Concrete Column Splice Repair
Concrete Column Splice Repair
(OP)
I am currently investigating an option to repair concrete columns, which would adjust the Class A lap splices to Class B lap splices, so that the columns can take direct tension, as a result of net uplift.
I was curious if anyone has had any experience with this. My thoughts were to either splice the lower bar to upper bar with a mechanical connector or to splice additional length onto the lower bar and extend the lap length. Offset bars may complicate the mechanical coupler option.
I am also concerned about how the re-concreting operations might work. The columns are supporting a PT slab and I am very concerned about movement that might arise from concrete consolidation, shrinkage and jacking operations.
If you have any insight, I'd appreciate it.
I was curious if anyone has had any experience with this. My thoughts were to either splice the lower bar to upper bar with a mechanical connector or to splice additional length onto the lower bar and extend the lap length. Offset bars may complicate the mechanical coupler option.
I am also concerned about how the re-concreting operations might work. The columns are supporting a PT slab and I am very concerned about movement that might arise from concrete consolidation, shrinkage and jacking operations.
If you have any insight, I'd appreciate it.






RE: Concrete Column Splice Repair
RE: Concrete Column Splice Repair
As for concrete, a form and pump could work with the right admixtures and the right contractor. Avoid excessive water in the repair mix to reduce shrinkage issues. Get with a local Sika or Ciba rep and the contractor to be sure the right material gets used properly. And when a contractor says "oh, yeah, I can do that" don't believe him, and require the material supplier to be present for the prep and pump operations. (I have experience with this.)
Another problem may be finding a way to jack the floor(s) above, since an elevated slab below will not have sufficient shear capacity to hold that kind of load. It will have been designed for just what it needs, and not for everything above.
RE: Concrete Column Splice Repair
RE: Concrete Column Splice Repair
An expert is a man who has made all the mistakes which can be made in a very narrow field
RE: Concrete Column Splice Repair
The ready-mix and admix rep (from Euclid, Sika, BASF, etc.) can advise you on how to get it to pump properly, consolidate without much, if any, internal vibration, and reduce the risks of segregation, incomplete filling, and drying shrinkage.
If the lift will be fairly high and the volume of concrete warrants it, you might do it in two stages, one with forms which are open to the top; just pump and vibrate, leaving a rough top to accept the final segment. Then form and pump a layer to span the gap between new below and old above. Usually, the added cost of mobilizing the pump twice makes doing it in one run more economical.