W 36X318 vs HE 1000 x 438
W 36X318 is an W section from the American AISC Shapes Database; HE 1000 x 438 is the closest equivalent in the European (Continental) range. W 36X318 carries more bending: 21303.2 cm³ of plastic modulus against 20800 cm³, 2.4% more. HE 1000 x 438 is the lighter of the two at 438 kg/m against 473.2 kg/m, a saving of 8.0% on steel weight. HE 1000 x 438 is deeper, 1026 mm against 970.3 mm, which matters where the floor zone is tight.
| Property | W 36X318 W | HE 1000 x 438 HE | Difference |
|---|---|---|---|
| Mass | 473.2 kg/m | 438 kg/m | +8.0% |
| Depth | 970.3 mm | 1026 mm | -5.4% |
| Width | 315 mm | 305 mm | +3.3% |
| Web thickness | 30 mm | 26.9 mm | +11.5% |
| Flange thickness | 54.1 mm | 49 mm | +10.4% |
| Area | 602.6 cm² | 556 cm² | +8.4% |
| Second moment, major (Iy) | 882,411 cm⁴ | 909,000 cm⁴ | -2.9% |
| Plastic modulus, major (Wpl,y) | 21,303.2 cm³ | 20,800 cm³ | +2.4% |
| Elastic modulus, major (Wel,y) | 18,189.6 cm³ | 17,700 cm³ | +2.8% |
| Second moment, minor (Iz) | 28,387 cm⁴ | 23,400 cm⁴ | +21.3% |
| Plastic modulus, minor (Wpl,z) | 2,884.1 cm³ | 2,460 cm³ | +17.2% |
| Radius of gyration, minor (iz) | 6.86 cm | 6.48 cm | +5.9% |
| Torsion constant (It) | 4,092 cm⁴ | 3,180 cm⁴ | +28.7% |
W 36X318 to AISC Shapes Database v16.0; HE 1000 x 438 to EN 10365 · Continental Steel. Difference is expressed relative to HE 1000 x 438.
How to choose between them
On stiffness, HE 1000 x 438 has the larger second moment of area: 909,000 cm⁴ against 882,411 cm⁴, a difference of 2.9%. 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, HE 1000 x 438 is the more efficient section: 47.5 against 45.0 cm³ per kg/m, 5.2% 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: W 36X318 has 2884.1 cm³ of minor-axis plastic modulus against 2460 cm³, 17.2% 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 8.0% weight.
In short, W 36X318 is the stronger section and HE 1000 x 438 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.