Extraction of forward-directivity velocity pulses using S-Transform-based signal decomposition technique

Amiri, G. Ghodrati; Moghaddam, Saied

doi:10.1007/s10518-013-9581-x

Cited by 21 publications

(6 citation statements)

References 52 publications

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“…Basically, there are two ways to do this. The first is by using some kind of signal processing techniques, like the data smoothing and filtering, [54][55][56][57][58] the windowed Fourier transform, 59,60 the wavelet analysis, 20,[61][62][63][64][65][66] the empirical mode decomposition, [67][68][69][70] and the variational mode decomposition. [71][72][73] Although by properly using these techniques the dominant long-period pulses can be well extracted and T p and the pulse amplitude (V pk ) as well as its epoch (t pk , time location of amplitude) can be determined accordingly, other pulse-like features, such as the number of oscillations (N c ) and the phase (𝜑) of the pulse, however, may not be desirably estimated.…”

Section: Introductionmentioning

confidence: 99%

Automated parameterization of velocity pulses in near‐fault ground motions

Chang,

Wu,

Goda

2023

Earthq Engng Struct Dyn

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Proper parameterization of near‐fault ground motions is of critical importance in earthquake engineering, and this process is traditionally performed by directly fitting an analytical pulse model to the original motion. Yet such a process is usually limited by the trial‐and‐error procedure, which is strongly dependent on the initial guesses and may converge to local rather than global minimums. In this study, we propose a progressive (step‐by‐step) iterative approach that can achieve a fully automated parameterization of the velocity pulse contained in near‐fault motions. Assuming that a velocity pulse can be characterized by a pulse model with four key parameters, the approach is conducted by iteratively matching the pulse model to the smoothed ground motion, and the parameterized pulse is analytically derived by best fitting to the smoothed motion not only in the time domain but also in the spectral domain. Specifically, the velocity time history of interest is initially smoothed by a moving average filter so that the low‐frequency content can be filtered out of the original motion, from which the pulse amplitude as well as its epoch is accordingly determined. The coherent velocity pulse is then progressively extracted by performing the nonlinear least‐square‐fitting of the pulse model to the filtered low‐frequency content, during which the remaining parameters, that is, the pulse period, the number of cycles and the phase of the pulse, are estimated successively. Finally, the above procedure is applied repeatedly to the original ground motion by changing an empirical factor controlling the extent of smoothing of the motion so that convergence to local minimums that frequently occurs in the trial‐and‐error procedure could be largely avoided, and best match of the spectrum of the extracted pulse to that of the original motion can be acquired. Fitting quality of the velocity pulses is examined by comparing with existing methods. Prospective applications of the proposed procedure include the stochastic simulations of near‐fault ground motions and parametric investigations of the influence of velocity pulses on various engineered structures.

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Section: Introductionmentioning

confidence: 99%

Automated parameterization of velocity pulses in near‐fault ground motions

Chang,

Wu,

Goda

2023

Earthq Engng Struct Dyn

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“…When the structure is located within an area close to the seismic fault, eg, within 30 km, 1 particularly high seismic demands are usually imposed. From the seismological perspective, numerous studies have been carried out by using analytical models to characterize the velocity pulses, [4][5][6] accounting for the pulse effects in seismic hazard analysis, 7,8 simulating pulse-like ground motions using stochastic approaches, 9,10 and classifying velocity pulses through automated algorithms. In contrast, the damage resulting from far-field ground motions is typically caused by the repeated cycles of inelastic deformation that accumulates in the structural components.…”

Section: Introductionmentioning

confidence: 99%

“…3 During the past two decades, near-fault pulse-like ground motions have been extensively studied by the seismology and earthquake engineering communities. From the seismological perspective, numerous studies have been carried out by using analytical models to characterize the velocity pulses, [4][5][6] accounting for the pulse effects in seismic hazard analysis, 7,8 simulating pulse-like ground motions using stochastic approaches, 9,10 and classifying velocity pulses through automated algorithms. [11][12][13] From the engineering perspective, the effects of pulse-like ground motions on various structures have been investigated, including idealized single (or multi)-degree-of-freedom (SDOF) systems, 14,15 seismically base-isolated structures, 16,17 bridge structures, 18,19 and some other special buildings or elements.…”

Section: Introductionmentioning

confidence: 99%

Near‐fault acceleration pulses and non‐acceleration pulses: Effects on the inelastic displacement ratio

Chang

Luca

Goda

2019

Earthq Engng Struct Dyn

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Summary Near‐fault ground motions can impose particularly high seismic demands on the structures due to the pulses that are typically observed in the velocity time‐histories. The velocity pulses can be further categorized into either a distinct acceleration pulse (acc‐pulse) or a succession of high‐frequency, one‐sided acceleration spikes (non‐acc‐pulse). The different characteristics of velocity pulses imply different frequency content of the ground motions, potentially causing different seismic effects on the structures. This study aims to investigate the characteristics of the two types of velocity pulses and their impacts on the inelastic displacement ratio (CR) of single‐degree‐of‐freedom systems. First, a new method that enables an automated classification of velocity pulses is used to compile a ground motion dataset which consists of 74 acc‐pulses and 45 non‐acc‐pulses. Several intensity measures characterizing different seismological features are then compared using the two groups of records. Finally, the influences of acc‐pulses and non‐acc‐pulses on the CR spectra are studied; the effects of pulse period and hysteretic behavior are also considered. Results indicate that the characteristics of the two types of velocity pulses differ significantly, resulting in clearly distinct CR spectral properties between acc‐pulses and non‐acc‐pulses. Interestingly, mixing acc‐pulses and non‐acc‐pulses can lead to local “bumps” that were found in the CR spectral shape by previous studies. The findings of this study highlight the importance of distinguishing velocity pulses of different types when selecting near‐fault ground motions for assessing the nonlinear dynamic response of structures.

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“…[16]. Amiri and Moghaddam [17] have proposed a modified version of the S-Transform for the decomposition of seismic signals in order to identify the pulse-like part of near-fault velocity records. Chang et al [18] have identified the dominant impulsive mode from the original record by minimizing the difference between a numerical pulse model and the velocity time-history of the seismic ground motion.…”

Section: Introductionmentioning

confidence: 99%

A Variational Approach for Energy-Based Analysis of Near-Fault Pulse-Like Seismic Records

Quaranta¹,

Mollaioli²

2019

Proceedings of the 7th International Conference on Computational Methods in Structural Dynamics and Earthquake Engineering (COM

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Near-fault earthquakes often exhibit a pulse in the velocity time-history that mainly occurs in the strike-normal direction at locations towards which the earthquake rupture has propagated. The extraction of the dominant impulsive component embedded into such kind of seismic records and the proper consideration of the other signal modes are critical tasks for a reliable prediction of the behavior of structural systems subjected to earthquakes close to active faults. Within this framework, the present work is concerned with the application of the Variational Mode Decomposition technique for processing near-fault pulse-like seismic signals. Specifically, this numerical technique is herein applied to some fault-normal horizontal pulselike seismic velocity time-histories in order to evaluate its suitability in detecting the mode with the dominant pulse. Final results demonstrate that such variational approach is able to extract the impulsive component of the seismic records, and the corresponding estimates of the pulse period are in good agreement with the results obtained by means of existing methods. Input power and energy as well as acceleration, displacement, velocity and energy spectra have been calculated for the original seismic record and the modes extracted by means of the Variational Mode Decomposition technique. 2220 COMPDYN 2019 7 th ECCOMAS Thematic Conference on Computational Methods in Structural Dynamics and Earthquake Engineering M. Papadrakakis, M. Fragiadakis (eds.

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Extraction of forward-directivity velocity pulses using S-Transform-based signal decomposition technique

Cited by 21 publications

References 52 publications

Automated parameterization of velocity pulses in near‐fault ground motions

Automated parameterization of velocity pulses in near‐fault ground motions

Near‐fault acceleration pulses and non‐acceleration pulses: Effects on the inelastic displacement ratio

A Variational Approach for Energy-Based Analysis of Near-Fault Pulse-Like Seismic Records

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