UB 457×152×74 vs IPE 450
UB 457×152×74 is an UB section from the UK Blue Book (SCI P363); IPE 450 is the closest equivalent in the European (Continental) range. IPE 450 carries more bending: 1700 cm³ of plastic modulus against 1630 cm³, 4.1% more. UB 457×152×74 is the lighter of the two at 74.2 kg/m against 77.6 kg/m, a saving of 4.4% on steel weight. UB 457×152×74 is deeper, 462 mm against 450 mm, which matters where the floor zone is tight.
| Property | UB 457×152×74 UB | IPE 450 IPE | Difference |
|---|---|---|---|
| Mass | 74.2 kg/m | 77.6 kg/m | -4.4% |
| Depth | 462 mm | 450 mm | +2.7% |
| Width | 154.4 mm | 190 mm | -18.7% |
| Web thickness | 9.6 mm | 9.4 mm | +2.1% |
| Flange thickness | 17 mm | 14.6 mm | +16.4% |
| Area | 94.5 cm² | 98.8 cm² | -4.4% |
| Second moment, major (Iy) | 32,700 cm⁴ | 33,700 cm⁴ | -3.0% |
| Plastic modulus, major (Wpl,y) | 1,630 cm³ | 1,700 cm³ | -4.1% |
| Elastic modulus, major (Wel,y) | 1,410 cm³ | 1,500 cm³ | -6.0% |
| Second moment, minor (Iz) | 1,050 cm⁴ | 1,680 cm⁴ | -37.5% |
| Plastic modulus, minor (Wpl,z) | 213 cm³ | 276 cm³ | -22.8% |
| Radius of gyration, minor (iz) | 3.33 cm | 4.12 cm | -19.2% |
| Torsion constant (It) | 65.9 cm⁴ | 66.7 cm⁴ | -1.2% |
UB 457×152×74 to BS EN 10365:2017; IPE 450 to EN 10365 · Continental Steel. Difference is expressed relative to IPE 450.
How to choose between them
On stiffness, IPE 450 has the larger second moment of area: 33,700 cm⁴ against 32,700 cm⁴, a difference of 3.0%. 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 (22.0 against 21.9 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: IPE 450 has 276 cm³ of minor-axis plastic modulus against 213 cm³, 22.8% 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 4.4% weight.
In short, IPE 450 is the stronger section and UB 457×152×74 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.