text: Concrete column saw cut spiral reinforcing - Demolition & Renovation engineering - Eng-Tips
  thread488-281721
  20 Sep 10 12:12
  I have a demo contractor that was to cut away a concrete beam framed into a round concrete column. The building is about 80 years old. A demo saw was used and the angle was wrong, they cut through the spiral tie reinforcing, about 40" of vertical length or 13 passes of the spiral. The spiral looks to be 3/8" smooth bar, spaced about 3".
  Has anyone successfully repaired something like this? How would you go about it? We've considered chipping away to expose enough to re-weld all the bars, although I'm not sure of the weldability of this metal. The other idea was to patch the concrete and wrap the column with steel plates or even FRP.
  RE: Concrete column saw cut spiral reinforcing
  msquared48 (Structural) 20 Sep 10 12:16
  The circular steel plates or FRP wrap would be the best option.
  JAE (Structural) 20 Sep 10 13:27
  csd72 (Structural) 30 Sep 10 10:21
  What is going to replace the beam at this level? If this section is going to be inside a slab then it will be adequately restrained in the final condition. Could be a temporary issue though.
  rscassar (Structural) 2 Oct 10 01:26
  It is a requirement of modern concrete codes the longitudinal reinforcement of concrete columns be restrained by lateral reinforcement so they cut spirals will need to be re-instated. My opinion would be the use of externally bonded CFRP. I am unsure whether there is any requirement to protect the CFRP for fire.