Steel Beam Sizes / AISC / S-Shapes / S8x18.4
S8x18.4 Dimensions, Weight and Section Properties
AISC American standard beams · v16.0
S8x18.4: 8 in depth, 4 in flange width, 18.4 lb/ft weight. View the full dimensions and properties in imperial and metric units below.
Need this steel supplied or fabricated?
Request project pricing for delivery in the United States or Canada.
Get a steel quote →Diagram, properties emphasis, and nearby alternatives use the selected unit system.
Section diagram
S8x18.4 dimensions
Not to scale. Dimensions shown for reference.
Section properties
Symbols match the steel section finder. Imperial and metric values are shown side by side.
| Property | Imperial | Metric |
|---|---|---|
| Weight | 18.40 lb/ft | 27.40 kg/m |
| Depth, d | 8.00 in | 203.00 mm |
| Flange width, bf | 4.00 in | 102.00 mm |
| tw | 0.271 in | 6.880 mm |
| tf | 0.425 in | 10.800 mm |
| Area | 5.40 in² | 3,480.00 mm² |
| Ix | 57.50 in⁴ | 23,900,000 mm⁴ |
| Iy | 3.69 in⁴ | 1,540,000 mm⁴ |
| Sx | 14.40 in³ | 236,000.00 mm³ |
| Sy | 1.84 in³ | 30,200.00 mm³ |
| Zx | 16.50 in³ | 270,000.00 mm³ |
| Zy | 3.18 in³ | 52,100.00 mm³ |
| rx | 3.26 in | 82.80 mm |
| ry | 0.83 in | 21.00 mm |
| J | 0.34 in⁴ | 139,000.00 mm⁴ |
| Cw | 52.90 in⁶ | 14,200,000,000 mm⁶ |
Alternatives
Useful nearby sections
Compare weight neighbors, another Ix option, and a nearby depth series when available, with percent change versus S8x18.4.
Source: AISC Shapes Database v16.0 · Methodology