Cold-Formed Worked Example - Z-Purlin to Eurocode 3

A worked Eurocode 3 capacity check for cold-formed sections (Z-purlins and lipped channels). These thin-walled members use an effective cross-section (EN 1993-1-3); the worked example is published once the cold-formed engine is in the tool.

Cold-formed sections such as Z-purlins and lipped channels are thin-walled members rolled from strip at ambient temperature. Their design follows EN 1993-1-3 rather than the hot-rolled rules: because the flat plate elements buckle locally before the section yields, an effective cross-section is used, and the small return lips introduce a distortional buckling mode unique to thin-walled steel.

A full numerical worked example for these sections will be published here once the cold-formed capacity engine is added to the interactive tool, so that every number is machine-verified rather than hand-derived. In the meantime, the cold-formed design theory explains the effective-section method, local and distortional buckling, and the role of purlins as restrained secondary members.