Seismic Behavior of End Connection Plates in Concentrically Steel Braced Frame

The aim of this study was to investigate the length of the gusset-plate hinge zone proposed by Iranian National Building Code (Part 10) for Special concentrically braced frames (SCBF). For this purpose, numerical studies were done on the seismic behavior of this frames using ABAQUS software. Numerical modelling procedure is validated using the reproduction of the results of an experimental study. A five story building with Special diagonal concentrically braced frames was modeled in ETABS software and a portal frame from the first story of the building was considered for investigation. The detailing of the frame was designed for tension and compression based on Iranian code. Seismic behavior of single and double tapered gusset plates with various connection angles and dimensions as well as various length of the hinge zones including -3t, -2t, -t, 0t, t, 2t and 3t were investigated using nonlinear cyclic deformation loading to the ATC-24 test protocol.Seismic behavior of the connections were studied based on ductility, number of cycles before failure, drift before failure and tension and compression strength.Evaluation of the failure limit of the models was carried out using the concept of equivalent plastic strain. Based on the results of the investigated models it can be said that: It is not recommended to use double gusset plates instead of single ones for SCBFs. Gusset plates with a 15 degree angle of inclination have higher ductility capacity and better seismic behavior than ones with a 25 degree angle of inclination. For single gusset plates with a 15 degree angle of inclination, the appropriate length of the hinge zone is -2t, which is not consistent with Iranian code. For single gusset plates with a 25 degree angle of inclination, the appropriate length of the hinge zone is 2t, which is consistent with the Iranian code.