Universal Beams UB
AS/NZS 3679.1Hot-rolled I-sections with flanges narrower than the depth, used mainly as beams and rafters. Dimensions, section properties, AS 4100 capacities and free DXF drawings for all 28 sizes.
Universal beams (UB) are the workhorse of Australian structural steel framing. They are hot-rolled to AS/NZS 3679.1 in Grade 300 (often branded 300PLUS), with a flange width roughly one-third to one-half of the depth. That shape puts most of the material in the flanges, far from the neutral axis, so UBs are efficient in major-axis bending but comparatively weak about the minor axis and in lateral-torsional buckling.
The designation gives the nominal depth in millimetres, the section type and the mass per metre: a 310UB40.4 is about 310 mm deep (actual depth 304 mm) and weighs 40.4 kg/m. Sizes from 150UB14.0 to 610UB125 are produced in Australia; heavier and deeper members are fabricated as welded beams (WB).
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 610UB125 | 125.0 | 612 | 229 | 19.6 | 11.9 | 15961 | 988 | 3228 | 3683 | 39.3 | 49.6 | 1561 | 928.0 | 3822 |
| 610UB113 | 113.0 | 607 | 228 | 17.3 | 11.2 | 14468 | 875 | 2882 | 3291 | 34.3 | 48.7 | 1136 | 829.3 | 3375 |
| 610UB101 | 101.0 | 602 | 228 | 14.8 | 10.6 | 12985 | 761 | 2528 | 2897 | 29.3 | 47.5 | 790 | 782.3 | 3114 |
| 530UB92.4 | 92.4 | 533 | 209 | 15.6 | 10.2 | 11807 | 554 | 2080 | 2371 | 23.8 | 44.9 | 775 | 640.1 | 2960 |
| 530UB82.0 | 82.0 | 528 | 209 | 13.2 | 9.6 | 10501 | 477 | 1807 | 2066 | 20.1 | 43.8 | 526 | 557.8 | 2557 |
| 460UB82.1 | 82.1 | 460 | 191 | 16.0 | 9.9 | 10461 | 371 | 1613 | 1834 | 18.6 | 42.2 | 701 | 495.1 | 2767 |
| 460UB74.6 | 74.6 | 457 | 190 | 14.5 | 9.1 | 9516 | 334 | 1463 | 1659 | 16.6 | 41.8 | 529 | 448.0 | 2436 |
| 460UB67.1 | 67.1 | 454 | 190 | 12.7 | 8.5 | 8581 | 296 | 1303 | 1479 | 14.5 | 41.2 | 378 | 399.3 | 2135 |
| 410UB59.7 | 59.7 | 406 | 178 | 12.8 | 7.8 | 7636 | 216 | 1064 | 1199 | 12.1 | 39.7 | 337 | 323.7 | 1935 |
| 410UB53.7 | 53.7 | 403 | 178 | 10.9 | 7.6 | 6889 | 188 | 934 | 1058 | 10.3 | 38.6 | 234 | 304.7 | 1811 |
| 360UB56.7 | 56.7 | 359 | 172 | 13.0 | 8.0 | 7248 | 162 | 900 | 1014 | 11.0 | 39.0 | 338 | 273.7 | 1947 |
| 360UB50.7 | 50.7 | 356 | 171 | 11.5 | 7.3 | 6476 | 142 | 799 | 898 | 9.60 | 38.5 | 241 | 242.5 | 1683 |
| 360UB44.7 | 44.7 | 352 | 171 | 9.7 | 6.9 | 5724 | 121 | 689 | 777 | 8.10 | 37.6 | 161 | 221.7 | 1533 |
| 310UB46.2 | 46.2 | 307 | 166 | 11.8 | 6.7 | 5928 | 100 | 653 | 728 | 9.01 | 39.0 | 233 | 196.6 | 1586 |
| 310UB40.4 | 40.4 | 304 | 165 | 10.2 | 6.1 | 5208 | 86.4 | 569 | 633 | 7.65 | 38.3 | 157 | 182.2 | 1428 |
| 310UB32.0 | 32.0 | 298 | 149 | 8.0 | 5.5 | 4080 | 63.2 | 424 | 475 | 4.42 | 32.9 | 86.5 | 134.4 | 1075 |
| 250UB37.3 | 37.3 | 256 | 146 | 10.9 | 6.4 | 4750 | 55.6 | 434 | 486 | 5.66 | 34.5 | 158 | 139.9 | 1368 |
| 250UB31.4 | 31.4 | 252 | 146 | 8.6 | 6.1 | 4012 | 44.7 | 355 | 398 | 4.47 | 33.4 | 89.3 | 114.1 | 1155 |
| 250UB25.7 | 25.7 | 248 | 124 | 8.0 | 5.0 | 3268 | 35.4 | 285 | 319 | 2.55 | 27.9 | 67.4 | 92.0 | 893 |
| 200UB29.8 | 29.8 | 207 | 134 | 9.6 | 6.3 | 3824 | 29.1 | 282 | 316 | 3.86 | 31.8 | 105 | 90.9 | 1101 |
| 200UB25.4 | 25.4 | 203 | 133 | 7.8 | 5.8 | 3230 | 23.5 | 232 | 260 | 3.06 | 30.8 | 62.7 | 74.5 | 930 |
| 200UB22.3 | 22.3 | 202 | 133 | 7.0 | 5.0 | 2870 | 21.1 | 208 | 232 | 2.75 | 30.9 | 45.0 | 65.5 | 827 |
| 200UB18.2 | 18.2 | 198 | 99 | 7.0 | 4.5 | 2318 | 15.8 | 160 | 180 | 1.14 | 22.1 | 38.6 | 51.8 | 661 |
| 180UB22.2 | 22.2 | 179 | 90 | 10.0 | 6.0 | 2822 | 15.3 | 171 | 195 | 1.22 | 20.8 | 81.6 | 56.2 | 813 |
| 180UB18.1 | 18.1 | 175 | 90 | 8.0 | 5.0 | 2303 | 12.1 | 139 | 157 | 0.975 | 20.6 | 44.8 | 45.2 | 663 |
| 180UB16.1 | 16.1 | 173 | 90 | 7.0 | 4.5 | 2044 | 10.6 | 123 | 138 | 0.853 | 20.4 | 31.5 | 39.8 | 589 |
| 150UB18.0 | 18.0 | 155 | 75 | 9.5 | 6.0 | 2296 | 9.05 | 117 | 135 | 0.672 | 17.1 | 60.5 | 38.9 | 661 |
| 150UB14.0 | 14.0 | 150 | 75 | 7.0 | 5.0 | 1785 | 6.66 | 88.8 | 102 | 0.495 | 16.6 | 28.1 | 29.3 | 514 |
Frequently asked questions
- What does 310UB40.4 mean?
- Nominal depth 310 mm, universal beam, mass 40.4 kg/m. The actual depth is 304 mm.
- What is the difference between a UB and a UC?
- A UB has a narrow flange and is efficient in bending. A UC has a flange about as wide as it is deep and is efficient as a column, with a much higher minor-axis stiffness.
- What steel grade are universal beams?
- Australian UBs are rolled to AS/NZS 3679.1 Grade 300, with a yield stress of 320 MPa for elements up to 11 mm thick and 300 MPa from 11 to 17 mm.
- Why does φMb reduce with length?
- Long unrestrained compression flanges can buckle sideways and twist (lateral-torsional buckling). AS 4100 Clause 5.6 reduces the moment capacity by the slenderness factor αs.
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. - 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.