UC 203×203×52 vs HP 8X36
UC 203×203×52 is an UC section from the UK Blue Book (SCI P363); HP 8X36 is the closest equivalent in the American AISC Shapes Database. UC 203×203×52 carries more bending: 567 cm³ of plastic modulus against 550.61 cm³, 3.0% more. UC 203×203×52 is the lighter of the two at 52 kg/m against 53.6 kg/m, a saving of 3.0% on steel weight. Both are about 205 mm deep, so either fits the same construction zone.
| Property | UC 203×203×52 UC | HP 8X36 HP | Difference |
|---|---|---|---|
| Mass | 52 kg/m | 53.6 kg/m | -3.0% |
| Depth | 206.2 mm | 203.7 mm | +1.2% |
| Width | 204.3 mm | 207.3 mm | -1.4% |
| Web thickness | 7.9 mm | 11.3 mm | -30.1% |
| Flange thickness | 12.5 mm | 11.3 mm | +10.6% |
| Area | 66.3 cm² | 68.4 cm² | -3.1% |
| Second moment, major (Iy) | 5,260 cm⁴ | 4,953 cm⁴ | +6.2% |
| Plastic modulus, major (Wpl,y) | 567 cm³ | 550.61 cm³ | +3.0% |
| Elastic modulus, major (Wel,y) | 510 cm³ | 488.33 cm³ | +4.4% |
| Second moment, minor (Iz) | 1,780 cm⁴ | 1,677 cm⁴ | +6.1% |
| Plastic modulus, minor (Wpl,z) | 264 cm³ | 249.08 cm³ | +6.0% |
| Radius of gyration, minor (iz) | 5.18 cm | 4.95 cm | +4.6% |
| Torsion constant (It) | 31.8 cm⁴ | 32.05 cm⁴ | -0.8% |
UC 203×203×52 to BS EN 10365:2017; HP 8X36 to AISC Shapes Database v16.0. Difference is expressed relative to HP 8X36.
How to choose between them
On stiffness, UC 203×203×52 has the larger second moment of area: 5,260 cm⁴ against 4,953 cm⁴, a difference of 6.2%. This matters more often than the strength comparison, because on normal floor spans deflection rather than bending capacity sets the beam size - so if the two are close on modulus but apart on inertia, the stiffer one is usually the better answer even when it is not the stronger one.
Measured as bending capacity per kilogram of steel, UC 203×203×52 is the more efficient section: 10.9 against 10.3 cm³ per kg/m, 6.1% better. Over a floor of repeated beams that difference is real tonnage, though it is often outweighed by whichever section the fabricator can actually source.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. UC sections are specified to BS EN 10365:2017 and HP to AISC Shapes Database v16.0; the steel grades, tolerances and available lengths differ, connection details and bolt gauges are set out differently, and the two are rarely both stocked in the same market. Check availability before changing a section on a drawing to save 3.0% weight.
In short, UC 203×203×52 is the stronger section and UC 203×203×52 is the lighter one; where those are the same section, it is the clear choice, and where they are not, decide on whether your design is governed by capacity or by tonnage.