W 33X318 vs HE 900 x 466
W 33X318 is an W section from the American AISC Shapes Database; HE 900 x 466 is the closest equivalent in the European (Continental) range. W 33X318 carries more bending: 20811.6 cm³ of plastic modulus against 20400 cm³, 2.0% more. They weigh essentially the same, 473.2 kg/m and 466 kg/m. HE 900 x 466 is deeper, 938 mm against 894.1 mm, which matters where the floor zone is tight.
| Property | W 33X318 W | HE 900 x 466 HE | Difference |
|---|---|---|---|
| Mass | 473.2 kg/m | 466 kg/m | +1.5% |
| Depth | 894.1 mm | 938 mm | -4.7% |
| Width | 406.4 mm | 312 mm | +30.3% |
| Web thickness | 26.4 mm | 30 mm | -12.0% |
| Flange thickness | 48 mm | 54 mm | -11.1% |
| Area | 604.5 cm² | 594 cm² | +1.8% |
| Second moment, major (Iy) | 811,651 cm⁴ | 815,000 cm⁴ | -0.4% |
| Plastic modulus, major (Wpl,y) | 20,811.6 cm³ | 20,400 cm³ | +2.0% |
| Elastic modulus, major (Wel,y) | 18,189.6 cm³ | 17,400 cm³ | +4.5% |
| Second moment, minor (Iz) | 53,694 cm⁴ | 27,600 cm⁴ | +94.5% |
| Plastic modulus, minor (Wpl,z) | 4,096.8 cm³ | 2,830 cm³ | +44.8% |
| Radius of gyration, minor (iz) | 9.42 cm | 6.81 cm | +38.3% |
| Torsion constant (It) | 3,513 cm⁴ | 4,230 cm⁴ | -17.0% |
W 33X318 to AISC Shapes Database v16.0; HE 900 x 466 to EN 10365 · Continental Steel. Difference is expressed relative to HE 900 x 466.
How to choose between them
On stiffness, HE 900 x 466 has the larger second moment of area: 815,000 cm⁴ against 811,651 cm⁴, a difference of 0.4%. 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, the two are equally efficient (44.0 against 43.8 cm³ per kg/m), so on a pure steel-tonnage basis there is nothing to choose between them. The decision comes down to availability, connection detailing and what the rest of the frame uses.
The two diverge much more about the minor axis: W 33X318 has 4096.8 cm³ of minor-axis plastic modulus against 2830 cm³, 44.8% 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. W sections are specified to AISC Shapes Database v16.0 and HE to EN 10365 · Continental Steel; 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, W 33X318 is the stronger section and HE 900 x 466 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.