22.9.4 Nominal Shear Strength
|Vn = µAvf fy||(184.108.40.206)|
where Avf is the area of reinforcement crossing the assumed shear plane to resist shear, and µ is the coefficient of friction in accordance with Table 220.127.116.11.
Table 18.104.22.168—Coefficients of friction
|Contact surface condition||Coefficient of friction µ|
|Concrete placed monolithically||1.4λ||(a)|
|Concrete placed against hardened concrete that is clean, free of laitance, and intentionally roughened to a full amplitude of approximately 1/4 in.||1.0λ||(b)|
|Concrete placed against hardened concrete that is clean, free of laitance, and not intentionally roughened||0.6λ||(c)|
|Concrete placed against as-rolled structural steel that is clean, free of paint, and with shear transferred across the contact surface by headed studs or by welded deformed bars or wires.||0.7λ||(d)|
λ = 1.0 for normalweight concrete; λ = 0.75 for all lightweight concrete. Otherwise, λ is calculated based on volumetric proportions of lightweight and normalweight aggregate as given in 19.2.4, but shall not exceed 0.85.
|Vn = Avffy(µsinα + cosα)||(22.214.171.124)|
Table 126.96.36.199—Maximum Vn across the assumed shear plane
|Normalweight concrete placed monolithically or placed against hardened concrete intentionally roughened to a full amplitude of approximately 1/4 in.||Least of (a), (b), and (c)||0.2fc'Ac||(a)|
|(480 + 0.08fc')Ac||(b)|
|Other cases||Lesser of (d) and (e)||0.2fc'Ac||(d)|