Browsing by Author "Espinoza, Gilda"

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    Optimal TMD design for torsional balance of asymmetrical 3D structures considering soil-structure interaction
    (2022) Espinoza, Gilda; Casanova, Euro; Benedetti, Franco; Mena, Richard; Luis Almazan, Jose
    In this paper, the behavior of a tuned mass damper (TMD), to torsionally control a linear structure subjected to seismic excitations, is investigated. The dynamic system is analyzed taking into account lateral-torsional coupling, soil-structure interaction, and the rotational components of the foundation motion. The system model consists of an asymmetrical structure, founded on a soil modeled as a homogeneous semi-space. A stationary stochastic analysis is performed in the time domain, and a double Clough-Penzien filter of broad frequency content is used to define the random process for the X and Y directions. The torsional balance criterion is employed for the optimization of the TMD design parameters. The influence of the plan static eccentricity over optimum TMD parameters' behavior is also addressed, taking into account the fixed base period, flexible period, torsional frequency ratio, and soil type. Compliance with the torsional balance is verified. The results show that the inclusion of the soil rotational component has a notorious influence on the optimum TMD parameters. Moreover, torsionally flexible structures founded on soft and medium soil show significant influence on the torsional balance. Finally, a transitory response analysis is carried out for a 15-story model, subjected to an artificial bidirectional earthquake with a broadband frequency content. The multistory model response validates the results derived from the stochastic analysis.
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    Torsional balance of asymmetric structures by means of tuned mass dampers
    (ELSEVIER SCI LTD, 2012) Luis Almazan, Jose; Espinoza, Gilda; Jesus Aguirre, Juan
    This research studies the response of asymmetrical linear and nonlinear structures subjected to unidirectional and bidirectional seismic excitation, equipped with one or two Tuned Mass Dampers (TMDs). The optimized parameters of each TMD are obtained by applying the concept of general torsional balance. The results show that the TMDs reduce the edge deformation in values varying from 20% to 50%. The highest reductions are obtained at the edges where deformation is greater. As a general rule, it has been found that the TMD should be located towards the corner where the uncontrolled response (without TMD) is greater. If the excitation is a broad-band process, the TMD tends to synchronize with the frequencies associated to the two translationally dominant modes of the structure. Instead, if the excitation is a narrow-band process, the TMD tends to synchronize with the characteristic frequency of the excitation. The findings for one or two TMDs are very similar, therefore, there is no significant improvement resulting from adding a second TMD. Preliminary results indicate that, when moderate, the inelasticity of the main structure does not significantly affect the optimized TMD frequency. However, for torsionally hybrid and flexible structures, the optimized TMD position is sensitive to inelasticity of the main structure. (C) 2012 Elsevier Ltd. All rights reserved.