A90 at Brechin- why has there been so many repairs?

[slf2012]

I travel the A90 occasionally and am always frustrated at the quality of the road at the Brechin bypass.

Normally when road is dug up it’s to allow services to be installed or modified, but I can’t understand why this piece of road has had so much work done to it. It’s almost as if it’s been dug up and badly repaired every 10 mtrs or so.

Does anyone know the reason for this?

[trevalvole]

Yes, it is bad. On the rare occasions I travel on it, if it is quiet then some people drive in the northbound outside lane as it is better than the inside lane, presumably due to fewer HGVs.

I have some recollection that the underlying road surface might be concrete laid in sections, perhaps that's part of the issue? And perhaps the repairs are at the joints between these sections? I also recall that the northbound carriageway is much worse than the southbound one - may be for historical reasons - I don't know if this section of the road was ever single carriageway?

Edited by trevalvole on Thursday 3rd October 18:48

[dlks151]

This section is one of the few remaining sections of concrete pavements. The replacement of this would mean full carriageway reconstruction which due to the fact the slab extends over both running lanes would mean complete closure and the A90 going down to single lane Contraflow for a very considerable period of time.

Its currently a case of mend and make do until Transport Scotland can find some money I’d guess.

[trevalvole]

Thinking about it a bit more, I have a vague recollection that the road was originally single carriageway and that the southbound carriageway was built to the east while traffic continued to use what is now the northbound carriageway. That would explain why the northbound carriageway is concrete and in much worse condition than the southbound one.

[slf2012]

The concrete base would make sense right enough. They seem to have repaired a lot of the southbound carriageway a few years ago so hopefully the rest will follow as money becomes available.

[Desiderata]

It's very similar construction to how the M9 passing Stirling was originally, concrete slabs as "floating" foundations. It was fine for the first few years, then the slabs settled unevenly until the whole stretch became a giant rollercoaster. I'm not sure about the A90, but the M9 was laid over the flood plain for the river Forth, basically an enormous bog for thousands of years until it was drained for farmland relatively recently. I remember digging down over 7 metres at one point to find solid ground only to find the hole filling up with water as the tide came in further down river.
They rebuilt that section of the M9 one carriageway at a time using enormous quantities of shale as a foundation the second time.

[rossybee]

trevalvole said:

Thinking about it a bit more, I have a vague recollection that the road was originally single carriageway and that the southbound carriageway was built to the east while traffic continued to use what is now the northbound carriageway. That would explain why the northbound carriageway is concrete and in much worse condition than the southbound one.

I'm old enough to remember the Brechin section still being single carriageway - can't recall if it was the northbound section as would have been at least 30yrs ago!!!

[Patrick Bateman]

This is the longest poor stretch of tarmac I’ve ever experienced. I sit in the outside lane going north when it’s quiet enough, much better than the inside lane.