W 12X58 vs H-300x300x9x14
W 12X58 is an W section from the American AISC Shapes Database; H-300x300x9x14 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 1415.8 cm³ against 1389 cm³ of plastic modulus, a difference of 1.9%. They weigh essentially the same, 86.3 kg/m and 87 kg/m. W 12X58 is deeper, 309.9 mm against 298 mm, which matters where the floor zone is tight.
| Property | W 12X58 W | H-300x300x9x14 MB & MC | Difference |
|---|---|---|---|
| Mass | 86.3 kg/m | 87 kg/m | -0.8% |
| Depth | 309.9 mm | 298 mm | +4.0% |
| Width | 254 mm | 299 mm | -15.1% |
| Web thickness | 9.1 mm | 9 mm | +1.1% |
| Flange thickness | 16.3 mm | 14 mm | +16.4% |
| Area | 109.7 cm² | 111 cm² | -1.2% |
| Second moment, major (Iy) | 19,771 cm⁴ | 18,850 cm⁴ | +4.9% |
| Plastic modulus, major (Wpl,y) | 1,415.8 cm³ | 1,389 cm³ | +1.9% |
| Elastic modulus, major (Wel,y) | 1,278.2 cm³ | 1,265 cm³ | +1.0% |
| Second moment, minor (Iz) | 4,454 cm⁴ | 6,242 cm⁴ | -28.6% |
| Plastic modulus, minor (Wpl,z) | 532.58 cm³ | 634 cm³ | -16.0% |
| Radius of gyration, minor (iz) | 6.38 cm | 7.51 cm | -15.0% |
| Torsion constant (It) | 87.41 cm⁴ | 71.3 cm⁴ | +22.6% |
W 12X58 to AISC Shapes Database v16.0; H-300x300x9x14 to Continental Steel. Difference is expressed relative to H-300x300x9x14.
How to choose between them
On stiffness, W 12X58 has the larger second moment of area: 19,771 cm⁴ against 18,850 cm⁴, a difference of 4.9%. 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, W 12X58 is the more efficient section: 16.4 against 16.0 cm³ per kg/m, 2.8% 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: H-300x300x9x14 has 634 cm³ of minor-axis plastic modulus against 532.58 cm³, 16.0% 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 MB & MC to 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, these two are genuine equivalents. Pick whichever your supplier stocks and the rest of the frame already uses.