Section properties helper
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Catalogue A, I and mass are taken from the attached FrameCalc section helper. J and Iw are calculated where not supplied. Custom hollow-section formulae use sharp-corner geometry and are approximate. PFC sections are deliberately excluded because they are not doubly symmetric.
Working table — inputs
| Input | Value | Unit |
|---|---|---|
| Member and frame type | ||
| Check typeBeam only, beam-column, or sway-frame column | ||
| Member length LSpan or member/storey length | m | |
| Effective length factor KcCompression buckling | — | |
| LTB length factor KLTUnrestrained length factor | — | |
| Sway moment amplificationUse 1.0 if no amplification is required | — | |
| Design actions | ||
| Left/end moment M1Signed end moment | kNm | |
| Right/end moment M2Signed end moment | kNm | |
| Maximum span moment MspanMaximum sagging or hogging moment | kNm | |
| Axial force FCompression positive, tension negative | kN | |
| Shear VMaximum design shear | kN | |
| Material and applied section properties | ||
| Design strength pyAdjust for grade and thickness | N/mm² | |
| Area AEditable after helper application | mm² | |
| Elastic modulus Sx / ZxSelected bending-axis elastic modulus | mm³ | |
| Shear area AvApproximate design shear area | mm² | |
| Compression buckling radius ryRadius about the axis normal to selected bending plane | mm | |
| LTB transverse inertia IzTransverse principal inertia for open sections | mm⁴ | |
| Torsion constant JCatalogue-derived or geometry formula | mm⁴ | |
| Warping constant IwZero for closed hollow sections | mm⁶ | |
| Formula coefficients | ||
| Young's modulus E | N/mm² | |
| Shear modulus G | N/mm² | |
| ηcPerry compression imperfection factor | — | |
| ηLTPerry LTB imperfection factor | — | |
| C1Elastic critical moment gradient factor | — | |
| m factor override0 = automatic | — | |
| High shear limitFraction of Pv | Pv | |
Graphic and utilisation
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Governing utilisation—
Scope note
The checker remains a simplified formula-route design aid. Confirm section classification, effective lengths, restraints, LTB assumptions, second-order effects, local capacity checks, serviceability and connection design separately.