At cold joints between columns or walls and footings (especially for systems resisting lateral forces ) , ACI code requires to check horizontal force transfer !
At design stage , we are assuming monolithic concrete but in reality cold joints will occur .
Cold joints may reduce shear capacity for concrete section , so ACI code requires simple check using shear friction provisions in section 22.9.4.2 (ACI318-19) .
We are calculating the required area of steel by the strength load combinations and required area of steel using shear friction reinforcement then we shall provide the larger one .
This concept also can be used to check Wall-Slab connection in a buildings when using Jump System Formwork where we are casting the walls first then casting floors will be later on .
