This research is an experimental study attempting to use MR-dampers to control the complex behavior of multi-span bridge structures due to external loads such as seismic loads. For the purposes of this study, the model of components in each structure is identified, and then based on the results, a simplified system of the structure is derived. The performance of MR-dampers for complex behavior control is evaluated separately, according to the self-performance of MR-dampers and according to the performance based on applications of control algorithms. Based on the simplified system, Lyapunov control algorithm and Clipped-optimal control algorithm are applied. As a result, MR-damper is proven to be effective in the complex behavior control of multi-span bridge structures.

This study attempted to assess performances of adopted MR-damper to control the complex behavior caused by the interaction of independent continuous structures. For this, MR-damper (30kN) was designed and fabricated, and the MR-damper model was investigated using the Nonlinear Bingham Plastic Damper (NBPD). To assess experimental performances, a control test on the model structure was performed while El-centro 150% of seismic load was being applied. Then, MR-damper was placed between two independent structures to have it control independent displacement and complex behavior between the two structures. This study found that MR-damper is effective in controlling complex behavior of structures.