SHS 400×400×10 vs CF SHS 400×400×10
SHS 400×400×10 is an SHS Hot-finished section from the UK Blue Book (SCI P363); CF SHS 400×400×10 is the closest equivalent in the UK Blue Book (SCI P363). SHS 400×400×10 carries more bending: 2260 cm³ of plastic modulus against 2210 cm³, 2.3% more. They weigh essentially the same, 122 kg/m and 120 kg/m. Both are about 400 mm deep, so either fits the same construction zone.
| Property | SHS 400×400×10 SHS Hot-finished | CF SHS 400×400×10 SHS Cold-formed | Difference |
|---|---|---|---|
| Mass | 122 kg/m | 120 kg/m | +1.7% |
| Depth | 400 mm | 400 mm | same |
| Width | 400 mm | 400 mm | same |
| Web thickness | 0 mm | 0 mm | same |
| Flange thickness | 0 mm | 0 mm | same |
| Area | 155 cm² | 153 cm² | +1.3% |
| Second moment, major (Iy) | 39,100 cm⁴ | 38,200 cm⁴ | +2.4% |
| Plastic modulus, major (Wpl,y) | 2,260 cm³ | 2,210 cm³ | +2.3% |
| Elastic modulus, major (Wel,y) | 1,960 cm³ | 1,910 cm³ | +2.6% |
| Second moment, minor (Iz) | 39,100 cm⁴ | 38,200 cm⁴ | +2.4% |
| Plastic modulus, minor (Wpl,z) | 2,260 cm³ | 2,210 cm³ | +2.3% |
| Radius of gyration, minor (iz) | 15.9 cm | 15.8 cm | +0.6% |
| Torsion constant (It) | 60,100 cm⁴ | 60,400 cm⁴ | -0.5% |
SHS 400×400×10 to BS EN 10210-2:2006; CF SHS 400×400×10 to BS EN 10219-2:2006. Difference is expressed relative to CF SHS 400×400×10.
How to choose between them
On stiffness, SHS 400×400×10 has the larger second moment of area: 39,100 cm⁴ against 38,200 cm⁴, a difference of 2.4%. 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, the two are equally efficient (18.5 against 18.4 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.
In short, SHS 400×400×10 is the stronger section and CF SHS 400×400×10 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.