Infrastructure: Memphis I40 bridge over Mississippi river closed indefinitely after stress fracture discovered

[TIDE-HSV]

Friend just sent me this:

View attachment 16371

Well, I was trying to imagine what worse news could come. There it is...

 

[Go Bama]

UPS, FEDEX, Amazon - Memphis is a major shipping hub - Memphis International is the busiest cargo airport in the world.

This is why I-40 is such a nightmare.

Barge traffic is also stopped.

Potential 'catastrophic event' avoided by routine I-40 bridge inspection, officials say. Reopening timeline unclear

The I-40 bridge crack outside of Memphis has closed interstate and Mississippi River traffic and the timeline for reopening is unclear, officials said

www.commercialappeal.com

 

[dayhiker]

Cable or no, it seems it has to be hanging from the arch. I don't see how it can be resting on that bottom chord...

That bottom chord isn’t the bearing assembly.

 

[TexasBama]

This is why I-40 is such a nightmare.

Barge traffic is also stopped.

Potential 'catastrophic event' avoided by routine I-40 bridge inspection, officials say. Reopening timeline unclear

The I-40 bridge crack outside of Memphis has closed interstate and Mississippi River traffic and the timeline for reopening is unclear, officials said

www.commercialappeal.com

So they’re inspecting the I55 bridge. This might get worse.

 

[TexasBama]

View attachment 16368

Ok, this gives a much different feel to it. That diagonal we saw and were talking about isn't doing much of anything for what we were speculating. It looks to me like it's there to stabilize the bottom of the perpendicular plate girder.

Note to the left of the big bolted connection. You can see some waviness in the member there too.

There’s a spot at the top of the left beam where it looks like the paints bubbled.

 

[TIDE-HSV]

That bottom chord isn’t the bearing assembly.

I thought the cables were holding it up and it was holding up the roadbed assembly in turn?

 

[TexasBama]

I thought the cables were holding it up and it was holding up the roadbed assembly in turn?

The cables are attached to the big girders.

 

[NationalTitles18]

I read that they also shut down the river. It may be open now.

Damn. All that water's gonna back up and cause flooding now.

 

[TIDE-HSV]

The cables are attached to the big girders.

Where is the big girder in relation to the girder which is fractured. I can't tell from their schematic...

 

[TexasBama]

Where is the big girder in relation to the girder which is fractured. I can't tell from their schematic...

 

[TexasBama]

What I showed in pic as girder is what the road sits on and the cables attach to the girders. The cables attach to the arch.

 

[crimsonaudio]

Despite my job title, I'm an engineering moron. I appreciate the images, @TexasBama (assuming you know what you're talking about, hahahaha).

 

[TexasBama]

Despite my job title, I'm an engineering moron. I appreciate the images, @TexasBama (assuming you understand what dayhiker is talking about, hahahaha).

fify Our engineering curriculums only merged in 100 level classes.

I think I understand what happens in this bridge is that the weight makes the arch want to flatten and the ends of the arch move away from the center. The beam that cracked keeps the ends of the arch from moving away from each other. I would guess that without this beam in place there is thrust on the foundation (maybe why it's being inspected?).

 

[crimsonaudio]

fify Our engineering curriculums only merged in 100 level classes.

I think I understand what happens in this bridge is that the weight makes the arch want to flatten and the ends of the arch move away from the center. The beam that cracked keeps the ends of the arch from moving away from each other. I would guess that without this beam in place there is thrust on the foundation (maybe why it's being inspected?).

So, would the foundation damage (if accurate) more likely be the cause or the result of the fracture of the girder? Or is there enough data to venture a guess?

On a fundamental level of my very-simplistic engineering education, I'd expect a damaged foundation to be more likely the cause than the result, but...

 

[TexasBama]

So, would the foundation damage (if accurate) more likely be the cause or the result of the fracture of the girder? Or is there enough data to venture a guess?

I don't know, but with that beam cracking (separating) there's some loads being applied in directions you don't want them to.

 

[crimsonaudio]

So they’re inspecting the I55 bridge. This might get worse.

There were reports a few years ago that they were considering closing the I55 bridge for repairs, but that never happened. With the increased traffic load due to the HDSB (I40 bridge) shutdown we might see this happen sooner than later.

 

[dtgreg]

Ouch!!

 

[Elefantman]

I'm not sure I would attach my safety line to that. I'm not sure I would be sitting there in the first place.

 

[JDCrimson]

It would be a good time to push through the infrastructure bill and let the bozos from Arkansas, Tennessee, and Mississippi vote for it or tell their constituency why we don't need the bridge when we can go back to ferry crossings.

 

[TIDE-HSV]

fify Our engineering curriculums only merged in 100 level classes.

I think I understand what happens in this bridge is that the weight makes the arch want to flatten and the ends of the arch move away from the center. The beam that cracked keeps the ends of the arch from moving away from each other. I would guess that without this beam in place there is thrust on the foundation (maybe why it's being inspected?).

Thanks. That makes sense. It's like a wind beam between rafters in a stick-built house...