We use analytics cookies to understand how you use this site and improve our content. See our privacy policy and cookie policy for details.

Calcs.com
EN 1993-1-1:2005 (Eurocode 3)EN 1993-1-5:2006

Steel Column

Column loads link from beam reactions above to footing calculations below automatically - change a load once and the whole load path updates. Design steel columns and studs to Eurocode 3 (EN 1993-1-1) with checks for cross-section compression, biaxial bending, combined bending and axial interaction, flexural buckling about both axes, and lateral torsional buckling.

Start free trial

14-day free trial - no credit card required

What it calculates

Column loads link from beam reactions above to footing calculations below automatically. Design steel columns and studs to Eurocode 3 with multiple end fixity conditions - checks cover axial compression, bending about both axes, combined bending and axial interaction, lateral torsional buckling, and three deflection limits.

Code standards

  • EN 1993-1-1:2005 (Eurocode 3)
  • EN 1993-1-5:2006

How it calculates

Structural model and load combinations

The calculator models the steel column as a member under combined axial force and biaxial bending. Loads are entered by type - permanent (G), variable (Q), wind (W) - and EN 1990:2002 governing ULS combinations are generated automatically. Bending moments can be entered directly or linked from beam calculations above. Three serviceability combinations generate deflection checks.

Cross-section classification (EN 1993-1-1:2005 Cl 5.5.2)

Cross-section class (Class 1 through 4) is determined independently for major-axis bending, minor-axis bending, and axial compression based on element slenderness and epsilon = sqrt(235/fy). The governing class controls which section moduli (plastic, elastic, or effective) are used in the resistance calculations.

Cross-section resistance

Axial compression (Cl 6.2.4): N_c,Rd = A × fy / gamma_M0 for Class 1-3, or A_eff × fy / gamma_M0 for Class 4.

Bending (Cl 6.2.5): M_c,Rd uses W_pl for Class 1-2, W_el for Class 3, and W_eff for Class 4, independently for both axes.

Shear (Cl 6.2.6): V_Rd is computed from the shear area A_v and yield strength fy for each axis.

Biaxial bending criterion: For combined major and minor axis bending without axial force, the biaxial criterion limits the sum of moment utilization ratios.

Simplified biaxial bending and axial criterion (Cl 6.2.9.2): For combined axial and biaxial bending, the simplified linear interaction is checked alongside the more precise longitudinal stress criterion at the extreme fibres.

Flexural buckling resistance (EN 1993-1-1:2005 Cl 6.3.1)

Flexural buckling resistance N_b,Rd is computed for each axis using the reduction factor chi, derived from the relative slenderness lambda = sqrt(A×fy/N_cr). N_cr is the Euler critical load based on the effective buckling length. The imperfection factor alpha depends on the section type and axis (buckling curves a0, a, b, c, d per Table 6.2).

buckling utilization = N_Ed / N_b,Rd ≤ 1.0

Lateral torsional buckling (EN 1993-1-1:2005 Cl 6.3.2.1)

When the compression flange is not fully laterally restrained, LTB resistance M_b,Rd is computed using chi_LT from the relative slenderness lambda_LT derived from M_cr. The critical moment M_cr accounts for unbraced length, end conditions, and section warping and torsional properties.

Combined bending and axial compression - member buckling (EN 1993-1-1:2005 Cl 6.3.3)

The combined buckling interaction is checked through two equations using interaction factors k_yy, k_yz, k_zy, k_zz:

  • N_Ed/(chi_y × N_Rk/gamma_M1) + k_yy × M_y,Ed/M_b,Rd + k_yz × M_z,Ed/M_Rk × gamma_M1 ≤ 1.0
  • N_Ed/(chi_z × N_Rk/gamma_M1) + k_zy × M_y,Ed/M_b,Rd + k_zz × M_z,Ed/M_Rk × gamma_M1 ≤ 1.0

The governing equation and utilization ratio are reported. Interaction factors are derived from the moment distribution (C_m factors) and relative slendernesses.

Deflection checks (EN 1990:2002 Cl 6.5.3)

Characteristic, frequent, and quasi-permanent deflections are checked against user-defined span-ratio limits and optional absolute limits in mm.

Load linking

The column's base reaction is exported as a linked output to connected footing calculations. Axial load at the column top can be linked from beam reactions above, completing the full load path from beam to column to footing automatically.

Related calculators

Steel Beam (Eurocode 3)→Timber Column (Eurocode 5)→Timber Beam (Eurocode 5)→

What engineers say

I like using different software packages, but the reason why I use Calcs.com more often now is load linking.

Richard Faulkner

Senior Structural Engineer, Kusch Consulting Engineers

Calcs.com simplified my beam analysis. It made structural checks easy and impressively fast. I went with Calcs.com for simple residential beam analysis. The reports are strong, especially the one-page summary. I've also gotten used to...

Aaron D. Obermiller, P.E.

Engineer, REO Engineering

Frequently asked questions

What design standard does this calculator use?
The calculator designs steel columns to EN 1993-1-1:2005 (Eurocode 3), with shear buckling per EN 1993-1-5:2006 where applicable. Load combinations follow EN 1990:2002. Partial factors can be adjusted per the relevant National Annex. Cross-section classes are determined for both axes, and buckling curves are selected based on section type and axis of buckling.
What are the key inputs?
Key inputs include the steel section (from the built-in European section database), steel grade, column height, effective length factors for both major and minor axes, loads by type (permanent G, variable Q, wind W), bending moments about both axes, and deflection limit ratios. End fixity conditions (pinned, fixed, cantilever) can be set independently for each axis.
What checks and outputs does it produce?
The calculator checks cross-section axial compression, axial tension, section bending capacity about both axes (EN 1993-1-1:2005 Cl 6.2.5), shear resistance about both axes (Cl 6.2.6), biaxial bending and the simplified biaxial bending-plus-axial criterion, longitudinal stress (Cl 6.2.9.2), buckling resistance about both axes, lateral torsional buckling (Cl 6.3.2.1), combined bending-and-axial-compression buckling (Cl 6.3.3), shear buckling, and three EN 1990:2002 deflection limits.
How are flexural buckling and LTB checks combined with axial compression?
The combined buckling check follows EN 1993-1-1:2005 Cl 6.3.3 using interaction factors k_yy, k_zy, k_yz, k_zz from Annex A or B (method 1 or 2). These factors account for the ratio of end moments, moment gradient correction C_m, and the relative slendernesses about each axis. The calculator applies both interaction equations and reports the governing utilization ratio.
How is the cross-section class determined for biaxial bending?
Cross-section class is determined independently for major-axis bending, minor-axis bending, and axial compression. The most onerous classification governs for each check. For Class 1 and 2 sections, plastic resistances are used; Class 3 uses elastic section moduli; Class 4 uses effective cross-section properties accounting for local buckling of slender elements.
Does this calculator support load linking with beam and footing calculations?
Yes - axial load at the column top can be linked from beam reactions above, and the column's base reaction links to connected footing calculations. The full load path - beam to column to footing - updates automatically whenever any upstream input changes.

Access this calculator and 100+ more

All verified, standards-aligned. Start a free trial - no credit card required.

Start free trialAlready a member? Sign in