Enhanced Damping Mechanisms for Deep Tuned Liquid Dampers to Control Lateral Seismic Structural Vibrations

Abstract

Applications of tuned liquid dampers (TLDs) are mostly confined to the shallow and intermediate-depth variety of the damper. In contrast, the deep TLD or deep tank damper (DTD) has received limited research attention due to its low intrinsic damping and low volumetric efficiency. This study aims to develop practically feasible designs of deep TLDs that will enhance their effectiveness and will utilize the dead or impulsive liquid mass in the damping mechanism. For this, threenovel configurations of the deep TLD, namely, deep TLD with cylindrical pendulum appendage (DTD-CPA), deep TLDwith submerged suspended plate (DTD-SSP), membrane assisted-deep TLD (MA-DTD) are proposed.The theoretical models, working mechanisms, and designs of the proposed dampers are presented. The performances of the proposed dampers under seismic base excitation are significant and found to be comparable to that of an equivalent tuned mass damper. Further, functional liquid-containing tanks are generally not considered for design as deep TLDs, as the liquid level fluctuation in these tanks leads to detuning. To overcome this, two designs, namely, adeep tankfitted with a movable floating base, termed the TLD-FB, and a TLD with stiffness-varying support (TLD-SVS) arepresented, that maintain a constant tuning frequency despite a wide range of fluctuation in the liquid level in the tank. Results from the current study indicate that the proposed enhanced damping mechanisms of deep TLDs have significant potential as seismic vibration control devices for structures and open up the opportunity for multi-purpose regular utilization of the damper liquid as well.