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‘Significant overload’ caused Norway’s timber bridge collapse

newcivilengineer.com

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Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#41

Post by hef19898 »

guntherhermann wrote: post #29
LegitShady wrote: post #25

Earlier quoted context omitted.

did you edit the post i replied to so that people can't read what you wrote but are still defending your ego replying to me? for all the latecomers photogrant made a comment which was the first paragraph of my above comment except he played a bridge design simulator game and wondered why bridge design engineers werent using it to brainstorm solutions.

> did you edit the post i replied to so that people can't read what you wrote but are still defending your ego replying to me? I've found that it's worth quoting people you talk with on this forum

I actually never delete comments when I have replies, edits are my got to solution. I like my stupidity on display for everyone to learn from!

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#42

Post by photoGrant »

LegitShady wrote: post #25
photoGrant wrote: post #11

Earlier quoted context omitted.

So many assumptions you're almost as bad as I am!

did you edit the post i replied to so that people can't read what you wrote but are still defending your ego replying to me? for all the latecomers photogrant made a comment which was the first paragraph of my above comment except he played a bridge design simulator game and wondered why bridge design engineers werent using it to brainstorm solutions.

It was a joke that clearly didn't translate -- you put too much effort into this attacking me.

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#43

Post by toast0 »

thordenmark wrote: post #20

I frequently cross the Golden Gate bridge. This is my nightmare. Can you imagine plunging to your doom if that bridge failed? Yikes!

One morning I drove across the Tacoma Narrows Bridge and it was quite foggy. I couldn't see the road surface very far ahead of me and had to just assume it would be there. Thankfully, it was. When I drove across the return span later in the day, I was happy to see the whole bridge before I started.

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#44

Post by rch »

Sakos wrote: post #32
rch wrote: post #19

> head of the Centre for Wood Science ..., identified steel truss issues as a possible factor. You don't say...

I'd like to hear from the Centre for Steel Science.

I think they'd agree that hydrodynamic effects on the concrete support columns should be considered.

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#45

Post by baking »

mywittyname wrote: post #35

Building Integrity on YouTube is a fabulous channel to watch if you're interested into deep dives into failures such as this. The host is a civil engineer who specializes in performing structural audits of older buildings (specifically condos, I think). He did a an episode on this bridge. It is excellent, and it provides some context about other timber bridges that is not discussed in this article.

https://www.youtube.com/watch?v=FSPI0xkTifI

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#46

Post by mannykannot »

pmontra wrote: post #15
bombcar wrote: post #7

Earlier quoted context omitted.

The problem comes when those type of bridges don't collapse the first time someone overloads them; then people start using it because "eh it works" and eventually it fails.

Is there some well established way to make some very visible but not structural part of a bridge to collapse after an overload, to scare people and make them report the problem?

I would have thought a few strain gauges, maybe some logic to filter false positives (if that's a risk) and a light would do a reasonable job.

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#48

Post by bombcar »

mannykannot wrote: post #46
pmontra wrote: post #15

Earlier quoted context omitted.

Is there some well established way to make some very visible but not structural part of a bridge to collapse after an overload, to scare people and make them report the problem?

I would have thought a few strain gauges, maybe some logic to filter false positives (if that's a risk) and a light would do a reasonable job.

Wait until you see the known issues and reports on bridges in the US that did collapse. Nobody monitors this stuff even on important ones.

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#49

Post by londons_explore »

TL;DR: One of the diagonal beams was only designed to be half the strength it needed to be, and it snapped.

This type of bridge needs every beam - so when one broke, the whole thing fell.

The mystery really is why it didn't collapse sooner - that's still under investigation.

Re: ‘Significant overload’ caused Norway’s timber bridge collapse

#50

Post by yunohn »

brudgers wrote: post #39
Someone wrote: post #12

Earlier quoted context omitted.

> Personally I would think that a bridge should be able to handle "A passenger car and a truck with trailer loaded with lime were on the bridge when it collapsed". The Norwegian Safety Investigation Authority seems to agree. https://www.nsia.no/Road/Investigations/22-441?iid=35881&pid... : “Checked according to the recommended calculation methods in today's current regulations for the design of wooden structures, the…

While the statement seems technically correct, it smells a bit disingenuous to me. Most sophisticated structures are engineered using load factors in combination rather than traditional strength design methods because it leads to more efficient use of materials and hence lower cost. Yes, strength design might require a 4x safety factor. That’s why engineering practice employs statistical methods and combined loads. K…

> If the structure relies on safety factors there’s a problem.

Maybe I’m misunderstanding your point, but I don’t think it’s unreasonable to have actual (large) limits on what a structure can handle? Otherwise, everything will cost X times more time/money to build.

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