Responses of a 64-story unique San Francisco, CA. building to four earthquakes and ambient motions

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Abstract

We analyze the ambient and earthquake responses of a 64-story, instrumented, concrete core shear wall building in San Francisco, Calif. equipped with tuned sloshing liquid dampers (TSDs) and buckling restraining braces (BRBs). In an earlier paper [1], only ambient data were used to identify dynamic characteristics. Recently, the 72-channel instrumental array of the building recorded the 24 August 2014 Mw6.0 South Napa and three other earthquakes – allowing comparison of the dynamic characteristics using ambient and earthquake data. Peak accelerations of ambient and the larger South Napa EQ responses at the basement are 0.12 and 5.2 cm/s/s, respectively – a factor of ~ 42 and, at the 61st level, are 0.30 and 16.8 cm/s/s, respectively –a factor of ~56. Fundamental frequencies determined from spectral ratios for the NS (~0.3Hz), EW (0.27Hz) and torsional accelerations for the earthquake response vary within an insignificant frequency band of ~ 0.02-0.03 Hz as compared to those determined from ambient data. At the level of shaking, BRBs or TSDs are not effective enough to alter dynamic characteristics (frequency or damping). Under future stronger (e.g. design level) shaking of the building, the nonlinearities caused by actions of TSDs and BRBs can substantially shift the dynamic characteristics of the building.

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Publication type Conference Paper
Publication Subtype Conference Paper
Title Responses of a 64-story unique San Francisco, CA. building to four earthquakes and ambient motions
Year Published 2017
Language English
Publisher National Information Centre of Earthquake Engineering
Contributing office(s) Earthquake Science Center
Description 12 p.
Larger Work Type Book
Larger Work Subtype Conference publication
Larger Work Title Proceedings of the 16th World Conference on Earthquake Engineering
Conference Title 16th World Conference on Earthquake Engineering
Conference Location Santiago, Chile
Conference Date January 9-13, 2017
Country United States
State California
City San Francisco
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