UB 610×229×125 vs H-600x200x13x23
UB 610×229×125 is an UB section from the UK Blue Book (SCI P363); H-600x200x13x23 is the closest equivalent in the European (Continental) range. H-600x200x13x23 carries more bending: 3893 cm³ of plastic modulus against 3680 cm³, 5.5% more. UB 610×229×125 is the lighter of the two at 125.1 kg/m against 134 kg/m, a saving of 6.6% on steel weight. Both are about 612 mm deep, so either fits the same construction zone.
| Property | UB 610×229×125 UB | H-600x200x13x23 MB & MC | Difference |
|---|---|---|---|
| Mass | 125.1 kg/m | 134 kg/m | -6.6% |
| Depth | 612.2 mm | 612 mm | same |
| Width | 229 mm | 202 mm | +13.4% |
| Web thickness | 11.9 mm | 13 mm | -8.5% |
| Flange thickness | 19.6 mm | 23 mm | -14.8% |
| Area | 159 cm² | 171 cm² | -7.0% |
| Second moment, major (Iy) | 98,600 cm⁴ | 103,500 cm⁴ | -4.7% |
| Plastic modulus, major (Wpl,y) | 3,680 cm³ | 3,893 cm³ | -5.5% |
| Elastic modulus, major (Wel,y) | 3,220 cm³ | 3,382 cm³ | -4.8% |
| Second moment, minor (Iz) | 3,930 cm⁴ | 3,178 cm⁴ | +23.7% |
| Plastic modulus, minor (Wpl,z) | 535 cm³ | 498 cm³ | +7.4% |
| Radius of gyration, minor (iz) | 4.97 cm | 4.32 cm | +15.0% |
| Torsion constant (It) | 154 cm⁴ | 237 cm⁴ | -35.0% |
UB 610×229×125 to BS EN 10365:2017; H-600x200x13x23 to Continental Steel. Difference is expressed relative to H-600x200x13x23.
How to choose between them
On stiffness, H-600x200x13x23 has the larger second moment of area: 103,500 cm⁴ against 98,600 cm⁴, a difference of 4.7%. 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, the two are equally efficient (29.4 against 29.1 cm³ per kg/m), so on a pure steel-tonnage basis there is nothing to choose between them. The decision comes down to availability, connection detailing and what the rest of the frame uses.
These come from different catalogues, so treat the swap as a design change rather than a like-for-like substitution. UB 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 6.6% weight.
In short, H-600x200x13x23 is the stronger section and UB 610×229×125 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.