The behavior of concentric brace with bounded fuse

Building constructions, buildings and structures

The concentrically braced system is one of the most common lateral load-bearing systems among the steel structures. This lateral loadbearing system has various apparent forms where the main characteristic of them all is their significant stiffness and lateral strength. The main weakness of the concentrically braced system is buckling in compression. This issue causes that concentric bracings have low compressive load-bearing capacity together with undesirable ductility and limited energy dissipation capacity. In this study to solve this problem use has been made of a heuristic method. In this method a local fuse has been used in the middle of bracing where its periphery and inner circumference have been covered with an auxiliary casing within a casing. The local fuse is designed in a way that after yielding, the bracing undergoes local buckling at this area. But presence of an auxiliary element placed around the fuse prevents this local buckling and thus the bracing would exhibit almost a symmetric behavior during compressive and tensile loadings. Thus the bracing would exhibit a wide and spindleshaped hysteresis curve under a cyclic loading with desirable ductility and high energy dissipation capacity. Also in this article a numerical study is performed utilizing ABAQUS Ver. 6.12 software to make comparison between concentric bracings with local fuse –auxiliary element (LF-AECB) and usual concentric bracings (UCB) in terms of ductility, energy dissipation capacity and loadbearing capacity. The results of numerical studies have indicated the extraordinary better performance of LF-AECB with respect to that of UCB.