construction joint - basement wall (concrete)

[PSUengineer1]

Hi. I have a concrete basement wall about 12 inches thick and about 8 feet high. The plan dimension of basement is about 24 feet wide and about 34 feet long.

My client is asking if half of the basement wall can be cut out and replaced with new concrete. Keep the footing.

I am requesting comments, code references, and typical details in regard to the two questions below:

1. is this feasible, and would you dowel post-installed reinforcing into existing wall? (a through e general outline)
a. remove backfill where conc. is to be demo'd
b. demo wall, including cutting off vertical steel
c. dowel new steel reinf. into existing footing
d. pour new wall and brace the wall until first-story joists are set
e. backfill w/ bracing in place

2. what is a good way to detail the construction joint? (a and b general outline)
a. apply a bond breaker between the existing and the new pour, prior to new pour
b. waterstop for construction joint (along wall and footing).

Thank you in advance for sharing comments, code references, and typical details.

 

[spieng89]

I'd detail it similar to if it was new construction except as you mention doweling into the existing footing and adjacent walls. Reinforcement would need to be designed for shear friction as well as lapped with wall reinforcement to develop the reinforcement within the wall for mid span bending. Add waterstop at all joints as well as mentioned. i can't think of any other items to note. I'm not sure if I'd apply bond breaker at vertical joints though. I'd rather add additional rebar in wall to keep the shrinkage cracks tight and have the extra adhesion at joints for possible water intrusion.

 

[darthsoilsguy2]

1. yes to all except e which might be unnecessary if 1st floor framing is attached in a way that assures top restraint.
2. did you mean to say "bond breaker" because the bond will already be pretty darn broke? maybe you meant "bonding agent". b) bentonite waterstop strips are good for concrete joints for anything 8" or more of wall thickness (if less the strip swells and spalls the concrete). Put the strip in the middle of the wall section and attach directly to existing concrete. They work better in a recess but you don't have to do that.

Why would you want to do this though? and if so... Why keep the footing? without knowing anything else.... it seems the footing will cost more to salvage and incorporate into the new wall than it would to cut it up into chunks and dispose of.