W14×311 vs W18×311
A side-by-side comparison of two AISC wide-flange beams, 16th Edition. Detailing dimensions to the nearest 1/16 in.
W14×311 and W18×311 both weigh 311 lb per foot, so the choice comes down to depth and stiffness rather than weight.
W18×311 is the deeper section at a nominal 18 in., versus 14 in.
W18×311 has the greater bending strength: section modulus Sx of 624 in³ versus 506, about 23% more.
| Property | W14×311 | W18×311 |
|---|---|---|
| Weight | 311 lb/ft | 311 lb/ft |
| Depth (d) | 17 1/8" | 22 3/8" |
| Flange width (bf) | 16 1/4" | 12" |
| Web thickness (tw) | 1 7/16" | 1 1/2" |
| Flange thickness (tf) | 2 1/4" | 2 3/4" |
| Area (A) | 91.4 in² | 91.6 in² |
| Moment of inertia (Ix) | 4330 in⁴ | 6970 in⁴ |
| Section modulus (Sx) | 506 in³ | 624 in³ |
| Plastic modulus (Zx) | 603 in³ | 754 in³ |
Open W14×311 in the interactive size chart →
Full detail: W14×311 · W18×311. Verify critical dimensions against the current AISC Steel Construction Manual before fabrication.
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