Anchor Plate at Edge of Concrete Slab

[bpiermat]

Hi,

I am designing a plate with rectangular plate with four welded headed studs near slab edge. The plate has a large shear force being applied to the plate (toward the edge). Concrete Breakout with or without reinforcing using Appendix D, indicates failure.

Use of slab reinforcing/ties to avoid Appendix D works, however...there are two row of anchors, the closest row to the edge does not have bars that are fully developed anchoring it. The row away from the edge is anchored to rebar that is fully developed. All anchors are welded to a common plate. If all the shear is design to be resisted by the row away from the edge, the anchors fail in shear.

Should I reject the design?

Thanks!

 

[bigmig]

If you are designing this plate, as compared to analyzing one that is already installed, I'm not clear as to why you just don't design a plate with edge distance, HAS size and reinforcement that works.

 

[KootK]

It sounds as though the row of studs closest to the edge are just along for the ride and are ineffective. As such, I would reject the design. A sketch would hep a great deal here.

The greatest trick that bond stress ever pulled was convincing the world it didn't exist.

 

[Mixtli]

I would check concrete break out resistance for the anchor in shear for the close to the edge anchors, and see how they contribute altogether with the other anchors.
If there's tension present, you would also need to use D.8 part: Interaction of tensile and shear forces.

Cheers

M

 

[bpiermat]

Thanks for the insight...I am checking a design, so its either yes its ok, or no. I rejected the design since the last row is ineffective (as suggested per Kootk). Since the far row studs (away from the edge) do not have enough shear strength to transfer the load to the plate.