Abstract: A device for assembling by riveting two or more sections of a sheet element structure wherein the sections (A, B) to be assembled are supported in a fixed stationary mode. A guide beam (16, 116) is clamped firmly against one side of the sections and supports a selectively movable working unit (17, 117) comprising drilling machines (45, 46) and rivet supplying and installing means (48,49) and a riveting hammer (50). A multiple or single point thrust and rivet bucking means (32, 132) is arranged on the opposite side of the sections (A, B) and comprises clamping force producing thrust elements (34; 134) as well as a rivet bucking die (41; 141). A computerized control system (43, 53) governs the operation cycles of the working unit (17;117) as well as the thrust and rivet bucking means (32; 132).