UC 356×406×287 vs HP 16X183
UC 356×406×287 is an UC section from the UK Blue Book (SCI P363); HP 16X183 is the closest equivalent in the American AISC Shapes Database. They are close to interchangeable in bending: 5810 cm³ against 5719.1 cm³ of plastic modulus, a difference of 1.6%. HP 16X183 is the lighter of the two at 272.3 kg/m against 287.1 kg/m, a saving of 5.4% on steel weight. HP 16X183 is deeper, 419.1 mm against 393.6 mm, which matters where the floor zone is tight.
| Property | UC 356×406×287 UC | HP 16X183 HP | Difference |
|---|---|---|---|
| Mass | 287.1 kg/m | 272.3 kg/m | +5.4% |
| Depth | 393.6 mm | 419.1 mm | -6.1% |
| Width | 399 mm | 414 mm | -3.6% |
| Web thickness | 22.6 mm | 28.7 mm | -21.3% |
| Flange thickness | 36.5 mm | 28.7 mm | +27.2% |
| Area | 366 cm² | 349 cm² | +4.9% |
| Second moment, major (Iy) | 99,900 cm⁴ | 104,474 cm⁴ | -4.4% |
| Plastic modulus, major (Wpl,y) | 5,810 cm³ | 5,719.1 cm³ | +1.6% |
| Elastic modulus, major (Wel,y) | 5,070 cm³ | 4,981.7 cm³ | +1.8% |
| Second moment, minor (Iz) | 38,700 cm⁴ | 34,048 cm⁴ | +13.7% |
| Plastic modulus, minor (Wpl,z) | 2,950 cm³ | 2,556.4 cm³ | +15.4% |
| Radius of gyration, minor (iz) | 10.3 cm | 9.88 cm | +4.3% |
| Torsion constant (It) | 1,440 cm⁴ | 1,120 cm⁴ | +28.6% |
UC 356×406×287 to BS EN 10365:2017; HP 16X183 to AISC Shapes Database v16.0. Difference is expressed relative to HP 16X183.
How to choose between them
On stiffness, HP 16X183 has the larger second moment of area: 104,474 cm⁴ against 99,900 cm⁴, a difference of 4.4%. 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, HP 16X183 is the more efficient section: 21.0 against 20.2 cm³ per kg/m, 3.6% 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: UC 356×406×287 has 2950 cm³ of minor-axis plastic modulus against 2556.4 cm³, 15.4% 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. UC sections are specified to BS EN 10365:2017 and HP to AISC Shapes Database v16.0; 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 5.4% weight.
In short, UC 356×406×287 is the stronger section and HP 16X183 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.