Numerical studies on the application of tuned liquid dampers with screens to control seismic response of structures

Tuned liquid damper (TLD) systems are nowadays increasingly being used as one of the economical and effective passive vibration absorbers. A TLD system consists of a water tank having the fundamental sloshing fluid frequency tuned to the frequency near to the natural frequency of structure. This research focuses on modelling tall buildings equipped with TLDs having inside screens subjected to strong ground motions. Strong excitation can cause wave-breaking phenomenon and makes turbulent in shallow rectangular tanks which could also contribute to the additional damping due to TLDs. On the other hand, wire screens placed inside a liquid tank can play an important role in reducing the structural response due to increasing the inherent damping of the structure. Based on equalizing dissipated energies, a TLD equipped with internal screens can be modelled by equivalent amplitude-dependent tuned mass damper (TMD). In this study, adopting this simple method, equations of motion for shear-type buildings equipped with nonlinear amplitude-dependent TMDs were developed. A complex modal analysis procedure was used to solve the governing equations. Coupling of TMD properties and structural response was solved with iteration on structural response and updating TMD properties. Performing a set of parametric studies on three proposed tall structures equipped with TLD subjected to different ground excitations showed that if the TLD is tuned to a frequency close to the natural frequency of the structure considering hardening behaviour of TLD, it could significantly reduce the seismic response (displacements and base shears) of the structures. Copyright (C) 2009 John Wiley & Sons, Ltd.