W 24X76 vs S 24X80
W 24X76 is an W section from the American AISC Shapes Database; S 24X80 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 3277.4 cm³ against 3343 cm³ of plastic modulus, a difference of 2.0%. W 24X76 is the lighter of the two at 113.1 kg/m against 119.1 kg/m, a saving of 5.0% on steel weight. Both are about 608 mm deep, so either fits the same construction zone.
| Property | W 24X76 W | S 24X80 S | Difference |
|---|---|---|---|
| Mass | 113.1 kg/m | 119.1 kg/m | -5.0% |
| Depth | 607.1 mm | 609.6 mm | -0.4% |
| Width | 228.3 mm | 177.8 mm | +28.4% |
| Web thickness | 11.2 mm | 12.7 mm | -11.8% |
| Flange thickness | 17.3 mm | 22.1 mm | -21.7% |
| Area | 144.5 cm² | 151.6 cm² | -4.7% |
| Second moment, major (Iy) | 87,409 cm⁴ | 87,409 cm⁴ | same |
| Plastic modulus, major (Wpl,y) | 3,277.4 cm³ | 3,343 cm³ | -2.0% |
| Elastic modulus, major (Wel,y) | 2,884.1 cm³ | 2,867.7 cm³ | +0.6% |
| Second moment, minor (Iz) | 3,434 cm⁴ | 1,748 cm⁴ | +96.5% |
| Plastic modulus, minor (Wpl,z) | 468.67 cm³ | 340.85 cm³ | +37.5% |
| Radius of gyration, minor (iz) | 4.88 cm | 3.4 cm | +43.5% |
| Torsion constant (It) | 111.6 cm⁴ | 203.5 cm⁴ | -45.2% |
W 24X76 to AISC Shapes Database v16.0; S 24X80 to AISC Shapes Database v16.0. Difference is expressed relative to S 24X80.
How to choose between them
On stiffness, S 24X80 has the larger second moment of area: 87,409 cm⁴ against 87,409 cm⁴, a difference of 0.0%. 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 24X76 is the more efficient section: 29.0 against 28.1 cm³ per kg/m, 3.2% 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: W 24X76 has 468.67 cm³ of minor-axis plastic modulus against 340.85 cm³, 37.5% 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.
In short, S 24X80 is the stronger section and W 24X76 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.