CSA S16 Canadian Steel Design
Perform factored resistance checks for structural steel members according to CSA S16-19. The calculator integrates Clause 11 classification, member stability, and Clause 13 interaction checks.
Design Check Overview
The calculator classifies your cross-section into Classes 1 through 4 based on Clause 11 width-to-thickness rules, then evaluates section and member resistances for tension, compression, bending, and shear. Where combined actions are present, interaction checks use the applicable Clause 13.8 or 13.9 path with the reported section properties and amplification factors.
Clause Compliance Coverage:
- Section classification (Cl 11.2 / Tables 1-2): Classification is action-specific and drives the section or effective-property branch.
- Tension (Cl 13.2): Gross yielding and net-section fracture are checked using optional member An and effective-net factor; blank An defaults to Ag because bolt-hole geometry is not inferred.
- Compression (Cl 13.3.1 / Cl 13.3.4): Member compression, supported flexural-torsional buckling, and Class 4 effective-area checks use the selected fabrication branch.
- Flexure and LTB (Cl 13.5 / Cl 13.6): Section bending, LTB, tee, angle, and biaxial bending rows use the active section family path.
- Shear and torsion (Cl 13.4 / Cl 14.6 / Cl 14.10): Local shear paths, plate-girder shear-moment interaction, and closed-section torsion are reported where applicable.
- Combined actions (Cl 13.8 / Cl 13.9): Compression-plus-bending and tension-plus-bending paths use station-coincident demands. Non-P-Delta compression interaction uses U1; Cf/Ce at or above 1.0, or invalid amplification inputs, fails closed and suppresses the interaction. P-Delta moments are not amplified again.
Supported Section Types
I-Shapes - W, WWF, S, HP
Channels - C, MC
Tees - WT, WWT
RHS / SHS
CHS / Pipe
Angles - L
Current Limitations
- Tension resistance under Cl 13.2 uses the entered An and U. Blank An defaults to Ag and blank U defaults to 1.0 because connection geometry is not inferred.
- Single member analysis only: no automatic frame buckling analysis or system-level effects.
- The standalone compression interaction is treated as non-P-Delta and applies Clause 13.8 U1. Cf/Ce at or above 1.0, or invalid E/I/K/L inputs, produces a visible FAIL/INCOMPLETE row and suppresses the affected interaction. Structural FEA P-Delta moments are not amplified again.
- No connection design, no composite construction, and no seismic provisions (Clause 27).
- CSA S16 local bearing, web local yielding, web crippling, web buckling, bearing-stiffener, and column force-transfer checks are not performed or derived from point loads, reactions, or connection forces. Check support bearing and concentrated load introduction regions separately.
- Effective length factors (K) must be user-specified (default 1.0). The cantilever switch forces ω2/ω3 = 1.0 and ignores the typed override while enabled.
- The calculator assumes the default section orientation shown in the preview. Major and minor axis inputs are relative to that orientation. Rotated or sideways mono-symmetric members, such as channels, tees, and angles, should be checked in the FEA workflow.
- Torsion is not an input in the standalone calculator. In the FEA tool, torsion (Cl 14.10) is checked for closed hollow sections (RHS/CHS) only; warping torsion for open sections is not performed.
Benchmarks: 50 independent test cases, 0.16% average difference
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