Interface Shear Strength ACI 318

[N G P]

Hello All,

I have been checking the interface shear strength between a precast block and the cast in-situ concrete portion above it for a gravity retaining wall as per ACI 318-14. I have a doubt about the shear strength and whether it is okay to consider section 16.4.4.1 as it is for the flexural composite members. In my case, the block is not in flexure and it only transfers shear. or should I follow the shear friction method in accordance with section 22.9 and provide interface shear reinforcement?
I was initially planning to check the shear strength without interface shear rebar.

Many Thanks

 

[KootK]

or should I follow the shear friction method in accordance with section 22.9 and provide interface shear reinforcement?

I'd do it that way. That doesn't necessarily mean that you need rebar however. The reliable dead load applied to the joint, and clamping it together, can take the place of the shear friction rebar.

..consider section 16.4.4.1 as it is for the flexural composite members. In my case, the block is not in flexure and it only transfers shear.

I share your concern with using that provision for this situation. I feel that provision is calibrated to the particular case of a composite member where there is a relatively small vertical offset between the origin of the shear (compression block) and the interface.

 

[N G P]

Thanks KootK.
I will use the 0.6x compression force for finding the resistance considering the surface is not intentionally roughened and for the remaining shear I will provide shear friction rebar.