W 27X129 vs H-700x300x13x24-185
W 27X129 is an W section from the American AISC Shapes Database; H-700x300x13x24-185 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 6472.9 cm³ against 6464 cm³ of plastic modulus, a difference of 0.1%. H-700x300x13x24-185 is the lighter of the two at 185 kg/m against 192 kg/m, a saving of 3.8% on steel weight. Both are about 701 mm deep, so either fits the same construction zone.
| Property | W 27X129 W | H-700x300x13x24-185 MB & MC | Difference |
|---|---|---|---|
| Mass | 192 kg/m | 185 kg/m | +3.8% |
| Depth | 701 mm | 700 mm | +0.1% |
| Width | 254 mm | 300 mm | -15.3% |
| Web thickness | 15.5 mm | 13 mm | +19.2% |
| Flange thickness | 27.9 mm | 24 mm | +16.2% |
| Area | 243.9 cm² | 235 cm² | +3.8% |
| Second moment, major (Iy) | 198,126 cm⁴ | 201,500 cm⁴ | -1.7% |
| Plastic modulus, major (Wpl,y) | 6,472.9 cm³ | 6,464 cm³ | +0.1% |
| Elastic modulus, major (Wel,y) | 5,653.5 cm³ | 5,757 cm³ | -1.8% |
| Second moment, minor (Iz) | 7,659 cm⁴ | 10,830 cm⁴ | -29.3% |
| Plastic modulus, minor (Wpl,z) | 943.89 cm³ | 1,116 cm³ | -15.4% |
| Radius of gyration, minor (iz) | 5.61 cm | 6.78 cm | -17.3% |
| Torsion constant (It) | 462 cm⁴ | 383 cm⁴ | +20.6% |
W 27X129 to AISC Shapes Database v16.0; H-700x300x13x24-185 to Continental Steel. Difference is expressed relative to H-700x300x13x24-185.
How to choose between them
On stiffness, H-700x300x13x24-185 has the larger second moment of area: 201,500 cm⁴ against 198,126 cm⁴, a difference of 1.7%. 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-700x300x13x24-185 is the more efficient section: 34.9 against 33.7 cm³ per kg/m, 3.5% 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-700x300x13x24-185 has 1116 cm³ of minor-axis plastic modulus against 943.89 cm³, 15.4% 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 3.8% weight.
In short, W 27X129 is the stronger section and H-700x300x13x24-185 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.