Browsing by Author "Ruiz García, Rafael Omar"

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    An innovative type of tuned liquid damper
    (2014) Ruiz García, Rafael Omar; Lopez-Garcia González, Diego; Taflanidis, A.A.
    This paper introduces a new type of Tuned Sloshing Damper (TSD) having a relatively simple, easy-to-model behavior and capable of effectively controlling earthquake vibrations. It consists of a traditional TSD with addition of a floating roof. Since the roof is much stiffer than water, it prevents wave breaking, hence making the response linear even at large amplitudes. The roof also facilitates the incorporation of supplemental devices (either passive, semi-active or active) with which the level of vibration suppression can be substantially augmented. This new proposed TSD, from now on denoted as Tuned Liquid Damper with Floating Roof (TLD-FR), maintains the traditional advantages of TSD (low cost, easy installation and tuning) but its numerical characterization is much simpler because the floating roof only allows one degree of freedom performance. An efficient numerical scheme, based on potential flow in which its dynamic behavior is expressed as a second order lineal system of equations, is discussed for the modeling of the TLD-FR. Preliminary results reveal that structures with TLD-FR can achieve significant reductions in their seismic response. This reduction is sensitive to the design characteristics of the TLD-FR, the fundamental frequency and the introduced damping. The overall study shows that the TLD-FR is an efficient alternative to reduce seismic responses on structures offering low cost, and easy-to-model and tune behavior.
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    Seismic optimization of a novel tuned sloshing damper for the Chilean region based on life-cycle cost criteria
    (2015) Ruiz García, Rafael Omar; Taflanidis, Alexandros A.; Lopez-Garcia, González Diego
    The design of a new liquid damper device is considered in this paper based on life-cycle criteria. This new device, called Tuned Liquid Damper with Floating Roof (TLD-FR) maintains the advantages of traditional Tuned Liquid Dampers (low cost, easy tuning, alternative use of water) while establishing a linear and generally more robust/predictable damper behaviour through the introduction of a floating roof. This behaviour can be characterized by four dimensional parameters that represent the design variables for the system and are all related to the tank geometry. A probabilistic framework is established to perform the design optimization considering seismic risk criteria specific to the Chilean region. Quantification of this risk through time-history analysis is considered and the seismic hazard is described by a stochastic ground motion model that is calibrated to offer hazard-compatibility with ground motion prediction equations available for Chile. Two different criteria related to life-cycle performance are utilized in the design optimization. The first one, representing overall direct benefits, is the life-cycle cost of the system, composed of the upfront TLD-FR cost and the anticipated seismic losses over the lifetime of the structure. The second criterion, focusing on the performance of building contents, is the peak acceleration with a specific probability of exceedance over the lifetime of the structure. A multi-objective optimization is therefore established and stochastic simulation is used to estimate all required risk measures, whereas a Kriging metamodel is developed to support an efficient optimization process.