Two-Way Shear Strength.

İnternational Design Codes

ACI 318-19 : Two-Way Shear Strength per ACI 318-19 with ideCAD

TSC 2018 : Punching Shear Stress at Critical Section (7.11.8)

Notation in ACI 318-19

A_v = area of shear reinforcement within spacing s, in.²
b_o = perimeter of critical section for two-way shear in slabs and footings, in.
d = distance from extreme compression fiber to centroid of longitudinal tension reinforcement, in.
d_b = nominal diameter of bar, wire, or prestressing strand, in.
f_c ^' = specified compressive strength of concrete, psi
√f_c‘ = square root of specified compressive strength of concrete, psi
f_yt = specified yield strength of transverse reinforcement, psi
v_c = stress corresponding to nominal two-way shear strength provided by concrete, psi
v_n = equivalent concrete stress corresponding to nominal two-way shear strength of slab or footing, psi
v_s = equivalent concrete stress corresponding to nominal two-way shear strength provided by reinforcement, psi
v_u = maximum factored two-way shear stress calculated around the perimeter of a given critical section, psi
α_s = constant used to calculate V_c in slabs and footings
β = ratio of long to short dimensions; clear spans for two-way slabs, sides of column, concentrated load or reaction area; or sides of a footing
ϕ = strength reduction factor
λ = modification factor to reflect the reduced mechanical properties of lightweight concrete relative to normalweight concrete of the same compressive strength
λ_s = factor used to modify shear strength based on the effects of member depth, commonly reffered to as the size effect factor

Nominal shear strength of the two-way members with and without shear reinforcement is calculated by using Codes.

Critical Sections for Two-way Members