[Pelican]

I'm bidding a retaining wall of Unilock Roman Pisa. A portion of the wall will be on a slope that is 45 degrees or more. I've never worked under these conditions and have some concern about the stability of the footing and slope after the wall is built. The wall will be nearly 4' high on this section and will be holding back soil behind it to form a level yard.

Are there any special concerns or steps to be taken to ensure the wall does not want to slide down the slope over time? Thanks!

[Stonehenge]

You'll have to bury more than a couple courses. You might contact Unilock, or the designer of the Pisa system (I can't recall the name at the moment - Dan D? Help?) to get a sense for how many. Wouldn't hurt to talk to an engineer, too.

[4seasons]

Risi Stone makes pisa.
I agree go with an engineer

[Paul]

You may have to start with grid at your first layer, and as we all know an engineer is the best choice in this mater. Unilock can give you some good guide lines.

[Stonehenge]

Believe it or not I just got a note from Bill Schwab about this thread. Here's what he had to say:

He is placing a wall in the center of a slope. So, he has a global
stability issue. What will seem to be a 4' wall out of ground is going to
have to be about 3' below ground in the footing on a 2-1 slope. Typically,
he will need grid at the base course, then every 18"

I would not recommend Roman Pisa for this application, he will need
something more substantial like a Keystone pinned system.

Typically, he will also need a make the face of the wall 7' in using the
place where a level would exit the face of the slope to keep the wall in
place.

He also attached this quick sketch:

[HRLand]

What's up with Bill? I haven't seen a post from him in about a year or 2.

[Pelican]

Thank you all for your responses, and thanks Bill for jumping in here! I don't have a scanner and don't know how to use paint well enough to show my conditions, but Bill is close, the difference being that the grade behind the wall will be level rather than an incline as shown.

I had a feeling this application wouldn't be straightforward, I appreciate everyone's input.

[Stonehenge]

Bill said he's been extremely busy, and that things are going well for him.

[4seasons]

I agree Roman pisa shouldn't be used either.
Seems like when they are tumbled they just dont seem to be as stable as regular pisa.
meaning...
the groove and nub are a lot more loose.
Still think it looks good when someone can afford to put one in though.

[HRLand]

If you want the tumbled look with a pinned system you could use keystone century wall.

[NCSULandscaper]

or versa-lok tumbled standard or mosaic

[AZTLANLC]

Steve last year we started using Keystone products and I can really tell you that they know about wall systems if you need the phone number for my supplier I can e-mail it to you or just pm me, he can surely ship it to your job site and also the price is much more competitive than roman pisa.

[Hardscape Hank]

Originally Posted by NCSULandscaper

or versa-lok tumbled standard or mosaic

Call their national office at 800-770-4525 and ask for engineering. Theire weathered product is beautiful and their pinning system much easier to install than Keystone.

[Uni Bob]

Just some facts vs. miths. Pisa 2 or Roman Pisa...135 lbs/face foot. There is also data showing that it meets or exceeds any pin system for grid pullout. I am not saying it is better then any other system, however it works easily as well as any wall that is 12" deep.

So with that in mind there is no reason the Pisa system couldn't handle anything Keystone, Versa-Lok, Rockwood or Mesa would do. It is just lighter per unit, but still the heaviest wall in the 12" deep class of wall.

The global stability is the true problem there and you should contact your local rep and perhaps on that project an engineer would be a very good thing.