# Concrete Shear Friction Capacity (Interface Shear)

This calculation determines the shear friction capacity according to ACI 318 or CSA A23.3

psi
ksi
in2
kip
in
in

## Output:

1. Definitions
• ϕv = Resistance factor for shear
• fc = Specified concrete strength (psi)
• fy = Specified reinforcing steel yield strength (ksi)
• λ = Concrete density modification factor; 1.0 for normal density concrete
• Avf = Area of reinforcing crossing the shear plane (in2)
• N = Axial load; compression positive (kip)
• ts = Slab / member thickness (in)
• b = Effective width of cross section (in)
• μ = Coefficient of friction
2. Coefficient of friction
• Surface = Intentionally roughened
• μ = 1 λ = (1) (1) = 1
3. Max permissible shear
• ϕVn,max = ϕv b ts * min( 0.2 fc , (480 + 0.08fc) , 1600 )/1000
• ϕVn,max = (0.75) (12) (12) * 0.88
• ϕVn,max = 95 kip
4. Shear friction capacity
• ϕVn = ϕv μ (Avf fy + N) ≤ ϕVn,max
• ϕVn = (0.75) (1) [(0.31) (60) + (0)] ≤ 95
• ϕVn = (0.75) (1) (18.6) ≤ 95
• ϕVn = 13.95 kip