W 27X102 vs HE 700 AA
W 27X102 is an W section from the American AISC Shapes Database; HE 700 AA is the closest equivalent in the European (Continental) range. W 27X102 carries more bending: 4998.1 cm³ of plastic modulus against 4840 cm³, 3.3% more. They weigh essentially the same, 151.8 kg/m and 150 kg/m. W 27X102 is deeper, 688.3 mm against 670 mm, which matters where the floor zone is tight.
| Property | W 27X102 W | HE 700 AA HE | Difference |
|---|---|---|---|
| Mass | 151.8 kg/m | 150 kg/m | +1.2% |
| Depth | 688.3 mm | 670 mm | +2.7% |
| Width | 254 mm | 300 mm | -15.3% |
| Web thickness | 13.1 mm | 13 mm | +0.8% |
| Flange thickness | 21.1 mm | 17 mm | +24.1% |
| Area | 193.5 cm² | 191 cm² | +1.3% |
| Second moment, major (Iy) | 150,676 cm⁴ | 143,000 cm⁴ | +5.4% |
| Plastic modulus, major (Wpl,y) | 4,998.1 cm³ | 4,840 cm³ | +3.3% |
| Elastic modulus, major (Wel,y) | 4,375.3 cm³ | 4,260 cm³ | +2.7% |
| Second moment, minor (Iz) | 5,786 cm⁴ | 7,670 cm⁴ | -24.6% |
| Plastic modulus, minor (Wpl,z) | 711.2 cm³ | 800 cm³ | -11.1% |
| Radius of gyration, minor (iz) | 5.46 cm | 6.34 cm | -13.9% |
| Torsion constant (It) | 219.8 cm⁴ | 186 cm⁴ | +18.2% |
W 27X102 to AISC Shapes Database v16.0; HE 700 AA to EN 10365 · Continental Steel. Difference is expressed relative to HE 700 AA.
How to choose between them
On stiffness, W 27X102 has the larger second moment of area: 150,676 cm⁴ against 143,000 cm⁴, a difference of 5.4%. 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 27X102 is the more efficient section: 32.9 against 32.3 cm³ per kg/m, 2.0% 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: HE 700 AA has 800 cm³ of minor-axis plastic modulus against 711.2 cm³, 11.1% 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 HE to EN 10365 · 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 27X102 is the stronger section and HE 700 AA 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.