Seismic performance analysis of reinforced multi-story frames with external fractal dimension-buckling restrained braces

Leveraging fractal theory and the construction principle of diamond-shaped perforations for easy cutting, a regularly structured yet disorderly fractal dimension-buckling restrained brace (FD-BRB) core unit with diamond-shaped perforations was designed. ABAQUS simulations verified the seismic performance enhancement of FD-BRBs in an eight-story frame, demonstrating improved ductility coefficients and energy dissipation capacity. Extended to SAP2000 analyses of four- and twelve-story frames, nonlinear dynamic analyses confirmed that reinforced multi-story frames achieved approximately 24.5% reduction in maximum inter-story drift angles, with plastic hinges shifting from the base to upper structures, while high-rise frames showed enhanced hysteretic energy dissipation in base shear. The study proves that the fractal configuration achieves structural collaborative reinforcement through displacement constraint mechanisms, providing new insights for seismic engineering.