W 16X100 vs H-450x300x13x21
W 16X100 is an W section from the American AISC Shapes Database; H-450x300x13x21 is the closest equivalent in the European (Continental) range. H-450x300x13x21 carries more bending: 3323 cm³ of plastic modulus against 3244.6 cm³, 2.4% more. H-450x300x13x21 is the lighter of the two at 145 kg/m against 148.8 kg/m, a saving of 2.6% on steel weight. H-450x300x13x21 is deeper, 446 mm against 431.8 mm, which matters where the floor zone is tight.
| Property | W 16X100 W | H-450x300x13x21 MB & MC | Difference |
|---|---|---|---|
| Mass | 148.8 kg/m | 145 kg/m | +2.6% |
| Depth | 431.8 mm | 446 mm | -3.2% |
| Width | 264.2 mm | 302 mm | -12.5% |
| Web thickness | 14.9 mm | 13 mm | +14.6% |
| Flange thickness | 25 mm | 21 mm | +19.0% |
| Area | 189.7 cm² | 184 cm² | +3.1% |
| Second moment, major (Iy) | 62,018 cm⁴ | 66,380 cm⁴ | -6.6% |
| Plastic modulus, major (Wpl,y) | 3,244.6 cm³ | 3,323 cm³ | -2.4% |
| Elastic modulus, major (Wel,y) | 2,867.7 cm³ | 2,977 cm³ | -3.7% |
| Second moment, minor (Iz) | 7,742 cm⁴ | 9,658 cm⁴ | -19.8% |
| Plastic modulus, minor (Wpl,z) | 899.65 cm³ | 981 cm³ | -8.3% |
| Radius of gyration, minor (iz) | 6.38 cm | 7.24 cm | -11.9% |
| Torsion constant (It) | 321.7 cm⁴ | 253 cm⁴ | +27.2% |
W 16X100 to AISC Shapes Database v16.0; H-450x300x13x21 to Continental Steel. Difference is expressed relative to H-450x300x13x21.
How to choose between them
On stiffness, H-450x300x13x21 has the larger second moment of area: 66,380 cm⁴ against 62,018 cm⁴, a difference of 6.6%. 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-450x300x13x21 is the more efficient section: 22.9 against 21.8 cm³ per kg/m, 4.9% 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-450x300x13x21 has 981 cm³ of minor-axis plastic modulus against 899.65 cm³, 8.3% 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 2.6% weight.
In short, H-450x300x13x21 is the stronger section and H-450x300x13x21 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.