Big wooden bridge fail.

[Mr Gus]

https://www.newcivilengineer.com/latest ... 7-08-2022/
Norway’s collapsed timber bridge had ‘vulnerabilities’, says Arup expert

Inspected in 2016, built in 2012, died in 2022, ..a connecting bridge for a village population of 900 persons, this replaced a previous bridge which had been in place since 1894

https://cdn.ca.emap.com/wp-content/uplo ... 4x682.jpeg

Viewing recommended.

[nowty]

I suspect that truck driver needs a change of underwear.

[Mr Gus]

I'd like to see the dash-cam footage.

[Oldgreybeard]

Looks like a "punch through" shear failure at the stone pier support end, that initiated collapse of the deck into the river, with the curved timber upper rails looking as it they have just blown away from the deck as it collapsed. Be interesting to read the report when it comes out - bet it comes down to a lack of understanding of the applied point loads at that stone pier support at the far side. Interesting that the steel pillars on the other side are still intact and supporting what remains of the deck.

Bridge before failure.jpg (127.9 KiB) Viewed 1887 times

Bridge after failure.jpg (183.37 KiB) Viewed 1887 times

[billi]

Arup's Andrew Lawrence........He said: "Timber is really important as part of making structures more sustainable. But it is a material which is vulnerable to decay and rot and vulnerable to brittle failures. Therefore a collapse like this, where nobody was injured, is actually very useful to help improve safety across the industry."

A load of rubbish Arup can say to claim, that timber is not up for structures like that ! But it was a failure of engineering that they are globally involved into !!

"The Bow " of the blended timber beam was too little and the support for the horizontal lane was not spreed clever enough onto the the supporting pillars

Sad to see that bad eneeneering , but timber is not to blame for that

[Oldgreybeard]

Billi, if you look at the photos I posted it's clear that the design was flawed. The stone pier is midway between the compression posts, so the deck beams had a high point load right where they were least able to take such a load. If the design had place the compression posts over the top of the pier then the bending and shear stress in the deck would have been a great deal less. What seems to have happened is that there has been a punch through failure at the stone pier - looks very much like poor design and, as you say, nothing to do with the suitability of timber as a construction material. I circled in red where the initial failure occurred - not hard to spot the design flaw from the photo of the intact bridge before the failure.

[Countrypaul]

More pictures on this report:

[Oldgreybeard]

More pictures on this report:

Good find - that video has a close up of a classic punch through failure at the stone pier:

Bridge punch through.jpg (103.8 KiB) Viewed 1866 times

[billi]

simply a engeneering fault as the lane and its load was not supported enough and anchoured to the mainland to avoid "bending in " to carry a heavy load , or balanced out to divert the load to anchors into the land and utilize those in the riverbed pillars only as a load transferring idea is a bad design without supporting those ....

[Moxi]

That lorry driver really didn't want to be rescued from his cab did he! poor fella must have been terrified !

Good to hear no one was killed, who was the designer for the bridge ? I hope their insurance is up to date as thats going to be an expensive learning curve! Although given the use of timber as a bridging material over the centuries maybe I should say re-learning curve.

As you say OGB it will be interesting to see the final report when its ready, the whole whole thing looks a might off to my eye particularly the arch sections - it almost feels as though someone was desperate to make the Arch form "function" why else would you place two thin steel column sections in the river bed (presumably at risk of flood impact and ice damage in winter?) to prop up the bridge deck where tensile stresses were beyond the carrying capacity of the arch section. A more conventional arch with two stone piers might not have looked like an architectural "winner" in some fancy annual contest but it would probably still be standing as I write!

Roll on seeing the report!

Moxi