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ACI 318-19 : Beam Flexural Design
TSC 2018 :
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Notation in ACI 318-19
As = area of nonprestressed longitudinal tension reinforcement, in2
Ag = gross area of concrete section, in2
α = depth of equivalent rectangular stress block, in.
bw = web width or diameter of circular section, in.
c = distance from extreme compression fiber to neutral axis, in.
Cc = concretecompressive force, lb
Cs = reinforcement tension force, lb
d = distance from extreme compression fiber to centroid of longitudinal tension reinforcement, in.
D = dead load
E = earthquake load
fc'= specified compressive strength of concrete, psi
fy = specified yield strength for nonprestressed reinforcement, psi
fyt = specified yield strength of transverse reinforcement, psi
L = live load
Lr = roof live load
Mn = nominal flexural strength at section, in.-lb
Mu = factored moment at section, in.-lb
Pu = factored axial force; to be taken as positive for compression and negative for tension, lb
R = rain load
S = snow load
U = strength of a member or cross section required to resist factored loads or related internal moments and forces in such combinations
Vn = nominal shear strength, lb
Vu = factored shear force at section, lb
W = wind load
ρ = ratio of As to bd
ϕ = strength reduction factor
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