fix secondary sections to a h shaped receiving section or similar according to the invention accessories are provided at the assembly points said accessories being fitted into the receiving section and the secondary sections are fixed using screwed attachments which pass through the corresponding assembly parts of the sections as well as the corresponding accessories application_number US 59708404 A description the object of the invention relates to an assembly system for forming metal building frame structures and the like for the purpose of carrying out an assembly between the component elements of said structures with the particularities of resistance of rigid welded assemblies but with the ease of mounting of articulated screwed assemblies this system is useful for the assembly of beam sections on the column sections and vice versa in the corresponding structures and it is further applicable with any type of conventional sections used in said structures such as those of an h shaped section an i shaped section a u shaped section etc the system is based on the incorporation of accessories 1 in the areas of the assemblies so as to arrange the anchoring of the corresponding elements 2 and 3 to be assembled in each case.