Nuneham Viaduct shut - Didcot- Oxford

[plugwash]

Might be answered already, is there enough coach/bus drivers in local area to provide RRB service. I know Oxford and Swindon buses have been running recruitment campaigns for a long while.

The advice on NRE for long distance crosscountry customers is that they should avoid the area due to "limited" road transport and should travel via bristol or London instead.

 

[oxfordrelayer]

It was. Specifically to take a 5 car IET.

== Doublepost prevention - post automatically merged: 8 Apr 2023 ==


I generally find Google maps measurements to be highly accurate, and certainly no where near giving a 7m error over 140m.

I've used the feature to measure for scheme plans, either as a double check or when I'm waiting for 'proper' survey data. I've never found any noticeable discrepancies when I've corresponded it with survey data later on.

 

[Greybeard33]

This Network Rail tweet has an embedded video in which Stuart Calvert gives a clear explanation of the problem and planned solution:

We're working 24/7 to get the railway between Oxford and Didcot reopened. Prior to the recent rapid deterioration of the viaduct, its condition posed no safety risk. Stuart Calvert explains how we have been looking after the viaduct and what our permanent fix will look like.

https://twitter.com/networkrailwest/status/1646540219959721987

He says that they will put temporary piles in the middle of the Thames with a trestle to support the bridge span. Then demolish the failed abutment and pile 25m deep to provide solid foundations for a new abutment.

 

[D6130]

In this Network Rail video, Stuart Calvert gives a clear explanation of the problem and planned solution:
https://twitter.com/networkrailwest...219959721987&currentTweetUser=networkrailwest

When I tried to look at this, I was informed by Twitter that "This page doesn't exist. Try searching for something else".

 

[JamesT]

https://twitter.com/networkrailwest/status/1646540219959721987 is a link to the tweet, does that work better?

 

[Mr_B]

https://twitter.com/networkrailwest/status/1646540219959721987

 

[GRALISTAIR]

Piles 25 metres deep - wow.

 

[InOban]

That's an impressive amount of work to do in 8 weeks.

 

[bspahh]

Piles 25 metres deep - wow.

For the Ely Southern Bypass, they initially planned on 30m deep piles. They ended up with piles which were over 42m deep and 1200mm diameter.

In the second document, I like the comment:

In addition Site Investigation data did not provide soil information to the depth that the piles were expected to need to reach.

In a previous discussion, @Bald Rick commented:

There’s a saying in civil engineering:

You pay for your ground investigations whether you do them or not.

 

[zwk500]

Piles 25 metres deep - wow.

Sounds painful!

 

[Parham Wood]

Bridge looks as though it could have done with repainting by now given the amount flaking off. Perhaps it was delayed due to the abutment issue.

 

[webweasel]

Does beg the question, if the south abutment needs 25m piles, how long will the central and north piers last with foundations only 11 feet below the riverbed?

 

[GRALISTAIR]

For the Ely Southern Bypass, they initially planned on 30m deep piles. They ended up with piles which were over 42m deep and 1200mm diameter.

The Fens ground conditions I assume?

Sounds painful!

LOL

 

[D6130]

https://twitter.com/networkrailwest/status/1646540219959721987 is a link to the tweet, does that work better?

Yes, that worked fine. Thanks very much!

 

[edwin_m]

Piles 25 metres deep - wow.

Hope they remember how to do large piles from the electrification.

 

[GRALISTAIR]

Hope they remember how to do large piles from the electrification.

On GWML there was a possession issue. Since the line is shut that won’t be a problem.

 

[Mikey C]

Does beg the question, if the south abutment needs 25m piles, how long will the central and north piers last with foundations only 11 feet below the riverbed?

I have visions of the north abutment subsiding a couple of months after reopening...

 

[GRALISTAIR]

I have visions of the north abutment subsiding a couple of months after reopening...

Surely to goodness they will do a very thorough ground inspection and survey while they are onsite and have possession?

 

[The exile]

Surely to goodness they will do a very thorough ground inspection and survey while they are onsite and have possession?

Some highly paid bean-counter will probably argue that that isn’t in the spec.

 

[zwk500]

Some highly paid bean-counter will probably argue that that isn’t in the spec.

It's been said before, you pay for ground inspections whether you do them or not.

 

[EveningStar]

Thank you all for the link ... very informative. Wearing my civil engineering qualifications, my expectation was some form of piling to bypass the failed abutment, except was not sure how they were going to support the bridge structure during the process. Solution proposed is clever, and doubtless been urgent discussions with the Environment Agency concerning the river hydrology and bed conditions.

It's been said before, you pay for ground inspections whether you do them or not.

Absolutely the truth! Have seen sites that look benign and moment one digs into the ground are a nightmare.

I have visions of the north abutment subsiding a couple of months after reopening...

Taking a look at the geological maps, south bank appears to be alluvial clay and silt (so am sure everybody involved is aware that 25m is a best guess), while north bank appears to be sandstone and hopefully more stable.

 

[Snow1964]

It's been said before, you pay for ground inspections whether you do them or not.

As Bam found out on Sheffield University social science building, piles started sinking, whole concrete shell had to be taken down, new piles and rebuilt.

Back to Nuneham, does rather make you wonder if bored piles filled with concrete that grip irregular drilled holes would be safer for electrification masts than using wobble (vibrate) them in smooth tubes and hope they grip.

Would be rather sensible to do as many mast bases as possible whilst line is shut. Before anyone goes can't do that as its unplanned expenditure, none of what is being done now was planned expenditure. The design for where masts go was all worked out about 8 years ago before work was stopped about 5 years ago.

 

[zwk500]

Would be rather sensible to do as many mast bases as possible whilst line is shut. Before anyone goes can't do that as its unplanned expenditure, none of what is being done now was planned expenditure. The design for where masts go was all worked out about 8 years ago before work was stopped about 5 years ago.

1. No Authority to do so (emergency works are only to put the railway back to operable state),
2. Would be a separate stream of funding otherwise every rail enhancement would find a major piece of infrastructrue to suddenly fail and pile in on the budget,
3. The design work would need to be rechecked at the very least, in no small part because of the recent events!

 

[Robin Procter]

It may have already been posted in this thread but I didn't find it : Latest I heard was 10th June was the currently expected reopening date for rail traffic.

 

[Mcr Warrior]

It may have already been posted in this thread but I didn't find it : Latest I heard was 10th June was the currently expected reopening date for rail traffic.

Yes, has been mentioned a few times upthread, hopefully there won't be any unforeseen 'slippage'.

(And that applies to the repaired viaduct itself as well as the line re-opening date!)

 

[Doms1]

Some photos of the site from yesterday afternoon.

 

[GRALISTAIR]

Some photos of the site from yesterday afternoon.

Thank you and welcome to the forum. Your first post I see.

 

[Taunton]

Bridge looks as though it could have done with repainting by now given the amount flaking off. Perhaps it was delayed due to the abutment issue.

I actually wonder whether the civils had identified it as a long term issue, but were hopeful that they could address it out of the electrification expenditure, as opposed to the routine maintenance and renewals budget. Then the electrification got cancelled ...

 

[GRALISTAIR]

I actually wonder whether the civils had identified it as a long term issue, but were hopeful that they could address it out of the electrification expenditure, as opposed to the routine maintenance and renewals budget. Then the electrification got cancelled ...

Was exactly what I was thinking and badly explained upthread.

 

[Benjwri]

I actually wonder whether the civils had identified it as a long term issue, but were hopeful that they could address it out of the electrification expenditure, as opposed to the routine maintenance and renewals budget. Then the electrification got cancelled ...

I was under the impression preparatory work for electrification was completed to Oxford. In The same way it was between Chippenham and Bath?