Concrete shear transfert between new and existing
Concrete shear transfert between new and existing
(OP)
I would like to know a reference or a method to calculate the shear transfert of a new concrete beam to a concrete existing column.
News rebars will be anchored on the side of the column, I don’t know if I can use the steel area of the rebars to transfert the shear?
Thanks
Waldo





RE: Concrete shear transfert between new and existing
RE: Concrete shear transfert between new and existing
Best to use dowel bars to transfer the shear if this is possible.
RE: Concrete shear transfert between new and existing
RE: Concrete shear transfert between new and existing
For concrete cast against hardened concrete not roughened to a full amplitude of approximately 1/4", shear resistance is primarily due to dowel action of the reinforcement.
Waldoa, I would only use the shear capacity obtained by the reinforcement. If I were placing my stamp on this design, I would not count on the new-old concrete friction shear capacity.
RE: Concrete shear transfert between new and existing
Another option may be to attach some kind of steel saddle seat to the face of the existing column, where the vertical leg of the plate is plumb against the existing column and the horizontal leg sticks out from the face of the existing column into the bottom of the new beam. I'd use "stiffeners" at each edge of the plate. Use epoxy or other anchors to attach the bent plate seat to the existing column. Make sure the plate sits at the underside of the new beam.
Another option may be to chip out a keyway from the existing column, probably no more than 1 1/2" to avoid rebar.
No matter what you do, be conservative.
RE: Concrete shear transfert between new and existing