Combined rings and horizontal steel pipe as hysteretic dampers

A new combined rings and horizontal steel pipe as hysteretic dampers for seismic resistant steel structures have been developed. Simulation studies for various models of the dampers have been carried out under cyclic shear loadings. In each model, different strengthening strategy applied to the combined rings and horizontal steel pipe damper was explored. The chosen model among simulated dampers experienced extensive yield under different cyclic loadings. The specimens of the chosen model have been tested using the same four different cyclic shear loadings, which are ultralow-cycle fatigue (ULCF) loads representing extreme earthquakes. At the end of each testing, all tested dampers experienced ductile fracture. The test results showed all dampers have a stable hysteretic response under ULCF loads. All dampers exhibit excellent ductility represented by many plastic cycles before failures. If enough number of dampers are installed in building structures, the combined rings and horizontal steel pipe dampers can be used as the seismic energy dissipating devices for steel structures.