W21×73 vs W21×83
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W21×83 is the heavier section at 83 lb per foot, versus 73 for W21×73 (10 lb/ft more).
Both are nominally 21 in. deep.
W21×83 has the greater bending strength: section modulus Sx of 171 in³ versus 151, about 13% more.
| Property | W21×73 | W21×83 |
|---|---|---|
| Weight | 73 lb/ft | 83 lb/ft |
| Depth (d) | 21 1/4" | 21 3/8" |
| Flange width (bf) | 8 1/4" | 8 3/8" |
| Web thickness (tw) | 7/16" | 1/2" |
| Flange thickness (tf) | 3/4" | 13/16" |
| Area (A) | 21.5 in² | 24.4 in² |
| Moment of inertia (Ix) | 1600 in⁴ | 1830 in⁴ |
| Section modulus (Sx) | 151 in³ | 171 in³ |
| Plastic modulus (Zx) | 172 in³ | 196 in³ |
Open W21×73 in the interactive size chart →
Full detail: W21×73 · W21×83. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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