Nonlinear column (uniaxial)
TCVN 5574:2018Uniaxial eccentric column check per the nonlinear deformation model of TCVN 5574:2018 §8.1.2.7 + Annex K.
About the nonlinear column tool
Check a rectangular column in uniaxial eccentric compression with the nonlinear deformation model of §8.1.2.7 TCVN 5574:2018 (formulas 59–87): internal–external force equilibrium over a subdivided section mesh using bilinear σ–ε diagrams for concrete (§6.1.4.3) and steel (§6.2.4.2).
What you enter
Rectangular section, materials, longitudinal bars and stirrups, the (N, M) combination; optionally the Annex-H confined-concrete parameters and the effective length for slender columns.
What the results mean
The section's nonlinear N–M response and a verdict against the strain limits εb,u/εs,u (§8.1.2.7.5, §8.1.2.7.11); second-order slenderness effect η per §8.1.2.4.2 is included when enabled.
When to use this tool
Large-eccentricity columns where linear interaction diagrams look pessimistic; projects that require the §8.1.2.7 model; studying the effect of dense confinement steel per Annex K.
Method
This tool checks rectangular columns under uniaxial eccentric compression per the nonlinear deformation model of TCVN 5574:2018 §8.1.2.7 (equations (59)–(87)): solving the internal–external equilibrium on a strip mesh with a two-linear concrete σ–ε diagram (§6.1.4.3) and two-linear steel diagram (§6.2.4.2), with strength governed by strain limits εb,u/εs,u (§8.1.2.7.5, §8.1.2.7.11). It supports laterally confined compression concrete per Annex K (Rb,red, εb0,red, εb2,red) and second-order slenderness effects via the η factor of §8.1.2.4.2.