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ACI 318-19 : Minimum Flexural Strength of Columns
TSC 2018 : Conditions for Columns to be Stronger than Beams (Strong columns)
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Notation
Ag = gross area of concrete section, in2
fc'= specified compressive strength of concrete, psi
fy = specified yield strength for nonprestressed reinforcement, psi
Mn = nominal flexural strength at section, in.-lb
Mnb = nominal flexural strength of beam including slab where in tension, framing into joint, in.-lb
Mnc = nominal flexural strength of column framing into joint, calculated for factored axial force, consistent with the direction of lateral forces considered, resulting in lowest flexural strength in.-lb
Mpr = probable flexural strength of members, with or without axial load, determined using the properties of the member at joint faces assuming a tensile stress in the longitudinal bars of at leasts 1.25fy and a strength reduction factor ϕ of 1.0, in.-lb
Pu= factored axial force; to be taken as positive for compression and negative for tension, lb
ϕ = strength reduction factor
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