StructureCalcs686x254x125 UB
Universal Beam · BS 4-1 · United Kingdom
686x254x125 UB is a British universal beam 677.9 mm deep with a 253.0 mm wide flange, weighing 125.2 kg/m. The dimensions below are the published BS 4-1 values; the drawing is generated from them.
British Universal Beams to BS 4-1 are the UK’s standard I-beam — the same designation style as the Australian UB, but a distinct dimension table.
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Published dimensions
| Property | Metric | Imperial |
|---|---|---|
| Depth, d | 677.9 mm | 26.69 in |
| Flange width, bf | 253.0 mm | 9.96 in |
| Flange thickness, tf | 16.2 mm | 0.638 in |
| Web thickness, tw | 11.7 mm | 0.461 in |
| Mass per metre | 125.2 kg/m | 84.1 lb/ft |
| Area, A | 15,900 mm² | 24.65 in² |
| Second moment, Ix | 1,179,920,000 mm⁴ | 2,834.8 in⁴ |
| Second moment, Iy | 43,830,000 mm⁴ | 105.3 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 686x254x125 UB the computed area agrees with the published value to 0.01% and Ix to 0.42%. Where a value is also published, the published one above is the one to quote.
| Property | Value |
|---|---|
| Elastic modulus, Zx | 3,466,568 mm³ |
| Elastic modulus, Zy | 346,428 mm³ |
| Plastic modulus, Sx | 3,978,636 mm³ |
| Plastic modulus, Sy | 541,879 mm³ |
| Radius of gyration, rx | 271.9 mm |
| Radius of gyration, ry | 52.5 mm |
Z is the elastic modulus and S the plastic modulus, following British practice (BS 5950 notation). Under AISC 360 the letters are reversed.
Neighbouring sizes
Where these numbers come from
Published BS 4-1 values. How StructureCalcs verifies its numbers · Understanding steel section properties · Query this section over the API