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Structural Engineering and Mechanics
  Volume 75, Number 1, July10 2020, pages 33-47
DOI: http://dx.doi.org/10.12989/sem.2020.75.1.033
 


Dimensional analysis of base-isolated buildings to near-fault pulses
Denis Istrati, Constantine C. Spyrakos, Panagiotis G. Asteris and Eleni Panou-Papatheodorou

 
Abstract
    In this paper the dynamic behavior of an isolated building subjected to idealized near-fault pulses is investigated. The building is represented with a simple 2-DOF model. Both linear and non-linear behavior of the isolation system is considered. Using dimensional analysis, in conjunction with closed form mathematical idealized pulses, appropriate dimensionless parameters are defined and self-similar curves are plotted on dimensionless graphs, based on which various conclusions are reached. In the linear case, the role of viscous damping is examined in detail and the existence of an optimum value of damping along with its significant variation with the number of half-cycles is shown. In the nonlinear case, where the behavior of the building depends on the amplitude of the excitation, the benefits of dimensional analysis are evident since the influence of the dimensionless Π-terms is easily examined. Special consideration is given to the normalized strength of the non-linear isolation system that appears to play a complex role which greatly affects the response of the 2-DOF. In the last part of the paper, a comparison of the responses to idealized pulses between a linear fixed-base SDOF and the respective isolated 2-DOF with both linear and non-linear damping is conducted and it is shown that, under certain values of the superstructure and isolation system characteristics, the use of an isolation system can amplify both the normalized acceleration and displacement of the superstructure.
 
Key Words
    seismic response; near-fault pulses; base-isolation; dimensional analysis; non-linear analysis; earthquake engineering
 
Address
Denis Istrati: Department of Civil Engineering, University of Nevada-Reno, NV 89577, USA
Constantine C. Spyrakos and Eleni Panou-Papatheodorou: Laboratory of Materials Science and Engineering, School of Chemical Engineering, National Technical University of Athens,
Zografou Campus, 9 Iroon Polytechniou str, 15780, Athens, Greece
Panagiotis G. Asteris: Computational Mechanics Laboratory, School of Pedagogical and Technological Education, Heraklion, GR 14121, Athens, Greece
 

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