StructureCalcsS12X31.8
American Standard Beam · AISC Shapes Database v15.0 · United States
S12X31.8 is an American Standard beam 304.8 mm deep with a 127.0 mm wide flange, weighing 47.3 kg/m. The dimensions below are the published AISC Shapes Database v15.0 values; the drawing is generated from them.
S-shapes are American Standard beams with narrow, tapered flanges — the oldest rolled I-profile in the catalogue, still used for crane rails and work on older structures.
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Published dimensions
| Property | Metric | Imperial |
|---|---|---|
| Depth, d | 304.8 mm | 12.00 in |
| Flange width, bf | 127.0 mm | 5.00 in |
| Flange thickness, tf | 13.8 mm | 0.544 in |
| Web thickness, tw | 8.9 mm | 0.350 in |
| Mass per metre | 47.3 kg/m | 31.8 lb/ft |
| Area, A | 6,006 mm² | 9.31 in² |
| Second moment, Ix | 90,322,219 mm⁴ | 217.0 in⁴ |
| Second moment, Iy | 3,883,439 mm⁴ | 9.3 in⁴ |
Derived section properties
Integrated from the section's own outline including the root and toe radii, whose arcs are integrated analytically rather than approximated by facets. For S12X31.8 the computed area agrees with the published value to 0.01% and Ix to 0.13%. Where a value is also published, the published one above is the one to quote.
| Property | Value |
|---|---|
| Elastic modulus, Sx | 593,424 mm³ |
| Elastic modulus, Sy | 62,332 mm³ |
| Plastic modulus, Zx | 684,786 mm³ |
| Plastic modulus, Zy | 105,674 mm³ |
| Radius of gyration, rx | 122.7 mm |
| Radius of gyration, ry | 25.7 mm |
S is the elastic modulus and Z the plastic modulus, following AISC 360. Australian and British practice reverse the letters.
Neighbouring sizes
Where these numbers come from
Published AISC Shapes Database v15.0 values. How StructureCalcs verifies its numbers · Understanding steel section properties · Query this section over the API