# 50CT7.4 Column Tee (cut from UC)

> Source page: [https://steelinfo.au/column-tees/50ct7-4/](https://steelinfo.au/column-tees/50ct7-4/)

Cut from AS/NZS 3679.1 UC Grade 300

The **50CT7.4** is a column tee (cut from a UC) to Cut from AS/NZS 3679.1 UC. It is 48.5 mm deep with a 99 mm wide flange, has a mass of 7.40 kg/m and a gross area of 943 mm². Its major-axis second moment of area is I_x = 0.127 × 10⁶ mm⁴. It is cut from a [100UC14.8](https://steelinfo.au/universal-columns/100uc14-8/). Download its free [DXF drawing](https://steelinfo.au/column-tees/50ct7-4/50ct7-4.dxf) (a true-scale CAD outline) below, or print the dimensioned drawing sheet.

Also written as: 50 CT 7.4, 50CT7, 50 CT 7

[DXF (AutoCAD R12)](https://steelinfo.au/column-tees/50ct7-4/50ct7-4.dxf) · [SVG drawing](https://steelinfo.au/column-tees/50ct7-4/50ct7-4.svg) · [JSON data](https://steelinfo.au/column-tees/50ct7-4/50ct7-4.json)

## Dimensions

**50CT7.4 dimensions**

| Symbol | Property | Value | Unit |
|---|---|---|---|
| d | Depth of tee | 48.5 | mm |
| b_f | Flange width | 99 | mm |
| t_f | Flange thickness | 7.0 | mm |
| t_w | Stem thickness | 5.0 | mm |
| r_1 | Root radius | 10.0 | mm |

## Section properties

**50CT7.4 section properties**

| Symbol | Property | Value | Unit |
|---|---|---|---|
| m | Mass per metre (nominal) | 7.40 | kg/m |
| A_g | Gross cross-section area | 943 | mm² |
| I_x | Second moment of area about x-axis | 0.127 | 10⁶ mm⁴ |
| Z_x | Elastic section modulus, x-axis (stem tip) | 3.21 | 10³ mm³ |
| Z_xf | Elastic section modulus, x-axis (flange) | 13.9 | 10³ mm³ |
| S_x | Plastic section modulus, x-axis | 6.33 | 10³ mm³ |
| r_x | Radius of gyration, x-axis | 11.6 | mm |
| I_y | Second moment of area about y-axis | 0.568 | 10⁶ mm⁴ |
| Z_y | Elastic section modulus, y-axis | 11.5 | 10³ mm³ |
| S_y | Plastic section modulus, y-axis | 17.6 | 10³ mm³ |
| r_y | Radius of gyration, y-axis | 24.5 | mm |
| y_c | Centroid from top of flange | 9.1 | mm |
| J | Torsion constant | 13.0 | 10³ mm⁴ |
| A_s | External surface area per metre | 0.286 | m²/m |
| A_s/t | External surface area per tonne | 38.7 | m²/t |

Axes: x-x (major) and y-y through the centroid. y_c is measured from the top of the flange.

## Design capacities to AS 4100

**AS 4100 design capacities – Grade 300**

| Symbol | Property | Value | Unit |
|---|---|---|---|
|  | Steel grade | 300 (AS/NZS 3679.1) |  |
| f_y | Yield stress used | 320 | MPa |
| f_u | Tensile strength | 440 | MPa |
| k_f | Form factor (Cl. 6.2.2) | 1.000 |  |
| φN_s | Section compression capacity (Cl. 6.2.1) | 272 | kN |
| φN_t | Tension capacity, gross section (Cl. 7.2, k_t=1, A_n=A_g) | 272 | 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) | φN_cx (kN) | φN_cy (kN) |
|---|---|---|
| 0.5 | 221 | 259 |
| 1 | 136 | 226 |
| 1.5 | 77.1 | 186 |
| 2 | 47.7 | 145 |
| 2.5 | 32.0 | 110 |
| 3 | 22.9 | 84.2 |
| 3.5 | 17.2 | 65.8 |
| 4 | 13.3 | 52.6 |
| 5 | 8.7 | 35.5 |
| 6 | 6.1 | 25.5 |
| 7 | 4.5 | 19.1 |
| 8 | 3.5 | 14.8 |
| 9 | 2.8 | 11.9 |
| 10 | 2.2 | 9.7 |
| 12 | 1.6 | 6.8 |

φN_c: Cl. 6.3.3, pin-ended effective length L_e = k_e L, concentric load.

## 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 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 7.41 kg/m. Verify against current manufacturer literature before use in design. Spotted an error? [Report it](mailto:info@steelinfo.au?subject=Data%20error%3A%2050CT7.4).

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From SteelInfo (https://steelinfo.au/column-tees/50ct7-4/), 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.