Part of the viaduct at Nine Elms has collapsed.

[PG]

I would think a full report, given that the reasons for the collapse - and for the apparent underlying (and clearly undetected) structural weakness may be complex.

As randyrippley has noted above, the exterior wall appears to have disintegrated, rather than fallen off in large pieces still bonded together. Why wasn't the state of the mortar bonding picked up on inspection? It surely won't have deteriorated 'overnight'. Are there implications for the rest of the structure, and other similar ones?

To me this has shades of Lamington viaduct when RAIB said:

Although unrelated to the incident, the RAIB found that defects in the central river pier had not been fully addressed by planned maintenance work. There was also no datum level marked on the structure which meant that survey information from different sources could not easily be compared to identify change.

Clearly as others have noted it raises questions about the condition and inspection regime for many other similar structures across the network.

 

[EvoIV]

There's a video that seems to have been widely shared on social media showing the moment of collapse. It appears to be a rearward CCTV view from a piece of moving plant equipment. The track and ballast has already been lifted. The machine stops as the collapse starts but it's not clear if the machine has struck the wall or has any part in what happens. There is what appears to be a cable visible under the track of the machine that doesn't fall with the others in the collapse. The collapse propagates away rearwards in stages like a wave. The above mentioned orange army members can just be seen narrowly avoiding danger.

Onlookers who were thankfully walking on the other side of the street stop and watch as the debris deforms the palisade fencing at ground level.

Before anyone asks, no I will not further share the video.

 

[dgl]

Best understatement I've ever seen came from the Duty Engineer in the log at Emley Moor TV transmitter: "1265ft Mast - Fell down across Jagger Lane (corner of Common Lane) at 17:01:45. Police, ITA HQ, RO etc all notified.".

Yes, more info on the collapse is available on the Transmission Gallery website, http://tx.mb21.co.uk/emley/index.php

OT but one of two cylindrical steel masts to come down, the other was at Waltham during construction (the first such mast to be built, designed by BICC), supposedly the bloke that was managing the build went to the local post office in the morning after the collapse not knowing it had collapsed and on being told by whoever it was manning the post box that it had fallen down brushed it off as a joke, he later came back and had to sit down due to the shock.

txfeatures.mb21.co.uk/waltham/index.shtml

The foreman in charge of erection, Mr. John Mason, had watched the mast grow since its beginning in March this year.
Wednesday was just another day, he left Melton, where he is living, and stopped at Waltham post office to pick up tea, sugar and mail.
“Did you know your mast is down!” said Mr Steve Watts from behind the counter. Mr Mason dismissed the remark as a joke. He left but returned minutes later, he sat down until he had sufficiently recovered from the shock.

 

[swt_passenger]

Believe that was a power failure as National Grid engineers were called out to restore power as per TL and SN Twitter feeds.

They've just reopened the lines affected but services still subject to delay, alteration and cancellation.

No, that item was a signal post hit by on track plant, as they explained right at the end of the NRES link. The SN/TL power failure is another unrelated fault.

 

[theironroad]

There's a video that seems to have been widely shared on social media showing the moment of collapse. It appears to be a rearward CCTV view from a piece of moving plant equipment. The track and ballast has already been lifted. The machine stops as the collapse starts but it's not clear if the machine has struck the wall or has any part in what happens. There is what appears to be a cable visible under the track of the machine that doesn't fall with the others in the collapse. The collapse propagates away rearwards in stages like a wave. The above mentioned orange army members can just be seen narrowly avoiding danger.

Onlookers who were thankfully walking on the other side of the street stop and watch as the debris deforms the palisade fencing at ground level.

Before anyone asks, no I will not further share the video.

That's not very helpful if it is widely available.

 

[Aictos]

No, that item was a signal post hit by on track plant, as they explained right at the end of the NRES link. The SN/TL power failure is another unrelated fault.

I was actually referring to the TL/SN issue as a separate issue, apologies if you thought otherwise.

 

[Nicholas Lewis]

That's not very helpful if it is widely available.

Its not but the plant operators will be castigated by NR for allowing it to be leaked to social media. Generally they do put stuff out on twitter to explain to people whats happened when its been sanitised. As the lines are under possession they can keep it suppressed currently.

 

[Ian Hardy]

Interesting..do we know if the failed portion is part of the original structure or the widened side? (Or was the structure widened outwards on both sides?)

Looking at an 1893 Ordnance Survey map on the National Library of Scotland website, it is the north side of the original 1848 viaduct that has failed, the widening at that point was all on the south side of the original 4 track line, which cut a slice off the site of the Nine Elms works which closed in stages between 1891 and 1909: https://maps.nls.uk/geo/explore/#zoom=17&lat=51.47990&lon=-0.13470&layers=163&b=1

 

[Snow1964]

Interesting..do we know if the failed portion is part of the original structure or the widened side? (Or was the structure widened outwards on both sides?)

Originally 4 tracks, then 6, then widened again to 8

It was not all done same side (on Vauxhall-Waterloo section) and the large curve in the Vauxhall area was to avoid the former Vauxhall pleasure grounds

I have old photo in a book (not the same bit of the viaduct) where parapet looks higher. Appears the parapet was lowered at some stage and replaced by cable troughs and a metal fence bolted to brickwork below.

I am guessing that work would have been done here when the reversible line for Eurostar was done around 1994. Possibly at time some extra recesses etc were created moving the cabling further out. Would have affected the loading, the trains weight will be downward loading, the items bolted to side are pulling sides outwards, but more of a twisting outwards force.

No idea if work was done recently, but would be easy for an excavator to put sideways loadings if something was pushed rather than cleanly scooped downwards. I suspect the weight of cables pulled long length down when short part became detached. A very similar thing happened recently on District line near Plaistow (forgotten exact location)

 

[Horizon22]

Must admit one that sprung to mind recently was when walking over the road footbridge just outside Vauxhall, the wall adjacent to that looks just ready to fall over.

I wonder if this very lucky escape could lead to a 'Hatfield' type inspection of similar structures? The state of some of brick railway structures in South London is appalling, trees, bushes etc growing through them, water flowing through them etc.

This and embankments up and down the country - not forgetting tragic Stonehaven - are two of the largest and growing risks. This includes condition of the assets and the landscape but also the likelihood of more severe weather.

 

[Dan17H]

As someone who examines these types of viaducts, I very much doubt the parapet has just given way. Either a vehicle strike, or possible the weight of the RRV in the dig (track does awfully well at spreading load over a Structure) has caused this.

There is no flattening within the arch which is a good sign, but also points to it not failing in its own.

With regards to the inspection of a viaduct such as this, and any additional works (cables attached to the parapet etc), it'll be down to the Route Assest Manager to take ownwership and sign off any alterations.

It'll have a detailed full tactile examination every 6 years, using tools and measurements to check its condition, both underneath in the arch and on top trackside. Then, every year it'll have a visual examination, that monitors any change to previously reported defects by a quailified structures Examiner (the role I do), and notes any serious new defects.

All of this is reviewed by both an external Engineer, and NWRs own Engineers. Recommendations are then made for repairs to be carreid out based on a scoring system, called BCMI. In an ideal world every defect would be repaired, but in reality with lack of funding only the worst defects are repaired.

To be fair if examined and funded/repaired properly structures very rarely collapse on their own, its ususally an outside influence (weather, vehicle, fire etc) that causes such a collapse.

 

[konstant]

Caused by compaction of the substrate from a roller which was being undertaken without taking into account the hydraulic effects caused by the compaction process against the side walls of the structure.

Civil Engineering 101.. here's a video of it collapsing..

Watch Norton Bridge | Streamable

Watch "Norton Bridge" on Streamable.

streamable.com

The science behind the problem...

http://www.acee-journal.pl/cmd.php?cmd=download&id=dbitem:article:id=256&field=fullpdf

 

[Paul180]

Looking at street view it looks like part of the viaduct towards Waterloo has had replacement/reinforcement work done on it at some point.

 

[Dan17H]

Caused by compaction of the substrate from a roller which was being undertaken without taking into account the hydraulic effects caused by the compaction process against the side walls of the structure.

Civil Engineering 101.. here's a video of it collapsing..

Watch Norton Bridge | Streamable

Watch "Norton Bridge" on Streamable.

streamable.com

The science behind the problem...

http://www.acee-journal.pl/cmd.php?cmd=download&id=dbitem:article:id=256&field=fullpdf

Substrate?

 

[konstant]

Substrate?

The stone element of the formation layer which was being compacted in this conventional renewal.

 

[Dan17H]

The stone element of the formation layer which was being compacted in this conventional renewal.

Sub base you mean? I've never heard it called that before.

 

[konstant]

Sub base you mean? I've never heard it called that before.

You are free to call it whatever you wish, I worry that to discuss this further might detract somewhat from the more relevant parts of this conversation.

 

[Dan17H]

You are free to call it whatever you wish, I worry that to discuss this further might detract somewhat from the more relevant parts of this conversation.

The stuff you can see in the video is called 'the fill'. Which is what was added to the arch when it was built. The sub base is a different thing altogether. Also, nothing is 'rolled' on the railway not on a Viaduct at least.

 

[konstant]

The stuff you can see in the video is called 'the fill'. Which is what was added to the arch when it was built. The sub base is a different thing altogether. Also, nothing is 'rolled' on the railway not on a Viaduct at least.

Spent 10 years managing conventional renewals, without demolishing a viaduct. Plenty of stuff is rolled on the railway, and that's not the "fill". FYI substrate is a Latin term used frequently in professional civil engineering terminology. Oddly enough it was a Dan who was managing this job when it went down - was that you? If not perhaps, again, this off-topic discussion solely happening because you didn't like my use of an accepted term could be drawn to a close?

 

[BRX]

I live next to a brick viaduct in south london. There is loads of buddliea. I've watched them 'repair' it. The buddliea is cut back and there's a kind of half hearted attempt to remove the roots. In some cases that seems to mean cutting them far back enough that a few bricks can be replaced, thenit's all repointed (not particularly well) and you can't see anything except maybe a bit of distortion in the mortar width where the roots have pushed things out of line.

A few months later: the buddliea re-sprouts from nearly all of the previous locations.

I'd be interested to know what the structural implications of the buddliea growth are. Whether there's a big long term problem lurking there or not. I understand it's something that was allowed to get somewhat out of hand post privatisation.

Regarding lime mortar - without wanting to overstep my level of expertise here - there's nothing fundamentally wrong with it as long as its cared for, and repointed at the appropriate time. It's water ingress that causes damage and allows the mortar to degrade. Properly pointed brickwork should stop that from happening. I see a lot of viaduct parapets where the pointing is in terrible condition. Replacing with stronger cement based mortar can cause its own issues and using the right mix is important.

It often saddens me to see the neglect and badly executed repair that so many of these really quite amazing and beautiful structures have suffered. A lot of it relatively recent.

 

[Dan17H]

Spent 10 years managing conventional renewals, without demolishing a viaduct. Plenty of stuff is rolled on the railway, and that's not the "fill". FYI substrate is a Latin term used frequently in professional civil engineering terminology. Oddly enough it was a Dan who was managing this job when it went down - was that you? If not perhaps, again, this off-topic discussion solely happening because you didn't like my use of an accepted term could be drawn to a close?

I'll see your 10 years and raise you 5, on both renewals, and Structures work. And in those years I've never seen a roller on an old Viaduct, and I've been on hundreds. I've also never heard a single person use the term substrate.

No, I was busy examing another Viaduct that day, so it wasn't me.

Civil engineering and railway are a world apart, as you'd know.

I raised the original question about your statement because you'd used a word I'd never heard of. There's countless posts on here with others correcting mistakes or misunderstandings.

I live next to a brick viaduct in south london. There is loads of buddliea. I've watched them 'repair' it. The buddliea is cut back and there's a kind of half hearted attempt to remove the roots. In some cases that seems to mean cutting them far back enough that a few bricks can be replaced, thenit's all repointed (not particularly well) and you can't see anything except maybe a bit of distortion in the mortar width where the roots have pushed things out of line.

A few months later: the buddliea re-sprouts from nearly all of the previous locations.

I'd be interested to know what the structural implications of the buddliea growth are. Whether there's a big long term problem lurking there or not. I understand it's something that was allowed to get somewhat out of hand post privatisation.

Regarding lime mortar - without wanting to overstep my level of expertise here - there's nothing fundamentally wrong with it as long as its cared for, and repointed at the appropriate time. It's water ingress that causes damage and allows the mortar to degrade. Properly pointed brickwork should stop that from happening. I see a lot of viaduct parapets where the pointing is in terrible condition. Replacing with stronger cement based mortar can cause its own issues and using the right mix is important.

It often saddens me to see the neglect and badly executed repair that so many of these really quite amazing and beautiful structures have suffered. A lot of it relatively recent.

Buddliea is a massive issue on Structures, the roots cause fractures throughout. Its one of the main things examiners look out for, root infestation.

The problem with repairs are there just isn't enough time to carry out proper repair work, that would include removing the roots, and rebuilding the whole parapets and spandrels (the bit between the arch and parapet). And money, the funding isn't there.

 

[Nicholas Lewis]

Spent 10 years managing conventional renewals, without demolishing a viaduct. Plenty of stuff is rolled on the railway, and that's not the "fill". FYI substrate is a Latin term used frequently in professional civil engineering terminology. Oddly enough it was a Dan who was managing this job when it went down - was that you? If not perhaps, again, this off-topic discussion solely happening because you didn't like my use of an accepted term could be drawn to a close?

When we did renewals from bethnal green upto hackney downs side loading onto the parapet wall structure was a key risk and we used smaller dozers to avoid material building up against the wall and exerting pressure and hand cleared sections where clearance was really tight.

Also along this section the parapet walls were lowered to provide a continuous position of safety i believe as the adjacent line was made reversible when Waterloo International was built.

 

[philthetube]

If buddleia,was cut back to root level twice yearly then it would never grow to a size where the roots cause serious structural problems.

Probably a lot of this could be done without scaffolding though harnesses would be needed.

This must be cheaper than the costs involved in repairing the damage done.

Cut it back four times and it dies

 

[Crossover]

That's not very helpful if it is widely available.

Its not but the plant operators will be castigated by NR for allowing it to be leaked to social media. Generally they do put stuff out on twitter to explain to people whats happened when its been sanitised. As the lines are under possession they can keep it suppressed currently.

I think that ship has sailed. I have seen the video, I believe, on Facebook shared from YouTube so it’s very much in the public domain

 

[theironroad]

Seems the clip on You Tube (linked below) is only 11 seconds long, viewed by over 1300 people already, but clearly shows the parapet falling away and two lucky staff in distance making a run for it.

 

[Class 170101]

Seems the clip on You Tube (linked below) is only 11 seconds long, viewed by over 1300 people already, but clearly shows the parapet falling away and two lucky staff in distance making a run for it.

But whats that orange in the forefront of the shot?

 

[Peter Mugridge]

But whats that orange in the forefront of the shot?

Looks like it's for on screen data but which either hasn't been set up properly or it's been obscured in some way.

 

[Nicholas Lewis]

But whats that orange in the forefront of the shot?

Looks like it would a GPS readout as its got N and S prefixing the zeros

 

[KingJ]

Network Rail have put out a statement.

On Christmas Day a section of brick wall collapsed from our viaduct in the Nine Elms area of London while engineering work took place. There were no injuries.

Investigations into what happened are ongoing but we do know that the original collapse was quite small. The wall was connected with a substantial handrail, which was bolted through the bricks, and when the small section failed, the handrail pulled a much longer length down – along the handrail’s entire 70m length.

The exact cause of the collapse is yet to be determined, however we do know that the wall was not struck by machinery. Work in the area was taking place using a digger, to remove old rails and sleepers. We are carrying out a thorough survey of the surrounding area to help us understand how this happened.

Sadly, without the wall in place, we cannot reinstate a small section of track and therefore run trains on one of the 8 lines. We are working hard to rebuild the affected area as soon as we can to minimise disruption to South Western Railway services and our passengers.

From 4th January South Western Railway will run an amended service and the rest of our work at Nine Elms is continuing as planned.

 

[Nicholas Lewis]

Sadly, without the wall in place, we cannot reinstate a small section of track and therefore run trains on one of the 8 lines. From 4 January South Western Railway will run an amended service

Sadly is an interesting way to describe the situation but at least gives an insight into what happened an excuse for SWR to cull the train service further although no one will notice.