D.6.2 Conc Breakout Strength in Shear for Embed Plate
D.6.2 Conc Breakout Strength in Shear for Embed Plate
(OP)
I have an 3/4" studs on an embed plate w/5" embedment cast into an 8" thick wall. Clip angles will be welded to the plate for a simple beam shear connection. I am assuming 3" of eccentricity to add some moment to the connection.
I am going through App D equations for ACI 318-05 without any problems except for the Concrete breakout strength in shear found in D.6.2. My loads are modest, 16.4k and another load a little bit higher.
I am new to App D. The only thing that I could imagine helping my situation would be introducing some sort of reinforcing in the wall that would allow me to skip the failure mode in D.6.2.
Does anyone know how to do that kind of reinforcing?
I am going through App D equations for ACI 318-05 without any problems except for the Concrete breakout strength in shear found in D.6.2. My loads are modest, 16.4k and another load a little bit higher.
I am new to App D. The only thing that I could imagine helping my situation would be introducing some sort of reinforcing in the wall that would allow me to skip the failure mode in D.6.2.
Does anyone know how to do that kind of reinforcing?






RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
The trick here may be hanging the plate from welded rebar, with anchored bars or clips at an angle. You simply will need to develop the reaction. You may add just for direct tension if any anchors as a complement.
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
How about side edges?
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
I agree with you that Shear Breakout shouldn't happen in a wall going down a "large enough" distance. Although, the ACI App D equations don't seem to acknowlege this. In my case, I have a large elevator door opening below some of these beams and I have beam reinforcing above the opening. In other cases, the wall keeps going.
From the beam centerline to the parallel edges, the distance varies from 4", 6", 16" to 3'-0".
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
Even if the embed plate is only 6" above the bottom of the wall, the shear breakout can't physically happen without a footing failure first. Here is how I rationalize it - the shear breakout failure is for an anchor that is being "held back" by a mass of concrete. That is not the case here. The anchor is being "held up" by the wall and footing. If the footing doesn't fail, the wall can't have a breakout failure in that direction.
You'll never get the App. D equations to work out for this. The equations start working against you when you have a large edge distance in the direction of the load and small side edge distances. If you have small side edge distances, your capacity will DECREASE as you increase the edge distance in the direction of the load. That is not intuitive, and ACI has tried to address it in the '08 version with a new provision for large edge distances in a thin member, but it still doesn't completely close the hole.
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate
thread507-241415: ACI 318 Appendix D Vcb
RE: D.6.2 Conc Breakout Strength in Shear for Embed Plate