C20024 C Purlin (Lysaght Cee)
AS 1397 / AS/NZS 4600Grade G450The C20024 is a C purlin (Lysaght Cee) to AS 1397 / AS/NZS 4600. It is 203 mm deep with 2.4 mm base metal thickness, has a mass of 7.24 kg/m and a gross area of 904 mm². Its major-axis second moment of area is Ix = 5.69 × 10⁶ mm⁴. Download its free DXF drawing (a true-scale CAD outline) below, or print the dimensioned drawing sheet.
Also written as: C200-24, C 200 24
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Dimensions
| Symbol | Property | Value | Unit |
|---|---|---|---|
| D | Depth | 203 | mm |
| B | Flange width | 76 | mm |
| L | Lip depth | 21 | mm |
| t | Base metal thickness (BMT) | 2.4 | mm |
| ri | Inside bend radius | 5.0 | mm |
Section properties
| Symbol | Property | Value | Unit |
|---|---|---|---|
| m | Mass per metre (nominal) | 7.24 | kg/m |
| Ag | Gross cross-section area | 904 | mm² |
| Ix | Second moment of area about x-axis | 5.69 | 10⁶ mm⁴ |
| Zx | Elastic section modulus, x-axis | 56.0 | 10³ mm³ |
| Sx | Plastic section modulus, x-axis | 65.6 | 10³ mm³ |
| rx | Radius of gyration, x-axis | 79.3 | mm |
| Iy | Second moment of area about y-axis | 0.681 | 10⁶ mm⁴ |
| Zy | Elastic section modulus, y-axis (min.) | 12.7 | 10³ mm³ |
| Sy | Plastic section modulus, y-axis | 19.1 | 10³ mm³ |
| ry | Radius of gyration, y-axis | 27.4 | mm |
| xc | Centroid from outside face of web | 22.3 | mm |
| J | Torsion constant | 1.74 | 10³ mm⁴ |
| As | External surface area per metre | 0.758 | m²/m |
| As/t | External surface area per tonne | 104.7 | m²/t |
Axes: x-x is the major axis and y-y the minor axis, both through the centroid.
Material
| Symbol | Property | Value | Unit |
|---|---|---|---|
| Steel grade | G450 (AS 1397) | ||
| fy | Yield stress | 450 | MPa |
| fu | Tensile strength | 480 | MPa |
Cold-formed purlins and girts are designed to AS/NZS 4600, where local and distortional buckling, bridging and cladding restraint govern. Use the manufacturer’s span and capacity tables (e.g. the Lysaght Zeds & Cees User Guide) for design. Gross section properties are shown here.
Other c purlins (cees)
Relevant Australian Standards
- AS/NZS 4600:2018 Cold-formed steel structures
The design Standard for thin-walled cold-formed members such as C and Z purlins and light-gauge framing. - AS 1397:2021 Continuous hot-dip metallic coated steel sheet and strip
Covers the G450, G500 and G550 zinc-coated (Z350, Z450) and zinc/aluminium coated steel strip from which purlins, girts and light-gauge framing are roll-formed. - AS/NZS 1170 series Structural design actions
Defines dead, live (1170.1), wind (1170.2), snow (1170.3) and earthquake (AS 1170.4) actions and the load combinations (1170.0) that produce the design actions resisted by the capacities shown here.
See all Australian Standards for structural steel.
Properties are calculated from nominal dimensions, including root and toe radii, as described in notation & method. Mass is the nominal catalogue mass; the calculated mass at 7850 kg/m³ is 7.10 kg/m. Verify against current manufacturer literature before use in design. Spotted an error? Report it.