UB 610×305×149 vs IPE O 600
UB 610×305×149 is an UB section from the UK Blue Book (SCI P363); IPE O 600 is the closest equivalent in the European (Continental) range. UB 610×305×149 carries more bending: 4590 cm³ of plastic modulus against 4470 cm³, 2.7% more. UB 610×305×149 is the lighter of the two at 149.2 kg/m against 154 kg/m, a saving of 3.1% on steel weight. Both are about 611 mm deep, so either fits the same construction zone.
| Property | UB 610×305×149 UB | IPE O 600 IPE | Difference |
|---|---|---|---|
| Mass | 149.2 kg/m | 154 kg/m | -3.1% |
| Depth | 612.4 mm | 610 mm | +0.4% |
| Width | 304.8 mm | 224 mm | +36.1% |
| Web thickness | 11.8 mm | 15 mm | -21.3% |
| Flange thickness | 19.7 mm | 24 mm | -17.9% |
| Area | 190 cm² | 197 cm² | -3.6% |
| Second moment, major (Iy) | 126,000 cm⁴ | 118,000 cm⁴ | +6.8% |
| Plastic modulus, major (Wpl,y) | 4,590 cm³ | 4,470 cm³ | +2.7% |
| Elastic modulus, major (Wel,y) | 4,110 cm³ | 3,880 cm³ | +5.9% |
| Second moment, minor (Iz) | 9,310 cm⁴ | 4,520 cm⁴ | +106.0% |
| Plastic modulus, minor (Wpl,z) | 937 cm³ | 640 cm³ | +46.4% |
| Radius of gyration, minor (iz) | 7 cm | 4.79 cm | +46.1% |
| Torsion constant (It) | 200 cm⁴ | 316 cm⁴ | -36.7% |
UB 610×305×149 to BS EN 10365:2017; IPE O 600 to EN 10365 · Continental Steel. Difference is expressed relative to IPE O 600.
How to choose between them
On stiffness, UB 610×305×149 has the larger second moment of area: 126,000 cm⁴ against 118,000 cm⁴, a difference of 6.8%. 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, UB 610×305×149 is the more efficient section: 30.8 against 29.0 cm³ per kg/m, 6.0% 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.
The two diverge much more about the minor axis: UB 610×305×149 has 937 cm³ of minor-axis plastic modulus against 640 cm³, 46.4% 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 IPE to EN 10365 · 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 3.1% weight.
In short, UB 610×305×149 is the stronger section and UB 610×305×149 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.