W18×283 vs W18×311
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W18×311 is the heavier section at 311 lb per foot, versus 283 for W18×283 (28 lb/ft more).
Both are nominally 18 in. deep.
W18×311 has the greater bending strength: section modulus Sx of 624 in³ versus 565, about 10% more.
| Property | W18×283 | W18×311 |
|---|---|---|
| Weight | 283 lb/ft | 311 lb/ft |
| Depth (d) | 21 7/8" | 22 3/8" |
| Flange width (bf) | 11 7/8" | 12" |
| Web thickness (tw) | 1 3/8" | 1 1/2" |
| Flange thickness (tf) | 2 1/2" | 2 3/4" |
| Area (A) | 83.3 in² | 91.6 in² |
| Moment of inertia (Ix) | 6170 in⁴ | 6970 in⁴ |
| Section modulus (Sx) | 565 in³ | 624 in³ |
| Plastic modulus (Zx) | 676 in³ | 754 in³ |
Open W18×283 in the interactive size chart →
Full detail: W18×283 · W18×311. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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