UB 610×178×100 vs H-600x200x11x17-103
UB 610×178×100 is an UB section from the UK Blue Book (SCI P363); H-600x200x11x17-103 is the closest equivalent in the European (Continental) range. H-600x200x11x17-103 carries more bending: 2904 cm³ of plastic modulus against 2790 cm³, 3.9% more. UB 610×178×100 is the lighter of the two at 100.3 kg/m against 103 kg/m, a saving of 2.6% on steel weight. Both are about 604 mm deep, so either fits the same construction zone.
| Property | UB 610×178×100 UB | H-600x200x11x17-103 MB & MC | Difference |
|---|---|---|---|
| Mass | 100.3 kg/m | 103 kg/m | -2.6% |
| Depth | 607.4 mm | 600 mm | +1.2% |
| Width | 179.2 mm | 200 mm | -10.4% |
| Web thickness | 11.3 mm | 11 mm | +2.7% |
| Flange thickness | 17.2 mm | 17 mm | +1.2% |
| Area | 128 cm² | 132 cm² | -3.0% |
| Second moment, major (Iy) | 72,500 cm⁴ | 75,560 cm⁴ | -4.0% |
| Plastic modulus, major (Wpl,y) | 2,790 cm³ | 2,904 cm³ | -3.9% |
| Elastic modulus, major (Wel,y) | 2,390 cm³ | 2,519 cm³ | -5.1% |
| Second moment, minor (Iz) | 1,660 cm⁴ | 2,274 cm⁴ | -27.0% |
| Plastic modulus, minor (Wpl,z) | 296 cm³ | 358 cm³ | -17.3% |
| Radius of gyration, minor (iz) | 3.6 cm | 4.16 cm | -13.5% |
| Torsion constant (It) | 95 cm⁴ | 97.3 cm⁴ | -2.4% |
UB 610×178×100 to BS EN 10365:2017; H-600x200x11x17-103 to Continental Steel. Difference is expressed relative to H-600x200x11x17-103.
How to choose between them
On stiffness, H-600x200x11x17-103 has the larger second moment of area: 75,560 cm⁴ against 72,500 cm⁴, a difference of 4.0%. 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 (27.8 against 28.2 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.
The two diverge much more about the minor axis: H-600x200x11x17-103 has 358 cm³ of minor-axis plastic modulus against 296 cm³, 17.3% more. If the member sees any minor-axis bending, or if it is unrestrained over a long length and lateral-torsional buckling governs, that gap decides the comparison even though the major-axis numbers looked equivalent.
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 2.6% weight.
In short, H-600x200x11x17-103 is the stronger section and UB 610×178×100 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.