Shear Breakout for Anchors according to ACI 318
Shear Breakout for Anchors according to ACI 318
(OP)
I've got a question about determining the concrete breakout for shear loading according to Appendix D of ACI 318. From the attached sketch, I have a steel column (which is part of a braced frame) anchored to a concrete T-beam below (24" beam + 8" slab). The shear load is pretty big and I'm getting the section to fail under concrete breakout, but I'm not sure about my breakout area calculation.
In reference to Section A-A from my sketch, I've used the edge distance from the anchors to the edge of the concrete beam, but this neglects the continuity of the 8" slab above, which I would think would add significant shear resistance.
The beam is heavily reinforced, so I think I'm just going to rely on the reinforcement to restrain breakout and check it as per Chapter 12, but I'm curious as to how you'd arrive at a concrete breakout resistance for this type of section.
Any input is appreciated.
In reference to Section A-A from my sketch, I've used the edge distance from the anchors to the edge of the concrete beam, but this neglects the continuity of the 8" slab above, which I would think would add significant shear resistance.
The beam is heavily reinforced, so I think I'm just going to rely on the reinforcement to restrain breakout and check it as per Chapter 12, but I'm curious as to how you'd arrive at a concrete breakout resistance for this type of section.
Any input is appreciated.






RE: Shear Breakout for Anchors according to ACI 318
App. D properly accounts for shear failure when you are close to an edge when you get away from an edge the equations get a little screwie there is technically no exception for shear breakout like there is for concrete breakout. I would add additional rebar developed into the slab to take the shear load.
RE: Shear Breakout for Anchors according to ACI 318
RE: Shear Breakout for Anchors according to ACI 318
RE: Shear Breakout for Anchors according to ACI 318
ACI 318-08 has some good sketches in Appendix D.
RE: Shear Breakout for Anchors according to ACI 318