The experimental study of the cyclic behavior of a new T-shaped flexural connection of steel beam to steel column filled with concrete (CFT)

Due to the abundant advantages, such as ease of implementation, economic efficiency, and appropriate ductility T-shaped elements are widely used in many beam-column connections.  In this research, the through bolts were utilized to connect the Tee profile to the column flange. The direct transfer of stresses to the body of the column increases the length of the intermediate bolts under cyclic loads. Therefore, in an innovative effort, the external diaphragm of the column was used together with the through bolt. Finally, the joint performance of them was examined.
 In this study, based on the validated models in Abacus software, two samples were designed and tested in the laboratory. One of these samples contained a connection with through bolts and, another one had an external diaphragm. The overall performance of both joints was quite good and, they passed the acceptance criteria of rigid joints in the especial bending frames according to AISC and FEMA codes. Both laboratory samples achieved a relative rotation of 0.06 radians without declining resistance. The final failure in the sample without the external diaphragm occurred in the first cycle relative rotation of 0.07 radians and with the separation of the nut from the through bolts, while this issue in the sample with an external diaphragm is ductile and deformable in the flange and the web.