عنوان مقاله [English]
Numerous studies have been carried out within the last two decades on improvement in the ductility of the concentrically-braced frames (CBFs). Despite advantages of the CBFs such as ease of execution and adequate reparability, seismically-induced ultimate displacements of the frames braced by the CBFs have raised concerns. Moreover, low ductility of the CBFs has resulted in their inadequate performance during seismic events. To improve the ductility of the CBFs, various approaches have been proposed such as use of the circular elements made out of hyper-elastic materials in the dual moment resisting frame (MRF) and CBF. By the way, most of these approaches require special materials and technology to assemble the braces. Thus, the application of the steel ring as the seismic fuse has been proposed by which ductility and energy absorption could be significantly enhanced. Various solutions have been proposed to enhance the ductility of the bracings system in recent years. Accordingly, the development of steel rings as structural fuses could be counted as one of the successful attempts which need to be further studied. In this respect, this paper addresses a novel diamond-scheme bracing system equipped with a steel ring whose function is to act as a sacrificial fuse. This system has been highly developed to improve ductility and energy absorption capacity of the conventional bracing system that is known as the prime shortfalls of this system. In this system, diagonals and ring are arranged in such a way to act in parallel. To conduct the analyses, a test specimen with pinned and semi-rigid connections was studied using ABAQUS software. Furthermore, numerical analyses were carried out on large-scale models once including the ring with varying thicknesses and also, on the bracing system without the ring (i.e. a link element with high rigidity was replaced for the ring) and lastly, the results were compared with the performance of a concentrically-braced frame (CBF). The results indicate that promisingly, the presence of the link enhances the load-carrying capacity of the system by 9 and 1.75 greater than that of the semi-rigid model and CBF. In general, it was concluded that despite adequate reparability, the proposed system benefits from sufficient ductility and energy absorption capacity.