CMU Retaining Wall leaning forward
CMU Retaining Wall leaning forward
(OP)
I'm investigating a wall that is approximately 300' long and 10' high. the wall is leaning out away from the retaining side by 1/2" - 2 1/4" inches. The contractor is claiming that 2" out of plumb in 10' vertical is an acceptable industry standard (this is in New Mexico, bear with me) my position is that there is no allowable tolerance for being out of plumb. I'm having a hard tme finding anything published that states one way or the other. Beyond common sense, does anyone know of a resource to answer this?





RE: CMU Retaining Wall leaning forward
My guess is that either the footing is too small or the reinforcement is not in the right place. Either way, the leaning will probably get worse.
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
civilperson is correct in that the face should have been battered, but it is seldom done with CMU walls. If this movement has occurred in a short period of time, it is beyond normal.
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
realistically (for construction tolerances...not movement) from my perspective, a "good" wall is within a 1/2" or less and an "kinda sorta okay" wall is 1" or less for a 10' height. however, i have seen fairly strict construction tolerances from the EOR for CIP retaining walls.
and never take a contractor's word for anything...whether you actually know the answer or not...
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
It doesn't matter in which face the wall is reinforced, that could not explain a lean in the wall, maybe cracking, but not a lean. The wall is rotating, apparently about the toe, so it is a global failure rather than (or additionally to)a structural one. My first guess would be that the fill used behind the wall is significantly weaker, or more poorly drained, than assumed in the design. My second guess would be that the foundation soils are weaker than assumed and aren't strong enough to support the toe pressures.
RE: CMU Retaining Wall leaning forward
This question has been asked and answered.
Back to basics indeed. If the reinforcement is in the wrong face, as the OP has found is the case, the wall certainly will lean.
RE: CMU Retaining Wall leaning forward
RE: CMU Retaining Wall leaning forward
I find it difficult to design with this assumption.
I always assume a cantilevered wall has a fixed connection to the base.
I know the question has been dealt with, but I wouldn't be suprised at 0.5" movement at the top of a 10' wall.
RE: CMU Retaining Wall leaning forward
have the wall's dimensions.
There could be several reasons for these deflections one of which is construction procedures. Did the contractor perform any compaction behind the wall ?
If not, I am willing to bet that the 2.5" is occurring towards the middle of the panel and the 0.5" towards the edges. If that is the case, the design should be looked at again. It does not necessarily mean that the wall is going to fall (we're reinforcing a 100' long wall that bulged and tilted in excess of 4" and it has been holding for the past 2 years), but it should checked again to make sure that it is inded performing as it should.
RE: CMU Retaining Wall leaning forward
We never quite came up with a reason. There were no drawings to be found and the owner didn't want to spend the money.
RE: CMU Retaining Wall leaning forward
If you model such a wall and assume say a thickness of 8-9" the expected deflection with a fill with a friction angle of 30 degrees, the expected deflection is in the order of 4-5" assuming no hydrostatic pressures.
RE: CMU Retaining Wall leaning forward
The wall didn't have any weepholes. The upper side of the wall supports a service road that sees quite a bit of bus traffic. At the time of our first inspection in 2005, the asphalt pavement and drainage was in poor condition. A month after our first inspection we went back to check and discovered that some sections had moved up to 2".
The is a water main and sewer underneath the service road. Our assumtion was that one or both were leaking and building up the hydrostatic pressure along with the poor surface drainage.
Our client decided not to investigate and just braced the wall. It's presently under construction.
RE: CMU Retaining Wall leaning forward
Are you saying that you believe there is a rigid connection between the base (which is normally a thick reinforced concrete section) of the retaining wall and the vertical CMU portion? You are implying that the base slab will rotate at the same rate as the CMU portion? For a thick reinfoced wall, I could imagine that, but not CMU.
RE: CMU Retaining Wall leaning forward
A CMU wall is slightly less stiff than a CIP wall of the same thickness, but not enough to class it as having a flexible conection to the base.