W18×311 wide-flange beam
Detailing dimensions and section properties from the AISC Shapes Database, 16th Edition. Values are shown to the nearest 1/16 in. as they appear on a shop drawing.
W18×311 measures 22 3/8 in. deep with a 12 in. flange, on a 1 1/2 in. web and 2 3/4 in. flanges.
At 311 lb per foot it is the heaviest of the 23 W18 sizes, which run from 35 to 311 lb/ft.
For strong-axis bending its section modulus is Sx = 624 in³ and its moment of inertia Ix = 6970 in⁴, with a plastic modulus Zx = 754 in³.
Detailing dimensions
| Depth (d) | 22 3/8" |
|---|---|
| Flange width (bf) | 12" |
| Web thickness (tw) | 1 1/2" |
| Flange thickness (tf) | 2 3/4" |
| k (detailing) | 3 9/16" |
| Workable gage (g) | 5 1/2" |
Section properties
| Weight | 311 lb/ft |
|---|---|
| Area (A) | 91.6 in² |
| Ix | 6970 in⁴ |
| Sx | 624 in³ |
| Zx | 754 in³ |
| rx | 8.72 in |
| Iy | 795 in⁴ |
| Sy | 132 in³ |
| Zy | 207 in³ |
| ry | 2.95 in |
| J | 176 in⁴ |
Other W18 sizes
Same nominal size, different weight — useful when you are checking a substitution or a lighter section.
All W18 sizes and dimensions →
Similar weight wide-flange beams
Comparable 311 lb/ft sections in other wide-flange beam sizes.
Compare W18×311 with a nearby size
Detailing values are rounded to the nearest 1/16 in. per the AISC Steel Construction Manual. Verify critical dimensions against the current Manual before fabrication. Need W18×311 cut, formed, or fabricated? Huntington Steel & Supply Co.
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