Control Strategies for 3D Smart Base Isolation Sysytems Using Modal and Nodal Approaches
Application of control technologies to structures is expected to be able to enhance a structure’s performance in response to natural hazards. Specifically, smart base isolation systems, which consist of a passive isolator at the base with controllable semiactive devices, attract much attention for efficacy and economical reasons. This study focuses on the development of control design strategies using physical knowledge of the system dynamics that had not been investigated systematically and applied for civil structures previously. Structural characteristics that are helpful to disclose structural properties yet are often ignored by civil engineers are integrated with these control techniques in both nodal and modal coordinates to construct indices for the determination of the control actions to take full advantage of their capabilities. A 3D base isolated building is employed for the demonstration and validation of these strategies.MR dampers are used as the smart control devices.Effective design for this complexsystem requires the use of control device and sensor placement techniques and optimal control weighting selection, which is achieved through the application of the structural physical properties. A correlation technique is proposed and is first applied for the placement problem to minimize redundancies. Controller order reduction is also examined for more implementable controllers, where both open-loop and closed-loop balancing are taken into account. Responses of this system to seven specified earthquakes demonstrate that the proposed strategies are effective for the control of the base isolation system. The modal approach is advocated because it has explicit physical interpretation and is more straightforward for the design engineer.
Submitted to the Graduate School of Washington University in St. Louis for Partial Fulfillment of the requirements for the Degree of Doctor of Science by Yumei Wang, M.S., Dept. of Civil and Environmental Engineering, University of Illinois at Champaign-Urbana, August, 2003.
This work was supported in part by the Mid-America Earthquake Center through NSF grant EEC-9701785.
Researchers should cite this work as follows:
Wang, Y., and Dyke, S. J., (2007), “Smart System Design for a 3D Base Isolated Building”, Journal of Structural Control and Health Monitoring, 15(7): 939-957, Published Online: Sep 18 2007 9:06AM, DOI: 10.1002/stc.228.