This paper proposes a new viscoplastic damper called Rubber-Steel Core Damper (RSCD) for improving the seismic performance of chevron braced frame which does not satisfy seismic requirements based on the codes such as capacity design principles in accordance with AISC 341-16 which may exhibit poor inelastic response under seismic excitement. Also, the proposed damper can be used in new structures to decrease the damages due to an intense earthquake and reduce the size of the main structural elements such as beams, columns, braces, and their connections. The passive hybrid viscoelastic damper is made of a combination of rubber with high damping and ductile steel cores. Under earthquake excitations, the proposed viscoplastic damper has the role of a fuse in the chevron braced frames where all the damages are concentrated in the damper and the main elements such as beams, columns, braces, and their connections remain undamaged. To investigate the behavior of the proposed system, six specimens of RSCD damper are tested under cyclic loading. The experimental results show that the proposed viscoplastic damper provides a ductile behavior with completely regular and stable hysteresis loops. For evaluating the invented damper and its effect on the seismic behavior of chevron braced frames, finite element models of the chevron frames equipped with RSCD viscoplastic damper are studied with ABAQUS software. In addition, besides providing a method to design this damper, the results from the finite element analysis give the optimum values of the main components of the RSCD damper such as rubber thickness, height, diameter and the number of steel cores.
