عنوان مقاله [English]
One of the most widely used structural systems in existing buildings is reinforced concrete moment-resisting frames that offer high ductility and acceptable strength when lateral loads are applied. But test concrete buildings need to be reinforced due to operational problems in many older buildings. In recent years, the simultaneous use of steel braces and dampers in strengthening and improving the behavior of concrete frames has always been of interest to researchers. In the present paper, a laboratory and numerical study of the effect of using non-uniform gap (NSD) dampers in concrete flexural frames has been performed. In the present study, 2 models including a simple frame and a frame with a damper were examined. The reference concrete flexural frame is modeled in a 1: 3 scale, the lengths of beams and columns in the laboratory sample were 1.45 and 1 m, respectively, and the dimensions of the beam and column sections were 150 by 150 mm. Reinforcement of the concrete frame was done in such a way as to provide medium torque resistance conditions in the frame. Displacement control loading was used. To study the behavior of the studied samples, force-displacement diagrams of the models were extracted. The results showed that deep cracks were created at the junction of the beam to the column and the structure was damaged. Also, at the junction of the column with the foundation of the structure, it has undergone irreversible deformations and major damage. The study of the effect of NSD damper on deformation and failure showed that the damper can reduce the damage in the concrete frame by absorbing permanent deformation. Also, due to the stresses, the concrete beam underwent plastic deformation. The final strength of the concrete frame with the damper was recorded more than three times the final strength of the frame without the damper. The results showed that the stresses and deformations of the plastic are concentrated in the damper and the frame performance is almost linear and without damage.