Experimental and analytical study of a seismic energy dissipation device made of butterfly-shaped steel plates and viscoelastic pads

This paper presents the seismic performance of a new hybrid seismic damper combining a metallic and viscoelastic damper. Two damper specimens with different configurations were tested under cyclic loading to investigate their hysteretic response to increasing loading. A curve-fitting procedure based on genetic algorithm was developed to make an analytical model for viscoelastic dampers based on the test results, and the analytical model of the hybrid damper was constructed by combining the individual models of the metallic-yielding damper and the viscoelastic damper. Both hybrid damper configurations exhibited a high energy dissipation capacity due to the complementary behavior of their components at different loading displacements. The viscoelastic component showed a relatively higher energy-dissipation capacity but a lower strength at small displacements. In comparison, the butterfly-shaped metallic yielding component exhibited a lower energy-dissipation capacity but higher strength at the same displacement. Conversely, the opposite was true at large displacements. The effectiveness of the damper was further investigated by retrofitting a four-story case study structure. Based on the test and the analysis results, it was concluded that the proposed hybrid damper has the potential to enhance the seismic performance of structures by increasing their strength and energy dissipation capacity, and that the developed analytical model turned out to simulate the nonlinear behavior of the damper adequately. •The seismic performance of a new hybrid seismic damper combining a metallic and viscoelastic damper was presented.•A curve-fitting procedure based on genetic algorithm was developed to make an analytical model.•Cyclic loading tests were conducted to verify hysteretic behavior of the hybrid damper.•The effectiveness of the damper was further investigated by retrofitting a four-story case study structure.