Design Code Checks

Run steel member capacity checks directly on analysed members within Structural FEA. Design checks are accessed through the Design tab in the Member Analysis dialog. Available to all users with monthly usage limits (3 anonymous, 10 free, unlimited Pro).

Supported Design Codes

CodeRegionDesign Methods
AISC 360-16United StatesLRFD / ASD
Eurocode 3 (EN 1993-1-1)EuropeLimit State
AS 4100:2020AustraliaLimit State
CSA S16-19CanadaLimit State

Accessing the Design Tab

  1. Run the analysis - design checks require valid analysis results.
  2. Select a member in the 3D view.
  3. Open Member Analysis - right-click the member and choose "Member Analysis", or click the Member Analysis button in the Properties panel.
  4. Switch to the Design Check tab (third tab, after Diagrams and Stress).

How It Works

The Design Check tab takes the internal forces from the FEA results and checks the selected member against the chosen design code. Forces are extracted automatically from the analysis - you do not need to input them manually.

The check uses the member's assigned section properties (from the library) and material properties, along with the internal force envelope or a specific load combination.

Combo Mode

  • Selected - Check against the currently selected load combination only.
  • Envelope - Check against all load combinations and report the governing result. This is the recommended mode for final design verification.

Design Parameters

The following parameters can be configured before running a check:

Effective Length Factors

  • Ky - Effective length factor for flexural buckling about the y-axis (default 1.0)
  • Kz - Effective length factor for flexural buckling about the z-axis (default 1.0)
  • KLT - Effective length factor for lateral-torsional buckling (default 1.0)

The effective buckling length is K × L, where L is the member length. Note that the definition of y and z axes (major vs minor) varies by code - EC3 uses y for the strong axis, while AISC, AS4100, and CSA use y for the weak axis.

Lateral Restraint

  • Full Lateral Restraint - When enabled, the lateral-torsional buckling check is skipped. Use this when the compression flange is continuously braced (e.g. by a concrete slab or metal decking).

Moment Factor Override

Each design code uses a moment gradient factor to account for non-uniform bending moment distributions along the member:

  • AISC 360-16: Cb (Eq. F1-1)
  • Eurocode 3: C1 (NCCI SN003)
  • AS 4100:2020: αm (Cl 5.6.1.1)
  • CSA S16-19: ω2 (Cl 13.6)

By default, the factor is computed automatically from the member's moment diagram. You can override it if you have a specific value from your engineering judgement or a more detailed analysis.

Code-Specific Options

  • Load Height (EC3, AS4100) - Whether the load is applied at the shear centre or the top flange. Top flange loading is more conservative for lateral-torsional buckling.
  • Cantilever (AS4100) - Toggle for cantilever members with a fixed root and free tip, with load type selection (point load or distributed).
  • Design Method (AISC) - Toggle between LRFD and ASD.

Results

After running a check, the Design Check tab displays:

  • Overall Status - Pass, Warning, or Fail with a colour-coded indicator.
  • Utilisation Ratio - The governing demand-to-capacity ratio as a percentage.
  • Governing Check - The name and clause of the most critical check.
  • Governing Combination - Which load combination produces the worst result (in envelope mode).

Individual Check Results

A detailed table lists every capacity check performed:

  • Check Name - e.g. "Lateral-Torsional Buckling (F2)", "Axial Compression (E3)"
  • Demand - The applied force or moment from the analysis
  • Capacity - The calculated member resistance
  • Ratio - Demand / Capacity (values above 1.0 indicate failure)
  • Status - Pass, Warning, or Fail

Checks Performed

Depending on the design code and section type, checks include:

  • Section classification (compact/non-compact/slender or Class 1–4)
  • Axial tension and compression (flexural buckling, torsional buckling, flexural-torsional buckling)
  • Flexure - yielding, lateral-torsional buckling, flange and web local buckling
  • Shear - web yielding
  • Torsion - for closed hollow sections (RHS/SHS/CHS)
  • Combined actions - axial + biaxial bending interaction

PDF Hand Calculations

Export a detailed PDF showing every step of the design check calculation. The handcalc report includes section properties, applied forces, intermediate values, clause references, and final capacity ratios - suitable for submission to checking engineers.

Warnings

The design engine may produce advisory warnings alongside the check results. These highlight situations where the results should be reviewed with care:

  • Slenderness ratio exceeds code limits
  • Section classification changes under combined loading
  • Effective width reductions applied for slender elements
  • Torsion not checked for open sections (warping torsion not implemented)

Supported Section Types

All four design codes support the following section shapes from the library:

  • I-Sections - Rolled and welded (UB, UC, W-shapes, doubly-symmetric and mono-symmetric)
  • Channels - PFC, C-shapes
  • Tee Sections - BT, WT
  • Rectangular Hollow Sections - RHS, SHS
  • Circular Hollow Sections - CHS, pipe
  • Angles - Equal and unequal

Limitations

  • Warping torsion for open sections is not checked - torsion checks apply to closed hollow sections only.
  • Effective length factors must be user-specified. The FEA does not automatically calculate system-level buckling lengths.
  • Built-up, plate girder, and fabricated sections are not supported in the current version.
  • Connection design is not included.

Standalone Design Calculators

The same design engines are also available as standalone calculators, where you can input member forces directly without building a full FEA model:

Further Reading