Shear plane reinforcing

[haynewp]

I have inherited a project that has issues. There are embed plates supporting beams that do not meet ACI Apendix D requirements. An idea that has been presented that involves crossing the possible shear failure planes with new rebar epoxied into the wall and welded to a plate to develop the rebar strength on either side of the possible shear planes.

I have not used this approach before. ACI gives examples of providing reinforcing when it is parallel to the force and within a distance from the anchor which I have used many times before. In this case the new reinforcing for the existing plate and studs will be perpendicular to the shear force. My concern is the theoretical shear planes may not be the actual shear plane and the new reinforcing I am showing may not be located where it will be required, and will therefore not intersect the plane as needed to develop the yield strength of the bars on either side of the plane.

The idea is to keep the shear plane intact thru shear friction using new epoxied rebar. I have attached a sketch of the concept. Anyone done this before?

 

[KootK]

I can't say that I fully understand the proposed concept but I'm pretty skeptical none the less. What are the critical failure modes in the original embed that need to be addressed? In my estimation, shear breakout wouldn't be improved at all and shear pry out would be improved only very modestly.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[KootK]

Analytically, it might be simpler to just post install a new plate over the old and work with that. At least you can make use of established procedures that way.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[haynewp]

Shear breakout controls in the original. Looking at the section, it looks like the breakout could push the rebar over into bending and not develop any shear friction.

 

[KootK]

For the shear breakout mode, it doesn't appear that the proposed anchors would alter the shape of the breakout surface much at all. Maybe a row of anchors 6" above the plate, and possibly out past the sides, would be more convincing.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.