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

Code	Region	Design Methods
AISC 360-16	United States	LRFD / ASD
AISC 360-22	United States	LRFD / ASD
Eurocode 3 (EN 1993-1-1)	Europe	Limit State
AS 4100:2020	Australia	Limit State
CSA S16-19	Canada	Limit State

Accessing the Design Tab

Run the analysis - design checks require valid analysis results.
Select a member in the 3D view.
Open Member Analysis - right-click the member and choose "Member Analysis", or click the Member Analysis button in the Properties panel.
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 / AISC 360-22: C_b (Eq. F1-1)
Eurocode 3: C₁ (NCCI SN003)
AS 4100:2020: α_m (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.
AS4100 imported metadata - k_f, α_b, and β_x are normally derived from the section and code rules. Imported models may carry explicit values for replaying known section metadata; these are not ordinary required manual inputs.
M_cr / k_c,LT (EC3) - Optional elastic critical moment override for EC3 LTB, plus a Table 6.6 correction factor for the 6.3.2.3 I/H method only.
Cantilever (AS4100) - Toggle for cantilever members with a fixed root and free tip, with load type selection (end moment, point load, or UDL).
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, including code-specific member stability checks
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)
AISC cantilever cases may require a manual C_b override where the standard or commentary requires C_b = 1.0
EC3 cantilever LTB cases should have C₁, L_b/KLT, and load-height assumptions checked separately because fixed-free boundary conditions are not auto-detected
CSA S16 cantilever LTB cases should use a manual ω₂ override of 1.0 because fixed-free boundary conditions are not auto-detected

Supported Section Types

All hot-rolled steel 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.
Support, point-load, and connection-region local checks are not automatically derived from the model. Examples include concentrated-force web checks, bearing stiffeners, doubler plates, local flange bending, and web crippling.
Connection design is separate from member design. A passing member check does not verify bolt holes, connection net sections, welds, bolts, brace attachments, or transfer-region detailing unless a separate connection check is run.
Brace and restraint design is separate from member design. The check uses effective lengths, unbraced lengths, load-height settings, and full-restraint flags as inputs; it does not verify brace strength, stiffness, diaphragm action, or restraint connection capacity.
Compound member detailing such as laced, battened, back-to-back, or multi-component member interconnections is not automatically generated unless stated in the code-specific documentation.
Built-up and fabricated section support varies by code and section type. AISC includes selected built-up I-shape and plate-girder provisions; verify the code-specific documentation before relying on fabricated-section results.
Ponding, fatigue, fire, corrosion, composite action, seismic detailing, and serviceability limits are outside the steel member-strength checks unless covered by another tool or workflow.

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: