UB 1016×305×272 vs W 40X183
UB 1016×305×272 is an UB section from the UK Blue Book (SCI P363); W 40X183 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 12800 cm³ against 12683.6 cm³ of plastic modulus, a difference of 0.9%. They weigh essentially the same, 272.3 kg/m and 272.3 kg/m. Both are about 990 mm deep, so either fits the same construction zone.
| Property | UB 1016×305×272 UB | W 40X183 W | Difference |
|---|---|---|---|
| Mass | 272.3 kg/m | 272.3 kg/m | same |
| Depth | 990.1 mm | 990.6 mm | -0.1% |
| Width | 300 mm | 299.7 mm | +0.1% |
| Web thickness | 16.5 mm | 16.5 mm | same |
| Flange thickness | 31 mm | 30.5 mm | +1.6% |
| Area | 347 cm² | 343.9 cm² | +0.9% |
| Second moment, major (Iy) | 554,000 cm⁴ | 549,425 cm⁴ | +0.8% |
| Plastic modulus, major (Wpl,y) | 12,800 cm³ | 12,683.6 cm³ | +0.9% |
| Elastic modulus, major (Wel,y) | 11,200 cm³ | 11,061.3 cm³ | +1.3% |
| Second moment, minor (Iz) | 14,000 cm⁴ | 13,777 cm⁴ | +1.6% |
| Plastic modulus, minor (Wpl,z) | 1,470 cm³ | 1,447 cm³ | +1.6% |
| Radius of gyration, minor (iz) | 6.35 cm | 6.32 cm | +0.5% |
| Torsion constant (It) | 835 cm⁴ | 803.3 cm⁴ | +3.9% |
UB 1016×305×272 to BS EN 10365:2017; W 40X183 to AISC Shapes Database v16.0. Difference is expressed relative to W 40X183.
How to choose between them
On stiffness, UB 1016×305×272 has the larger second moment of area: 554,000 cm⁴ against 549,425 cm⁴, a difference of 0.8%. 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 (47.0 against 46.6 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.