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Peak response of 2‐DOF uncoupled oscillator under two‐directional base motion
Author(s) -
Slafak E.,
Bendimerad M. F.
Publication year - 1988
Publication title -
earthquake engineering and structural dynamics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.218
H-Index - 127
eISSN - 1096-9845
pISSN - 0098-8847
DOI - 10.1002/eqe.4290160708
Subject(s) - weighting , amplitude , physics , base (topology) , acceleration , natural frequency , mathematics , mathematical analysis , motion (physics) , acoustics , classical mechanics , optics , vibration
This paper investigates the peak response of a 2‐DOF uncoupled linear oscillator under arbitrarily oriented two‐component horizontal earthquake motion. Input data consist of 22 two‐component acceleration records from the magnitude 6.6, October 15, 1979 Imperial Valley earthquake. One‐directional response spectra for each principal direction of the oscillator, and two‐directional response spectra (amplitude of the peak resultant response and its direction with respect to principal directions) are calculated by considering all angles of incidence of the excitation. The results indicate that, for oscillators that are not too flexible (i.e. with natural frequencies greater than 0.8 Hz), the two‐directional peak response is controlled by the weaker direction of the oscillator. For flexible oscillators the two‐directional peak response is controlled by the direction whose natural frequency is closer to dominant ground motion frequencies. The results also show that when the two‐directional peak response is expressed as a weighted sum of one‐directional peak responses, the weighting factors are not constants, but functions of oscillator and dominant ground motion frequencies.