Double small-sized lever-arm system with steel slit damper for seismic energy dissipation of structures

This paper proposes a double lever-arm system using a steel slit damper for the seismic energy dissipation of structures. Small lever-arm members are used to apply the displacement amplification mechanism. The brace members in the proposed system do not buckle. This is because the brace can maintain the tensile axial force by introducing an initial tension, which enables the use of rod braces. First, the formulas for the lateral strength and stiffness of the system were derived. Cyclic loading tests revealed that the proposed energy-dissipation system performed adequately. The experimental results demonstrated that all the specimens yielded at a small story drift angle and, thereby, had high energy dissipation capability. The loading tests verified that the amplification factor of the lever-arm and slit damper configuration could control the stiffness and strength of the system. Seismic response analyses of five-story steel frames were conducted to demonstrate the efficacy of the proposed damping system. A reduction in the story drift angle and number of plastic hinges was achieved. The seismic energy dissipation in the slit dampers was verified by the energy responses. • A double small-sized lever-arm system with steel slit damper was proposed. • Displacement amplification mechanism was achieved by lever-arm members. • Cyclic loading test demonstrated its structural performance and applicability. • Seismic response analysis of frames revealed its energy-dissipation efficacy.