چكيده به لاتين
Conventional braces can have acceptable performance in tension, but in compression loads they buckle before entering the yield area, thus providing the building for damage. Buckling Restrained braces (BRBs) act relatively symmetrically against tensile and compressive loads and before buckling, the load-bearing member enters the nonlinear area. Therefore, they can have high ductility and absorbing energy and show acceptable seismic performance. The purpose of this thesis is to achieve a kind of all-steel buckling restrained braces with a tubular core (load-bearing member) that improves the seismic behavior of conventional braces and reduces the imperfections of the current BRBs. In this regard, eleven specimens were proposed for experimental study. The studied specimens consist of a steel tube as a load bearing member (core), which is placed inside a larger tube or two angles as a buckling restraining member (pod). At the two ends of the core member, different end details and connection (compared to the common BRBs) are provided as the elastic transitional region. The performance of the specimens were evaluated based on indices, such as damage mode, repeatable behavior, adjusted strength factors, load-bearing capacity, and cumulative inelastic displacement. The evaluation of the results indicated that, the specimens, which welded variable cross-section steel lids at both ends of the core and is placed inside a larger tube as a buckling restraining member (pod) , have superior cyclic performance. The superior specimens, for all cycles with larger displacements of the yielding displacement, exhibited a stable hysteresis behavior in bearing of cyclic loads. As the bearing compression was about 1.07 times greater than the tensile load. The cumulative inelastic axial displacements of these specimens is at least 200 times of their yield displacement.
