Column Reinforcement Limits.

İnternational Design Codes

ACI 318-19 : Column Reinforcement Limits

TSC 2018 :

A_ch = cross-sectional area of a member measured to the outside edges of transverse reinforcement, in.²
A_g = gross area of concrete section, in²
A_sh = total cross-sectional area of transverse reinforcement, including crossties, within spacing s and perpendicular to dimension b_c, in.²
A_v = area of shear reinforcement within spacing s, in.²
A_v,_min = minimum area of shear reinforcement within spacing s, in.²
b_c = cross-sectional dimension of member core measured to the outside edges of the transverse reinforcement composing area A_sh, in.
b_w = width of compression face of member, in.
d_b = nominal diameter of bar, wire, or prestressing strand, in.
f_c^' = specified compressive strength of concrete, psi
f_y = specified yield strength for nonprestressed reinforcement, psi
f_yt = specified yield strength of transverse reinforcement, psi
h_x = maximum center-to-center spacing of longitudinal bars laterally supported by corners of crossties or hoop legs around the perimeter of a column or wall boundary element, in.
k_f = concrete strength factor
k_n = confinement effectiveness factor
l_o = length, measured from joint face along axis of member, over which special transverse reinforcement must be provided, in.
l_u = unsupported length of column or wall, in.
l_w = length of entire wall, or length of wall segment or wall pier considered in direction of shear force, in.
n_l = number of longitudinal bars around the perimeter of a column core with rectilinear hoops that are laterally supported by the corner of hoops or by seismic hooks.
P_u = factored axial force; to be taken as positive for compression and negative for tension, lb
s = center-to-center spacing of items, such as longitudinal reinforcement, transverse reinforcement, tendons, or anchors, in.
s_o = center-to-center spacing of transverse reinforcement within the length l_o, in.
V_c = nominal shear strength provided by concrete, lb
V_n = nominal shear strength, lb
V_u = factored shear force at section, lb
ϕ = strength reduction factor
ρ_s = ratio of volume of spiral reinforcement to total volume of core confined by the spiral, measured out-to-out of spirals

Minimum and maximum longitudinal reinforcement

Minimum shear reinforcement