# Retaining wall problem



## concretemasonry (Oct 10, 2006)

The Anchor Diamond wall units have been used for years in the U.S. Those and similar reputable brands with approvals and testing have been accepted by by many for use a standards for contractors, DOTs, and municipalities in the U.S. and internationally for walls under 4' high but some areas put the dividing line at 5', but after that they must be engineered and can be used for up to 40' high walls.

You have to look closely at the installation methods and materials to see if it was actually done right right. With proper base, backfill material and drain tile (if used, but usually not necessary since the joints are open). Other wise put the contractor on notice of the problem, so they are responsible if there is a failure and they are still in business.

Dick


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## sippinjoes (Mar 7, 2011)

Their website says max 4' without reinforcing. I've never heard of installing a wall and expecting it to move or tolerating any movement especially that soon

Edit: what was the sand for? Depending on use it could slow drainage and increase hydro pressure.


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## concretemasonry (Oct 10, 2006)

sippinjoes -

Go back to sipping.

Sand can increase the drainage, but the velocity of the water drained may carry and silt or sand from adjacent materials down and plug any pipe or sleeves. The proper backfill is ideally a mix of sand and graded rock to provide a better drainage system and insure that wider area around the pipe or behind the wall can be dewatered. This dramtically decreases the lateral pressure on the wall and is commonly speced on earthen gravity dams because of the functional life and reliability. Anything like silt or clay would be the worst hing to use as a backfill.

The 4' was inserted in the product specifications since some codes have an arbitrary height limit of 4', while others accept 5' for dry stack gravity walls. Our municipalities usually have a standard plate showing a "canned" unengineerd design for use by the municipal employee crews, contractors and residents. The 4' in the specs is common for all recognized systems since it is conservative.

A segmental retaining wall (SRW to engineers) is classified as a "flexible" wall system that can move seasonally without loss of strength or stability and that is also why it is recommended to NEVER use a rigid concrete footing that can be destroyed by frost/freezing. The general concept is accepted, proven and is used internationally in all conditions.

Dick


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## sippinjoes (Mar 7, 2011)

Moderate use of sand makes since. I never considered putting it behind the wall. 

I would think the acceptable movement wouldn't be lateral? Sounds like frost/freezing would move it mostly vertical and if on a good footing never really be noticeable.

I guess I need to state I'm not an expert (or maybe I don't need to state). Thanks for correcting me. I really don't want to mislead people. Just want to learn myself.

Joe


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## jomama45 (Nov 13, 2008)

Is this a straight wall where it is clearly evident that's it's actually moving, or have you taken actual physical measurements to ensure that part of the wall has lost it's batter?


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## FMS (Jul 3, 2011)

*Retaining wall*

My retaining wall is straight and the backfill is rock (#57) and sand witha french drain. The movement is slight but noticeable because half the wall is straight vertical and the other half still has the expected lean in toward the backfill. I have notified the contractor because I too, am concerned about any movement after only two weeks.


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