W 12X72 vs H-300x300x11x17
W 12X72 is an W section from the American AISC Shapes Database; H-300x300x11x17 is the closest equivalent in the European (Continental) range. W 12X72 carries more bending: 1769.8 cm³ of plastic modulus against 1705 cm³, 3.8% more. They weigh essentially the same, 107.1 kg/m and 106 kg/m. W 12X72 is deeper, 312.4 mm against 304 mm, which matters where the floor zone is tight.
| Property | W 12X72 W | H-300x300x11x17 MB & MC | Difference |
|---|---|---|---|
| Mass | 107.1 kg/m | 106 kg/m | +1.0% |
| Depth | 312.4 mm | 304 mm | +2.8% |
| Width | 304.8 mm | 301 mm | +1.3% |
| Web thickness | 10.9 mm | 11 mm | -0.9% |
| Flange thickness | 17 mm | 17 mm | same |
| Area | 136.1 cm² | 135 cm² | +0.8% |
| Second moment, major (Iy) | 24,849 cm⁴ | 23,380 cm⁴ | +6.3% |
| Plastic modulus, major (Wpl,y) | 1,769.8 cm³ | 1,705 cm³ | +3.8% |
| Elastic modulus, major (Wel,y) | 1,596.1 cm³ | 1,538 cm³ | +3.8% |
| Second moment, minor (Iz) | 8,117 cm⁴ | 7,733 cm⁴ | +5.0% |
| Plastic modulus, minor (Wpl,z) | 806.24 cm³ | 781 cm³ | +3.2% |
| Radius of gyration, minor (iz) | 7.72 cm | 7.57 cm | +2.0% |
| Torsion constant (It) | 122 cm⁴ | 125 cm⁴ | -2.4% |
W 12X72 to AISC Shapes Database v16.0; H-300x300x11x17 to Continental Steel. Difference is expressed relative to H-300x300x11x17.
How to choose between them
On stiffness, W 12X72 has the larger second moment of area: 24,849 cm⁴ against 23,380 cm⁴, a difference of 6.3%. 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 12X72 is the more efficient section: 16.5 against 16.1 cm³ per kg/m, 2.7% 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.
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, W 12X72 is the stronger section and H-300x300x11x17 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.