Experimental evaluation of a tuned liquid damper system

To improve the serviceability of tall buildings, several types of vibration control system are developed and used. One such system is the tuned liquid damper (TLD), the advantages of which include a low cost, easy adjustment of natural frequency, easy installation and reduced maintenance when compared with the tuned mass damper and the hybrid mass damper. Water tanks at the top of tall buildings can be directly remodelled as a vibration control system that is more practical than others. But as the damping ratio of a TLD depends on several factors, including the magnitude and frequency of the applied load, the shape of the tank and wall roughness, it is difficult to evaluate the control performance of the tank accurately. In this study, the characteristics of a TLD with wire screens and small blocks attached to the wall are evaluated and an equation for the equivalent damping ratio of the TLD is proposed. To clarify the damping effect for a high-rise building subjected to the El Centro, Taft and Mexico earthquakes, an experiment comprising a coupled structural model with a water tank was conducted. The parameters included the mass ratio of the water to the model structure, the number of wire screens, and the aspect ratio of the water tank. The maximum response and standard deviation value of experiment results were analysed. The coupled structural model with the water tank exhibited lower maximum and standard deviation response than those of the structural model only. For the water tank with no wire screen, the damping effect could be neglected. Because of wavefront attenuation after the peak response of the TLD system, remarkable damping effects were observed. The higher damping effect was found in the model with the larger mass ratio, more wire screens and larger aspect ratio.