Tee 140×203×23 vs WT 8X15.5
Tee 140×203×23 is an Tees (from UB) section from the UK Blue Book (SCI P363); WT 8X15.5 is the closest equivalent in the American AISC Shapes Database. WT 8X15.5 carries more bending: 135.52 cm³ of plastic modulus against 132 cm³, 2.6% more. They weigh essentially the same, 23 kg/m and 23.1 kg/m. Both are about 202 mm deep, so either fits the same construction zone.
| Property | Tee 140×203×23 Tees (from UB) | WT 8X15.5 WT | Difference |
|---|---|---|---|
| Mass | 23 kg/m | 23.1 kg/m | -0.4% |
| Depth | 201.5 mm | 201.7 mm | -0.1% |
| Width | 142.2 mm | 140.5 mm | +1.2% |
| Web thickness | 6.8 mm | 7 mm | -2.9% |
| Flange thickness | 11.2 mm | 11.2 mm | same |
| Area | 29.3 cm² | 29.4 cm² | -0.3% |
| Second moment, major (Iy) | 1,120 cm⁴ | 1,145 cm⁴ | -2.2% |
| Plastic modulus, major (Wpl,y) | 132 cm³ | 135.52 cm³ | -2.6% |
| Elastic modulus, major (Wel,y) | 74.2 cm³ | 76.036 cm³ | -2.4% |
| Second moment, minor (Iz) | 269 cm⁴ | 258.1 cm⁴ | +4.2% |
| Plastic modulus, minor (Wpl,z) | 59 cm³ | 57.519 cm³ | +2.6% |
| Radius of gyration, minor (iz) | 3.03 cm | 2.97 cm | +2.0% |
| Torsion constant (It) | 9.49 cm⁴ | 9.57 cm⁴ | -0.8% |
Tee 140×203×23 to BS EN 10365:2017; WT 8X15.5 to AISC Shapes Database v16.0. Difference is expressed relative to WT 8X15.5.
How to choose between them
On stiffness, WT 8X15.5 has the larger second moment of area: 1,145 cm⁴ against 1,120 cm⁴, a difference of 2.2%. 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 of steel, WT 8X15.5 is the more efficient section: 5.9 against 5.7 cm³ per kg/m, 2.2% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
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 8X15.5 is the stronger section and Tee 140×203×23 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.