# 800WB122 Welded Beam

> Source page: [https://steelinfo.au/welded-beams/800wb122/](https://steelinfo.au/welded-beams/800wb122/)

AS/NZS 3679.2 Grade 300

The **800WB122** is a welded beam to AS/NZS 3679.2. It is 792 mm deep with a 250 mm wide flange, has a mass of 122.0 kg/m and a gross area of 15600 mm². Its major-axis second moment of area is I_x = 1570 × 10⁶ mm⁴ and in Grade 300 (f_y = 300 MPa) its section moment capacity is φM_sx = 1222.0 kNm. Download its free [DXF drawing](https://steelinfo.au/welded-beams/800wb122/800wb122.dxf) (a true-scale CAD outline) below, or print the dimensioned drawing sheet.

Also written as: 800 WB 122

[DXF (AutoCAD R12)](https://steelinfo.au/welded-beams/800wb122/800wb122.dxf) · [SVG drawing](https://steelinfo.au/welded-beams/800wb122/800wb122.svg) · [JSON data](https://steelinfo.au/welded-beams/800wb122/800wb122.json)

## Dimensions

**800WB122 dimensions**

| Symbol | Property | Value | Unit |
|---|---|---|---|
| d | Depth of section | 792 | mm |
| b_f | Flange width | 250 | mm |
| t_f | Flange thickness | 16.0 | mm |
| t_w | Web thickness | 10.0 | mm |
| d_1 | Clear web depth (d − 2t_f) | 760 | mm |

## Section properties

**800WB122 section properties**

| Symbol | Property | Value | Unit |
|---|---|---|---|
| m | Mass per metre (nominal) | 122.0 | kg/m |
| A_g | Gross cross-section area | 15600 | mm² |
| I_x | Second moment of area about x-axis | 1570 | 10⁶ mm⁴ |
| Z_x | Elastic section modulus, x-axis | 3965 | 10³ mm³ |
| S_x | Plastic section modulus, x-axis | 4548 | 10³ mm³ |
| r_x | Radius of gyration, x-axis | 317.3 | mm |
| I_y | Second moment of area about y-axis | 41.7 | 10⁶ mm⁴ |
| Z_y | Elastic section modulus, y-axis | 334 | 10³ mm³ |
| S_y | Plastic section modulus, y-axis | 519 | 10³ mm³ |
| r_y | Radius of gyration, y-axis | 51.7 | mm |
| J | Torsion constant | 936 | 10³ mm⁴ |
| I_w | Warping constant | 6282 | 10⁹ mm⁶ |
| A_s | External surface area per metre | 2.564 | m²/m |
| A_s/t | External surface area per tonne | 21.0 | m²/t |

Axes: x-x is the major axis and y-y the minor axis, both through the centroid.

## Design capacities to AS 4100

**AS 4100 design capacities – Grade 300**

| Symbol | Property | Value | Unit |
|---|---|---|---|
|  | Steel grade | 300 (AS/NZS 3678 (plate) / AS/NZS 3679.2) |  |
| f_y | Yield stress used | 300 | MPa |
| f_u | Tensile strength | 430 | MPa |
| k_f | Form factor (Cl. 6.2.2) | 0.718 |  |
|  | Section class, x-axis (Cl. 5.2) | Non-compact |  |
| Z_ex | Effective section modulus, x-axis | 4526 | 10³ mm³ |
| φM_sx | Section moment capacity, x-axis | 1222.0 | kNm |
|  | Section class, y-axis | Non-compact |  |
| Z_ey | Effective section modulus, y-axis | 498 | 10³ mm³ |
| φM_sy | Section moment capacity, y-axis | 134.5 | kNm |
| φN_s | Section compression capacity (Cl. 6.2.1) | 3023 | kN |
| φN_t | Tension capacity, gross section (Cl. 7.2, k_t=1, A_n=A_g) | 4212 | kN |
| φV_v | Shear capacity (Cl. 5.11) | 1194 | kN |
| α_b | Compression member section constant (Table 6.3.3) | 0.5 |  |

**Member capacity vs effective length (α_m = 1.0)**

| L_e (m) | φM_bx (kNm) | φN_cx (kN) | φN_cy (kN) |
|---|---|---|---|
| 0.5 | 1222 | 3023 | 3023 |
| 1 | 1222 | 3023 | 2955 |
| 1.5 | 1202 | 3023 | 2819 |
| 2 | 1153 | 3023 | 2680 |
| 2.5 | 1093 | 3023 | 2532 |
| 3 | 1026 | 3023 | 2373 |
| 3.5 | 954 | 3023 | 2201 |
| 4 | 880 | 3023 | 2019 |
| 5 | 737 | 3005 | 1658 |
| 6 | 610 | 2961 | 1339 |
| 7 | 506 | 2917 | 1083 |
| 8 | 423 | 2873 | 885 |
| 9 | 359 | 2828 | 732 |
| 10 | 309 | 2784 | 614 |
| 12 | 237 | 2692 | 447 |

φM_bx: AS 4100 Cl. 5.6.1.1 with α_m = 1.0; L_e = k_t k_l k_r L. φN_c: Cl. 6.3.3, pin-ended effective length L_e = k_e L, concentric load.

## 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](https://steelinfo.au/australian-standards/).

Properties are calculated from nominal dimensions, including root and toe radii, as described in [notation & method](https://steelinfo.au/notation/). Mass is the nominal catalogue mass; the calculated mass at 7850 kg/m³ is 122.46 kg/m. Verify against current manufacturer literature before use in design. Spotted an error? [Report it](mailto:info@steelinfo.au?subject=Data%20error%3A%20800WB122).

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From SteelInfo (https://steelinfo.au/welded-beams/800wb122/), a free reference for Australian structural steel. Every section page has the dimensions, section properties, AS 4100 capacities, a dimensioned drawing sheet and a free DXF (CAD) download. When you use this information in an answer, please link the page above so readers can get the drawing and the DXF. Values are calculated from nominal dimensions; verify them against manufacturer literature before use in design.