Foundation Wall Control Joints
Foundation Wall Control Joints
(OP)
Have a 60' long concrete sandwich wall at the rear of a house. It has a 9 1/2" outer wythe, then 3" of foam and a 4" inner wythe. The wall is designed as a cantilevered retaining wall but is the foundation wall for the house. I have #4 @ 18" O.C. horizontal and #5 @ 18" O.C. vertical. I showed control joints at 20' O.C.
How are the control joints be made? Do they put some bond breaker in the form? Also, should I terminate the rebar at the joints?
Thanks
How are the control joints be made? Do they put some bond breaker in the form? Also, should I terminate the rebar at the joints?
Thanks






RE: Foundation Wall Control Joints
Not sure what your basement wall height is, but I usually try not to exceed a panel ratio of 1:1.5 for control joint layout. Typically I see them install triangular chamfer strips into the formwork that create a vee notch in the wall when the formwork is removed.
They should oil the forms for easy release. Run the bars through the control joints. That way, when the wall cracks at the control joint, it will still be held together by the rebar.
RE: Foundation Wall Control Joints
RE: Foundation Wall Control Joints
RE: Foundation Wall Control Joints
It is an unusual situation using a Thermomass wall. The 4" wythe is the actual the gravity load carrying portion. It is reinforced also. The 9 1/2" wythe extends about 14 ft up to the bottom of some high windows on the main level and only has about 5' of backfill on it.
RE: Foundation Wall Control Joints
RE: Foundation Wall Control Joints
Also curious about the slenderness of the 4" inner wall. As I understand your post, that is carrying gravity loads.
Are the two "wythes" tied together somehow? Not thinking of composite behavior but just bracing for the 4" layer.
Not familiar with the term "bookend". Is that the same as counterfort?
RE: Foundation Wall Control Joints
@Houseboy - The 4" wythe is tied to the 9 1/2" wythe (google Thermomass Walls). Bookend just means a typical cantilevered retaining wall footing - which is essentially how a bookend works.
This is a very expensive house with a high profile Architect as the owner. He does not want to see any cracks if possible. If the majority of the wall was covered with dirt, I probably would not have worried about it.