Performance Evaluation of Friction Spring Seismic Damper

Use of passive energy dissipators is emerging as an accepted practice for the seismic design and retrofit of civil engineering structures. One such new device, based on a self-centering friction mechanism is investigated in this paper. This device uses ring springs, also known as friction springs, as the key components to dissipate seismic-induced energy. Results of characterization tests performed on a 200-kN capacity damper prototype and shake table tests on a half-scale moment-resisting steel frame equipped with the same damper prototype are presented. Results of the shake table tests are also compared with numerical predictions. The results of the characterization tests showed that the force-displacement hysteresis loops of the damper were self-centering, repeatable, stable, identical in tension-compression, and nearly identical for all frequencies considered. In the shake table tests, the damper was effective in reducing the lateral displacements of the test structure. The damper was also efficient in reducing acceleration levels under earthquake intensity that caused slight yielding of the structure without a damper.