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Before and after retrofit behavior and performance of a 55-story tall building inferred from distant earthquake and ambient vibration data

Earthquake Spectra
By: , , , , , and 
https://doi.org/10.1193/122216EQS249M

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Abstract

A sparsely instrumented 55-story building in Osaka, Japan had recorded unprecedented, severe and long-duration long-period resonating responses during the March 11, 2011 M9.0 Tohoku earthquake that occurred at 767 km distance. Thereafter, studies of the records resulted in implementation of a significant retrofit design, comprising dampers and buckling restrained braces (BRBs). The responses of the retrofitted building were also recorded during the April 24, 2016 M7.3 Kumamoto earthquake that occurred at 478 km. The earthquake and on-demand acquired ambient response data are analyzed in this study to assess the impact of this rare, retrofitted and instrumented tall building subjected to long period strong shaking from events originating at far distances. As expected, the fundamental frequency and critical damping ratio of the building increased, albeit small, after the retrofit as compared to before the retrofit. Increase of damping percentage is a positive finding and indicates that even larger percentages may be attained under shaking stronger than the 2016 event. The records indicate that the building still experiences significant resonance, torsion, as well as a beating effect.

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Publication type Article
Publication Subtype Journal Article
Title Before and after retrofit behavior and performance of a 55-story tall building inferred from distant earthquake and ambient vibration data
Series title Earthquake Spectra
DOI 10.1193/122216EQS249M
Volume 33
Issue 4
Year Published 2017
Language English
Publisher Earthquake Engineering Research Institute
Contributing office(s) Earthquake Science Center
Description 28 p.
First page 1599
Last page 1626
Country Japan
City Osaka
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