Electronic Thesis and Dissertation Repository

Degree

Doctor of Philosophy

Program

Civil and Environmental Engineering

Supervisor

Dr. Ashraf El Damatty

2nd Supervisor

Dr. Michael Tait

Joint Supervisor

Abstract

The resonant vibration motion of tall buildings due to dynamic loading, such as wind storms and earthquakes, can be reduced by adding passive dynamic vibration absorbers (DVAs). A single sway mode of vibration is usually considered, however, for certain structures, multiple modes may need to be suppressed. Furthermore, the location of the TLD on the floor plate is important for certain modes, such as the torsional mode. As a result, a three dimensional finite element structure-TLD system model capable of dynamically analyzing a 3D structure is developed and validated. Two different nonlinear TLD models are considered. A full dynamic analysis of a 3D single-story structure-TLD system is carried out utilizing the two TLD models and results under harmonic and random excitation are compared with experimental values. The three dimensional finite element structure-tuned liquid damper system model (3D-Structure-TLD) is expanded to include multiple tuned liquid dampers (3D-Structure-MTLD) and employed to estimate the response of a full-scale model of a 38-story multi-modal high-rise building subjected to wind tunnel loads recorded at different locations along the building’s width and height.

To further improve TLD effectiveness, the nonlinear TLD fluid model is modified in order to simulate the influence of inclined damping screens. The updated passive TLD model is used to investigate the performance of both a single-story structure-TLD system and a 38-story structure-MTLD system with inclined damping screens over a range of structural response amplitudes utilizing random excitation and wind tunnel loads, respectively. Thus, the methodology to optimize the effective damping provided by the TLD over a range of structural responses is addressed.

Finally, a control strategy based on gain scheduling scheme is developed, by actively controlling the damping screen inclination angle. The updated nonlinear fluid model of a TLD equipped with inclined damping screens is used to determine the resulting TLD base shear force and free surface response of a novel semi-active (SA) TLD. The semi-active TLD control technique is also expanded to include semi-active multiple TLDs (3D-Structure-SA-MTLD) and employed to analyze a 38-story building over a range of wind angles and return periods. The improved performance of a semi-active TLD system over a passive TLD system is addressed.

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