The study of British and Irish roads - their construction, numbering, history, mapping, past and future official roads proposals and general roads musings.
There is a separate forum for Street Furniture (traffic lights, street lights, road signs etc).
Registered users get access to other forums including discussions about other forms of transport, driving, fantasy roads and wishlists, and roads quizzes.
Johnathan404 wrote: ↑Wed Sep 26, 2018 18:53
Indeed it is, but adding a hard shoulder where there is currently concrete requires a lane closure which is supposedly something they don’t like, especially seeing as Highways England’s own publicity for this scheme states that the motorway is heavily congested.
However if they say they can do it then good luck to them. There will be complaints about it being so close to the major work happening at J4.
It also looks like the new bridge will be in the position of one of the old carriageways only. Much as I love redundancy it did seem excessive at this location.
As I live within a few miles of the area of this bridge, I am glad that the 1970s concrete engineers built two bridges alongside each other; it means that local traffic can continue to flow during the rebuild (without clogging the roundabout above J3) and the entire programme will only inconvenience M27 through traffic on three weekends over a 13-month period (tonight, March 2018 and finally in October 2019).
To me, this piece of change management is well-planned and well-publicised. However, we are going to hit Sainsbury's on the south side of Winchester tonight, in case the satnav-following numpties do (as feared) b*ll*x up the local roads across the top, middle and swampy bit of Southampton this weekend.
Looking forward to reviewing on Monday morning.
Mike
Mike Hindson-Evans. Never argue with a conspiracy theorist.
They will drag you down to their level and beat you with experience.
Berk wrote: ↑Wed Sep 26, 2018 23:57
What’s the reason for the replacement. Has it become life expired??
Shouldn't be, it's only 40 years old but I believe there is a structural fault with the bridge that can't be fixed so they are having to replace it.
Doesn't bode well for other bridges on the same age on that section of motorway.
Technical term - it's sh**ged; All the beams have cracks because the bearings are shot and the bridge cannot expand and move as was designed. This situation has been "building" for a while - if you look on Streetview, there has been a 28T mgw limit on the bridge for a while and the original two-lanes-in-either-direction flow has been single-lined for a while to reduce the load.
Whatever the pros and cons - in general - of the 1970s concrete teams, in this case "It's worse than that, it's dead, Jim"!
Mike Hindson-Evans. Never argue with a conspiracy theorist.
They will drag you down to their level and beat you with experience.
It was quite common when building motorways at that time to dual the realigned roads “just in case”. M27 J10 is a great example.
I will concede that in this instance it has proven invaluable in that the bridge can be replaced in two phases.
I doubt the lane closure has anything to do with the structure - more like managing the traffic flow as the road has got busier. I suspect the road has been painted down since the roundabout was built 25 years ago. The weight restriction is definitely related though.
Good day out yesterday along the old A31 around Romsey, Part 2 later today. A27 North Baddesley is the main er, beneficiary of the diversion. Already now at 09.40 Sunday morning, the e/bnd queue is almost back to the A3057 rbt. Romsey should build up later. Yesterday, queues in both directions along the A3090, or A31 as I prefer to call it. Just how I remember it in the early 70's.
Weekend diversions are so much more civilised, no rushing, no late night expeditions. Now, when are those 1970/71 M3 Hampshire bridges going to need replacing?
Put in a couple of hours before the early end to proceedings around 1pm, although they were still coming through in smaller numbers until 2 ish. Do Sat Navs automatically pick up changes or, do they have to be informed by in this case HE?
Attachments
They came to spoil the fun.
Earlier, at the end of the D2 into Romsey
Last edited by SteveA30 on Sun Sep 30, 2018 20:08, edited 1 time in total.
A good 1 and a half days around Romsey. Rare territory and new ground for div pics. (no, div)
One of the best old dual carriageways west of Romsey, no hatching, no central barriers on the wide reservation. Nice to see it humming again with long distance traffic.
Berk wrote: ↑Sun Sep 30, 2018 17:23
Have they removed all of the bridge at this time, or just half of it??
And next time, will that be permanently replacing half the bridge, or all of it??
Bridge is actually 2 together. One half removed now, to allow new one to be built in its place then second half will be removed. Whole process will take 18 months. 2 further closures like this weekend will be needed. One in April, the other next autumn.
I vote this past weekend's closure of the M27 (and Romsey Road obviously) as a success - delivered within the advertised timescale (actually early but you cannot count on that next time) and with good communications in advance. Fair enough, North Baddesley looked like a car park at times, but the traffic lights by the Co-Op frequently give you time to read the latest offers in the shop windows!
Information flow: the information on Google traffic was excellent throughout the weekend, whilst the HE website didn't actually show the Westbound carriageway as being closed until some time between 14:44hrs and 21:39hrs on Saturday evening.
So "well done" one and all. Looking ahead, the late-April 2019 closure is sandwiched between the Easter weekend and the May Bank Holiday weekend - might get a little messier perhaps, as this would be "end of school holidays" weekend?
But a good start - "one out of three in the bag".
Mike
Last edited by mikehindsonevans on Mon Oct 01, 2018 10:01, edited 2 times in total.
Mike Hindson-Evans. Never argue with a conspiracy theorist.
They will drag you down to their level and beat you with experience.
mikehindsonevans wrote: ↑Mon Oct 01, 2018 09:15
Looking ahead, the late-April closure is sandwiched between the Easter weekend and the May Bank Holiday weekend - might get a little messier perhaps, as this would be "end of school holidays" weekend?
For our school, they go back the week before, on the day after Easter Monday, so this is a good weekend to pick.
As a local I completely agree - this seemed to be well managed and well publicised.
The first was why was it built as a Dual Carriageway given the short length, was there a DC here before? I can't see that being built as two structures today.
The second is, isn't it a bit concerning that a bridge just over 40 years old has to be demolished as it is unsafe. How many more are there around the Country. Glad HE are doing the works we do not want a Genoa here.
A303Chris wrote: ↑Mon Oct 01, 2018 13:27
I have two questions regarding the bridge.
The first was why was it built as a Dual Carriageway given the short length, was there a DC here before? I can't see that being built as two structures today.
The second is, isn't it a bit concerning that a bridge just over 40 years old has to be demolished as it is unsafe. How many more are there around the Country. Glad HE are doing the works we do not want a Genoa here.
There are plenty of other concrete bridges in trouble around the country. Consider how much remedial work was needed on the Thelwall Viaduct and the deterioration of the A14 viaduct at Huntingdon. In the 60's and early 70's the potential problems of getting the mix even slightly wrong was simply not appreciated. Today every concrete delivery is given a slump test before being poured. A common problem is corrosion of rebar inside the concrete which results in spalling - basically the rust expands and chunks of concrete break off. Before it was demolished this could clearly be seen on the old Palace of Engineering in Wembley built in the 20's for the British Empire Exhibition. Even Wembley Arena needed extensive repair in the 80's due to this issue. In 1974 there was a major roof collapse at Sir John Cass School, Stepney due to the failure of concrete roof beams.
In many ways road bridges are a worst case scenario due to the deposition of salt on the road in winter. The brine can often penetrate the structure through unsealed expansion joints and attack rebar or steel tendons which happened at Thelwall and Huntingdon. The Romans rarely used iron reinforcing in concrete but where they did they seem to have dipped the bars in lead before placing them in position. Roman concrete also used Pozzolana (a volcanic ash) rather than sand. When pozzolana based concrete instead of decaying as modern Portland cement does it actually reacts favourable becoming stronger. This is why in Italy you can find 2000 year old concrete bridges still standing while 50 year old structures need replacing. HE have actually been very proactive in inspecting the concrete bridges in its care, I do worry about some of the older concrete structures maintained by cash strapped County Councils.
This is far from being a UK specific problem. In the 1990's the Ohio Dept Of Transportation had to replace pretty much all of the concrete overpasses on the freeway section of SR 315 as a result of failing 60's era concrete structures and of course in Genoa we saw what can happen if adequate remediation is not done.
A303Chris wrote: ↑Mon Oct 01, 2018 13:27
I have two questions regarding the bridge.
The first was why was it built as a Dual Carriageway given the short length, was there a DC here before? I can't see that being built as two structures today.
The second is, isn't it a bit concerning that a bridge just over 40 years old has to be demolished as it is unsafe. How many more are there around the Country. Glad HE are doing the works we do not want a Genoa here.
Snip....Concrete....snip
While some of what was said in the concrete lesson is correct, perhaps there could be more specific discussion on the mechanisms at play at Huntingdon and perhaps the significance of permeability of concrete and the development of standards following BRE's work. This thread is probably not the place however.
A303Chris wrote: ↑Mon Oct 01, 2018 13:27
I have two questions regarding the bridge.
The first was why was it built as a Dual Carriageway given the short length, was there a DC here before? I can't see that being built as two structures today.
There are quite a few examples of this in the South - of the HE of the day planning for the future by dualling some bridges over motorways and making underpasses wide enough for D2 as well. Some examples I can think of in a 50 mile radius of me are:
M27 junction 10
M3 between junctions 4 and 5 - there are actually two in this short stretch with a D2 bridge over the motorway near Fleet and a D2 width underpass just a few miles west.
M4 between juncs 15 and 16 at Swindon - there is a D2 overbridge on the road between Swindon and Wroughton.
With all of those examples, either side of the motorway the roads quickly revert to S2. Good examples of forward planning maybe as grander schemes were planned in these areas? Or simply "just in case" maybe?
BOH wrote: ↑Tue Oct 02, 2018 07:37
With all of those examples, either side of the motorway the roads quickly revert to S2. Good examples of forward planning maybe as grander schemes were planned in these areas? Or simply "just in case" maybe?
Fashion. Two lanes are better than one, and while now we would worry about people going too fast or struggling to merge, this wasn't considered an issue at the time.
The clue is that the both ends of that dual carriageway are almost exactly where you would expect the construction boundary to have been when they dug the cutting.
Another local example is M27 J1. No need at all for that road to be a dual carriageway, but it had to be built so it was decided to build it well.
A303Chris wrote: ↑Mon Oct 01, 2018 13:27
I have two questions regarding the bridge.
The first was why was it built as a Dual Carriageway given the short length, was there a DC here before? I can't see that being built as two structures today.
The second is, isn't it a bit concerning that a bridge just over 40 years old has to be demolished as it is unsafe. How many more are there around the Country. Glad HE are doing the works we do not want a Genoa here.
There are plenty of other concrete bridges in trouble around the country. Consider how much remedial work was needed on the Thelwall Viaduct and the deterioration of the A14 viaduct at Huntingdon. In the 60's and early 70's the potential problems of getting the mix even slightly wrong was simply not appreciated. Today every concrete delivery is given a slump test before being poured. A common problem is corrosion of rebar inside the concrete which results in spalling - basically the rust expands and chunks of concrete break off. Before it was demolished this could clearly be seen on the old Palace of Engineering in Wembley built in the 20's for the British Empire Exhibition. Even Wembley Arena needed extensive repair in the 80's due to this issue. In 1974 there was a major roof collapse at Sir John Cass School, Stepney due to the failure of concrete roof beams.
In many ways road bridges are a worst case scenario due to the deposition of salt on the road in winter. The brine can often penetrate the structure through unsealed expansion joints and attack rebar or steel tendons which happened at Thelwall and Huntingdon. The Romans rarely used iron reinforcing in concrete but where they did they seem to have dipped the bars in lead before placing them in position. Roman concrete also used Pozzolana (a volcanic ash) rather than sand. When pozzolana based concrete instead of decaying as modern Portland cement does it actually reacts favourable becoming stronger. This is why in Italy you can find 2000 year old concrete bridges still standing while 50 year old structures need replacing. HE have actually been very proactive in inspecting the concrete bridges in its care, I do worry about some of the older concrete structures maintained by cash strapped County Councils.
This is far from being a UK specific problem. In the 1990's the Ohio Dept Of Transportation had to replace pretty much all of the concrete overpasses on the freeway section of SR 315 as a result of failing 60's era concrete structures and of course in Genoa we saw what can happen if adequate remediation is not done.
There is nothing new in replacing bits of 1960s or 1970s concrete; I remember that, when based in Sheffield in 1992, work was beginning on the M1 south of J35 to replace the centre supports of a couple of overbridges:
Sometimes, a concrete batching plant got it wrong in the past; as usually happens, the lessons were learned and, as has been mentioned here several times, the modern "slump" test on each batch of delivered concrete has significantly raised the confidence amongst civil engineers that the structure will stay up for (closer to) its intended lifespan.
As to the original A303Chris question in this post ("why a DC bridge?"): perhaps in the 1960s planning mind, the South Coast motorway would take east-west traffic, but Romsey-Southampton traffic was likely to increase? Therefore, future-proofing the overbridge at the time of construction made sense to include a bit more concrete, ignoring the impending presence of M27j3 just a mile to the west.
I just remember flying over the Southampton area in a Chipmunk from Hamble in about 1974 and marvelling at the massive chalk scar which - at that time without doubt (given the state/capacity of the A27 through the Southampton area) - marked "progress".
Mike
Mike Hindson-Evans. Never argue with a conspiracy theorist.
They will drag you down to their level and beat you with experience.
