The Effects of Steel Core Imperfection, Gap Size and Friction Coefficient on the Behavior of All-Steel Buckling Restrained Braces

Buckling restrained braces (BRBs) which are generally composed of a steel core and encasing(buckling restrainers) utilized to resist lateral forces in high seismic regions since BRBs exhibit energy dissipation capacity, ductility stiffness. The carries both compressive tensile forces. During the compression, starts buckling encasing tries prevent this buckling. However, due unbonding layer/gap between core, eventually buckles contacts with encasing. phenomenon is also associated initial imperfection gap size. In study, effects imperfectionof size (1-5 mm)and friction coefficient (0.01-0.5)between on behavior investigated. Pursuant goal, numerical analyses using finite element tool ABAQUS were conducted. A total 19 models developed monotonically loaded. Initial was implemented mode shapes.The results revealed that increasing leads reduction load-carrying capacity. It recommended keep sizes 1 2 mm. On other hand, does not significantly affect capacity global behavior. it observed fluctuations load increase as amplitude shape increase. Moreover, should be kept 0.01 0.05; otherwise, undesired behaviors can observed.