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Smart Structures and Systems   Volume 20, Number 6, December 2017, pages 641-656
Effects of vertical component of near-field ground motions on seismic responses of asymmetric structures supported on TCFP bearings
Nasim Partovi Mehr, Faramarz Khoshnoudian and Hamed Tajammolian

Abstract     [Full Text]
    The effects of vertical component of earthquakes on torsional amplification due to mass eccentricity in seismic responses of base-isolated structures subjected to near-field ground motions are studied in this paper. 3-, 6- and 9-story superstructures and aspect ratios of 1, 2 and 3 have been modeled as steel special moment frames mounted on Triple Concave Friction Pendulum (TCFP) bearings considering different period and damping ratios. Three-dimensional linear superstructures resting on nonlinear isolators are subjected to both 2 and 3 component near-field ground motions. Effects of mass eccentricity and vertical component of 25 near-field earthquakes on the seismic responses including maximum isolator displacement and base shear as well as peak superstructure acceleration are studied. The results indicate that the effect of vertical component on the responses of asymmetric structures, especially on the base shear is significant. Therefore, it can be claimed that in the absence of the vertical component, mass eccentricity has a little effect on the base shear increase. Additionally, the impact of this component on acceleration is remarkable so the roof acceleration of a nine-story structure has been increased 1.67 times, compared to the case that the structure is subjected to only horizontal components of earthquakes.
Key Words
    TCFP isolators;near-field earthquakes; eccentricity;vertical component; steel frames
Nasim Partovi Mehr and Faramarz Khoshnoudian: Faculty of Civil Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
Hamed Tajammolian: Faculty of Civil Engineering, Yazd University, Yazd, Iran

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