W, HP and HSS
Wide-flange and HP shapes as well as square, rectangular and round hollow structural sections, with n = 2.24 for Class H HSS and 1.34 otherwise.
SKL-000125 · Skill
CSA S16:24NBCC 2020Design a steel column to CSA S16:24
Describe the column height, end conditions, frame and bracing, section (W, HP or HSS) and steel grade, and the loads. Mia classifies the section, checks flexural and torsional buckling or tension, bending with lateral-torsional buckling and the interaction of Clause 13.8 or 13.9, and names the governing check.
Mia guides you step by stepShe guides you through the inputs and explains the results.
Worked example
W250x73 · 350W · 3.6 m · Cf 900 kN + Mfx = Mfy = 50 kNm · braced frame
Design verified: 13.8.2 c) lateral-torsional buckling strength governs- System
- Pinned–pinned column, K = 1.0, braced frame
- Section
- W250x73 · 350W (Fy = 350 MPa)
- Height
- 3.6 m, laterally unsupported (L = 3.6 m)
- Factored loads
- Cf = 900 kN · Mfx = 50 kNm · Mfy = 50 kNm, at one end
- Standard
- CSA S16:24
Check a W250x73 column in 350W steel, 3.6 m tall, pinned at both ends in a braced frame and laterally unsupported over its height, for Cf = 900 kN with Mfx = 50 kNm and Mfy = 50 kNm at the top end (zero at the base), per CSA S16:24.
Key results
- Factored compressive resistance Cr
- 2217 kN (y-y flexural buckling, n = 1.34)
- Factored moment resistance Mrx
- 310 kNm (13.6.1 a), omega_2 = 1.75)
- Factored moment resistance Mry
- 146 kNm (13.5 a), Class 2)
- Governing utilization
- 0.749 (13.8.2 c))
All values are deterministic for the stated inputs and reproduced by the skill's calculation code (E = 200 000 MPa, G = 77 000 MPa). The STAAD.Pro verification problem for the same member uses E = 205 000 MPa and full lateral support and reports 0.831 for an unbraced frame; the skill reproduces it with those inputs.
- — The factored moments include the stability effects of Clause 8.4; U1 is applied per 13.8.5 because the frame is braced.
- — kappa = 0 (moment at one end only), so omega_1 = 0.6 and omega_2 = 1.75.
- — Kz = 1.0 for torsional buckling, both ends restrained against twisting.
- — The flange (bel/t = 8.94) is Class 2 for bending; the web is classified with the biaxial-bending limit of Table 2.
Required inputs
- Column height, end conditions, frame and bracing
- Section (W, HP or HSS with its class C or H) and steel grade
- Compression or tension; for tension the bolted end connection
- Dead, live and wind loads (end moments or a uniform lateral load), or factored load effects
What you receive
- Governing check and utilization
- Section class for compression and for bending about both axes
- Factored compressive resistance and the buckling mode that produced it
- Factored tensile resistance with An and Ane
- Factored moment resistance about both axes, with Mu and omega_2
- The 13.8 or 13.9 interaction case that governs
- Assumptions and clause references
Start from an input template
These templates prefill the form with typical inputs. They are not calculated results; the calculation runs in CALC.
Prepare your calculation
Configure your column
System sketch
L = 3.6 mCf = 900 kNMfx = 50 kNmMfy = 50 kNm
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All required fields completed
All required fields completed
kN
kN
kNm
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kN/m
kN/m
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kNm
All required fields completed
All required fields completed
Inputs completeReady to calculate
What this skill checks
Every section class
Classification to Tables 1 and 2, including Class 4 compression elements with reduced widths or an effective yield stress per Clause 13.3.4.
Lateral-torsional buckling
M_u with omega_2 from the moment diagram per Clause 13.6.1, for Class 1 to 4 W-shapes and rectangular HSS.
The 13.8 interaction, case by case
Cross-sectional strength, overall member strength and lateral-torsional buckling strength with U_1 for braced and unbraced frames, for I-shapes and HSS.
Axial tension per Clause 13.2
Gross yielding and net-section rupture with the standard holes of Table 5 and the effective net area of Clause 12.3, combined with bending per 13.9.
Normative basis
Standards & references
The checks follow these standards. Nationally determined parameters come from the National Annex selected in the form.
CSA S16:24
CurrentCSA S16:24 Design and construction of steel structures
Edition used: CSA S16:24 (April 2024)
- §11
- §12.3
- §13.2
- §13.3
- §13.5
- §13.6
- §13.8
- §13.9
Status checked on
NBCC 2020
CurrentNational Building Code of Canada 2020
Edition used: NBC 2020
- §4.1.3.2
Status checked on
Frequently asked questions
Frequently asked questions
VerificationWhich edition of CSA S16 does the skill use?
CSA S16:24. Where the 2019 edition differs (for example the flange limit of Table 1 or the second check of 13.9.1), the 2024 text applies.
VerificationIs lateral-torsional buckling checked?
Yes, per Clause 13.6.1 with omega_2 from the moment diagram, and it enters the 13.8 interaction as case c). Square and round HSS need no lateral-torsional buckling check per 13.6.1 c).
VerificationDo I have to say whether the frame is braced?
Yes. U1 and the cross-sectional strength check of Clause 13.8 depend on it, so the frame is always confirmed rather than assumed.
VerificationCan it check a member in tension?
Yes. Mia checks gross yielding and net-section rupture per Clause 13.2 with the standard holes of Table 5 and the effective net area of Clause 12.3, and combines tension with bending per 13.9. Block shear depends on the connection and is not checked.
VerificationAre Class 4 sections covered?
Yes, in compression per Clause 13.3.4 and in bending per 13.5 c) and 14.3.4. Only a section whose flange and web are both slender in bending is referred to RFEM, because S16 sends it to AISI S100.
Ready for your first check?
Start with the example and adapt it to your structural system.
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