Universal Beams
Australia / New Zealand · AS/NZS 3679.1 (designed to AS 4100)
Universal Beams (UB) are hot-rolled steel I-sections with a deep web and relatively narrow flanges. That proportion puts material where it does the most work in bending, so UBs are the default choice for flexural members: floor beams, rafters, purlins support, lintels and headers.
Because the flanges are narrow relative to the depth, a UB is much stiffer about its major (x-x) axis than its minor (y-y) axis. Where a member also needs minor-axis or compression capacity - a column, for instance - a Universal Column (UC) is usually the better section.
Reading the size: A UB is named by nominal depth then mass per metre: "460UB67.1" is about 460 mm deep and weighs 67.1 kg/m. (UK practice writes the same section as a serial size, e.g. 457x191x67.)
Properties are indicative - verify against the governing standard before professional use.
Universal Beams sizes (16)
| Designation | Profile | Mass kg/m | Depth mm | Width mm | tw mm | tf mm | Area mm² | Ix mm⁴ | Zx mm³ | Sx mm³ |
|---|---|---|---|---|---|---|---|---|---|---|
| 150UB14.0 | 14 | 150 | 75 | 5 | 7 | 1,780 | 6,660,000 | 88,800 | 102,000 | |
| 150UB18.0 | 18 | 155 | 75 | 6 | 9.5 | 2,300 | 9,050,000 | 117,000 | 135,000 | |
| 200UB22.3 | 22.3 | 202 | 133 | 5 | 7 | 2,870 | 21,000,000 | 208,000 | 230,000 | |
| 200UB25.4 | 25.4 | 203 | 133 | 5.8 | 7.82 | 3,230 | 23,600,000 | 232,000 | 260,000 | |
| 250UB25.7 | 25.7 | 248 | 124 | 5 | 8 | 3,270 | 35,400,000 | 285,000 | 320,000 | |
| 250UB31.4 | 31.4 | 252 | 146 | 6.1 | 8.64 | 4,010 | 44,500,000 | 354,000 | 396,000 | |
| 310UB32.0 | 32 | 298 | 149 | 5.5 | 8 | 4,080 | 63,200,000 | 424,000 | 471,000 | |
| 250UB37.3 | 37.3 | 256 | 146 | 6.4 | 10.9 | 4,750 | 55,700,000 | 435,000 | 485,000 | |
| 310UB40.4 | 40.4 | 304 | 165 | 6.1 | 10.2 | 5,210 | 86,400,000 | 569,000 | 624,000 | |
| 360UB44.7 | 44.7 | 352 | 171 | 6.9 | 9.73 | 5,720 | 121,000,000 | 689,000 | 774,000 | |
| 310UB46.2 | 46.2 | 307 | 166 | 6.7 | 11.8 | 5,930 | 100,000,000 | 654,000 | 723,000 | |
| 360UB50.7 | 50.7 | 356 | 171 | 7.3 | 11.5 | 6,470 | 142,000,000 | 798,000 | 895,000 | |
| 410UB53.7 | 53.7 | 403 | 178 | 7.6 | 10.9 | 6,890 | 188,000,000 | 933,000 | 1,050,000 | |
| 460UB67.1 | 67.1 | 454 | 190 | 8.5 | 12.7 | 8,580 | 296,000,000 | 1,300,000 | 1,470,000 | |
| 530UB82.0 | 82 | 528 | 209 | 9.6 | 13.2 | 10,500 | 477,000,000 | 1,810,000 | 2,060,000 | |
| 610UB101 | 101 | 602 | 228 | 10.6 | 14.8 | 13,000 | 761,000,000 | 2,530,000 | 2,880,000 |
tw web thickness · tf flange thickness · Ix second moment of area · Zx elastic / Sx plastic section modulus, major axis. Open any size for the full table, an SI / imperial toggle and a scaled cross-section.
Frequently asked
- What is a Universal Beam?
- A Universal Beam (UB) is a hot-rolled steel I-section with a deep web and narrow flanges, designed to carry loads in bending about its major axis. It is the standard beam section for floors, roofs and lintels.
- What is the difference between a UB and a UC?
- A UB (Universal Beam) is deep and narrow, optimised for bending. A UC (Universal Column) has its flange width close to its depth, giving balanced stiffness for axial compression. Use UBs as beams and UCs as columns, broadly speaking.
- How do I read a UB size?
- The numbers are nominal depth and mass per metre. "310UB40.4" is roughly 310 mm deep and weighs 40.4 kg/m. The actual rolled depth is close to, but not exactly, the nominal value.
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