Influence of Joint Type on Member Forces in Metal Ribbed-Ring Dome Frame Taking into Account Different Number of Supporting Columns

The influence of the type of joint on the internal forces in the elements of the metal frame of a ribbed-ring dome, and specifically considering different number of supporting columns, was studied. In this respect, cyclic symmetry of the columns along the entire contour of the dome is preserved. All elements of the dome frame and the columns are made of steel pipes. The objects of the study were dome frames, which differed from each other, both in different nodal connections and in different numbers of supporting columns. The domes have the same geometric structure and dimensions, the same cross-sections of the same type of frame elements and carry the same loads. The study was performed by analyzing computer models of the frames. Models with different joints were obtained by gradually converting the originally assigned hinges into rigid connections, and variation in the number of columns was implemented by regularly removing them from the original computer model. In the calculation process, internal forces N and M in the frame elements of all models were determined, which were compared with each other. Comparative diagrams of internal forces N and M in the frame elements of the original and all transformed models are obtained. The behavior of the elements of ribbed-ring domes with different nodal connections for frames with different numbers of columns is evaluated. According to the results of the study, significant changes in bending moments M in the lower ring and axial forces N in the columns were noted. Moreover, the nature of these changes depends on the type of nodal connection.