Xponexus Engineering

Steel Beam-Column Interaction & Stability Design Tool

Comprehensive Eurocode EN 1993-1-1 (Clause 6.3) calculator for steel members under combined axial compression and biaxial bending. Includes buckling curves, sway/non-sway frames, interaction Method 1 & Method 2, and serviceability stress checks.

EN 1993-1-1 Buckling curves a–d Biaxial interaction SLS stress

SLS stress check Include shear

Scope note:
This is a preliminary design assistant aligned with EN 1993-1-1 Clause 6.3. Always verify with National Annex parameters, detailing, and project-specific requirements.

Member & section properties

Select section type and provide geometric properties for major/minor axes.

Section

Section type & catalogue Section type Section size Area A (cm²) Iy (cm⁴) (major) Iz (cm⁴) (minor) Wely (cm³) Welz (cm³) Wply (cm³) Wplz (cm³)

Lengths & effective lengths Lx (m) Ly (m) kx ky Frame condition Second-order factor (η)

Effective lengths Lcr = k·L. For sway frames, increase with second-order factor η.

Material & partial factors Steel grade fy (MPa) E (MPa) γM0 γM1 Imperfection factor α

Actions

Define design actions (ULS). Enter positive moments about both axes.

Actions

Axial & bending N_Ed (kN) M_Ed,y (kNm) M_Ed,z (kNm) My sign Mz sign

Shear (optional) V_Ed,y (kN) V_Ed,z (kN) Shear area A_vy (cm²) Shear area A_vz (cm²)

Shear check is optional (EN 1993-1-1 6.2). For interaction, only reported if enabled.

Moment distribution C_my C_mz ψ (moment gradient) Method

Serviceability & limits

SLS stress limits and optional axial/moment reduction factors.

SLS

SLS stresses σ_allow / f_y Include compression only? σ_allow (MPa) override

Overrides & notes Member class Override Wpl? (0 = auto) Override Wel? (0 = auto) Design notes

Check summary

ULS + SLS

Axial resistance

Buckling resistance

Bending resistance

Interaction

SLS stress

Shear

Governing failure mode: —
PASS/FAIL based on worst utilisation ≥ 1.0.

Detailed interaction report

Intermediate values for transparency and verification.