Results
Utilisation (demand / capacity) 0.85526
Squash load P₀ 5,001.6 kN Reference 0.85f′c(Ag−Ast)+fyAst = 5,001.6 kN · difference 0 %
Axial cap φPn,max 2,600.8 kN
Balanced point Pn 1,850 kN Reference c_b = d·εcu/(εcu+εy) = 1,850 kN · difference 2.2 × 10−14 %
Balanced point Mn 408.41 kN·m Reference c_b = d·εcu/(εcu+εy) = 408.41 kN·m · difference 1.1 × 10−14 %
Pure bending φMn 148.69 kN·m
Steel ratio 0.94248 %
Tie spacing 24 cm
No certificate: section capacity: the engine has no certificate for this analysis; the closed-form checks below are the verification
Interaction diagram φPn–φMn (kN)
A tied rectangular column with the same bars on the two faces across the bending direction, 10 mm ties and the clear cover given. The interaction diagram, the axial cap and the utilisation are computed by the engine’s CIRSOC 201 (2025) section kernel by strain compatibility. The squash load and the balanced point are shown beside their hand calculation. Tie spacing is the smallest of 12 bar diameters, 48 tie diameters and the least column dimension.
A teaching example, not a design check. SI units: m, kN, MPa. Published by Ergodic Group.