CMU Retaining Wall leaning forward 1

[nmdeveloper]

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?

 

[Doc09]

A 0.5in is not much I agree. However, 2.5" should be looked at more in details. It would be nice if we can
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.

 

[bridgebuster]

Here's a wall we looked at - 300' long, up to 20' tall. Some sections had displaced up to 6" at the joints.

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.

 

[Doc09]

bridgebuster, thanks for the pic.

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.

 

[bridgebuster]

Doc,

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.

 

[Riggly]

apsix,
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.

 

[apsix]

The basis of the design of a cantilever wall is a rigid wall to base joint.
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.