dégrafage

17:58 Nov 17, 2017 

"Opening up", because it means making something previously concealed by the structure visible, can be achieved in either a destructive or non-destructive way. As it's a "technique d’inspection" and not a test, I don't think that anything that would risk weakening the rebars themselves would be acceptable. It goes on to mention possible need for "rhabillage des armatures", but not replacement.

17:48 Nov 17, 2017 

I've sent an email to AFCAB (www.afcab.com), the Association Française de Certification des Armatures du Béton, to see if they can throw any light on the matter. I'll let you know what they say.

17:33 Nov 17, 2017 

It seems to me from Barbara's refs below, as well as from sheetpiling.arcelormittal.com/uploads/files/d62f1a74cd9dab640ab989c4f4d6747b.pdf (see p. 31:"Résistance au dégrafage"), that dégrafage implies something more violent, i.e. pulling out by force. Such a destructive test would certainly demonstrate the strength of at least one sample of the rebar in question, though it would then have to be reinstated using epoxy resin, perhaps. In the case of the steel piling in the refs above, they are indeed "hooked" together, but I'm not sure how it applies to rebar. I'm guessing, really, but dégrafage doesn't seem to be very common as a term. My dictionnaire du bâtiment et du génie civil is silent.