Contraction Joints in Retaining/Detention Walls

[sponcyv]

I have a detention wall that is 16" thick. Our typical contraction joint detail shows 3/4" chamfer strips on each side with pvc waterstop at joint. All reinforcement is cut 2" clear of each side of joint. I have used this detail with success on numerous walls. The crack occurs within the chamfer and then is sealed with the specified joint material. ACI 224 states that the joint needs to be 1/4 of the wall thickness minimum to ensure a crack. How does everyone out there detail their contraction joints? I have seen numerous engineers use the chamfer strip on each side. How is the joint formed using the minimum 1/4 thickness?

Thanks in advance.

 

[ATSE]

Is this a shrinkage contraction joint or a movement joint or a construction joint? Terminology is important here.
Is this a watertight joint? If so, then you should be using ACI 350 and the horiz reinforcing should extend thru the joint; otherwise, the joint will behave more like a movement joint.
Horiz wall reinforcing should be much more than minimum shrinkage and temperature (0.002bh). More like 0.005bh.
For sealant on the outside (such as for Sikaflex 2c), a square groove with backer will work better than a V-groove.

 

[sponcyv]

It is a contraction joint which is used as a temperature/shrinkage joint. We use expansion joints for movement and construction joints and contraction joints for non movement. It is a watertight joint hence the waterstop but the reinforcement does not extend through the joint. This is a full contraction joint, which no reinforcement is carried through. ACI 350 allows partial or full contraction joints. A partial is only allowing up to 50% of the reinforcement through the joint. Minimum temp shrink is actually 0.003bh since joints are spaced at a maximum of 25 ft. on center.