WT 3X6 vs Tee 152×76×12
WT 3X6 is an WT section from the American AISC Shapes Database; Tee 152×76×12 is the closest equivalent in the UK Blue Book (SCI P363). Tee 152×76×12 carries more bending: 16.9 cm³ of plastic modulus against 16.551 cm³, 2.1% more. WT 3X6 is the lighter of the two at 8.9 kg/m against 11.5 kg/m, a saving of 22.6% on steel weight. Both are about 76 mm deep, so either fits the same construction zone.
| Property | WT 3X6 WT | Tee 152×76×12 Tees (from UC) | Difference |
|---|---|---|---|
| Mass | 8.9 kg/m | 11.5 kg/m | -22.6% |
| Depth | 76.7 mm | 76.1 mm | +0.8% |
| Width | 101.6 mm | 152.2 mm | -33.2% |
| Web thickness | 5.8 mm | 5.8 mm | same |
| Flange thickness | 7.1 mm | 6.8 mm | +4.4% |
| Area | 11.5 cm² | 14.6 cm² | -21.2% |
| Second moment, major (Iy) | 54.94 cm⁴ | 58.5 cm⁴ | -6.1% |
| Plastic modulus, major (Wpl,y) | 16.551 cm³ | 16.9 cm³ | -2.1% |
| Elastic modulus, major (Wel,y) | 9.242 cm³ | 9.41 cm³ | -1.8% |
| Second moment, minor (Iz) | 62.43 cm⁴ | 200 cm⁴ | -68.8% |
| Plastic modulus, minor (Wpl,z) | 19.009 cm³ | 40.1 cm³ | -52.6% |
| Radius of gyration, minor (iz) | 2.33 cm | 3.7 cm | -37.0% |
| Torsion constant (It) | 1.87 cm⁴ | 2.3 cm⁴ | -18.7% |
WT 3X6 to AISC Shapes Database v16.0; Tee 152×76×12 to BS EN 10365:2017. Difference is expressed relative to Tee 152×76×12.
How to choose between them
On stiffness, Tee 152×76×12 has the larger second moment of area: 58.5 cm⁴ against 54.94 cm⁴, a difference of 6.1%. 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 3X6 is the more efficient section: 1.9 against 1.5 cm³ per kg/m, 26.5% 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.
The two diverge much more about the minor axis: Tee 152×76×12 has 40.1 cm³ of minor-axis plastic modulus against 19.009 cm³, 52.6% more. If the member sees any minor-axis bending, or if it is unrestrained over a long length and lateral-torsional buckling governs, that gap decides the comparison even though the major-axis numbers looked equivalent.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. WT sections are specified to AISC Shapes Database v16.0 and Tees (from UC) to BS EN 10365:2017; 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 22.6% weight.
In short, Tee 152×76×12 is the stronger section and WT 3X6 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.