Tee 165×152×23 vs WT 6X11
Tee 165×152×23 is an Tees (from UB) section from the UK Blue Book (SCI P363); WT 6X11 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 77.1 cm³ against 75.872 cm³ of plastic modulus, a difference of 1.6%. WT 6X11 is the lighter of the two at 16.4 kg/m against 23 kg/m, a saving of 40.2% on steel weight. WT 6X11 is deeper, 156.5 mm against 153.2 mm, which matters where the floor zone is tight.
| Property | Tee 165×152×23 Tees (from UB) | WT 6X11 WT | Difference |
|---|---|---|---|
| Mass | 23 kg/m | 16.4 kg/m | +40.2% |
| Depth | 153.2 mm | 156.5 mm | -2.1% |
| Width | 165.7 mm | 102.4 mm | +61.8% |
| Web thickness | 6.7 mm | 6.6 mm | +1.5% |
| Flange thickness | 11.8 mm | 10.8 mm | +9.3% |
| Area | 29.4 cm² | 20.9 cm² | +40.7% |
| Second moment, major (Iy) | 536 cm⁴ | 487 cm⁴ | +10.1% |
| Plastic modulus, major (Wpl,y) | 77.1 cm³ | 75.872 cm³ | +1.6% |
| Elastic modulus, major (Wel,y) | 43.7 cm³ | 42.442 cm³ | +3.0% |
| Second moment, minor (Iz) | 448 cm⁴ | 96.98 cm⁴ | +362.0% |
| Plastic modulus, minor (Wpl,z) | 82.8 cm³ | 29.988 cm³ | +176.1% |
| Radius of gyration, minor (iz) | 3.91 cm | 2.15 cm | +81.9% |
| Torsion constant (It) | 11.1 cm⁴ | 6.08 cm⁴ | +82.6% |
Tee 165×152×23 to BS EN 10365:2017; WT 6X11 to AISC Shapes Database v16.0. Difference is expressed relative to WT 6X11.
How to choose between them
On stiffness, Tee 165×152×23 has the larger second moment of area: 536 cm⁴ against 487 cm⁴, a difference of 10.1%. 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 6X11 is the more efficient section: 4.6 against 3.4 cm³ per kg/m, 27.5% 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 165×152×23 has 82.8 cm³ of minor-axis plastic modulus against 29.988 cm³, 176.1% 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. 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 40.2% weight.
In short, Tee 165×152×23 is the stronger section and WT 6X11 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.