Paging the builders

I've got a FO huge stone retaining wall that is leaning outwards and
looking like at some point it's going to collapss.

I'm thinking of propping it up wiv some buttresses.

I plan to:

1) dig out some foundations and cast some concrete 'plates' (couple of
feet thick) for the buttresses to sit on

2) build some buttress-shaped wooden shuttering that 'look about the
right shape and size'

3) fill with concrete

4) hope it's enough

Have I missed anything?

/Simon

 

One assumes that you will do this *after* propping the wall up in a
suitable manner?

 

Well I'm not sure how I could do that. I'm not planning to dig under the
wall at all, just close to it, at intervals. Hopefully whilst remaining
a diggers arm distance away from it just in case I guess.

I doubt the wall itself has any foundations.

 

<error circular reference>

If the wall is leaning enough for you to be concerned, and you doubt it
has any foundations - you really don't want to be digging anywhere near
it, without supporting the load.

Are you also wanting to reset the wall to upright, or happy to have in
angled but buttressed?

FWIW I would get hold of some of those, umm, forgot the name,
scaffolding building supports that are extendable. Acros? Wedge them in
at 45 degrees or so and extend them to just take the load. Then do your
digging and foundations etc.

How are you intendeding to tie the buttresses into the existing wall?

 

Yes , you need to support the wall prior to any works

You need to make the 'plates' wide as well as deep as it spreads the
loading .


You need some reinforcing bar placed and protruding out of your
concrete plates to stop lateral movement of butteress

You need to tie the butteress to the stone wall

You will need reinforcement bar in your butteress


When you fill your shuttering you need a vibrating poker to get the
air voids out

If you can cast in one it will be better but its not essential

 

Just digging next to it is enough sometimes to make it all go
pearshaped


Make up a couple of raking shores


6x3 against the wall prop it with similar timber wedged into the
ground and staked , brace to the lower edges along the greound with a
rip of 18mm ply 200mm wide both sides , from lower corner to centre
of brace attach another piece of ply this makes it rigid

When you have both in place tie along the top and but 2 corner braces
in followed by a timber about midline if the walls over a meter high


This should help to retain any stonework

 

GAMI. A dodgy wall, if collapses, can land you in a mountain of
trouble. We just had a small brick low garden wall that was rocking a
bit, and we had it torn down and properly rebuilt.

 

But *don't* get a Vauxhall Astra in:
http://www.facebook.com/photo.php?pid=584264&l=a6942e0e7b&id=613998892
http://www.facebook.com/photo.php?pid=584266&l=7d68dba486&id=613998892

 

If this is a rough stone wall, i.e. no bonding, it will still collapse,
you might just delay things slightly. The only long term repair is
rebuild from foundation upwards - nasty big job.
If it's dressed stone with a bond, like brickwork, your plan may
work[1][2].

[1] buttresses can be comparatively thin, but must spread load to a pad
with a vertical component, in order to resist horizontal loading[2].
[2]Theoretically.

 

Sounds like sensible advice, ta.

I reckon there's no chance of resetting it. It's near on 2ft thick, and
about 2m[1] high.

Yep, got about 10 acros.

Good question. Maybe ramming in a load of steel bars sticking out of the
wall?


[1] yeah I know, no worse than ordering 3m of 2x2

 

Yes. But it's not a house wall, if that's what you were thinking.

 

Ok, and sticking out of the wall wouldn't harm either I guess?

See above.

In addition to the 'tie' bars?

Was hoping to do it a mixer-load at a time - I don't think I could get a
lorry there.

 

hmmm. I wonder how long delay slightly is.

The only long term repair is

Indeed. Don't forget expensive.

 

I had one of those, it fell on my Volvo

 

Wasting your time if the buttresses are futher apart than six feet or
so. Eventually the wall will bulge out and collapse in between them.

Demolish and rebuild - preferably with some canal bank siding and a
stone face. Quick and simple.

 

hmmm. Still think that would be pretty darn expensive. The only plus
side to that is that I could use the stones elsewhere.

For those that are mildly interested, the wall I'm talking about is in
the middle of this picture:
http://www.flickr.com/photos/58125090@N00/4473384634/

 

In message <>, Simon Wilson

I like this one:

Optimism is often overlooked...

 

Is it just a wall, or holding back an earth bank?

 

I looked at your picture. How deep is the stuff that's retained?
How tall is the wall?

Thats a big wall to be digging near. Seen how quick they fall?
I was nearly killed by one that tall (not so long) 20 years ago.
I saw it 'sway' out of the corner of my eye and moved away.
It's about as quick as clapping your hands...........

Don't forget about depth and pressure.Half a psi per foot....
Make sure the shuttering can take it.

Throwing it in from the top has broken many a shutter...............

Buttresses do work and it's all common sense.

Is the ground hard enough to support them?
If the walls stone; then the concrete will get a good enough tie against
the wall. Other wise; some ties..
BIg enough that the big wall simply pushes them out of the way when it
goes..

Might be easier to pull it down and rebuild it?

 

Thats probably the best option you mix what you want and you wont be
tempted to dig everything out first .


One trick we learned years ago was have the ballast delivered in 1
tonne bags , lift them with the digger and place them against the
wall , gives added support

Looking at the picture your going to require quite a few tonnes