UB 762×267×134 vs W 30X90
UB 762×267×134 is an UB section from the UK Blue Book (SCI P363); W 30X90 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 4640 cm³ against 4637.5 cm³ of plastic modulus, a difference of 0.1%. They weigh essentially the same, 133.9 kg/m and 133.9 kg/m. Both are about 750 mm deep, so either fits the same construction zone.
| Property | UB 762×267×134 UB | W 30X90 W | Difference |
|---|---|---|---|
| Mass | 133.9 kg/m | 133.9 kg/m | same |
| Depth | 750 mm | 749.3 mm | +0.1% |
| Width | 264.4 mm | 264.2 mm | +0.1% |
| Web thickness | 12 mm | 11.9 mm | +0.8% |
| Flange thickness | 15.5 mm | 15.5 mm | same |
| Area | 171 cm² | 169.7 cm² | +0.8% |
| Second moment, major (Iy) | 151,000 cm⁴ | 150,260 cm⁴ | +0.5% |
| Plastic modulus, major (Wpl,y) | 4,640 cm³ | 4,637.5 cm³ | +0.1% |
| Elastic modulus, major (Wel,y) | 4,020 cm³ | 4,014.8 cm³ | +0.1% |
| Second moment, minor (Iz) | 4,790 cm⁴ | 4,787 cm⁴ | +0.1% |
| Plastic modulus, minor (Wpl,z) | 570 cm³ | 568.63 cm³ | +0.2% |
| Radius of gyration, minor (iz) | 5.3 cm | 5.31 cm | -0.2% |
| Torsion constant (It) | 119 cm⁴ | 118.2 cm⁴ | +0.7% |
UB 762×267×134 to BS EN 10365:2017; W 30X90 to AISC Shapes Database v16.0. Difference is expressed relative to W 30X90.
How to choose between them
On stiffness, UB 762×267×134 has the larger second moment of area: 151,000 cm⁴ against 150,260 cm⁴, a difference of 0.5%. This matters more often than the strength comparison, because on normal floor spans deflection rather than bending capacity sets the beam size - so if the two are close on modulus but apart on inertia, the stiffer one is usually the better answer even when it is not the stronger one.
Measured as bending capacity per kilogram, the two are equally efficient (34.7 against 34.6 cm³ per kg/m), so on a pure steel-tonnage basis there is nothing to choose between them. The decision comes down to availability, connection detailing and what the rest of the frame uses.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. UB sections are specified to BS EN 10365:2017 and W to AISC Shapes Database v16.0; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save a marginal amount of weight.
In short, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.