Influence of high-pass filtering of near-fault earthquake record on the responses of base-isolated building

Abstract

Filtering is one of the critical steps of earthquake ground motion processing before its application to engineering practice, and high-pass filtering is particularly important due to rich contents of low frequency in ground motion signals. In particular, the impulsive properties of the ground motion recorded in near-fault zones are susceptible to the high-pass filtering, and thus selecting a reasonable filtering method becomes a critical issue that determines the reliability of the structural analysis results. This study investigates how the high-pass filtering of pulse-like ground motions affect the subsequent responses of long-period base-isolated building. A set of near-fault ground motions were selected and classified into short-to-mid and mid-to-long period groups, with 2 s being the threshold, and they were subjected to filter with varied parameters. The filtering induced variations of elastic response spectra, inelastic response spectra, and the impulsive property identification were analyzed. The highest cutting frequency of 0.20 Hz and 0.10 Hz of the high-pass filter were recommended for short-to-mid and mid-to-long period pulse records, respectively, while the impulse properties and spectral properties of engineering interest were not disturbed considerably. The ground motions were input to a high-rise base-isolated building, and the responses were computed from different filtering settings and compared, which further verified the suggested high-pass filtering method for pulse-like ground motions.