A new modular seismic magneto-rheological (MR) fluid damper

In this study, a large-scale, magneto-rheological fluid (MRF) by-pass damper for seismic mitigation applications is designed, constructed and tested. The damper utilizes a simple design with a modular by-pass magneto-rheological (MR) fluid valve connected to a passive commercial seismic damper. The modular feature of the new MRF valve provides flexibility of adding as much force as needed to the damper with minimal modification to an existing passive damper. The performance of the MRF valve and the combined semi-active by-pass MRF damper are examined by means of quasi-static and dynamic tests. The results show that the largescale by-pass MRF damper can generate a considerable dynamic force range which meet the large force requirements of a large structure subjected to seismic or man-made hazards.