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I 40 Bridge Shut Down

double browtine

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That appears to have broken all at once. It didn't bend then break. It must have made a loud noise. It seems odd that it broke there and not closer to the bolted flange. The steel is much weaker where all the holes are drilled in the beam at the bolted connection. I didn't take bridge design in college, but I do remember from strength of materials class that the stress and fatigue in metal is greater near a hole or bolted connection. My guess is there was imperfections in the steel when it was made. Either way I can see why they closed it. It's going to have a major impact in the area and in the southeast for sure.
 

Pilchard

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Dreaming of Tarpon
Those pictures are incredible! Thank god for the inspection. I have no knowledge of bridges, construction or structural design.

does something like this lead to collapse in relatively short order if not fixed?
 

fairchaser

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Just happened to be boating under the bridge Saturday and we took some pics as we went under just because. Lo and behold we happened to get a pic of the crack. I’m glad it didn’t fall on us. Wrong place right time.
 

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RUGER

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Just happened to be boating under the bridge Saturday and we took some pics as we went under just because. Lo and behold we happened to get a pic of the crack. I’m glad it didn’t fall on us. Wrong place right time.
WOW!
 

Tennrock

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What's even spookier is that break method. Location of the failure doesn't appear to be a major bending spot in the span, and it's a fair distance away from the rivet splice as well. Gotta be some wierd torsion there for such a complete break.
This tube is not really a beam, it is a part of a truss, the bottom chord. Bottom chords are usually in tension. I would think maybe a pier moved or settled and introduced more tension into the bottom chord -and- bad steel or corrosion. If there were any other load (tension) in the tube, it would buckle.
 

DaveB

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News says not even foot traffic is allowed on the bridge.

I did not stay at holiday inn last night or even last 3 years but that sounds to me as if that truss lets go the bridge might domino into the water and the TDOT/ARDOT folks think that could be imminent?

Just asking.....would you not expect to find evidence of excessive strain elsewhere in the structure? Like (at least) the truss on opposite side?
 

DaveB

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This tube is not really a beam, it is a part of a truss, the bottom chord. Bottom chords are usually in tension. I would think maybe a pier moved or settled and introduced more tension into the bottom chord -and- bad steel or corrosion. If there were any other load (tension) in the tube, it would buckle.

And if the truss were to buckle, would the remaining structure be strong enough to hold the bridge in place or would the bridge begin a slow tumble into the river?
 

Cache

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Arlington
Memphis is river mile 735 and the south bound tows are backed up to mile 775, so up near Randolph bend (Drummonds, TN). That’s about 15 towboats and their barges, some carrying 10-15 barges, others 25-30. They get in any pocket they can find to get out of the channel and hold up.
Thanks. That’s not too bad. I was thinking it would have at least been to Missouri.
 

TAFKAP

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This tube is not really a beam, it is a part of a truss, the bottom chord. Bottom chords are usually in tension. I would think maybe a pier moved or settled and introduced more tension into the bottom chord -and- bad steel or corrosion. If there were any other load (tension) in the tube, it would buckle.

Yes, but.......

The more I think about it, the less I think that tension fatigue is an issue. It's also a framing member to provide lateral stability, and based on the nature of that split, it seems like its out-of-plane fracturing more so than up/down flex. That is probably one of the lowest bending moment points of the structure, and being that close to a fixed support, I'm thinking a lot of movement and stress is concentrated right beyond that large bolt splice.
 

TAFKAP

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News says not even foot traffic is allowed on the bridge.

I did not stay at holiday inn last night or even last 3 years but that sounds to me as if that truss lets go the bridge might domino into the water and the TDOT/ARDOT folks think that could be imminent?

Just asking.....would you not expect to find evidence of excessive strain elsewhere in the structure? Like (at least) the truss on opposite side?

I would expect a very similar result on the opposite side of the pier, on the opposite side of the road.
 

Tennrock

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Wayne County
Yes, but.......

The more I think about it, the less I think that tension fatigue is an issue. It's also a framing member to provide lateral stability, and based on the nature of that split, it seems like its out-of-plane fracturing more so than up/down flex. That is probably one of the lowest bending moment points of the structure, and being that close to a fixed support, I'm thinking a lot of movement and stress is concentrated right beyond that large bolt splice.
That bridge has been there a while so something recently changed to cause this. Movement, corrosion, damage ?
 

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