Pouring fresh concrete over half cast columns

[Sheraz Khattak]

Hello everyone
The column height in the structure is 11 ft. The columns had been cast already but then demolished to a height of about 3 ft i.e columns that are currently standing are of 3 to 4 ft. The columns ar 12 in x 18 in. I need to pour freah concrete over these pre existing columns to raise them to 11 ft height. These columns are in the basement rising from the raft. Will using sbr and providing holes for the fresh concrete to create a lock be enough? Any research papers related to this will be very helpful. Thank you.

 

[hardbutmild]

Could you provide a sketch of the current state of the column and the solution you propose?

 

[r13]

I suggest to demolish the 3' stubs to the floor elevation and rebuild the columns. If all rebars are spliced at the floor level, I would rerun my model with columns pinned, and modify affected structures above.