The finite element analysis of unbonded layer of all-steel plate-like buckling-restrained brace

Design 26 all-steel plate-like buckling-restrained braces(PBRBs) specimens which including 18 with unbonded layer specimens and 8 specimens with no unbonded layer. Studying how unbonded layer's area, thickness, shear modulus and other parameters to effect PBRBs energy dissipation behavior and the friction between core and encasing unit, and using finite element analysis software ABAQUS to simulate all-steel PBRBs, The results show that the unbonded layer on witch the weak axis of core is the key factor to reduce the friction between core and encasing unit; The thicknesses of the unbonded layer have greater impact on PBRB's energy dissipation capacity; Unbonded layer used the tangential deformation of its material to reduce friction and was affected less by friction coefficients; The unbonded layer's contact pressure increase with the increase of the shear modulus; Unbonded layer can solve the problem of all-steel PBRB due to the size effect caused serious tension and compression imbalance.