Framing Connections for Square Structural Tubing

Five types of simple connections for framing beams into square and rectangular structural steel tubular columns are treated. Two types were adequate in all respects-the conventional angle seat, and a connection made by welding a length of structural tee to the tube face. A beam web connection consisting of a piece of plate fillet welded to the center of the tube wall tended to induce excessive local deformation and weakening of the tubular column section. A similar connection made by welding the plate on the corner of the tube, at 45? to the principal axes, also produced tube distortion as well as being excessively stiff. The final type studied consisted of a plate inserted through vertical slots cut in the center of the tube wall and then welded at the faces of both walls. It proved to be excessively stiff and probably should not be classed as a simple connection.