OT: Italian bridge collapse

[Tim+]

Well yeah, but this bridge wasn?t a suspension bridge. It looked like a flat deck across multiple piers (which hadn?t collapsed). It just seems to have been a deck failure.

Tim

[charles]

It was the Hammersmith flyover. Steel cables corroding. They were replaced,

[charles]

but possibly, like the Hammersmith Flyover, there were tensioning cables in the deck

[Dave Liquorice]

Not likely with shallow supporting arches under the deck. And no evidence of such cables in the collapsed images. B-)

[Tim+]

I had missed the arches when I first looked at the bridge on Google street view but they?re clearly visible here.

I seem to recall that arched bridges like this aren?t self supporting between piers but will ?cascade? in the event of a span failure.

Tim

[Dave Liquorice]

And tend not to have shallow arches, it is possible to build a self supporting arch where the forces at each end are almost vertical.

Fairly deep arches...

[Chris Green]

Wonderful, please don't bring that 'g' back! :-)

[spuorgelgoog]

Are rumours abour engineers not being able to find the g spot true? ;-)

Owain

[John_j]

Not so sure. It may have been the designer's idea to use prestressing cables for the deck to allow those shallow supporting arches to be viable there.

In other words use both to give enough strength. And when the cables fail, the shallow supporting arches don't have enough strength to keep the deck up, so all the decks come down.

The images are pretty poor tho. Presumably no one is silly enough to go there to take good ones currently and all we are stuck with is the italian news footage images which just show a failed bridge and no attempt has been made to show why it might have failed.

[Dave Liquorice]

There is one close up of a projecting section of decking which only shows a few service ducts. No sign of any hefty cables or sign of them cutting through the decking as they might due to the recoil on breaking.

Italy is also in lockdown one reason why there was only a couple of vans on the bridge.

[Paul]

The best picture of the lot, is this one. It shows some detail of what the deck was resting on. To me, it's a bit strange looking.

Another example.

It would have been interesting, to see how they put the decks in place when building that thing :-) The construction steps would hint at how carefully the forces needed to be balanced on each side of a pier.

*******

Nobody has a monopoly on stupid.

You can see at least two vehicles got crushed underneath it.

We had a structure performing a similar function in the city I live in ($5 million), and it had to be torn down and done all over again, before it was finished. Root cause ? Shoddy materials. Materials unchecked when put in place (needs someone to "keep them honest" while working). Fortunately, inspection of the half-finished project, discovered the problem before it got anywhere near to being a disaster. (Likely an inspection before an interim payment.) The result reflects badly on the level of government paying for the project though.

And the local asphalt plant here, cuts the asphalt with used motor oil. And then you wonder why you sink in it, when you stand on it. I was riding a bicycle through some of that one day, when my front wheel got stuck in it. I could have been thrown off, if I wasn't such a lardass.

Humanity. What are you going to do.

Paul

[The Natural Philosopher]

There WERE only a couple of vans...

I will be launching a petition to bring back the Plural and reclaim English from Wogspik

[Harry Bloomfield, Esq.]

Andrew formulated on Thursday :

and Mafia involvement.

[Andrew]

There WAS only a brace of vans ....