Hot-rolled sections: the basics
The section families
Section titled “The section families”- I and H sections: the classic beams and columns. The I is optimised more for bending, the H more for compression.
- Channels: at edges, perimeters, or built up.
- Angles: web members, bracing, secondary elements.
- Hollow sections: square, rectangular, circular. Excellent torsional stiffness and a clean appearance.
- Bar and flat: secondary members, plates.
Why they are simpler to design
Section titled “Why they are simpler to design”Because the cross-section is stocky: the plate elements are thick relative to their width, so buckling generally does not limit.
It follows that most of the cross-section works at full value and design can go to the strength of the material — the stability questions appear at global level (buckling, lateral-torsional buckling), not at plate-element level.
That is the main difference from thin-walled sections. Cold-formed and hot-rolled steel.
Where it has the advantage
Section titled “Where it has the advantage”Long spans
Section titled “Long spans”Where a thin-walled section is no longer economic.
Concentrated loads
Section titled “Concentrated loads”Column ends, large transfer members, supporting plant.
Simpler connections
Section titled “Simpler connections”Thick plate, familiar connection types.
A thick section can be protected with a coating, and there are verified solutions for that — unlike with a thin-walled section. The limits of intumescent coatings.
Where it is a disadvantage
Section titled “Where it is a disadvantage”Self-weight
Section titled “Self-weight”Substantially heavier, which matters for the foundations and for rooftop additions.
Fabrication and erection
Section titled “Fabrication and erection”Workshop work, welding, craneage — greater organisational demands.
Cost at low loads
Section titled “Cost at low loads”Where the extra capacity is not needed, the thin-walled solution is cheaper.
The difference in verification
Section titled “The difference in verification”A separate standard covers the fabrication and execution of hot-rolled steelwork, with execution classes. EN 1090 and execution classes.
The point
Section titled “The point”Hot-rolled steel is the technology of large loads and long spans. Where those are not needed, the thin-walled solution reaches the same result with less material.