Analytical study of concrete- filled effect to the seismic behavior of restrained beam-column steel joints

Since placing continuity plates in panel zone of columns is difficult, and also has too much cutting and welding in connection area, it reduces the reliability of the connection, so the continuity plates are removed from inside of the column and are replaced with internal elements such as horizontal reinforcement network and with external elements such as Trapezoidal stiffeners. In this study, through finite element modeling and geometric- material nonlinear analysis under pushover and cyclic loading to investigation of loading. Results show that beam to Box column connection with and without in-filled with concrete with arrangement stiffeners using of concrete in model- with continuity plates causes to an increase of 0.12 percent in restraint, 4.98 percent in ductility and 96.92 percent in final resistance. More ever, in the proposed model, using of concrete leads to an increase of about 2 percent in restraint, 52.51 percent in resistance, while ductility connection formation was reduced, and all parameters have shown a significant increase with binding reinforcement by horizontal reinforcement networks. Therefore, a new proposed connection has satisfied all seismic parameters as well in present study, and this is a good alternative for continuity plates which are inside of the column.