Tee 102×127×11 vs WT 5X7.5
Tee 102×127×11 is an Tees (from UB) section from the UK Blue Book (SCI P363); WT 5X7.5 is the closest equivalent in the American AISC Shapes Database. WT 5X7.5 carries more bending: 44.409 cm³ of plastic modulus against 43.5 cm³, 2.0% more. They weigh essentially the same, 11 kg/m and 11.2 kg/m. Both are about 127 mm deep, so either fits the same construction zone.
| Property | Tee 102×127×11 Tees (from UB) | WT 5X7.5 WT | Difference |
|---|---|---|---|
| Mass | 11 kg/m | 11.2 kg/m | -1.8% |
| Depth | 126.9 mm | 127 mm | -0.1% |
| Width | 101.6 mm | 101.6 mm | same |
| Web thickness | 5.7 mm | 5.8 mm | -1.7% |
| Flange thickness | 6.8 mm | 6.9 mm | -1.4% |
| Area | 14 cm² | 14.3 cm² | -2.1% |
| Second moment, major (Iy) | 223 cm⁴ | 226.8 cm⁴ | -1.7% |
| Plastic modulus, major (Wpl,y) | 43.5 cm³ | 44.409 cm³ | -2.0% |
| Elastic modulus, major (Wel,y) | 24.1 cm³ | 24.581 cm³ | -2.0% |
| Second moment, minor (Iz) | 59.7 cm⁴ | 60.35 cm⁴ | -1.1% |
| Plastic modulus, minor (Wpl,z) | 18.6 cm³ | 18.845 cm³ | -1.3% |
| Radius of gyration, minor (iz) | 2.06 cm | 2.06 cm | same |
| Torsion constant (It) | 2.06 cm⁴ | 2.16 cm⁴ | -4.6% |
Tee 102×127×11 to BS EN 10365:2017; WT 5X7.5 to AISC Shapes Database v16.0. Difference is expressed relative to WT 5X7.5.
How to choose between them
On stiffness, WT 5X7.5 has the larger second moment of area: 226.8 cm⁴ against 223 cm⁴, a difference of 1.7%. 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 (4.0 against 4.0 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, WT 5X7.5 is the stronger section and Tee 102×127×11 is the lighter one; where those are the same section, it is the clear choice, and where they are not, decide on whether your design is governed by capacity or by tonnage.