UC 152×152×44 vs H-175x175x7.5x11-40.4
UC 152×152×44 is an UC section from the UK Blue Book (SCI P363); H-175x175x7.5x11-40.4 is the closest equivalent in the European (Continental) range. They are close to interchangeable in bending: 372 cm³ against 370 cm³ of plastic modulus, a difference of 0.5%. H-175x175x7.5x11-40.4 is the lighter of the two at 40.4 kg/m against 44 kg/m, a saving of 8.9% on steel weight. H-175x175x7.5x11-40.4 is deeper, 175 mm against 166 mm, which matters where the floor zone is tight.
| Property | UC 152×152×44 UC | H-175x175x7.5x11-40.4 MB & MC | Difference |
|---|---|---|---|
| Mass | 44 kg/m | 40.4 kg/m | +8.9% |
| Depth | 166 mm | 175 mm | -5.1% |
| Width | 155.9 mm | 175 mm | -10.9% |
| Web thickness | 9.5 mm | 7.5 mm | +26.7% |
| Flange thickness | 13.6 mm | 11 mm | +23.6% |
| Area | 56.1 cm² | 51.4 cm² | +9.1% |
| Second moment, major (Iy) | 2,700 cm⁴ | 2,895 cm⁴ | -6.7% |
| Plastic modulus, major (Wpl,y) | 372 cm³ | 370 cm³ | +0.5% |
| Elastic modulus, major (Wel,y) | 326 cm³ | 331 cm³ | -1.5% |
| Second moment, minor (Iz) | 860 cm⁴ | 984 cm⁴ | -12.6% |
| Plastic modulus, minor (Wpl,z) | 169 cm³ | 172 cm³ | -1.7% |
| Radius of gyration, minor (iz) | 3.92 cm | 4.37 cm | -10.3% |
| Torsion constant (It) | 31.7 cm⁴ | 21 cm⁴ | +51.0% |
UC 152×152×44 to BS EN 10365:2017; H-175x175x7.5x11-40.4 to Continental Steel. Difference is expressed relative to H-175x175x7.5x11-40.4.
How to choose between them
On stiffness, H-175x175x7.5x11-40.4 has the larger second moment of area: 2,895 cm⁴ against 2,700 cm⁴, a difference of 6.7%. 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, H-175x175x7.5x11-40.4 is the more efficient section: 9.2 against 8.5 cm³ per kg/m, 7.7% 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 MB & MC to Continental Steel; 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 8.9% weight.
In short, UC 152×152×44 is the stronger section and H-175x175x7.5x11-40.4 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.