Method of joining structural members, profile member and structural unit comprising a plurality of profile members

A method of joining structural members, said method comprising the steps of:

• providing a first member having an edge portion comprising two substantially parallelly extending ribs provided outwardly with respective laterally undercut recesses and adjacent projecting tabs, said tabs being interconnected by a unitary transversely extending inwardly arcuate web,
• providing a second member having an edge portion of transverse cross-sectional configuration complementarily shaped with locking tabs projecting into a slot defined by a transverse wall and opposite lateral side walls to engage said ribs of said first member,
• inserting said ribs into said slot, and
• permanently deforming said arcuate web by depressing said web to be flush with or below a transverse plane between opposite lateral edges of said web by means of a deformation tool employing said first member itself as a dolly, and thus forcing said outwardly projecting tabs laterally into a wedged frictional engagement with said slot of said second member.