Abstract: Two or more elementary sections are permanently assembled together to form continuous longitudinal slots with their longitudinal edges facing inwards and each inclined towards the opposite edge so that they converge inwardly. Fixing devices are provided and comprise a receiving matrix or plate forming a channel with walls inclined in the same way as the edges and one or more locking plugs or plates which also have lateral walls inclined in the same way as the edges. The devices may be fixed along the slots to grip the edges by a screw between matrices and plugs. The longitudinal edges of the elementary sections have corrugations corresponding to corrugations which are present in the walls of the matrices and in the lateral walls of the plugs.

Abstract: The structure comprises cold-formed sections built-up from elementary sections joined stably together by means of connecting braces inside the built-up section; said joined elementary sections define longitudinal slots with their longitudinal lips which are bent inwards and each inclined with respect to that opposite so as to converge towards the interior; fastening devices comprising a channel die and one or more pressure pieces are fitted along the slots in order to clamp with screw means the lips that define said slots and deform them with a locking action.