Experimental validation of a new type of tuned liquid damper

Abstract

The objective of this paper is to describe the main results of an experimental program intended to: (a) study the properties of a new type of Tuned Liquid Damper (TLD); and (b) validate a recently developed numerical model for the analysis of the sloshing response of liquids contained in rigid tanks and subjected to seismic excitations. The new type of TLD consists of a traditional TLD with the addition of a floating roof. Since the roof is much stiffer than water, it prevents wave breaking, which in turn makes the response linear even at large wave amplitudes. The stiff roof also makes possible the addition of supplemental dampers with which the level of damping can be substantially augmented. Further, the new device, denoted Tuned Liquid Damper with Floating Roof (TLD-FR), keeps the traditional advantages of TLDs, but its dynamic behavior is much simpler to characterize because it has only one degree of freedom. Analytical results obtained using the aforementioned numerical model indicate that the TLD-FR has the potential to significantly reduce the seismic response of building structures. A small scale specimen was subjected to unidirectional harmonic and seismic base excitations in a shaking table. Different schemes were considered, i.e., with and without the floating roof, and with and without supplemental dampers. Results confirm that the numerical model is able to predict the dynamic response of the TLD-FR with a significant degree of accuracy, and that the TLD-FR does behave linearly even at large wave amplitudes. The experimental results also show that the TLD-FR has some level of intrinsic damping, which was not expected but is certainly beneficial.