Improving of post buckling behavior concentric braces by using of restricted fuse based on experimental and numerical studies

The concentrically braced system is one of the most common lateral loadbearing systems among the steel structures. This system has various apparent forms where the main characteristic of them all is their significant stiffness and lateral strength. The weakness of these systems is buckling in compression. This issue causes that concentric bracings have low compressive loadbearing 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. The results of experimental and numerical researches of this study indicate the better performance of this structural system in terms of ductility and energy dissipation capacity compared to the common concentric braces. The suggested system can be utilized to reduce the capacity of bracing connection which results in reduced costs of the project.