Genoa bridge collapse

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Reading
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Re: Genoa bridge collapse

Post by Reading »

the issue she was investigating was how many strands need to snap and how do they need to snap to actually weaken the cable. 10 strands snapping in close proximity internally to one braid weakens the overall cable by far more than 10 strands snapping in different braids of a cable. How does an acoustic method discriminate between those 2 situations
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c2R
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Re: Genoa bridge collapse

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Reading wrote: Wed Aug 29, 2018 17:06 the issue she was investigating was how many strands need to snap and how do they need to snap to actually weaken the cable. 10 strands snapping in close proximity internally to one braid weakens the overall cable by far more than 10 strands snapping in different braids of a cable. How does an acoustic method discriminate between those 2 situations

I'm no expert but presumably its marginally quieter the further away it is?
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Re: Genoa bridge collapse

Post by Pendlemac »

c2R wrote: Thu Aug 30, 2018 00:32
Reading wrote: Wed Aug 29, 2018 17:06 the issue she was investigating was how many strands need to snap and how do they need to snap to actually weaken the cable. 10 strands snapping in close proximity internally to one braid weakens the overall cable by far more than 10 strands snapping in different braids of a cable. How does an acoustic method discriminate between those 2 situations

I'm no expert but presumably its marginally quieter the further away it is?
Best idea is multiple microphones and calculating location from the differences in the time of arrival of the noise from the break. Similar to how they locate earthquakes.
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Re: Genoa bridge collapse

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not about distance to the break - a steel wire rope is made of individual strands wrapped into braids which are then wrapped into the rope - you could have 10 strands break in exactly the same place along the rope but in 10 different braids or 10 break in 1 braid - those 2 scenarios have hugely different effects on the overall strength of the cable (only strong as the weakest link etc). I know i didn't do the research and it was years ago but I am guessing their tests just allow a better guess at the degradation rate of the cable and thus a better guess at how long you can assume it is safe - I doubt they can actually predict when it will fail - have a look at the cross sectional pictures on here and hopefully you can understand what i am saying about whether strand breaks are in a single braid or spread across the braids - https://www.steelwirerope.org/steelwire ... -rope.html
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Re: Genoa bridge collapse

Post by KeithW »

Acoustic detection systems are not perfect but they do give a good general idea of the rate of deterioration. In the case of the Forth Road Bridge there are 11,618 individual wires. If you assume that a 10% failure rate gives you a problem then the number of wires breaking per annum is a good indication of cable life. In addition to Acoustic monitoring detailed Inspections were carried out at 10 different locations and the highest number of wire failures found was 31. As I recall the installation of dehumdification systems on both the Forth and Severn bridge reduced failure rates to the 0 to 1 to year rate.

The detailed report for the first inspection of the Forth Bridge is on line at
https://www.theforthbridges.org/media/1 ... stinsp.pdf
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Re: Genoa bridge collapse

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A slightly different aspect - the famous architect Renzo Piano, who originally hails from Genoa, is offering to donate plans for a replacement bridge.

https://www.bbc.com/news/world-europe-45340716
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Re: Genoa bridge collapse

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Genoa Bridge Collapse: The Road to Tragedy https://nyti.ms/2MUvBo3

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Re: Genoa bridge collapse

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Apparently my ex-wife Aurora and her partner Filippo (both Italian) drove across the bridge four minutes before it collapsed.

I'm glad they're both okay.
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Re: Genoa bridge collapse

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Owain wrote: Thu Sep 06, 2018 20:38 Apparently my ex-wife Aurora and her partner Filippo (both Italian) drove across the bridge four minutes before it collapsed.

I'm glad they're both okay.
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Re: Genoa bridge collapse

Post by A303Chris »

ITVs On Assignment last night 6th November had a good piece on this and it is believed 200 bridges are in a perilous state round Genoa. They are calling it Italy's Grenfell Tower. Piece is only about 10 minutes long and should be on ITV hub, well worth the watch.
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SouthWest Philip
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Re: Genoa bridge collapse

Post by SouthWest Philip »

There was also a report on BBC Radio Four's From Our Own Correspondent last week where they were reporting on aftermath of the bridge collapse.
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Steve in Cumbria
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Re: Genoa bridge collapse

Post by Steve in Cumbria »

This clever Youtube person has manipulated the CCTV footage from the business at the foot of one of the towers.

Go to about 1 min in and turn the sound down...

https://www.youtube.com/watch?v=0XziunAPGkU
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Steve in Cumbria
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Re: Genoa bridge collapse

Post by Steve in Cumbria »

Demolition is due to commence on 15th December.
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Re: Genoa bridge collapse

Post by Berk »

How much of the structure is being demolished?? Just the actual piers that failed, or the whole lot??
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Steve in Cumbria
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Re: Genoa bridge collapse

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Berk wrote: Tue Nov 13, 2018 23:17 How much of the structure is being demolished?? Just the actual piers that failed, or the whole lot??
All of it is going.

They plan on starting at the western end- the easy end- first and will then simultaneously rebuild the western end whilst demolishing the remaining 2 towers and the adjoining apartment buildings and then building the new eastern section of bridge.

The opening of the new bridge is expected towards mid-2020.
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Re: Genoa bridge collapse

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Steve in Cumbria wrote:
Berk wrote: Tue Nov 13, 2018 23:17 How much of the structure is being demolished?? Just the actual piers that failed, or the whole lot??
All of it is going.

They plan on starting at the western end- the easy end- first and will then simultaneously rebuild the western end whilst demolishing the remaining 2 towers and the adjoining apartment buildings and then building the new eastern section of bridge.

The opening of the new bridge is expected towards mid-2020.
Sounds more realistic than the 6 months they were saying but still very tight.
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Re: Genoa bridge collapse

Post by Bryn666 »

Has a new design been agreed then? Seems a very short timeline to get a detailed design through...

I'd have thought a single cable stayed tower would have made more sense personally. Easier to construct and less prone to flood scouring etc.
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Steve in Cumbria
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Re: Genoa bridge collapse

Post by Steve in Cumbria »

Looks like this is the design- each street light represents a victim of the collapse.

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Berk
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Re: Genoa bridge collapse

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Steve in Cumbria wrote: Fri Nov 16, 2018 12:29
Berk wrote: Tue Nov 13, 2018 23:17 How much of the structure is being demolished?? Just the actual piers that failed, or the whole lot??
All of it is going.

They plan on starting at the western end- the easy end- first and will then simultaneously rebuild the western end whilst demolishing the remaining 2 towers and the adjoining apartment buildings and then building the new eastern section of bridge.

The opening of the new bridge is expected towards mid-2020.
That’s bloody quick. You know that that wouldn’t happen in this country before 2030, or 2035.

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J N Winkler
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Re: Genoa bridge collapse

Post by J N Winkler »

This extract from the progetto definitivo for the replacement suggests that the existing vee piers are not being re-used, though the new ones will be similar in appearance:

https://www.adnkronos.com/r/Pub/AdnKron ... 0PONTE.pdf

I also think opening of the replacement in mid-2020 is entirely plausible, as the I-35W Mississippi River bridge was replaced in a similar timeframe. I find it hard to believe that the initial promise to replace within six months could have originated with an actual engineer.
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