A new type of Tuned Liquid Damper and its effectiveness in enhancing seismic performance: Numerical characterization, experimental validation, parametric analysis and life-cycle based design

The research presented here introduces a new type of liquid mass damper, called Tuned Liquid Damper with Floating Roof (TLD-FR) which combines the favorable characteristics of traditional Tuned Liquid Dampers (TLD) and liquid column dampers, and further examines its efficiency for seismic applications for Chile. The TLD-FR consists of a traditional TLD (liquid tank filled with liquid) with the addition of a floating roof. The sloshing of the liquid within the tank is what still provides the inertia damper effect, but the roof prevents wave breaking phenomena and introduces a practically linear response and a dynamic behavior in a dominant only mode. This creates a vibratory behavior that resembles other types of a linear mass dampers and a framework is developed to characterize this behavior with a simple parametric description that can facilitate an easy comparison to such dampers. Within this framework, focus is given on a theoretical/computational characterization of the new device, coupled with an experimental validation of its capabilities and of the established numerical tools. The aforementioned parametric formulation is then used to develop an approach that facilitates a direct design in the parametric space, as well as an efficient mapping back to the different tank geometries that correspond to each parametric configuration. During this process the efficiency of mass dampers for seismic applications in Chile is also examined by comparing the performance across different types of ground motions, representing different regions around the world. Finally, a versatile life-cycle assessment and design of the new device is established considering risk characterizations appropriate for the Chilean region, so that the cost-benefits from its adoption can be directly investigated. This involves the development of a multi-criteria design approach that considers the performance over the two desired goals: (i) reduction of the total life-cycle cost considering the upfront damper cost as well as seismic losses and (ii) reduction of the consequences, expressed through the repair cost, for low likelihood but high impact events. Through this approach the financial viability of the TLD-FR (competitiveness against TMDs) for enhancing seismic performance is demonstrated.