— RC Column Axial Capacity (ACI 318)
Maximum usable axial compressive strength of a short reinforced-concrete column, Po = 0.85f'c(Ag − Ast) + fyAst, reduced for accidental eccentricity (0.80 tied / 0.85 spiral) and by φ (0.65 tied / 0.75 spiral) per ACI 318-19 §22.4 and §10.3.