Friction-based control of building complex for seismic mitigation: Numerical and experimental studies.

摘要

This thesis focuses on developing coupled control for the seismic protection of building complex, which is a grouped building of main and podium structures, and understanding the control performance under passive and semi-active control strategies using friction dampers. Numerical and experimental methods are employed to identify the effectiveness in this research.; The control effectiveness of passive coupled control is first evaluated experimentally. An experimental model of a building complex and laboratory-scale friction damper are developed for this purpose. Seismic behaviors of the building complex in three different coupling configurations are examined under several historical earthquake records.; Understanding of passive coupled control effectiveness is extended numerically by including factors of building configuration and damper deployment. The design matter of optimal friction force and the corresponding control efficiency are studied through parameters of earthquake excitation types, mass and height difference between two structures, and number of dampers.; Semi-active control strategy is next numerically studied to pursue increased vibration reduction. Two classes of control algorithms, global- and local-feedback controllers, are considered. A modified clipped algorithm is developed in the study of linear quadratic Gaussian (LQG) controller. Also, three local feedback controllers are examined, one of which is developed to allow effective design of damper capacity. Comparative evaluation of control strategies is conducted based on the parameters considered in the passive control case.; Experimental validation of the numerical findings regarding the semi-active control of building complex is also performed. A laboratory-scale is first developed and characterized. An operating scheme for real-time control of the damper is proposed accordingly, and precision of force replication is further considered by proposing a force-feedback controller. All the semi-active control strategies studied in the numerical study is evaluated in a series of shaking table tests.; This thesis finally investigates the design details of a variable friction damper. Particular attention is placed on evaluating the dynamic performance and force regulation ability of the damper configured with multiple friction surfaces and force amplifying unit to provide a larger friction force. Two variable friction dampers are developed and a series of cyclic tests under constant and varying input voltage are conducted.