Tee 312×267×110 vs WT 10.5X73.5
Tee 312×267×110 is an Tees (from UB) section from the UK Blue Book (SCI P363); WT 10.5X73.5 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 696 cm³ against 694.81 cm³ of plastic modulus, a difference of 0.2%. They weigh essentially the same, 109.4 kg/m and 109.4 kg/m. Both are about 280 mm deep, so either fits the same construction zone.
| Property | Tee 312×267×110 Tees (from UB) | WT 10.5X73.5 WT | Difference |
|---|---|---|---|
| Mass | 109.4 kg/m | 109.4 kg/m | same |
| Depth | 280.4 mm | 279.4 mm | +0.4% |
| Width | 317.4 mm | 317.5 mm | same |
| Web thickness | 18.3 mm | 18.3 mm | same |
| Flange thickness | 29.2 mm | 29.2 mm | same |
| Area | 139 cm² | 139.4 cm² | -0.3% |
| Second moment, major (Iy) | 8,530 cm⁴ | 8,491 cm⁴ | +0.5% |
| Plastic modulus, major (Wpl,y) | 696 cm³ | 694.81 cm³ | +0.2% |
| Elastic modulus, major (Wel,y) | 389 cm³ | 388.37 cm³ | +0.2% |
| Second moment, minor (Iz) | 7,790 cm⁴ | 7,825 cm⁴ | -0.4% |
| Plastic modulus, minor (Wpl,z) | 757 cm³ | 758.72 cm³ | -0.2% |
| Radius of gyration, minor (iz) | 7.48 cm | 7.49 cm | -0.1% |
| Torsion constant (It) | 320 cm⁴ | 320.1 cm⁴ | same |
Tee 312×267×110 to BS EN 10365:2017; WT 10.5X73.5 to AISC Shapes Database v16.0. Difference is expressed relative to WT 10.5X73.5.
How to choose between them
On stiffness, Tee 312×267×110 has the larger second moment of area: 8,530 cm⁴ against 8,491 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 (6.4 against 6.4 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. Tees (from UB) sections are specified to BS EN 10365:2017 and WT 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.