Rebar Design/Shear Values 2

[EIT2]

I intend on transferring wind shear forces from a precast plank roof to a masonry shear wall. Rebar projecting from the bond beam will serve as the collector element to which the side lap or bearing end of the plank will be penetrated.
(Any other suggestions?) To accomplish this, I believe I need to determine allowable shear for ASTM A 615-85. (0.4*Fy?) What is a resource for ASTM deformed rebar design values?

 

[JAE]

We never rely on shear through a rebar. There is no code provision for it that I'm aware of. Instead, you must use shear friction (ACI Chapter 11) and develop the rebar across the shear plane.

The idea of the shear friction is to use the friction on either side of a presumed crack plane and this is utilized by keeping the two sides tightly held together with the rebar (acting in tension). The ACI code requires that the rebar be FULLY DEVELOPED on either side of the crack plane.

This means that you cannot reduce the hook or straight development length by As(req'd)/As(provided). This means that using hollow core planks and CMU and TRULY meeting the ACI code is almost impossible...but many engineers simply run the bar down into the wall a distance and rely on straight devlepment length instead.

 

[ccr]

ACI 318 section 11.7 addresses shear-friction design for perpendicular reinforcing.