retaining wall support

[hornet]

I am building a poured concrete retaining wall and at its tallest point it is about 40" tall then tappering down to about 20" (total length 120') my question is do I need to or should I install some sort of reinforcing material ie geo grid or some sort of anchoring system. On the filled side of the wall will be my driveway right up to my garage

[agla]

A poured concrete retaining wall of 40" high with a surcharge on it (added pressure by a slope, or driveway, or something else) is typically what is called a "cantelevered wall". It works in conjunction with reinforcement steel and a footing that forms an "L". The mechanism for the wall to stand up to the forces exerted against it is the mass of the material sitting on the tail of that "L". In order for the wall to topple over, the bottom of the "L" would have to lift that mass in theory.

These can be designed by engineers who would calculate the force, analyze the soil, and calculate how thick the wall should be, how much steel needs to be in it, how wide the footing needs to be, what mix of concrete, ....

If you just pour an 8" wall on a 16" footing, it may or may not work. A wall failing while your putting the car in the garage with a kid playing on the other side would be aweful.

If you are not going to have it designed by a structural engineer, I'd rather see you do it out of modular block with geogrid. At least it would not be a 40" high slab of concrete flopping over onto someone if it failed.

I'M REALLY SICK OF PEOPLE ASKING FOR HELP, BUT WILL NOT GIVE US THE COURTESY OF LISTING A STATE OR PROVINCE!

[Paul]

agla he did on his intro thread http://groundtradesxchange.com/forums/showthread.php?s=&postid=40565#post40565