125x75x12UA Unequal Angle
AS/NZS 3679.1Grade 300The 125x75x12UA is a unequal angle to AS/NZS 3679.1. It is 125 × 75 mm legs, 12.0 mm thick, has a mass of 17.7 kg/m and a gross area of 2259 mm². Its major-axis second moment of area is Ix = 3.54 × 10⁶ mm⁴. Download its free DXF drawing (a true-scale CAD outline) below, or print the dimensioned drawing sheet.
Also written as: 125 x 75 x 12 unequal angle, 125x75x12 UA
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Dimensions
| Symbol | Property | Value | Unit |
|---|---|---|---|
| d | Leg length (vertical) | 125 | mm |
| b | Leg length (horizontal) | 75 | mm |
| t | Thickness | 12.0 | mm |
| r1 | Root radius | 8.0 | mm |
| r2 | Toe radius | 5.0 | mm |
Section properties
| Symbol | Property | Value | Unit |
|---|---|---|---|
| m | Mass per metre (nominal) | 17.7 | kg/m |
| Ag | Gross cross-section area | 2259 | mm² |
| Ix | Second moment of area about x-axis | 3.54 | 10⁶ mm⁴ |
| Zx | Elastic section modulus, x-axis (min.) | 43.3 | 10³ mm³ |
| Sx | Plastic section modulus, x-axis | 77.3 | 10³ mm³ |
| rx | Radius of gyration, x-axis | 39.6 | mm |
| Iy | Second moment of area about y-axis | 0.958 | 10⁶ mm⁴ |
| Zy | Elastic section modulus, y-axis (min.) | 16.9 | 10³ mm³ |
| Sy | Plastic section modulus, y-axis | 31.4 | 10³ mm³ |
| ry | Radius of gyration, y-axis | 20.6 | mm |
| Iu | Second moment of area, major principal axis | 3.91 | 10⁶ mm⁴ |
| Iv | Second moment of area, minor principal axis | 0.585 | 10⁶ mm⁴ |
| ru | Radius of gyration, u-axis | 41.6 | mm |
| rv | Radius of gyration, v-axis (minimum) | 16.1 | mm |
| α | Angle of u-axis to x-axis | 19.6 | ° |
| xc | Centroid from back of vertical leg | 18.4 | mm |
| yc | Centroid from back of horizontal leg | 43.3 | mm |
| J | Torsion constant | 108 | 10³ mm⁴ |
| As | External surface area per metre | 0.392 | m²/m |
| As/t | External surface area per tonne | 22.2 | m²/t |
Axes: x-x and y-y pass through the centroid parallel to the legs; u-u (major) and v-v (minor) are the principal axes, with u-u at angle α to x-x. xc, yc locate the centroid from the backs of the legs.
Design capacities to AS 4100
| Symbol | Property | Value | Unit |
|---|---|---|---|
| Steel grade | 300 (AS/NZS 3679.1) | ||
| fy | Yield stress used | 300 | MPa |
| fu | Tensile strength | 440 | MPa |
| kf | Form factor (Cl. 6.2.2) | 1.000 | |
| φNs | Section compression capacity (Cl. 6.2.1) | 610 | kN |
| φNt | Tension capacity, gross section (Cl. 7.2, kt=1, An=Ag) | 610 | kN |
| αb | Compression member section constant (Table 6.3.3) | 0.5 |
| Le (m) | φNc v-axis (kN) |
|---|---|
| 0.5 | 547 |
| 1 | 423 |
| 1.5 | 289 |
| 2 | 194 |
| 2.5 | 135 |
| 3 | 99.0 |
| 3.5 | 75.2 |
| 4 | 58.9 |
| 5 | 38.8 |
| 6 | 27.5 |
| 7 | 20.4 |
| 8 | 15.8 |
| 9 | 12.6 |
| 10 | 10.2 |
| 12 | 7.2 |
φNc: Cl. 6.3.3, pin-ended effective length Le = keL, concentric load. Single angles are rarely loaded concentrically. When connected through one leg, design them for combined actions (AS 4100 Section 8); Cl. 8.4.6 covers eccentrically loaded single angles in trusses.
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 unequal angles
Relevant Australian Standards
- AS/NZS 3679.1:2016 Structural steel – Part 1: Hot-rolled bars and sections
Specifies chemical composition, mechanical properties and tolerances for hot-rolled universal beams and columns, channels, angles, flats and bars in Grades 300 and 350. - 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 1252.1:2016 High-strength steel fastener assemblies for structural engineering
Property class 8.8 structural bolts, nuts and washers used in bolted connections designed to AS 4100. - AS/NZS 2312.1:2014 & 2312.2:2014 Guide to the protection of structural steel against atmospheric corrosion
Part 1 covers protective paint coatings and Part 2 hot-dip galvanizing; both use the external surface areas given on each section page.
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 17.73 kg/m. Verify against current manufacturer literature before use in design. Spotted an error? Report it.