Taper Flange Beams TFB
AS/NZS 3679.1Small hot-rolled I-beams with tapered (8°) flanges, used for lintels, light framing and trailers. Dimensions, section properties, AS 4100 capacities and free DXF drawings for all 2 sizes.
Taper flange beams (TFB) are small hot-rolled I-sections whose flanges taper at 8°. Only the 100TFB and 125TFB remain in common use, typically for lintels, light framing, trailer and truck bodies, and monorail beams for light hoists, where trolleys with tapered wheels run on the sloping bottom flange.
The flange thickness tf is quoted at the middle of the flange outstand. Use tapered washers for bolts through the sloping flange faces.
Select any section in the table to open its page, with a dimensioned drawing, all section properties, AS 4100 capacities and a free DXF download for your CAD software.
| Designation | Mass kg/m | d mm | bf mm | tf mm | tw mm | Ag mm² | Ix 10⁶mm⁴ | Zx 10³mm³ | Sx 10³mm³ | Iy 10⁶mm⁴ | ry mm | J 10³mm⁴ | φMsx kNm | φNs kN |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 125TFB | 13.1 | 125 | 65 | 8.5 | 5.0 | 1675 | 4.34 | 69.4 | 80.3 | 0.337 | 14.2 | 31.1 | 23.1 | 482 |
| 100TFB | 7.20 | 100 | 45 | 6.0 | 4.0 | 917 | 1.46 | 29.2 | 34.1 | 0.0794 | 9.3 | 8.36 | 9.8 | 264 |
Frequently asked questions
- Is a TFB the same as a small UB?
- No. TFB flanges slope at 8° on their inside faces and are thicker at the root, while UB flanges are parallel. Use tapered washers on the sloping faces.
- Which TFB sizes are available?
- The 100TFB (7.2 kg/m) and 125TFB (13.1 kg/m) are the sizes still in common use.
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.