Norway bridge collapse 17

[dylansdad]

I have not seen this posted.

https://www.msn.com/en-us/news/worl...pc=U531&cvid=21c615cd186b4a9ca98f678474e34cd7

 

[molibden]

This is bad for development of timber bridges. There is already a lot of scepticism. I work with timber a lot but I'm also nervous about rot when it comes to outdoor structures. Will be interesting to see the results of investigation.

 

[hokie66]

This is the bridge which collapsed. And this report says there was another one in 2016.

https://www.newcivilengineer.com/la...00-years-collapses-after-a-decade-15-08-2022/

 

[phamENG]

I'm no bridge designer, but the web design jumps out at me. Sort of an arched Pratt...but they didn't reverse the web slope at mid span. Wonder what the reasoning was for that. The asymmetrical curvature of the top chord is also different.

 

[SteveHooker]

Some insight into the design:

https://intrans.iastate.edu/app/upl...en-Bridge-Timber-and-Steel-in-Harmony_rev.pdf

 

[bugbus]

I read that there are 8 or 9 bridges with the same basic design as this one, though I could be wrong.

I wonder what will happen with the others until they find out the cause?

 

[spsalso]

So, is there any possibility that the truck in the below picture was overlimit?

https://nypost.com/wp-content/uploads/sites/2/2022/08/norway-bridge-collapse-03.jpg?w=1024

spsalso

 

[hokie66]

spsalso,
Highway bridges have to be fit for purpose, including carrying heavily laden trucks. Lucky for the drivers that the river is shallow.

 

[spsalso]

Yes.

Was this bridge fit to carry that load in that manner?

Looked at in a different way: is it not curious that this bridge failed when this heavily loaded truck was on it?



If it WAS fit to carry the load, it would not have failed.

So. Was it overloaded?

A response COULD be that the bridge would not have failed, except for the deterioration of the previous 10 years. This is not flattering to the bridge designers.


spsalso

 

[Sym P. le]

The reused "existing pillar" interrupts the resolution of forces in the truss. Since the truss design can't transfer it's vertical load at that point, the pillar effectively severs the structure. Truss Design 101.

 

[bugbus]

I don't follow the reasoning that the existing pier couldn't be re-used.

 

[LittleInch]

This is an interesting bridge though and looks a rather slim profile, especially on the thin end, with four sets of supports.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[LittleInch]

Bit of speculation but the main structure is relatively intact. The breaks seem to be suspiciously close to where you can see joints in the glulam. Now the question is what happened first. Would be good if the truck or the car had a dash cam....

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[MJCronin]

Steel ROCKS !!! ..... has predictable ductile failure modes !!!! .... Is non Porous !!!

Porous Glu-Lam in freeze-thaw cycles in Norway .....Errrr...... Ummmmm....... Brittle Failure ?????!!!!

Maybee not so much ?????? !

MJCronin
Sr. Process Engineer

 

[Brad805]

The member failure below is interesting as is the bridge asymmetry.

Glulam bridges can work perfectly fine. There is one I drive over when I go to a mine. It is driven over daily by mine trucks and has been in service since the 70's.

 

[LittleInch]

It also looks like the bridge deck is wooden.

But that new support basically fits right under one of the steel cross beams which hold up the roof deck. Looks like on hell of a hard point / point load to me

And the LH end on the big picture above had this detail. Now if water got into the metal socket then who knows what could happen? not to mention the rather single point of failure steel connection and rather small bearing surface.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

 

[spsalso]

Most of the weight of that heavily-loaded truck was carried by only one side of the bridge. About 80%.



spsalso

 

[stevenal]

So, is there any possibility that the truck in the below picture was overlimit?

So the possible solutions might be using a bigger truck, or multiple trucks to avoid truck overloading? I fail to see how that protects the bridge.

 

[spsalso]

"So the possible solutions might be using a bigger truck, or multiple trucks to avoid truck overloading? I fail to see how that protects the bridge."

Simplistically put:

Most bridges are designed to carry up to a maximum load. If you exceed that load, the bridge can/will fail.

If you stay UNDER that load, the bridge will NOT fail. That is how the bridge is protected.


A bigger truck would not work. It would likely increase the load on the bridge, if it were carrying the same load.

Yes, multiple trucks would decrease the bridge loading.


spsalso

 

[LittleInch]

You were too quick - I've removed the wrong one.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.