Two Neighbouring Sections in the Same Series
HEM 260 and HEM 280 stand next to each other in the heavy medium wide flange series, so they are rolled to the same dimensional standard and delivered in the same material condition. Both are available in S355JR, which means they share a minimum yield strength of 355 MPa for thicknesses up to 16 mm and the same tensile strength range of 470 to 630 MPa. The choice between them is therefore a question of section geometry and the load path, not of material quality.
Because the two profiles differ by only one step in the series, a designer can often swap one for the other late in the design without changing the connection concept, which makes the comparison a practical one during value engineering.
Section Dimensions Compared
| Property | HEM 260 | HEM 280 | Change |
|---|---|---|---|
| Section height h | 290 mm | 310 mm | +20 mm |
| Flange width b | 268 mm | 288 mm | +20 mm |
| Web thickness tw | 18 mm | 18.5 mm | +0.5 mm |
| Flange thickness tf | 32.5 mm | 33 mm | +0.5 mm |
| Mass per metre | approx. 172 kg/m | approx. 190 kg/m | about +10 % |
The dimensional pattern is typical of the series: every second step adds about 20 mm of height and width together with a small increase in plate thickness. That combination is efficient because height contributes to bending stiffness as a squared term, while the added flange area contributes only linearly.
Stiffness, Mass and Cost
Calculated from the section geometry, the second moment of area of HEM 280 in the strong axis is roughly 26 % higher than that of HEM 260, while the mass per metre increases by about 10 %. Put another way, the heavier section delivers noticeably more stiffness for every tonne of steel, and the elastic section modulus rises by roughly 18 %. Those ratios are the reason a deeper section frequently wins a long-span or deflection-controlled comparison.
A member controlled by bending stress can often stay on HEM 260, because the added section modulus of HEM 280 buys capacity the design does not need.
A member controlled by deflection or vibration, such as a 12 m span with a strict serviceability limit, normally justifies the step up to HEM 280.
A member with a tight headroom limit may be unable to accept the extra 20 mm of height, which keeps the design on HEM 260 regardless of stiffness.
Where Each Section Fits Best
HEM 260: columns of medium-rise industrial buildings, primary beams of typical portal frames, machine bases and transfer members where the span is moderate.
HEM 280: heavy crane runway girders, transfer beams collecting several column lines, columns carrying long-span roof trusses, and long-span roof beams where deflection governs.
The practical check is simple: dimension the frame on HEM 260, then verify the governing member against the deflection limit and the vibration criterion. If either limit is marginal, the step to HEM 280 usually resolves it without a change of connection detail.
Working with S355JR in Both Sections
S355JR is delivered as rolled and requires 27 J minimum Charpy absorbed energy at +20 °C, which suits structures without a demanding low-temperature design case. The grade permits a maximum carbon content of 0.24 % and a maximum carbon equivalent value of 0.45 for thicknesses up to 30 mm, so both sections weld with straightforward procedures.
Where the design temperature reaches −20 °C, the same geometry is available in S355J2 with 27 J at −20 °C and a tighter carbon limit of 0.22 %. Fabrication, bolting and surface treatment practice is otherwise unchanged, so the two grades can coexist in one frame as long as each member meets its own exposure case.
Frequently Asked Questions
Q: Is HEM 280 simply a taller version of HEM 260?
Nearly. The height increases from 290 mm to 310 mm and the flange width from 268 mm to 288 mm, while web and flange thickness rise by only 0.5 mm, so the extra capacity comes mainly from the deeper section.
Q: How much heavier is HEM 280 than HEM 260?
About 18 kg per metre more, roughly a 10 % increase in mass, against an increase of about 26 % in strong-axis bending stiffness.
Q: Can both sections be supplied in S355JR?
Yes. Both are routinely rolled in S355JR, and S355J2, S355J0, S355NL and S275JR are also available for the same geometry.
Q: Which section is better for a crane runway?
HEM 280 is usually preferred, because runway girders are governed by deflection and by fatigue at the wheel load, both of which benefit from the deeper section.
Q: Do the two sections need different connection details?
Not necessarily. The flange faces are flat and parallel in both cases, so end plate, fin plate and shear tab details can usually be reused, with bolt capacity rechecked for the larger member.