A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering, School of Civil Engineering

Thesis (M.Eng.) - Asian Institute of Technology, 2001

A structural response control approach, which uses the interaction between two parallel structures (a primary strncture and an auxiliary strncture) to reduce the aseismic response of the primary-auxiliary system while ensuring the vibration of primary-structure decreased during earthquake actions, is presented in this paper. Based on the proposed strategy, three control methodologies including optimal passive control, active control and semi-active control are studied. Firstly, optimum parameters of the passive-coupling element between two parallel structures under different circumstances are determined. Then, a simple, effective algorithm for semi-active control is derived. The influence of the strnctural parameters of the system on the optimum parameters and passive control effectiveness is also investigated. Finally, emphasis has been placed on the comparison among these control strategies to find the suitable methods for effectively controlling the vibration of the system. The comparison of the structural responses to El Centro 1940 ground excitation illustrates that the optimum stiffness associated with optimum damping of the passive-coupling element is more effective for primary-structure while the optimum damping acting alone is useful for auxiliary structure; and that the proposed semi-active control is superior to the passive control and comparable to the active control with the same degree of control force.