W16×57 vs W21×57
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W16×57 and W21×57 both weigh 57 lb per foot, so the choice comes down to depth and stiffness rather than weight.
W21×57 is the deeper section at a nominal 21 in., versus 16 in.
W21×57 has the greater bending strength: section modulus Sx of 111 in³ versus 92.2, about 20% more.
| Property | W16×57 | W21×57 |
|---|---|---|
| Weight | 57 lb/ft | 57 lb/ft |
| Depth (d) | 16 3/8" | 21" |
| Flange width (bf) | 7 1/8" | 6 1/2" |
| Web thickness (tw) | 7/16" | 3/8" |
| Flange thickness (tf) | 11/16" | 5/8" |
| Area (A) | 16.8 in² | 16.7 in² |
| Moment of inertia (Ix) | 758 in⁴ | 1170 in⁴ |
| Section modulus (Sx) | 92.2 in³ | 111 in³ |
| Plastic modulus (Zx) | 105 in³ | 129 in³ |
Open W16×57 in the interactive size chart →
Full detail: W16×57 · W21×57. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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