Stochastic simulation of regionalized ground motions using wavelet packets and cokriging analysis

Self Cite

Summary Seismic damage simulation of buildings on a regional scale is important for loss estimation and disaster mitigation of cities. However, the interaction among densely distributed buildings in a city and the site, ie, the “site‐city interaction (SCI) effects,” is often neglected in most regional simulations. Yet, many studies have found that the SCI effects are very important in regional simulations containing a large number of tall buildings and underground structures. Therefore, this work proposed a numerical coupling scheme for nonlinear time history analysis of buildings on a regional scale considering the SCI effects. In this study, multiple‐degree‐of‐freedom models are used to represent different buildings above the ground, while an open source spectral element program, SPEED, is used for simulating wave propagation in underlying soil layers. The proposed numerical scheme is firstly validated through a shaking table test. Then, a detailed discussion on the SCI effects in a 3D basin is performed. Finally, a nonlinear time history analysis of buildings on a regional scale is performed using the Tsinghua University campus in Beijing as a case study. The Tsinghua University campus case results show that the SCI effects will reduce the seismic responses of most buildings. However, some buildings will suffer much more severe damage when the SCI effects are considered, which may depend on the input motions, site characteristics, and building configurations.

Section: Shaking Table Test Validationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

A numerical coupling scheme for nonlinear time history analysis of buildings on a regional scale considering site‐city interaction effects

Tian

Wang

et al. 2018

Self Cite

“…As one special form of spectral presentation, the WPT was recently used to simulate nonstationary ground motions by Yamamoto and Baker [30]. The method has also been recently extended for simulating spatially correlated ground motions by Huang and Wang [31,32]. There are several salient features of the models: (i) Unlike the Gasparini-Vanmarcke model [19], these new stochastic models can effectively characterize both amplitude and frequency nonstationarity of ground motions.…”

Section: Stochastic Simulation Of Ground Motions Using Wavelet Packetsmentioning

confidence: 99%

“…According to Yamamoto and Baker [30], 13 wavelet packet parameters have been developed to fully characterize the statistical properties of the WPS, representing total energy, time-and frequency-domain distribution and correlation of the wavelet packet coefficients as summarized in Table I. One may consult Yamamoto and Baker [30], Huang and Wang [31,32] for detailed information on the definition of wavelet packet parameters. It should be noted that some of the wavelet packet parameters are closely related to ground motion IMs.…”

Section: Stochastic Simulation Of Ground Motions Using Wavelet Packetsmentioning

confidence: 99%

Energy‐compatible and spectrum‐compatible (ECSC) ground motion simulation using wavelet packets

Huang

Wang

2017

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Summary A stochastic ground‐motion simulation and modification technique is developed to generate energy‐compatible and spectrum‐compatible (ECSC) synthetic motions through wavelet packet characterization and modification in both frequency and time domains. The ECSC method significantly advances traditional spectral matching approaches, because it generates ground motions that not only match the target spectral accelerations, but also match Arias intensity build‐up and significant durations. The great similarity between the ECSC simulated motions and the actual recorded motions is demonstrated through one‐to‐one comparison of a variety of intensity measures. Extensive numerical simulations were also performed to validate the performance of the ECSC ground motions through nonlinear analyses of elasto‐plastic oscillators. The ECSC method can be easily implemented in the generalized conditional intensity measure framework by directly simulating a set of motions following a targeted distribution of multiple intensity measures. Therefore, the ECSC method has great potential to be used in performance‐based earthquake design and analysis. Copyright © 2017 John Wiley & Sons, Ltd.

“…Data-driven analysis of recorded historical earthquake ground motions [1][2][3][4][5][6] and complex physicsbased wave propagation theories [7] show that earthquake ground motion time histories are nonstationary in both amplitude and frequency content [8]. The time-varying intensity or nonstationarity in amplitude is typically characterized by the initial built-up phase, the high-intensity phase, and the gradually decaying tail.…”

Section: Introductionmentioning

confidence: 99%

Influence of time‐varying frequency content in earthquake ground motions on seismic response of linear elastic systems

Yong

Conte

Barbato

2016

SUMMARYEarthquake ground motion records are nonstationary in both amplitude and frequency content. However, the latter nonstationarity is typically neglected mainly for the sake of mathematical simplicity. To study the stochastic effects of the time-varying frequency content of earthquake ground motions on the seismic response of structural systems, a pair of closely related stochastic ground motion models is adopted here. The first model (referred to as ground motion model I) corresponds to a fully nonstationary stochastic earthquake ground motion model previously developed by the authors. The second model (referred to as ground motion model II) is nonstationary in amplitude only and is derived from the first model. Ground motion models I and II have the same mean-square function and global frequency content but different features of time variation in the frequency content, in that no time variation of the frequency content exists in ground motion model II. New explicit closed-form solutions are derived for the response of linear elastic SDOF and MDOF systems subjected to stochastic ground motion model II. New analytical solutions for the evolutionary crosscorrelation and cross-PSD functions between the ground motion input and the structural response are also derived for linear systems subjected to ground motion model I. Comparative analytical results are presented to quantify the effects of the time-varying frequency content of earthquake ground motions on the structural response of linear elastic systems. It is found that the time-varying frequency content in the seismic input can have significant effects on the stochastic properties of system response.