IPE 500 vs S 20X66
IPE 500 is an IPE section from the European (Continental) range; S 20X66 is the closest equivalent in the American AISC Shapes Database. S 20X66 carries more bending: 2277.8 cm³ of plastic modulus against 2190 cm³, 3.9% more. IPE 500 is the lighter of the two at 90.7 kg/m against 98.2 kg/m, a saving of 7.6% on steel weight. Both are about 504 mm deep, so either fits the same construction zone.
| Property | IPE 500 IPE | S 20X66 S | Difference |
|---|---|---|---|
| Mass | 90.7 kg/m | 98.2 kg/m | -7.6% |
| Depth | 500 mm | 508 mm | -1.6% |
| Width | 200 mm | 159 mm | +25.8% |
| Web thickness | 10.2 mm | 12.8 mm | -20.3% |
| Flange thickness | 16 mm | 20.2 mm | -20.8% |
| Area | 116 cm² | 125.2 cm² | -7.3% |
| Second moment, major (Iy) | 48,200 cm⁴ | 49,532 cm⁴ | -2.7% |
| Plastic modulus, major (Wpl,y) | 2,190 cm³ | 2,277.8 cm³ | -3.9% |
| Elastic modulus, major (Wel,y) | 1,930 cm³ | 1,950.1 cm³ | -1.0% |
| Second moment, minor (Iz) | 2,140 cm⁴ | 1,145 cm⁴ | +86.9% |
| Plastic modulus, minor (Wpl,z) | 336 cm³ | 252.36 cm³ | +33.1% |
| Radius of gyration, minor (iz) | 4.31 cm | 3.02 cm | +42.7% |
| Torsion constant (It) | 89.1 cm⁴ | 149 cm⁴ | -40.2% |
IPE 500 to EN 10365 · Continental Steel; S 20X66 to AISC Shapes Database v16.0. Difference is expressed relative to S 20X66.
How to choose between them
On stiffness, S 20X66 has the larger second moment of area: 49,532 cm⁴ against 48,200 cm⁴, a difference of 2.7%. 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, IPE 500 is the more efficient section: 24.1 against 23.2 cm³ per kg/m, 4.1% 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: IPE 500 has 336 cm³ of minor-axis plastic modulus against 252.36 cm³, 33.1% 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. IPE sections are specified to EN 10365 · Continental Steel and S to AISC Shapes Database v16.0; 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 7.6% weight.
In short, S 20X66 is the stronger section and IPE 500 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.