9528083 Spencer This project conducts research on development of high-tech devices for the safety and life extension of civil infrastructure systems. Passive and active retrofit strategies represent the two ends of the spectrum in the use of control for reducing the response of civil infrastructure system subjected to dynamic hazard such as earthquakes. Semiactive and hybrid control devices potentially combine the best features of both the passive and active approaches for mitigating undesirable response. An interdisciplinary investigation of a new semi-active control device that uses a magnetorheological (MR) fluid in a controllable fluid damper is carried out. The MR damper overcomes many of the cost and technical difficulties of current semi-active control devices, and has high potential for use in civil infrastructure systems. In addition to its great promise for retrofits, the MR dampers are also attractive for new construction. The research will involve: (1) testing of the MR damper to characterize its behavior and to identify control-oriented models, (2) development of device specific nonlinear control algorithms that can take maximum advantage of the unique features of the MR damper, (3) conducting proof of concept tests for several structural system configurations in the Structural Dynamics and Control/Earthquake engineering Laboratory (SDC/EEL) at the University of Notre Dame, and conducting larger scale implementation and verification tests at the National Center for Earthquake Engineering Research (NCEER) in Buffalo, New York. Successful completion of this research is expected to accelerate economic and practical implementations of innovative retrofit strategies for dynamics hazard mitigation in civil infrastructure systems. ***
