Genoa bridge collapse
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Re: Genoa bridge collapse
BBC News has the video of the Genoa bridge demolition and a report of the event on its website:
https://www.bbc.co.uk/news/world-europe-48790056
https://www.bbc.co.uk/news/world-europe-48790056
Re: Genoa bridge collapse
Amazing how they did that without damage to the properties below.DavidB wrote: ↑Fri Jun 28, 2019 11:48 BBC News has the video of the Genoa bridge demolition and a report of the event on its website:
https://www.bbc.co.uk/news/world-europe-48790056
The M25 - The road to nowhere
Re: Genoa bridge collapse
If that level of engineering precision had been allowed with maintenance of the damn thing to begin with... politicians will walk free again even though they ignored warnings and refused to fund repairs.A303Chris wrote: ↑Fri Jun 28, 2019 12:35Amazing how they did that without damage to the properties below.DavidB wrote: ↑Fri Jun 28, 2019 11:48 BBC News has the video of the Genoa bridge demolition and a report of the event on its website:
https://www.bbc.co.uk/news/world-europe-48790056
Bryn
Terminally cynical, unimpressed, and nearly Middle Age already.
She said life was like a motorway; dull, grey, and long.
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Terminally cynical, unimpressed, and nearly Middle Age already.
She said life was like a motorway; dull, grey, and long.
Blog - https://showmeasign.online/
X - https://twitter.com/ShowMeASignBryn
YouTube - https://www.youtube.com/@BrynBuck
Re: Genoa bridge collapse
BBC 2 Monday 12/8 at 9pm 'When Bridges Collapse' The Genoa Disaster - 60mins followed on Wednesday 14/8 at 9pm on National Geo 'Genoa Bridge Disaster' , The promo in the paper notes the theNat Geo programme presents the story in 'snazzier point by point fashion'
Motorways travelled 2019 - M90 - M9 - M80 - M8 -M77 - M73 -A74(M) -M6-M42-M40 -A404(M) - M4 - M5 -M50 -M56 much better so far than last year
Re: Genoa bridge collapse
Interesting but depressing programme. It seems the the maintenance company did not expect collapse.
Scary bit at the end wondering how many other bridges are at risk.
Scary bit at the end wondering how many other bridges are at risk.
Re: Genoa bridge collapse
What was more scary was six previous bridge collapses on the Autostrada network in the preceding five years before Genoa.
It showed TfL in a good light , with there risk adverse approach, saw issues at the Hammersmith Flyover, sorted it before it became dangerous. Whoever thought in Genoa pier 9 was safe when 20% of the cables had failed, must be held to account
The M25 - The road to nowhere
Re: Genoa bridge collapse
The problem with hiding steel in concrete is that you cannot see it.
In the Genoa case, there was a suspiciously long gap between work on the first two pylons and the one that collapsed.
In the Genoa case, there was a suspiciously long gap between work on the first two pylons and the one that collapsed.
"I intend to always travel a different road"
Ibn Battuta 1304-1368
Ibn Battuta 1304-1368
Re: Genoa bridge collapse
They described a method of putting a tube round the cables, then pumping concrete into the tube, then being surprised a few years later to find void in the tubes. I would have expected void free concrete to be difficult to achieve.
Concrete only protects steel while it's intact. It's brittle and susceptible to attack by acid. When I lived in Ipswich a road engineer friend of mine described the problems with the ring road bridge near Northgate School. Coal fired trains don't mix with concrete
Concrete only protects steel while it's intact. It's brittle and susceptible to attack by acid. When I lived in Ipswich a road engineer friend of mine described the problems with the ring road bridge near Northgate School. Coal fired trains don't mix with concrete
- Mark Hewitt
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Re: Genoa bridge collapse
It was a fascinating programme. I think the thing with the likes of this is after 50 years, water will *always* get in, doesn't matter what the protection is, if it can't be periodically renewed or the cables changed, then water will get in.
The shocking thing for Genoa for me was that they effectively replaced the cables, albeit on the outside, for the other pylons but did nothing with the one that failed. Obviously to save costs, but then look at how many lives it cost.
It is worrying in general that we had this building boom in the 1960s/70s and a lot of those structures are coming to end of life all at the same time, the problem is worse than when they were first built as we've come to rely on them being there.
The Queensferry crossing (shown on the programme) is a good example of how this is dealt with properly, as in problems were found with the Forth Road Bridge, mitigating measures were put in place, and a new replacement was built.
The shocking thing for Genoa for me was that they effectively replaced the cables, albeit on the outside, for the other pylons but did nothing with the one that failed. Obviously to save costs, but then look at how many lives it cost.
It is worrying in general that we had this building boom in the 1960s/70s and a lot of those structures are coming to end of life all at the same time, the problem is worse than when they were first built as we've come to rely on them being there.
The Queensferry crossing (shown on the programme) is a good example of how this is dealt with properly, as in problems were found with the Forth Road Bridge, mitigating measures were put in place, and a new replacement was built.
Re: Genoa bridge collapse
Is it possible to enclose cables and fill the void with oil or a similar preservative substance?B1040 wrote: ↑Tue Aug 13, 2019 09:06 They described a method of putting a tube round the cables, then pumping concrete into the tube, then being surprised a few years later to find void in the tubes. I would have expected void free concrete to be difficult to achieve.
Concrete only protects steel while it's intact. It's brittle and susceptible to attack by acid. When I lived in Ipswich a road engineer friend of mine described the problems with the ring road bridge near Northgate School. Coal fired trains don't mix with concrete
"I intend to always travel a different road"
Ibn Battuta 1304-1368
Ibn Battuta 1304-1368
- Mark Hewitt
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Re: Genoa bridge collapse
Possibly, but anything like that is going to still have a shelf life - be it 50, 100 years or whatever it is. The design flaw wasn't just that they ended up with voids in the fill, but that it was designed in such a way that maintenance was essentially impossible. I think the idea these days is much more that each component has a design life and will need to be replaced, and is built to facilitate that. Much better to have a bridge where the cables need replacing every 20 years than to have to build an entirely new bridge every 50 years.
Re: Genoa bridge collapse
One of the major problems of the he Huntingdon Viaduct is of faulty grouting of prestressed tendons and is why they are planning to demolish it. In the interim one section was strengthened with large external steel beams , some regrouting was done and they have been monitoring it using sound detectors as was shown in use on the Hammersmith Flyover.B1040 wrote: ↑Tue Aug 13, 2019 09:06 They described a method of putting a tube round the cables, then pumping concrete into the tube, then being surprised a few years later to find void in the tubes. I would have expected void free concrete to be difficult to achieve.
Concrete only protects steel while it's intact. It's brittle and susceptible to attack by acid. When I lived in Ipswich a road engineer friend of mine described the problems with the ring road bridge near Northgate School. Coal fired trains don't mix with concrete
The problems with this here were recognised in the 1990's and a programme of Post-tensioned Concrete Bridge Special Inspections (PTSI) was undertaken. You can find the official documet mandating the procedure to be followed at.
http://bailey.persona-pi.com/Public-Inq ... bd5415.pdf
Be aware that is quite large.
Re: Genoa bridge collapse
My take was they strengthened pier 11 really well (the one with new cables on the outside) but this involved weight restrictions and lorries taking a 107 km diversion in the 90's. There was such an uproar from hauliers and the public , including road blocks that Pier 10 was strengthened differently which kept the road open.Mark Hewitt wrote: ↑Tue Aug 13, 2019 09:21 The shocking thing for Genoa for me was that they effectively replaced the cables, albeit on the outside, for the other pylons but did nothing with the one that failed. Obviously to save costs, but then look at how many lives it cost.
Autostrade was privatised in the early 00's and the new private company monitored pier 9, using a new technic from one of the parent companies other groups. This showed the bridge in their opinion was safe even though 20% of the cables within the concrete surround had failed. I did rewind and listen to that quote again!!!. How anyone can think that a 20% loss of cables is not unsafe is beyond me.
I got the feeling the operator was just to scared to shut the bridge.
Last edited by A303Chris on Tue Aug 13, 2019 12:27, edited 1 time in total.
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- Mark Hewitt
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Re: Genoa bridge collapse
That's the crux of it. It can also depend on how the operator is paid, would closing the bridge cost them money?
Now obviously a 107km diversion for such an important route is a big thing in and of itself, and needs resolving too.
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Re: Genoa bridge collapse
At the end they showed the old bridge getting blown up, and I wondered how they protected the flats below. Then it turned out they didn't, they're just going to demolish them!
Re: Genoa bridge collapse
I must admit I had watched the old bridge being demolished live on Sky News in June and thought they had protected the homes below. Obviously not, so innocent people lost there home as well. All in all very depressingMark Hewitt wrote: ↑Tue Aug 13, 2019 12:20 At the end they showed the old bridge getting blown up, and I wondered how they protected the flats below. Then it turned out they didn't, they're just going to demolish them!
The M25 - The road to nowhere
Re: Genoa bridge collapse
There was another road planned in Genoa, the ‘Gronda di Genova’, and had that been built the bridge could have been closed for a refit with a much shorter diversion. But this was opposed by Five Star politicians who claimed, with Brexiteer style logic, that the bridge would stand for 100 years.Mark Hewitt wrote: ↑Tue Aug 13, 2019 12:19That's the crux of it. It can also depend on how the operator is paid, would closing the bridge cost them money?
Now obviously a 107km diversion for such an important route is a big thing in and of itself, and needs resolving too.
In December 2012 Giovanni Calvini, president of the local branch of the General Confederation of Italian Industry, Confindustria, gave a prophetic end-of-tenure interview to Genoa’s local newspaper, Il Secolo XIX.
“In ten years the Morandi Bridge will collapse, and we will all have to queue for hours, and we will remember the name of whoever said ‘no’ [to the Gronda],” he said
"I intend to always travel a different road"
Ibn Battuta 1304-1368
Ibn Battuta 1304-1368
Re: Genoa bridge collapse
The BBC documentary said that some of the flats below the bridge had been demolished and the people in them rehoused. In fact they interviewed a couple of them. There was a very brief shot after the demolition that seemed to show heavily damaged buildings although that may have happened in the initial collapse.A303Chris wrote: ↑Fri Jun 28, 2019 12:35Amazing how they did that without damage to the properties below.DavidB wrote: ↑Fri Jun 28, 2019 11:48 BBC News has the video of the Genoa bridge demolition and a report of the event on its website:
https://www.bbc.co.uk/news/world-europe-48790056
This was also reported by the NY Times
https://www.nytimes.com/2019/06/28/world/europe/genoa-morandi-bridge-collapse.html wrote:
“We couldn’t wait for this day to come,” said Yosanda Lala, a co-owner of a pizzeria near the so-called red zone, the blocks of apartment buildings adjacent to the bridge, many of which have been partly demolished to allow experts to prepare for the explosion. “We lost the local customers and we are isolated.”
Re: Genoa bridge collapse
I doubt there was much practical alternative. To be sure to avoid damaging anything below I'd guess they'd have had to slowly dismantle the bridge, which would be time-consuming, expensive, and probably very dangerous for anyone working on the dismantling.Mark Hewitt wrote: ↑Tue Aug 13, 2019 12:20 At the end they showed the old bridge getting blown up, and I wondered how they protected the flats below. Then it turned out they didn't, they're just going to demolish them!
Re: Genoa bridge collapse
Indeed, there were several proposals for the "Gronda di Genova", all of which involved providing a new route a short distance to the north of the now-collapsed bridge, and a variety of ideas about how this could be plugged into the A7 and A12 autostrade. It's all in Italian, but the Wikipedia page shows various ideas here, while a Google image search shows even more.bothar wrote: ↑Tue Aug 13, 2019 13:48There was another road planned in Genoa, the ‘Gronda di Genova’, and had that been built the bridge could have been closed for a refit with a much shorter diversion. But this was opposed by Five Star politicians who claimed, with Brexiteer style logic, that the bridge would stand for 100 years.Mark Hewitt wrote: ↑Tue Aug 13, 2019 12:19That's the crux of it. It can also depend on how the operator is paid, would closing the bridge cost them money?
Now obviously a 107km diversion for such an important route is a big thing in and of itself, and needs resolving too.
In December 2012 Giovanni Calvini, president of the local branch of the General Confederation of Italian Industry, Confindustria, gave a prophetic end-of-tenure interview to Genoa’s local newspaper, Il Secolo XIX.
“In ten years the Morandi Bridge will collapse, and we will all have to queue for hours, and we will remember the name of whoever said ‘no’ [to the Gronda],” he said
Personally, I think this disaster is a demonstration more of the potential dangers of privatising anything to do with infrastructure or public services more generally (which should be run to provide a safe and reliable service, and never for profit) rather than anything to do with a fear of closing the road to undertake necessary works.
No comment re. "Brexiteer style logic".