The use of the external diaphragm in the connection between an I beam section and tubular hollow section column

Abstract The external diaphragm in the connection between an I metal beam section and a hollow section tubular column is designed to increase efficiency in transfer of its efforts. This study aims at offering alternatives to the use of this structural system, reducing the limit imposed by its simple connection when this element is added, like a ring that surrounds the column and is connected to the beam flange. Studies investing the external diaphragm began in the 1970s in Japan, where theoretical and experimental analyses of its application were carried out. In Brazil, the first studies took place in 2005, but Brazilian steel structure standards have not yet addressed this issue. In this study numerical analyses were performed on connections with external diaphragm between I-beam section and hollow section tubular column for different widths and thicknesses of this stiffener. The analyses showed that there was considerable increase in the strength and stiffness of the connection.