The paper summarizes recent experimental research on determining the full-range behaviour of steel beam-to-column connections. Unlike the connection types in the literature, numerical modeling was done with various experiments to determine the behavior of two types of connection types. In these joints, T joints have been studied, but unlike the literature, T joint's element is made of plates; It was obtained from 1/2 IPE profile, not by welding. Thus, it is thought that the problems such as workmanship errors, break point formation and in situ welding failures, which occur in the welding of T joints, are eliminated. Necessary studies have been carried out to have sufficient information about the behavior of the T joint to be manufactured from the IPE profile and thus to provide the opportunity for its use. In the light of the data obtained, numerical modeling is done and the torque rotation relation and behavior of semi-rigid joints are numerically modeled. Thus, thanks to the calibrated model with the experiments, the closest results to the real behavior were obtained for the unexamined combinations.