Structural steel fabrication and erection · reference card
Shop-fabricated and site-erected steel under AWS D1.1 and EN 1090-2. The four monitoring pain points that cost structural fabricators most, and which Therness signal addresses each.
Structural steel fabrication splits cleanly into a shop half and a site half, and the two see different conditions under the same code. A shop weld is made indoors, at a fixed station, by a welder qualified to that exact procedure. A site weld on the same structure happens in wind, cold or rain, on a connection that may be harder to reach and impossible to re-position.
EN 1090-2’s execution classes and AWS D1.1’s inspection categories exist because not every connection carries the same consequence if it fails — a primary bracing member is not a secondary purlin — and the inspection and documentation burden is meant to track that difference. A fabricator that applies one inspection intensity everywhere either wastes effort on low-consequence connections or under-documents the ones that matter.
Heavy plate work adds its own failure mode: a long multi-pass seam can drift in interpass temperature over the course of a welding day without anyone noticing, because nothing before the pass or after it looks different — only the record of what happened between passes shows it. See the EN 1090-2 execution guide for how execution class is decided before a single connection is welded.
| Code | Why it applies |
|---|---|
| AWS D1.1 | Structural Welding Code — Steel, the dominant code for building and bridge steel fabricated to the US route. |
| EN 1090-2 | Execution standard for steel structures on the CE-marking route, setting execution classes tied to consequence of failure. |
| ISO 5817 | The quality-level standard EN 1090-2 and many structural specifications point to for weld imperfections. |
| ISO 3834-2 | The comprehensive quality-system part EN 1090-2 invokes at the higher execution classes; lower classes map to EN ISO 3834-3 or -4. |
| Pain point | Consequence | Signal that sees it |
|---|---|---|
| Execution class drives a different inspection and qualification burden per connection | A fabricator that treats every connection the same either over-inspects the low-consequence ones or under-documents the critical ones. | Process evidence tagged to the connection and its execution class as the weld is made, not sorted afterward. |
| Site welds happen in wind, cold and rain that a shop weld never sees | A procedure qualified indoors drifts outside its window on an exposed erection site without anyone measuring it. | Preheat and interpass measurement taken at the joint on site, not assumed from the shop procedure. |
| Heavy plate girders carry many passes across a long welding day | Interpass temperature creeps upward through the day and the later passes sit outside the qualified range. | Interpass measured on every pass and trended across the whole joint, not spot-checked once. |
| A steel erector's traceability spans shop welds, site welds and multiple subcontracted crews | Assembling the as-built welding record for handover becomes a manual reconciliation exercise. | Weld identifier, welder, procedure and process record joined automatically regardless of where the weld was made. |
Therness measures what happens while the arc is running — parameters, thermal signature, per-weld records — so the problems on this page surface on the shift that made them.
Progetto cofinanziato nell'ambito del PR Piemonte FSE+ 2021-2027,
Priorità I, Obiettivo Specifico a), Azione 4 – "Sostegno alla nascita delle start up"
