Maintaining ageing road infrastructure

[Via Bank]

There’s also the other end of the scale, there’s miles of very minor roads, which while they don’t cost the same to maintain as the high profile structures, still have a very low CBR. If they were railways they’d have been closed years ago.
Been driving around Cornwall the last two weeks and our sat-nav seems to delight in taking us down the most minor roads. All of these probably need a twice yearly hedge cutting (if you’ve been on a minor road in Cornwall you’ll know what I mean) even if the tarmac lasts for years. Surely there should be a rolling program of closure of the duplicate routes?

We could, and should, do what the Dutch do and close such duplicate routes to through traffic. Makes the surfacing last longer (because passing motorists' wheels aren't chewing it up) and makes them considerably more suitable for cycling when you're not going to encounter someone hooning around a blind corner following their sat-nav at 60mph.

 

[Lucan]

Tendons in post-stressed concrete can be withdrawn for periodic inspection and replaced if necessary. If the tendons, or groups of tendons, are anchored separately and they are present in redundant multiples, they can be withdrawn singly without closing the structure to traffic.

 

[edwin_m]

Tendons in post-stressed concrete can be withdrawn for periodic inspection and replaced if necessary. If the tendons, or groups of tendons, are anchored separately and they are present in redundant multiples, they can be withdrawn singly without closing the structure to traffic.

But how many structures of the Sixties and Sevventies are post-stressed?

As I understand it normal reinforced concrete can suffer from rusting of the re-bar, but it's usually obvious from the external cracking and other signs. Expensive to fix but at least you get some warning that something needs to be done. The worst is pre-stressed concrete, because if it degrades to the extent that the concrete is no longer holding the reinforcement in tension then the structure is in danger of catastrophic collapse. I believe that was the reason the canopies at Derby station had a very substantial steel supporting scaffold added a few years before they were eventuallly replaced.

 

[The exile]

Before we start proposing vast expansion of the M-way network, we need to ensure that the money is there to fix what are rapidly becoming life expired structures. The Gateshead flyover and A432/M4 bridge are at the moment outliers, but there may well be plenty more to come.

 

[MotCO]

Before we start proposing vast expansion of the M-way network, we need to ensure that the money is there to fix what are rapidly becoming life expired structures. The Gateshead flyover and A432/M4 bridge are at the moment outliers, but there may well be plenty more to come.

I also worry about the M4 elevated section - how old is that, and what is its life expectancy. To try to replace it would be disruptive to say the least.

 

[Cowley]

Before we start proposing vast expansion of the M-way network, we need to ensure that the money is there to fix what are rapidly becoming life expired structures. The Gateshead flyover and A432/M4 bridge are at the moment outliers, but there may well be plenty more to come.

I’ve added this post and the reply to a thread I started a few years ago, as it seems particularly relevant now due to the story below.

Gateshead flyover work to prop up dangerous structure

Gateshead Council says it is working with Nexus to "mitigate risks" and reopen Metro services.

www.bbc.co.uk

Work to prop up part of a dangerous flyover has begun, a council has confirmed.
Gateshead Highway closed suddenly on 13 December after investigations judged the 1960s structure to be unsafe.
Metro services between Monument and Heworth, which run in tunnels under the flyover, were also suspended and replaced by buses.
Gateshead Council said workers were on site to place props around a pillar directly over the tunnel, and they were working with Nexus to reopen Metro services "as soon as possible".

 

[SWT_USER]

I also worry about the M4 elevated section - how old is that, and what is its life expectancy. To try to replace it would be disruptive to say the least.

I'd be interested to know what the long term plan is for the M4 elevated section.

It was closed some years back for urgent structural repairs, and more recently there have been lane closures on the A4 underneath for works on the structure.

Presumably these are all just kicking the can down the road and at some point it will need knocking down and I suspect won't be replaced.

 

[EMU303]

An example from Glasgow … £150m to repair approx a half a mile stretch of urban elevated roadway.

Why are the roadworks on Scotland's busiest motorway taking so long?

Repairs to the M8's Woodside Viaducts have yet to start - after years of preparation.

news.stv.tv

Transport bosses have told STV News that roadworks on a section of the M8 are the “biggest on their books” after three-and a-half-years of delays for drivers – and repairs yet to even start.

Temporary propping works at the Woodside Viaducts in Glasgow began in March 2021 after the bridges’ supports were found to be in worse condition than expected.

Those initial works are not scheduled to be finished until early 2026, with the estimated cost now as high as £152m.

Costs and timescales for the repair works after that are still to be determined, with a contractor yet to be appointed.

STV News
Inspections in 2020 found the condition of the motorway bridges’ supports to be worse than expected.

What do the current works involve?​

Lane and speed restrictions have been in place since work started three years ago, with an estimated 150,000 vehicles travelling over the Woodside Viaducts daily.

The temporary propping works have involved building structures to take the load of that traffic off the existing supports, in order for them to be repaired.

 

[Southsider]

An example from Glasgow … £150m to repair approx a half a mile stretch of urban elevated roadway.

Why are the roadworks on Scotland's busiest motorway taking so long?

Repairs to the M8's Woodside Viaducts have yet to start - after years of preparation.

news.stv.tv

Transport bosses have told STV News that roadworks on a section of the M8 are the “biggest on their books” after three-and a-half-years of delays for drivers – and repairs yet to even start.

Temporary propping works at the Woodside Viaducts in Glasgow began in March 2021 after the bridges’ supports were found to be in worse condition than expected.

Those initial works are not scheduled to be finished until early 2026, with the estimated cost now as high as £152m.

Costs and timescales for the repair works after that are still to be determined, with a contractor yet to be appointed.

STV News
Inspections in 2020 found the condition of the motorway bridges’ supports to be worse than expected.

What do the current works involve?​

Lane and speed restrictions have been in place since work started three years ago, with an estimated 150,000 vehicles travelling over the Woodside Viaducts daily.

The temporary propping works have involved building structures to take the load of that traffic off the existing supports, in order for them to be repaired.

Meanwhile, half a mile away, lumps of concrete are falling off the M8 Kingston Bridge.

 

[Recessio]

I remember hearing that in London, parts of the Hammersmith Flyover are in pretty poor condition, and the nearby A40 Westway required repairs in 2021. I guess a lot of these sorts of elevated road structures are nearing 60 years old, and with reduced maintenance budgets due to local authority budgets being tight - not a great combination.

 

[dcbwhaley]

I remember hearing that in London, parts of the Hammersmith Flyover are in pretty poor condition, and the nearby A40 Westway required repairs in 2021. I guess a lot of these sorts of elevated road structures are nearing 60 years old, and with reduced maintenance budgets due to local authority budgets being tight - not a great combination.

Surely trunk roads are maintained by National Highways not local authorities?

 

[Recessio]

Surely trunk roads are maintained by National Highways not local authorities?

Good point - I wonder if TfL might be a special case in Greater London then, as they are responsible for the Westway at least. For example https://www.highwaysmagazine.co.uk/TfL-does-partial-Westway-fix-amid-funding-crisis/9413

 

[swt_passenger]

Good point - I wonder if TfL might be a special case in Greater London then, as they are responsible for the Westway at least. For example https://www.highwaysmagazine.co.uk/TfL-does-partial-Westway-fix-amid-funding-crisis/9413

TfL were given direct responsibility for all former trunk roads and motorways within Greater London. I think the traditional concept of a trunk road no longer exists within London. But even then TfL roads are only responsible for a small proportion of roads by mileage, around 5%.

 

[61653 HTAFC]

This BBC article reports on issues with the new A1 bridge carrying the upgraded A1 over the ECML near Gateshead. Hopefully this won't be something that bites us on the backside in a few decades.

Text of the article below:

A new bridge built as part of a project to widen a section of the A1 has been found to have defects.

The Allerdene Bridge, in Gateshead, was replaced by a new structure that opened in September 2023 under the A1 upgrade scheme.

Welding problems on the 3,400 tonne road bridge, which stretches across a section of the East Coast Main Line, were identified by steelwork contractor Severfield.

National Highways and the contractor said the deficiencies at the motorway bridge did not pose an "immediate safety risk".

Traffic restrictions, that were lifted elsewhere on that stretch of the A1 before Christmas, have remained in force around the bridge because of the issue, the Local Democracy Reporting Service said.

National Highways confirmed it was first made aware of a potential problem with the welding quality of steel beams on the bridge in August and that the defects could reduce the structure's 120-year lifespan if left unchecked.

It said that it had restrictions on vehicles with abnormal loads using the bridge and that the new, extra lane of traffic built in each direction will remain closed over the bridge, for approximately one mile, until the welding problem is resolved.

The company also said the bridge would open to full capacity when it was safe.

"This includes monitoring and maintaining ageing infrastructure, and we are applying our extensive expertise to this situation," it added.

Severfield said a comprehensive review was taking place to establish what action was required to resolve the issue.

 

[edwin_m]

This BBC article reports on issues with the new A1 bridge carrying the upgraded A1 over the ECML near Gateshead. Hopefully this won't be something that bites us on the backside in a few decades.

Text of the article below:

There seems to have been a specific problem with welding on recent work by this company, also affecting HS2. Embarrassing but not quite the same as the potential problems with older structures.

 

[Tetchytyke]

This BBC article reports on issues with the new A1 bridge carrying the upgraded A1 over the ECML near Gateshead. Hopefully this won't be something that bites us on the backside in a few decades.

As @edwin_m says, the welding issues are to do with that specific construction company. The welding issues were first identified on HS2 and, overall, the constructor has identified that it has messed up 12 bridges on HS2 and the road network.

At least it was identified. Back in the 60s and 70s those sorts of construction issues would simply have been hushed up. Which is why we see the issues we do now with things like RAAC and the steel in reinforced concrete corroding far more quickly than it should have done. And also why, in Ireland, there's the ongoing mica scandal.

 

[swt_passenger]

We had a thread about the problems with HS2 bridges using Severfield components back in November, I’d mentioned there that the A1 Team Valley bridge was another example:

Nine HS2 bridges with welding defects

£20.4m to rectify. https://www.constructionnews.co.uk/civils/hs2/severfield-reveals-costly-problems-with-hs2-bridges-26-11-2024/ Steel giant Severfield has slipped to a £5.8m pre-tax loss in its interim results after uncovering the need to remediate 12 bridges, nine of which form part of the...

www.railforums.co.uk

 

[thejuggler]

IIRC part of the reasoning behind redevelopment of Leeds General Informary is to demolish the Clarendon Wing which is built over the inner ring road tunnel.

The tunnel had repair and strengthening works about 10 years ago, but long term the dead weight of the buildings above needs removing to prevent further deterioration.

 

[Bletchleyite]

I suspect there is a huge time-bomb ticking on the M-Way network in the form of concrete structures at the end of their natural life. What’s more, they’re all going to get there within a relatively concentrated period of time.

Birmingham in particular. One wonders sometimes if it might be cheaper to nationalise and make free of charge the M6 Toll rather than replace all of them, and only replace the ones through Brum to the extent that is needed for traffic actually going to/from the city.

There have already been issues with the M4...

Certainly the ride on the viaduct sections through Brum is getting quite rough in places (the rail equivalent might be jointed track on the WCML - indeed it does give a pleasing clickety clack sound ), I suspect permanent speed restrictions to 50mph are not far away.

 

[LYradial]

I would think the areas most at risk are the M6 from its junction with the A5 north to Preston, the M1 from rugby to Watford gap and the M50 out to Ross on wye as these are the earlier ones.

The M 50 has had a lot of its bridges reinforced, the thelwall viaduct has mostly been replaced and widened, not sure about the M1.

it depends on whether it is reinforced concrete, with a lifetime of 50-100 years or, like that viaduct in Scotland,
can last a very long time.

short answer, yes I think you are correct

 

[PTR 444]

I would think the areas most at risk are the M6 from its junction with the A5 north to Preston, the M1 from rugby to Watford gap and the M50 out to Ross on wye as these are the earlier ones.

Don't you mean Rugby to Watford, or Watford to Watford Gap?

 

[ABB125]

The M8 in Glasgow is an example of what might happen. The viaducts to the north of the city centre are not in a good condition and options are being explored for what to do. In the meantime, 4 lanes each way have been reduced to 2 with a 40mph limit for several years, and will remain that way for several more to come whilst Transport Scotland dithers and delays making a decision

 

[The Planner]

Birmingham in particular. One wonders sometimes if it might be cheaper to nationalise and make free of charge the M6 Toll rather than replace all of them, and only replace the ones through Brum to the extent that is needed for traffic actually going to/from the city.

There have already been issues with the M4...

Certainly the ride on the viaduct sections through Brum is getting quite rough in places (the rail equivalent might be jointed track on the WCML - indeed it does give a pleasing clickety clack sound ), I suspect permanent speed restrictions to 50mph are not far away.

The M6 ones will be the expansion joints.

 

[Mr. SW]

I remember years ago problems with the elevated section of the M4 in Brentford. I've just checked online to see any changes and found this on Google Street View (first image) You can see bracing and clips on the crosshead. This section of the motorway was built 1962-64.
The second image is Apex Corner in Hanworth. Although it's not completely clear from the image, the left side of the abutment the concrete has spalled away leaving the heavily rusted rebar exposed. During wet weather water used to pour down the face of the abutment. Again dates from 1965 or so. I suspect both of these problems will eventually have to be fixed properly.
Edit: Third image: better view of exposed rebar.

 

[Merle Haggard]

Birmingham in particular. One wonders sometimes if it might be cheaper to nationalise and make free of charge the M6 Toll rather than replace all of them, and only replace the ones through Brum to the extent that is needed for traffic actually going to/from the city.

There have already been issues with the M4...

Certainly the ride on the viaduct sections through Brum is getting quite rough in places (the rail equivalent might be jointed track on the WCML - indeed it does give a pleasing clickety clack sound ), I suspect permanent speed restrictions to 50mph are not far away.

That has been the case back to soon after it was built. At one stage the cracks were so deep the impression was you could see through them to the ground below.
At the time, Private Eye covered the causes which allegedly centred around the construction allegedly not conforming to specification and alleged deficiencies in the inspections which should have highlighted these shortcomings. Lots of allegations but never resolved - unlike T Dan Smith in the North East, if anyone remembers. Seemed to be culture at the time.

 

[LYradial]

Don't you mean Rugby to Watford, or Watford to Watford Gap?

I’m from lancasheer tha knows, is there a difference

 

[Magdalia]

I’m from lancasheer tha knows, is there a difference

Only about 50 miles.

== Doublepost prevention - post automatically merged: 18 May 2026 ==

I remember years ago problems with the elevated section of the M4 in Brentford.

The Chiswick and Hammersmith flyovers were constructed by Marples Ridgway.

 

[The exile]

I would think the areas most at risk are the M6 from its junction with the A5 north to Preston, the M1 from rugby to Watford gap and the M50 out to Ross on wye as these are the earlier ones.

The M 50 has had a lot of its bridges reinforced, the thelwall viaduct has mostly been replaced and widened, not sure about the M1.

it depends on whether it is reinforced concrete, with a lifetime of 50-100 years or, like that viaduct in Scotland,
can last a very long time.

short answer, yes I think you are correct

Multi-million £ repairs soon to start on the M32.

 

[edwin_m]

The flyover in Gateshead that was suddenly closed, also affecting the Metro in tunnel underneath it, could be a portent of what is to come.

https://www.gateshead.gov.uk/article/30608/Gateshead-Highway-A167-flyover

The flyover was built in the late 1960s. It's getting old and water has got into the structure, so the concrete is starting to deteriorate - which is typical of any structure of this age.

Over recent years, we have brought forward bids for various funding streams but we have not been able to secure funding which would allow us to demolish the flyover.

Since 2017, we've carried out over 50 inspections on the flyover. They indicated that despite some deterioration, the structure could continue to be safely used with increased monitoring and maintenance, while we reviewed options and continued to pursue the funding needed.

As a result of the increased monitoring and maintenance, we identified the need for a more detailed inspection which was carried out by consultant structural engineers in December 2024.

This revealed more significant deterioration inside one of the pillars. The engineers advised that continued use of certain sections of the structure could put public safety at risk, so we acted on this advice to immediately close the flyover and part of the road beneath it.

 

[swt_passenger]

The flyover in Gateshead that was suddenly closed, also affecting the Metro in tunnel underneath it, could be a portent of what is to come.

https://www.gateshead.gov.uk/article/30608/Gateshead-Highway-A167-flyover

Good example, although it’s not part of the motorway network as such, it must have used the same or very similar technology and standards when built. The Newcastle central motorway (east) uses the unusual layout of the northbound carriageway being above the southbound, and it‘s doubtful if that would be easily replaced in situ if it was found to be failing...