Grade Beam Control Joints

[DCBII]

What considerations are important for grade beam control joints? Are there any special requirements for lap splicing reinforcement across control joints? This particular grade beam will be tied to a slab. Do I need grade beam control joints everywhere there is a slab control joint or can do every other one instead?

 

[ATSE]

At the risk of seeming uptight, terminology is very important when talking about joints in concrete.
"Control Joint" is ambiguous.
I believe ACI uses the term Construction Joint for what contractors term as a "cold joint." That is, a break in the pour. It is the engineer's responsibility to define the continuity (or not) of reinforcing across the joint.
Are you referring to a "Shrinkage Contraction Joint?" Here the reinforcing may be reduced to 0% or 50% - this is used primarily in slab-on-grade construction, and not for structural slabs.
If the grade beam is carrying axial load (interconnecting columns) or bending load, use a construction joint with 100% reinforcing running thru the joint.
You can have SCJs above and still have continuous reinf in the grade beams below. Cracking will be more unpredictable (that is, more than usual). Use sealant in the SCJs.

 

[ToadJones]

I always referred to a cold joint as an accidental joint in the concrete caused by trucks not showing up on time, leaving the concrete that was poured first to cure and thereby ruining what was supposed to be a monolithic pour.