1200WB278 Welded Beam
AS/NZS 3679.2Grade 300The 1200WB278 is a welded beam to AS/NZS 3679.2. It is 1170 mm deep with a 350 mm wide flange, has a mass of 278.0 kg/m and a gross area of 35420 mm². Its major-axis second moment of area is Ix = 7610 × 10⁶ mm⁴ and in Grade 300 (fy = 280 MPa) its section moment capacity is φMsx = 3789.2 kNm. Download its free DXF drawing (a true-scale CAD outline) below, or print the dimensioned drawing sheet.
Also written as: 1200 WB 278
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Dimensions
| Symbol | Property | Value | Unit |
|---|---|---|---|
| d | Depth of section | 1170 | mm |
| bf | Flange width | 350 | mm |
| tf | Flange thickness | 25 | mm |
| tw | Web thickness | 16.0 | mm |
| d1 | Clear web depth (d − 2tf) | 1120 | mm |
Section properties
| Symbol | Property | Value | Unit |
|---|---|---|---|
| m | Mass per metre (nominal) | 278.0 | kg/m |
| Ag | Gross cross-section area | 35420 | mm² |
| Ix | Second moment of area about x-axis | 7610 | 10⁶ mm⁴ |
| Zx | Elastic section modulus, x-axis | 13008 | 10³ mm³ |
| Sx | Plastic section modulus, x-axis | 15036 | 10³ mm³ |
| rx | Radius of gyration, x-axis | 463.5 | mm |
| Iy | Second moment of area about y-axis | 179 | 10⁶ mm⁴ |
| Zy | Elastic section modulus, y-axis | 1023 | 10³ mm³ |
| Sy | Plastic section modulus, y-axis | 1603 | 10³ mm³ |
| ry | Radius of gyration, y-axis | 71.1 | mm |
| J | Torsion constant | 5175 | 10³ mm⁴ |
| Iw | Warping constant | 58678 | 10⁹ mm⁶ |
| As | External surface area per metre | 3.708 | m²/m |
| As/t | External surface area per tonne | 13.3 | m²/t |
Axes: x-x is the major axis and y-y the minor axis, both through the centroid.
Design capacities to AS 4100
| Symbol | Property | Value | Unit |
|---|---|---|---|
| Steel grade | 300 (AS/NZS 3678 (plate) / AS/NZS 3679.2) | ||
| fy | Yield stress used | 280 | MPa |
| fu | Tensile strength | 430 | MPa |
| kf | Form factor (Cl. 6.2.2) | 0.733 | |
| Section class, x-axis (Cl. 5.2) | Compact | ||
| Zex | Effective section modulus, x-axis | 15036 | 10³ mm³ |
| φMsx | Section moment capacity, x-axis | 3789.2 | kNm |
| Section class, y-axis | Compact | ||
| Zey | Effective section modulus, y-axis | 1535 | 10³ mm³ |
| φMsy | Section moment capacity, y-axis | 386.7 | kNm |
| φNs | Section compression capacity (Cl. 6.2.1) | 6544 | kN |
| φNt | Tension capacity, gross section (Cl. 7.2, kt=1, An=Ag) | 8926 | kN |
| φVv | Shear capacity (Cl. 5.11) | 2710 | kN |
| αb | Compression member section constant (Table 6.3.3) | 0.5 |
| Le (m) | φMbx (kNm) | φNcx (kN) | φNcy (kN) |
|---|---|---|---|
| 0.5 | 3789 | 6544 | 6544 |
| 1 | 3789 | 6544 | 6544 |
| 1.5 | 3789 | 6544 | 6359 |
| 2 | 3754 | 6544 | 6150 |
| 2.5 | 3656 | 6544 | 5938 |
| 3 | 3541 | 6544 | 5720 |
| 3.5 | 3411 | 6544 | 5490 |
| 4 | 3270 | 6544 | 5249 |
| 5 | 2964 | 6544 | 4724 |
| 6 | 2648 | 6544 | 4163 |
| 7 | 2342 | 6537 | 3609 |
| 8 | 2061 | 6473 | 3103 |
| 9 | 1811 | 6409 | 2664 |
| 10 | 1596 | 6345 | 2295 |
| 12 | 1258 | 6217 | 1732 |
φMbx: AS 4100 Cl. 5.6.1.1 with αm = 1.0; Le = ktklkrL. φNc: Cl. 6.3.3, pin-ended effective length Le = keL, concentric load.
Check it for a span and loads with the beam calculator.
For restraint types, ktklkr and αm, use the lateral restraint calculator.
Instant check only. Effective lengths and moment modification factors must be determined by the designer in accordance with AS 4100 Cl. 4.6, 5.6.3 and 6.3.2. Not a substitute for a qualified engineer: see the disclaimer.
Other welded beams
Relevant Australian Standards
- AS/NZS 3679.2:2016 Structural steel – Part 2: Welded I sections
Covers three-plate welded beams (WB) and columns (WC) fabricated from AS/NZS 3678 plate, including weld requirements and dimensional tolerances. - AS/NZS 3678:2016 Structural steel – Hot-rolled plates, floorplates and slabs
Specifies the hot-rolled plate (Grades 250, 300, 350, 400 and others) used for welded sections, base plates, stiffeners and fabricated components. - AS 4100:2020 Steel structures
The Australian design Standard for steel members and connections. Covers section classification (Section 5), member moment capacity including lateral-torsional buckling (5.6), shear (5.11), axial compression (Section 6), tension (Section 7) and combined actions (Section 8). - AS/NZS 1554.1:2014 Structural steel welding – Welding of steel structures
Weld procedures, welder qualification, weld categories (SP and GP) and inspection requirements for structural welds. - AS/NZS 5131:2016 Structural steelwork – Fabrication and erection
Fabrication, erection, tolerances, inspection and construction categories (CC1–CC4) for structural steelwork.
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 278.05 kg/m. Verify against current manufacturer literature before use in design. Spotted an error? Report it.