Date of Award

Fall 2019

Document Type


Degree Name

Doctor of Philosophy (PhD)


Civil & Environmental Engineering


Civil Engineering

Committee Director

Yunbyeong Chae

Committee Member

Zia Razzaq

Committee Member

Duc Nguyen

Committee Member

Gene Hou


Base isolation system is one of the most effective seismic protection systems which is widely used to protect buildings of high importance against seismic hazards. However, the performance of these systems might be impaired under long-period earthquake ground motions due to the resonance effect. The main focus of this dissertation is the development of an adaptive semi-active control algorithm to improve the performance of conventional base isolation systems. The proposed control law works based on the transmissibility theory, called the transmissibility-based semi-active (TSA) controller, which can adaptively change the damping of the base-isolation system based on the response of the structure. Furthermore, a systematic design procedure was developed for the design of base-isolated structures with semi-active damping devices, which is called the simplified design procedure. The effectiveness of the proposed base isolation system with the TSA controller is investigated both numerically and experimentally, while using the simplified design procedure for design of the base-isolated buildings with magneto-rheological (MR) dampers. Nonlinear time history analyses are conducted with various long- and short-period earthquake ground motions to numerically evaluate the performance of the proposed base isolation system. Statistical analysis of the numerical simulation results are provided accordingly. Additionally, Real-Time Hybrid Simulations (RTHSs) are performed on a small-scale base-isolated building with an MR damper to experimentally validate the performance of the proposed base isolation system. It is shown that the proposed base isolation system makes the building work like a passive-on or passive-off isolation system as necessary to achieve high performance level under both long- and short-period earthquake ground motions, which can significantly improve the resiliency and sustainability of buildings.


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