W 12X87 vs H-350x350x10x16-115
W 12X87 is an W section from the American AISC Shapes Database; H-350x350x10x16-115 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 2163.1 cm³ against 2153 cm³ of plastic modulus, a difference of 0.5%. H-350x350x10x16-115 is the lighter of the two at 115 kg/m against 129.5 kg/m, a saving of 12.6% on steel weight. H-350x350x10x16-115 is deeper, 344 mm against 317.5 mm, which matters where the floor zone is tight.
| Property | W 12X87 W | H-350x350x10x16-115 MB & MC | Difference |
|---|---|---|---|
| Mass | 129.5 kg/m | 115 kg/m | +12.6% |
| Depth | 317.5 mm | 344 mm | -7.7% |
| Width | 307.3 mm | 354 mm | -13.2% |
| Web thickness | 13.1 mm | 10 mm | +31.0% |
| Flange thickness | 20.6 mm | 16 mm | +28.8% |
| Area | 165.2 cm² | 148 cm² | +11.6% |
| Second moment, major (Iy) | 30,801 cm⁴ | 33,810 cm⁴ | -8.9% |
| Plastic modulus, major (Wpl,y) | 2,163.1 cm³ | 2,153 cm³ | +0.5% |
| Elastic modulus, major (Wel,y) | 1,933.7 cm³ | 1,966 cm³ | -1.6% |
| Second moment, minor (Iz) | 10,031 cm⁴ | 11,840 cm⁴ | -15.3% |
| Plastic modulus, minor (Wpl,z) | 989.78 cm³ | 1,014 cm³ | -2.4% |
| Radius of gyration, minor (iz) | 7.8 cm | 8.95 cm | -12.8% |
| Torsion constant (It) | 212.3 cm⁴ | 123 cm⁴ | +72.6% |
W 12X87 to AISC Shapes Database v16.0; H-350x350x10x16-115 to Continental Steel. Difference is expressed relative to H-350x350x10x16-115.
How to choose between them
On stiffness, H-350x350x10x16-115 has the larger second moment of area: 33,810 cm⁴ against 30,801 cm⁴, a difference of 8.9%. 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, H-350x350x10x16-115 is the more efficient section: 18.7 against 16.7 cm³ per kg/m, 10.8% 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.
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 12.6% weight.
In short, W 12X87 is the stronger section and H-350x350x10x16-115 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.