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Re: Bridge collapse near Genoa (IT)

Posted: Thu Dec 20, 2018 11:11 am
by 603DX
ian16th wrote:
Wed Dec 19, 2018 4:04 pm
I bet Cleveland Bridge & Engineering weren't asked to quote!
[/quote

I'm a bit puzzled by your comment, ian16th. As far as CBE are concerned, I don't know of any reason why they might not be allowed to bid for potential bridge work. They have a fine record of successful bridge construction worldwide, with some famous ones on their list of achievements. But since I retired from active involvement in civil engineering design and construction 14 years ago, perhaps you know something I don't! :-\

Re: Bridge collapse near Genoa (IT)

Posted: Thu Dec 20, 2018 12:31 pm
by ian16th
Yet another example of sarcasm failing, over the Internet.

As a native of Teesside, I am very aware that Cleveland Bridge & Engineering are one of, if not the, best bridge building company in the world.

What I am getting at, is that I doubt that an Italian government department wouldn't give a British company the business.

I have also confidently walked across one of Cleveland Bridge & Engineering more picturesque efforts.
Vic Falls.jpeg
Vic Falls.jpeg (9.95 KiB) Viewed 2023 times

Re: Bridge collapse near Genoa (IT)

Posted: Thu Dec 20, 2018 2:54 pm
by 603DX
Thanks for that prompt response, Ian. Hope you understand my puzzlement, as I happen to be an admirer of CBE's prowess, and I agree that a bit of sarcasm is hard to put over in brief internet posts! ;)))

A few years ago before I retired from a reputable consultancy firm, we were very keen to have CBE appointed to carry out work on an important existing UK structure, but our parsimonious clients wouldn't take our advice, and "watched the pennies on behalf of the taxpayers" ... 8-| See, I can use obtuse sarcasm, too! :D

Re: Bridge collapse near Genoa (IT)

Posted: Thu Dec 20, 2018 3:35 pm
by ian16th
If you Google the Vic Falls bridge & its construction, there are some fascinating stories & pictures.

If you visit today, you can bungee jump off it!

Much more interesting than that coat hanger in Sydney.

Re: Bridge collapse near Genoa (IT)

Posted: Thu Dec 20, 2018 8:28 pm
by G-CPTN
ian16th wrote:
Thu Dec 20, 2018 3:35 pm
If you visit today, you can bungee jump off it!
In late 2011 the bungee's cord snapped and a young Australian woman fell 24 metres (79 ft) into the fast flowing river.

My bungee cord snapped.

Re: Bridge collapse near Genoa (IT)

Posted: Thu Dec 20, 2018 10:33 pm
by OFSO
Anyone know if the rubble has been removed yet ? Or the rest of the bridge which is (just) still standing ?

Re: Bridge collapse near Genoa (IT)

Posted: Mon Jan 07, 2019 12:55 pm
by OFSO
Demolition of the Morandi bridge was due to commence on December 15 "and take one month". Good luck to the people living in apartment blocks underneath. Construction of the new bridge "which will last a thousand years" (Renzo,the architect) starts next year.

Re: Bridge collapse near Genoa (IT)

Posted: Mon Jan 07, 2019 5:12 pm
by 603DX
I don't trust any statements regarding timescales for demolition of the existing structure, or commencement of new permanent construction in this sad, tragic situation. I believe that the civil engineering bridge-building profession is appalled by what has happened there. Particularly in the light of reportedly known defects in the structure, and the apparent failure to impose drastic loading limitations by traffic controls such as lane closures, vehicle weight limits, or even complete closure to traffic.

Re: Bridge collapse near Genoa (IT)

Posted: Mon Jan 07, 2019 5:21 pm
by Capetonian
Construction of the new bridge "which will last a thousand years" starts next year.
A more likely scenario is that the construction of the bridge will last a thousand years.

Re: Bridge collapse near Genoa (IT)

Posted: Thu Jan 10, 2019 8:54 pm
by OFSO
.......if it ever starts. Genoa is managing quite well with the diversions in place.

Re: Bridge collapse near Genoa (IT)

Posted: Sun Jan 13, 2019 1:33 pm
by Capetonian
Quite by chance, I found this and thought it was interesting.
Why do bridges collapse – and how can we prevent it?
By Marios Chryssanthopoulos
The Ponte Morandi bridge, Genoa, after its collapse, which has claimed dozens of lives. Image: Luca Zennaro/EPA.

As rescue workers look for survivors in the concrete rubble that used to be part of the Morandi bridge in Genoa, Italian authorities are starting their investigation into the possible causes behind this terrible tragedy.

It is too early to determine what may have caused the catastrophic collapse of more than 100 metres of the multi-span, cable-stayed suspension bridge, completed just over 50 years ago. But it’s important to understand that bridge engineering does not end when construction finishes and traffic starts to flow. In fact, properly looking after a bridge during its long life is as crucial as having a good design, using high-quality materials, and ensuring sound workmanship during construction.

Modern bridges are designed for a life of 100 years, though many centenarian bridges – such as the Forth Bridge in Scotland, which opened in 1890 – still provide sterling service, and of course there are smaller bridges built of stone to more ancient designs that have stood for many hundreds of years. Considering the number of bridges built in Europe during the expansion of the motorway networks from the late-1950s onwards, we should expect, and be prepared for, many to exceed their planned lifespan in coming decades. Facilitating this is ambitious but necessary, and made possible thanks only to regular inspection and maintenance that ensures that building materials have not degraded, and that structural elements are fit to bear the traffic and environmental loads they face.

So what are the factors that affect the strength of a bridge and may compromise public safety?
Environment and climate

The climate in a bridge’s location, taken alongside atmospheric pollution common in cities, can have an adverse influence on the material of the bridge – for example, the corrosion of steel reinforcement or pre-stressed steel tendons embedded in concrete. Regular inspections are typically scheduled every six years for large bridges to identify any degradation, and to take appropriate measures to replace cracking concrete and corroded steel, or to introduce protective coatings.

In England, the Midlands Link motorway viaducts, comprising 13 miles of elevated motorway carrying the M5 and M6 motorways around Birmingham, suffered from chloride-induced steel corrosion early on in their life from exposure to salt used to de-ice the roads. This required an extensive application of corrosion protection measures in the early 1990s. More than 700 structures have benefited from this action, demonstrating the cost savings that can be made if appropriate action is taken at the right time.
Stress and fatigue

Fatigue caused by use is another factor, and inspectors will look out for tell-tale signs of failure often associated with the cyclical stress produced by passing vehicles, particularly heavy trucks. This type of failure is especially relevant for metal bridge decks and the cables of suspension and cable-stayed bridges. Traffic has increased ever since these bridges were built, which inevitably leads to the need for more maintenance and strengthening work, such as additional steel, glass or carbon fibre-reinforced plates on critical parts in order to restore or enhance their strength compared to what was deemed necessary during their design. For example, Network Rail in the UK used fibre-reinforced polymers to strengthen more than 20 bridges carrying highway or railway traffic between 2001 and 2010.

Consider how we all tend to react to a road sign bearing the words: “Essential Bridge Works – Expect Long Delays”. One such situation prompted this comment from a member of the public: “We are doomed. I am going to buy a tent and pitch it outside work for the three months while the misery goes on.” Perhaps knowing why this is necessary – and the consequences of not doing so – might persuade people to reconsider such views.
Money and willingness to spend it

Equally, we must understand that maintenance budgets need to be set at levels that far exceed those that would allow engineers only to “firefight” the most severe problems, as is becoming worryingly commonplace. Instead, budgets need to allow for planned interventions and necessary upgrades over many decades. That requires public and government support, as well as skilled engineers committed to ensuring the safety of an ageing structure.

There are challenges in devising improved methods to assess bridge strength, developing new repair techniques, and new ways of collecting and using inspection and monitoring data to provide advance warning of problems. These constantly push technological boundaries, making it possible to operate existing bridges safely during their long service lives. And the experience gained feeds into new designs that will become reality in years to come.

Those investigating the collapse of the Morandi bridge will look at inspection and maintenance matters. Other lines of enquiry will no doubt include the unusual design of the multi-span bridge, with only a few cable stays to transfer deck loads to the towers, the ongoing work to shore up the foundations, and the heavy rainfall at the time of the collapse. In the shadow of this terrible loss of life, it is worth remembering that bridge inspection and maintenance may be annoying for commuters – but it is crucial.

Re: Bridge collapse near Genoa (IT)

Posted: Tue Jan 15, 2019 1:45 pm
by 603DX
Capetonian, that's a very informed and well expressed piece by Marios Chryssanthopoulos, who is the Professor of Structural Systems at the University of Surrey. Thanks for posting it here. I agree that it's interesting in the context of the Morandi structure's collapse, and having read it carefully through, I'm quite pleased that there is general accord with the content of my previous posts in this thread. Nice to feel after more than 40 years of involvement in bridge structures, and 14 retired years, that I still have a few marbles left rolling around in the noggin ... ;)))

Re: Bridge collapse near Genoa (IT)

Posted: Tue Jan 15, 2019 2:14 pm
by Capetonian
But 603DX, you wouldn't be posting here if you'd lost your marbles, we're all mostly completely sane, intelligent, and balanced here!

Re: Bridge collapse near Genoa (IT)

Posted: Tue Jan 22, 2019 8:08 am
by Capetonian
image.png
Motorway junction near Durban.

Re: Bridge collapse near Genoa (IT)

Posted: Tue Jan 22, 2019 8:53 am
by ian16th
Cape,

Do you know just where that is?

I may use that piece of road, and I'd rather avoid it.

Re: Bridge collapse near Genoa (IT)

Posted: Tue Jan 22, 2019 9:16 am
by Capetonian
According to the friend who sent it to me :
"Bridge over the N3 towards Durban on Town Hill"

Re: Bridge collapse near Genoa (IT)

Posted: Tue Jan 22, 2019 9:23 am
by ian16th
Capetonian wrote:
Tue Jan 22, 2019 9:16 am
According to the friend who sent it to me :
"Bridge over the N3 towards Durban on Town Hill"
So it is probably east of the N3/N2 interchange, where I don't often travel.

Re: Bridge collapse near Genoa (IT)

Posted: Sat Feb 09, 2019 3:40 pm
by OFSO
I see they started this week on demolition of the Morandi bridge. So on schedule for having a replacement ("which will last a thousand years") up in 12 months from the date of collapse, then

Re: Bridge collapse near Genoa (IT)

Posted: Mon Jun 17, 2019 5:12 am
by OFSO
Appears that the company removing the remains of the Morandi bridge is about to demolish the two central towers using explosive charges, and then - afterwards - demolish the blocks of flats under the bridge, the occupiers having already been evacuated. Water bladders have been attached to the bridge to reduce the amount of dust released. Interesting...

Re: Bridge collapse near Genoa (IT)

Posted: Mon Jun 17, 2019 8:05 am
by Capetonian
Maybe they should evacuate that part of Genoa in its entirety, demolish it, and start again. It's pretty grim