Beam Required and Design Strength.

International Design Codes

ACI 318-19 : Beam Required and Design Strength per ACI 318-19 with ideCAD

TSC 2018 :

Notation in ACI 318-19

A_g = gross area of concrete section, in²
A_v = area of shear reinforcement within spacing s, in.²
D = dead load
E = earthquake load
f_c^' = specified compressive strength of concrete, psi
f_yt = specified yield strength of transverse reinforcement, psi
L = live load
L_r = roof live load
M_n = nominal flexural strength at section, in.-lb
M_u = factored moment at section, in.-lb
P_n = nominal axial compressive strength of member, lb
P_u = factored axial force; to be taken as positive for compression and negative for tension, lb
R = rain load
S = snow load
T_n = nominal torsional moment strength, in.-lb
T_u = factored torsional moment at section, in.-lb
U = strength of a member or cross section required to resist factored loads or related internal moments and forces in such combinations
V_n = nominal shear strength, lb
V_u = factored shear force at section, lb
W = wind load
ϕ = strength reduction factor