogs, and chase the chickens

If there's anything to take from the thread, it should be a desire to research the deficiencies, and benefits, of truss construction. Or at least have a basic understanding of the structure.

[farmersammm]

CMVs with HazMat couldn't use it.

A discussion on CNBC this morning stated that fact. It's why the bridge was used heavily for such types of cargo. You'd be amazed at what is considered "hazardous". It's quite a list.