Dry-stack retaining wall repair/reinforcement

Old 03-07-05, 10:01 AM
Visiting Guest
Posts: n/a
Dry-stack retaining wall repair/reinforcement

Hello Everyone,

The back of my property is a rather large upsloping hill (25 feet at 70 degree angle) the top is a three tiered garden patio area that has been over grown for years. I am looking to clean it up and use it. My concern is the 2 retaining walls on two of the tiers. They are both between 4-5 feet high and are made of dry stacked concrete slabs. They appear to be slabs of concrete/rock from another site that were used. They appear from sight and touch to be very sturdy but given I live in Southern California and they are above my house I figure I should make sure they are safe. It looks like at some point there were Chain link fences right up against the wall- I would assume to aid them. I know this is a very broad question, but short of hiring a contractor out to tear them down and rebuild is there something that the DIY'er can do to assess their strength and possibly reinforce them with mortar or some sort of structure.

thanks for your insight.
Old 03-07-05, 02:08 PM
Join Date: Nov 2001
Location: Taylors, SC
Posts: 9,261
Upvotes: 0
Received 0 Upvotes on 0 Posts
You could hire a structural engineer to assess the walls. I would not be inclined to reinforce them if it were not needed. I would not simply replace them for the same reason. Sometimes it is good to have the experts involved.

Hope this helps.
Old 03-07-05, 06:50 PM
Join Date: Mar 2005
Location: USA
Posts: 5,650
Received 1 Upvote on 1 Post
Dry-stacked retaining wall repair/reinforcement

I would definitely have someone look at the walls. They may be only 4 or 5 feet high, but they are above your home and are in an area that has seismic activity.

In most areas of the county, anything over 4 feet should be engineered even if there is little or no seismic activity.

Specially concrete units have been used very succesfully around the country, but the walls are normally engineered if over 4 feet high. To give you an idea of the applications and limitations take a look at the web sites by submitting segmental retaining walls to Google.

A good gravity wall has two important features. The first is embedment or restraint at the base to prevent sliding (rain makes it easy to slide). The second is some way to prevent the block from sliding relative to each other. Manufactured units rely on shear keys(projections on the top or bottom) or pins to provide horizontal shear resistance. If you have reused concrete slabs or flat slabs I doubt they have enough shear resistance. Weight is not enough alone if the wall does not act as unit.

When if comes to soil, gravity and mother nature should be respected.
Old 03-08-05, 09:47 AM
Visiting Guest
Posts: n/a
thanks for the great advice. You are right and I should leave it in the hands of the professionals, I was really hoping to not have to throw out the money for the inspection- expensive. thanks again.

Thread Tools
Search this Thread
Ask a Question
Question Title: