Seismic performance of steel plate slit-friction hybrid dampers

In this study a new hybrid energy dissipation device is developed by combining a steel slit damper and rotational friction dampers in parallel to be used for seismic retrofit of structures. Compared with the conventional slit dampers with the same yield strength, the hybrid damper has an advantage in that only friction dampers are activated for small earthquakes or strong wind, and both friction and slit damper work simultaneously for strong earthquakes. Cyclic loading tests of the friction, slit, and the combined hybrid dampers are carried out to evaluate their seismic energy dissipation capability. Finite element analyses of the test specimens are also carried out for comparison, which correspond well with the test results. The hybrid dampers are applied to seismic retrofit of an reinforced concrete analysis model structure, where it is observed that the dampers are effective in restraining the building performance within a given target performance level. The fragility analysis of the structure shows that the probabilities of reaching four limit states decrease significantly after the seismic retrofit. The effect is most significant in the reduction of the probability of reaching the complete damage state.