Verification of rectangular cross-section made of plain concrete
The cross-section is rectangular, loaded by the bending moment M, normal force N (applied in the cross-section centroid) and by the shear force V.
Strength of concrete cross-section subject to the combination of bending moment and normal force with eccentricity e is derived from the following expressions:
The shear strength is provided by:
is the design value of shear stress in concrete for degree of longitudinal reinforcement ρ = 0 (see: Verification of spread footing for punching shear)
Interaction diagram N-M
Usage ratio of concrete cross-section subject to the combination of bending moment and normal force is determined as |0L| / |0R1| or |1L| / |1R2|. Where L is loading, R1 is strength with prescribed excentricity and R2 is strength with prescribed normal force.