The Cincinnati Infrastructure Institute and the University of Cincinnati - Structural Dynamics Research Laboratory are collaborating with Hewlett-Packard Co and Aura Systems, Inc. to design and implement an active-mass-driver closed-loop control system on a 250 feet span two-lane steel through- truss highway bridge. The bridge is located in Franklin County, Ohio and it will be loaded to destruction for structural identification by the Cincinnati Infrastructure Institute. This effort is being co-sponsored by the Ohio Department of Transportation, the Federal Highway Administration and Franklin County, Ohio. The field-research infrastructure which will be developed for the destructive test program will be exploited to explore the problems in designing and implementing an active-control system for an existing constructed facility which is vulnerable to torsional excitation. The bridge will be incrementally shaken-down to destruction by four servo-control actuators reacting against rock- anchors while simulating a stationary truck at mid-span in one lane. A linearized element-level model of the bridge will be identified by impact, harmonic forced-excitation and truck-load tests to reflect the existing state. This will be the basis for control design. Extensive strain, distortion, displacement and acceleration instrumentation will be installed for nondestructive and destructive testing; some of these will be used for control feedback. The active-mass driver system will utilize three linear electromagnetic linear actuators. Hardware will be used for signal conditioning and processing and for implementation of real time digital control strategies. The control system designed for the existing state will be tested as the bridge is located to various limit states. To test the control system the bridge will be excited by sudden release of an initial displacement (step relaxation) and by sinusoidal and broadband input from a linear servo-hydraulic exciter.
