WT 12X52 vs Tee 229×305×70
WT 12X52 is an WT section from the American AISC Shapes Database; Tee 229×305×70 is the closest equivalent in the UK Blue Book (SCI P363). Tee 229×305×70 carries more bending: 592 cm³ of plastic modulus against 575.19 cm³, 2.8% more. Tee 229×305×70 is the lighter of the two at 69.9 kg/m against 77.4 kg/m, a saving of 10.7% on steel weight. Both are about 307 mm deep, so either fits the same construction zone.
| Property | WT 12X52 WT | Tee 229×305×70 Tees (from UB) | Difference |
|---|---|---|---|
| Mass | 77.4 kg/m | 69.9 kg/m | +10.7% |
| Depth | 304.8 mm | 308.5 mm | -1.2% |
| Width | 325.1 mm | 230.2 mm | +41.2% |
| Web thickness | 12.7 mm | 13.1 mm | -3.1% |
| Flange thickness | 19 mm | 22.1 mm | -14.0% |
| Area | 98.7 cm² | 89.1 cm² | +10.8% |
| Second moment, major (Iy) | 7,867 cm⁴ | 7,740 cm⁴ | +1.6% |
| Plastic modulus, major (Wpl,y) | 575.19 cm³ | 592 cm³ | -2.8% |
| Elastic modulus, major (Wel,y) | 327.74 cm³ | 333 cm³ | -1.6% |
| Second moment, minor (Iz) | 5,411 cm⁴ | 2,250 cm⁴ | +140.5% |
| Plastic modulus, minor (Wpl,z) | 511.28 cm³ | 306 cm³ | +67.1% |
| Radius of gyration, minor (iz) | 7.39 cm | 5.03 cm | +46.9% |
| Torsion constant (It) | 97.81 cm⁴ | 108 cm⁴ | -9.4% |
WT 12X52 to AISC Shapes Database v16.0; Tee 229×305×70 to BS EN 10365:2017. Difference is expressed relative to Tee 229×305×70.
How to choose between them
On stiffness, WT 12X52 has the larger second moment of area: 7,867 cm⁴ against 7,740 cm⁴, a difference of 1.6%. 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 229×305×70 is the more efficient section: 8.5 against 7.4 cm³ per kg/m, 12.3% 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 12X52 has 511.28 cm³ of minor-axis plastic modulus against 306 cm³, 67.1% 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. 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 10.7% weight.
In short, Tee 229×305×70 is the stronger section and Tee 229×305×70 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.