Date of Award
Master of Science
Civil, Construction, and Environmental Engineering
This study was conducted as part of a research project aiming at understanding the dynamics of precast rocking concrete members. The characteristics and energy dissipation associated with the dynamic response of these systems were investigated.
The simple rocking model broadly used by the previous and current research society and a finite element modeling approach developed herein were used as guidelines and reference modeling methods to assess experimental free rocking responses and produce methodologies to more accurately estimate the actual rocking decay of motion. Two discrete energy dissipation mechanisms were identified, namely, instantaneous dissipation due to the impact phenomenon and continuous dissipation due to viscous behavior of the rocking interface. It was found that the instantaneous dissipation formula used in the simple rocking model serves as a lower-bound limit for the amount of energy dissipation per impact. The rocking coefficient of restitution can be alternatively expressed through its relationship with the impact velocity, base force and rocking body inertia. Finally, the continuous dissipation mechanism was modeled by using a viscous term in the original simple rocking model for accurately estimating the real-time displacement responses.
As far as controlled rocking is concerned, it was shown that its decay of motion is mainly dependent on the instantaneous dissipation mechanism, while the coefficient of restitution by the simple rocking model significantly overestimates decay of controlled rocking motion. To provide a safe upper bound limit for coefficient of restitution associated with controlled rocking systems, a simplified method which makes use of the original simple rocking model was proposed.
Kalliontzis, Dimitrios, "Dynamic decay of motion of rocking concrete members" (2014). Graduate Theses and Dissertations. 14188.