WT 9X43 vs Tee 191×229×53
WT 9X43 is an WT section from the American AISC Shapes Database; Tee 191×229×53 is the closest equivalent in the UK Blue Book (SCI P363). They are close to interchangeable in bending: 326.1 cm³ against 328 cm³ of plastic modulus, a difference of 0.6%. Tee 191×229×53 is the lighter of the two at 52.9 kg/m against 64 kg/m, a saving of 21.0% on steel weight. Both are about 234 mm deep, so either fits the same construction zone.
| Property | WT 9X43 WT | Tee 191×229×53 Tees (from UB) | Difference |
|---|---|---|---|
| Mass | 64 kg/m | 52.9 kg/m | +21.0% |
| Depth | 233.7 mm | 234.6 mm | -0.4% |
| Width | 281.9 mm | 194 mm | +45.3% |
| Web thickness | 12.2 mm | 12.6 mm | -3.2% |
| Flange thickness | 19.6 mm | 20.6 mm | -4.9% |
| Area | 81.9 cm² | 67.4 cm² | +21.5% |
| Second moment, major (Iy) | 3,430 cm⁴ | 3,260 cm⁴ | +5.2% |
| Plastic modulus, major (Wpl,y) | 326.1 cm³ | 328 cm³ | -0.6% |
| Elastic modulus, major (Wel,y) | 183.54 cm³ | 184 cm³ | -0.3% |
| Second moment, minor (Iz) | 3,646 cm⁴ | 1,260 cm⁴ | +189.4% |
| Plastic modulus, minor (Wpl,z) | 396.57 cm³ | 203 cm³ | +95.4% |
| Radius of gyration, minor (iz) | 6.68 cm | 4.32 cm | +54.6% |
| Torsion constant (It) | 84.91 cm⁴ | 72.6 cm⁴ | +17.0% |
WT 9X43 to AISC Shapes Database v16.0; Tee 191×229×53 to BS EN 10365:2017. Difference is expressed relative to Tee 191×229×53.
How to choose between them
On stiffness, WT 9X43 has the larger second moment of area: 3,430 cm⁴ against 3,260 cm⁴, a difference of 5.2%. 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, Tee 191×229×53 is the more efficient section: 6.2 against 5.1 cm³ per kg/m, 17.8% 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: WT 9X43 has 396.57 cm³ of minor-axis plastic modulus against 203 cm³, 95.4% 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 UB) 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 21.0% weight.
In short, Tee 191×229×53 is the stronger section and Tee 191×229×53 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.