Viaduct or Embankment - What Came First

[Andy873]

I know this will sound a very basic question, but I have wondered about this for a while.

Here I will mention Martholme viaduct, it carried the line 65 feet above the river Calder, and high embankments had to meet it on both sides.

On the Western side of the viaduct embankments were being constructed towards it for around 1 mile.

Knowing where the viaduct is going to be, would you start building it before the embankments got there?
Wait until you got to the river itself?

This might sound a rather basic question but it comes from the fact that the embankment on the Western end (even though the tip was closed) was said to be subsiding at a rate of 4 feet per day. You could end up with the viaduct being much higher than the embankment.

It is not said if they waited for the embankment to settle then build the viaduct to meet it at the settled height etc...

What was the common practice?, thoughts please?

EDIT: The era was around the 1870's in this case.

Thanks,
Andy.

 

[randyrippley]

I would have thought that as the viaduct would be a slow job needing skilled masons while the embankment just needed sheer musclepower and could be done quickly, that the viaduct would be started first with the intention of simultaneous completion. However it can't be quite that simple as the ends of the viaduct need the embankment in place to hang off, while access restrictions may mean that building stone and materials are best brought to site along the finished trackbed and lowered down to the building site, rather than being dragged across winding lanes and boggy fields

 

[LWB]

By Googling “building Ribblehead viaduct” and selecting ‘images’, contemporary drawings of the work in progress come up. To me these suggest that the abutments were built before the embankments were placed.

 

[Snow1964]

This photo might help, it shows the construction of the Bourne valley viaduct (when lines linking Bournemouth East to West were built) 1888 (this was closed in 1960s), the currently used viaduct on the direct line to Branksome was built 5 years later

It appears one embankment is built, and they are tipping off the other end of the viaduct to make second embankment.

Can also see the thicker pillars between sections, I understand have to build all the sections between the slim pillars at same time as the side thrust of arch would push them out, the wooden falsework supporting the nearest arch whilst bricks are laid is clearly visible

Picture of the Day: Bourne Valley viaducts under construction in the 19th century

The Victorian brick-built railway viaducts in Bourne Valley still stand proud today, this fascinating photo shows the construction back in circa…

www.bournemouthecho.co.uk

 

[High Dyke]

With the new southern relief road, at Grantham, the embankments are being constructed before the viaduct over the River Witham / ECML. However, stability issues have delayed the project.

BBC News - Grantham relief road delayed by up to 18 months and over budget

Grantham relief road delayed by up to 18 months and over budget

The Grantham southern relief road scheme was due to be completed by 2023, but could now run until 2025.

www.bbc.co.uk

Richard Davies, executive member for highways in Lincolnshire, said a section of "soft, unstable ground" had been identified where a new bridge over the East Coast Main Line and River Witham was being built.
"During construction of the relief road's new bridge, the on-site team found the ground on the eastern embankment had moved," he said.

 

[Rescars]

This may be a bit far removed from the OP, but travelling over the M6 Toll, you'll come across the Litchfield Canal Aqueduct, totally unsupported at either end! It's been like this since the road was built.

 

[Andy873]

Great points everyone, thanks.

With the new southern relief road, at Grantham, the embankments are being constructed before the viaduct over the River Witham / ECML. However, stability issues have delayed the project.

BBC News - Grantham relief road delayed by up to 18 months and over budget

Nothing new then! on my old line the embankment had problems in three places and because of that the line was eventually opened 6 years after originally planned.

Thanks,
Andy.

 

[MisterSheeps]

By Googling “building Ribblehead viaduct” and selecting ‘images’, contemporary drawings of the work in progress come up. To me these suggest that the abutments were built before the embankments were placed.

Correct, WR Mitchell's book 'Thunder in the mountains' about Ribblehead Viaduct says the end piers, seemingly part height, are full height. It got me thinking, why it was built as a viaduct? ... take a walk over Blea Moor, and see the extensive spoil heaps, ditto at the N end of the tunnel, and it seems as if you could have obviated the need for the viaduct, simply had a high embankment, an accommodation bridge and a high wall to shield passing trains from wind! One of the 1980s renovation ideas was to cover the viaduct in fill, as was done at Skinningrove (NER Saltburn - Whitby), and Eaton (GN/MR Jt Eastwell branch).
In terms of the piers, the obvious determinant is the depth to a solid foundation ... some of Ribblehead piers are 24ft through moraine to the limestone. The converse is spectacular examples such as Landwasser Viaduct, sprung from a vertical cliff.

 

[Pigeon]

take a walk over Blea Moor, and see the extensive spoil heaps, ditto at the N end of the tunnel, and it seems as if you could have obviated the need for the viaduct, simply had a high embankment, an accommodation bridge and a high wall to shield passing trains from wind!

Bit soggy for that. Batty Moss, after all.

Not as bad as Dandry Mire though, where they thought they were going to get away with just an embankment but it turned out that both the substrate and the fill were basically thinly disguised liquid and nothing would stay put. I think they had to go something like 30m down before they found anything firm enough to found the piers on. The waves of slumpage along the sides of the embankment are still very obvious today.

 

[MisterSheeps]

One of the interesting things about the S & C is that it was built late on, so there are photos and copious plans, ditto the GC London Extension, and you get an idea how they were built, such as timber arch formers to make the masonry arches. Re the Ribboehead, I would question the decision to make much of it in limestone, is much more weathering prone than is the gritstone edge & coping stones

 

[randyrippley]

One of the interesting things about the S & C is that it was built late on, so there are photos and copious plans, ditto the GC London Extension, and you get an idea how they were built, such as timber arch formers to make the masonry arches. Re the Ribboehead, I would question the decision to make much of it in limestone, is much more weathering prone than is the gritstone edge & coping stones

But from a mason's point of view limestone is a lot easier to quarry and work. To use the millstone grit would have needed a bigger skilled labour force (masons not navvies) and would have slowed the job. You may have had problems finding enough with experience of working Gritstone - it's damned hard and blunts chisels, wedges and feathers

 

[MisterSheeps]

But from a mason's point of view limestone is a lot easier to quarry and work. To use the millstone grit would have needed a bigger skilled labour force (masons not navvies) and would have slowed the job. You may have had problems finding enough with experience of working Gritstone - it's damned hard and blunts chisels, wedges and feathers

That's a good point ... I was thinking of sawing, which was used in the slate industry, though maybe slate is softer. There were masons on the contract, the stone coming from Littledale (where the aqueduct & track crosses near Blea Moor tunnel), but navvies would be cheaper. It, and every other Victorian era built line, were amazing achievements, horse, cart, manpower & some steam cranes.

 

[Pigeon]

Yes, you can get away with sawing slate using suitably treated steel for the blades. Millstone grit would have rapidly reduced them to plain discs. You'd be needing diamond blades to last reasonably well on that, and the S&C was a bit early for that development.

 

[MisterSheeps]

Interesting ... I was out cycling Wednesday, idly examining the coping stones at Aisgill Moor overbridge, have squared corners but knobbly tops ... seemed too uniform to be chiselled. I know some sandstones were sawn, as is Bath stone, in both cases you have to do it ASAP after removal or they case harden.

 

[Pinza-C55]

When the Queen Alexandra Bridge was built in Sunderland, the approach spans were built first then the main span was built out from either side before finally being joined up. BTW minor point is that the North Eastern Railway didn't use the word "Viaduct", only "Bridge" so the viaduct at Berwick On Tweed is the Royal Border Bridge.

The Sunderland Site Page 004

 

[Pigeon]

Interesting ... I was out cycling Wednesday, idly examining the coping stones at Aisgill Moor overbridge, have squared corners but knobbly tops ... seemed too uniform to be chiselled. I know some sandstones were sawn, as is Bath stone, in both cases you have to do it ASAP after removal or they case harden.

Probably they split them, at a guess, with plug and feathers. Occasionally you get to find a stone block that still has half the hole in it.

Gritstone is technically a felspathic sandstone, ie. one with a silicaceous binding material, which in this case means "quartz-like" and so it is jolly hard (although the word covers a multitude of sins and the cases where it means something closer to "clay-like" still get to be soft). The alternative is a carbonate-based binder, which generally results in a softer sandstone, although again the range is pretty wide and some types are far from soft.