Synthesis of Strong Ground Motions at Two Rock Stations during the Great Wenchuan Earthquake from a Hybrid Source Model

2013 ◽  
Vol 353-356 ◽  
pp. 1923-1929 ◽  
Author(s):  
Xia Xin Tao ◽  
Hai Ming Liu ◽  
Li Yuan Wang ◽  
Jiang Wei
Keyword(s):  
Wenchuan Earthquake ◽  
Response Spectrum ◽  
Ground Motions ◽  
Response Spectra ◽  
Source Model ◽  
Finite Fault ◽  
Time Histories ◽  
Source Models ◽  
Truncated Normal ◽  
Global And Local

In order to study the characteristics of ground motions at the two dam sites damaged during the great Wenchuan earthquake in 2008, the motions at two observation stations nearby are synthesized in this paper. 30 finite fault based hybrid source models of the great Wenchuan earthquake with magnitude 8.0 is built. The global and local parameters are both generated from the truncated Normal distribution with mean and standard deviation values estimated by a set of semi-experiential calibration laws and from the regional seismo-tectonics, structure of the crust, and seismicity. A representative source model is then chosen from the corresponding response spectrum mostly close to the average one. The result motions are presented, and the characteristics of the time histories, response spectra and the peak accelerations are quite close to the recordings.

Uniform Hazard Ground Motions for Mid-America Cities

2001 ◽  
Vol 17 (2) ◽  
pp. 359-384 ◽  
Author(s):  
Y. K. Wen ◽  
C. L. Wu
Keyword(s):  
Performance Evaluation ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Source Model ◽  
Motion Models ◽  
Finite Fault ◽  
Hazard Response ◽  
Linear And Nonlinear ◽  
Finite Fault Model

For performance evaluation of buildings and structures, synthetic uniform hazard (10% and 2% in 50 years) ground motions are generated for Memphis, Tennessee, St. Louis, Missouri, and Carbondale, Illinois. The method of simulation is based on the latest regional seismic information and stochastic ground motion models. Both point-source model and finite-fault model are used and the effects of soil profile are considered. The emphasis is on treatment of uncertainty and efficiency in application to evaluation of structural performance in both the linear and nonlinear range. The results show that the uniform hazard response spectra calculated from the simulated motions are comparable to those corresponding to USGS hazard maps. The suites of ten ground motions selected to match the uniform hazard response spectra represent events of different magnitudes, distances, and attenuation. The median value of the structural response to the selected ground motions matches closely the uniform hazard linear and nonlinear response spectra based on nine thousand ground motions and has a coefficient of variation of less than 10%. The suites of uniform hazard ground motions therefore can be used in probabilistic performance evaluation with good accuracy and efficiency.

Synthesis of Strong Ground Motions at Two Dam Sites during the Great Wenchuan Earthquake

2013 ◽  
Vol 353-356 ◽  
pp. 1934-1940
Author(s):  
Hai Ming Liu ◽  
Xia Xin Tao ◽  
Li Yuan Wang ◽  
Wei Jiang
Keyword(s):  
Wenchuan Earthquake ◽  
Peak Ground Acceleration ◽  
Ground Motions ◽  
Source Spectrum ◽  
Ground Acceleration ◽  
Mean Values ◽  
Strong Ground Motions ◽  
Finite Fault ◽  
Source Models ◽  
Strong Ground

The ground motions on two dam sites during the great Wenchuan earthquake with magnitude 8.0, motions are synthesized from 30 finite fault based hybrid source models and inversed regional parameters of source spectrum and motion attenuation. The results show that the peak ground acceleration values are less than those estimated directly from the Intensities Ⅹ and Ⅺ at the two sites, with mean values 259 and 716 gals. The motion at Shapai is much stronger than that at Zipingpu, and the spectrum is also wider than the latter, but the corresponding duration is shorter during the earthquake.

The Influence of Stress Drop on Synthesized Ground Motion

2013 ◽  
Vol 477-478 ◽  
pp. 1064-1068
Author(s):  
Xia Xin Tao ◽  
Hai Ming Liu
Keyword(s):  
Wenchuan Earthquake ◽  
Ground Motion ◽  
Stress Drop ◽  
Response Spectra ◽  
Source Model ◽  
Acceleration Time ◽  
The Wenchuan Earthquake ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
The Way

The stress drop during a earthquake is deal with by many papers, but has not been estimated very well yet at present. In order to study its influence on synthesized motion, the motions at two rock sites where records were obtained during the Wenchuan earthquake are synthesized by a hybrid source model from two stress drop values, 30 bar and 85 bars respectively. The result shows that the acceleration time histories, response spectra and mean peak values of motions from 85 bar are comparable to the records, but those of motions from 30 bar are much smaller than the records. It means that the way to inverse the regional parameters simultaneously from regional small quake records is acceptable.

A Stochastic Semi-Physical Model of Seismic Ground Motions in Time Domain

2018 ◽  
Vol 12 (03) ◽  
pp. 1850006 ◽  
Author(s):  
Yanqiong Ding ◽  
Yongbo Peng ◽  
Jie Li
Keyword(s):  
Probability Density ◽  
Ground Motions ◽  
Seismic Source ◽  
Response Spectra ◽  
Propagation Path ◽  
Superposition Method ◽  
Probability Density Evolution Method ◽  
Proposed Model ◽  
Time Histories ◽  
Seismic Accelerations

A stochastic function model of seismic ground motions is presented in this paper. It is derived from the consideration of physical mechanisms of seismic ground motions. The model includes the randomness inherent in the seismic source, propagation path and local site. For logical selection of the seismic acceleration records, a cluster analysis method is employed. Statistical distributions of the random parameters associated with the proposed model are identified using the selected data. Superposition method of narrow-band wave groups is then adopted to simulate non-stationary seismic ground motions. In order to verify the feasibility of the proposed model, comparative studies of time histories and response spectra of the simulated seismic accelerations against those of the recorded seismic accelerations are carried out. Their probability density functions, moreover, are readily investigated by virtue of the probability density evolution method.

An Improved Stochastic Finite-Fault Method Based on Energy

2015 ◽  
Vol 744-746 ◽  
pp. 878-883
Author(s):  
Ju Fang Zhong ◽  
Jun Wei Liang ◽  
Zhi Peng Fan ◽  
Luo Long Zhan
Keyword(s):  
Ground Motion ◽  
Amplification Factor ◽  
Response Spectrum ◽  
Near Field ◽  
Energy Accumulation ◽  
Accumulation Curve ◽  
Finite Fault ◽  
Acceleration Time Histories ◽  
Time Histories ◽  
Finite Fault Method

Owing to the simulated ground motion energy distribution by stochastic finite-fault method is not reasonable, near-field bedrock strong ground motion acceleration time histories are used to study. Fourier transform is adapted to analysis the variation of the energy accumulation curve with frequency. The results show that the record energy accumulation curve is a steep rise curve, 80% of total energy of the vertical ground motion is concentrated on the 2.5-15Hz, while the horizontal is mainly concentrated on the 2-11Hz. An improved stochastic finite-fault method is proposed by multiplying an amplification factor in some frequency. The results show that multiplying an amplification factor, the simulated acceleration energy accumulation curve matches to the record acceleration energy accumulation curve, and the peak of simulated acceleration response spectrum tends to the record acceleration value.

Finite Fault Modelling for the Wenchuan Earthquake Using Hybrid Slip Model with Truncated Normal Distributed Source Parameters

2012 ◽  
Vol 256-259 ◽  
pp. 2161-2167 ◽  
Author(s):  
Xiao Dan Sun ◽  
Xia Xin Tao ◽  
Cheng Qing Liu
Keyword(s):  
Wenchuan Earthquake ◽  
Ground Motion ◽  
Source Parameters ◽  
Field Investigation ◽  
Local Source ◽  
Slip Model ◽  
Fault Models ◽  
Average Spectrum ◽  
Finite Fault ◽  
Truncated Normal

An hybrid slip model combining asperity model and k square model was outlined. In the model, both the global and local source parameters follow a trancated normal distribution. The hybrid slip model was then applied to generate finite fault models for the great Wenchuan earthquake, where the fault plane was assumed to have two segments, a reverse segment on the southwestern of the fault and a right-lateral strike-slip segment on the northeastern of the fault. The location of the asperities on each segment was determined considering the results from inversion and field investigation. 30 different finite fault models were obtained, and the one which generates the ground motion best fitting the average spectrum was picked out using spectral deviation evaluation. Finally, ground motion at six near field stations were simualted based on the best-fit fault model and compared to the records.

Use of RVT for Computation of In-Structure Response Spectra and Peak Responses and Comparison to Time History and Response Spectrum Analysis

2018 ◽  
Vol 34 (4) ◽  
pp. 1913-1930 ◽  
Author(s):  
Irmela Zentner
Keyword(s):  
Response Spectrum ◽  
Structural Response ◽  
Time History ◽  
Strong Motion ◽  
Response Spectra ◽  
Combination Rules ◽  
Floor Response Spectra ◽  
Power Spectral ◽  
Time Histories ◽  
Definition Of

The random vibration theory offers a framework for the conversion of response spectra into power spectral densities (PSDs) and vice versa. The PSD is a mathematically more suitable quantity for structural dynamics analysis and can be straightforwardly used to compute structural response in the frequency domain. This allows for the computation of in-structure floor response spectra and peak responses by conducting only one structural analysis. In particular, there is no need to select or generate spectrum-compatible time histories to conduct the analysis. Peak response quantities and confidence intervals can be computed without any further simplifications such as currently used in the response spectrum method, where modal combination rules have to be derived. In contrast to many former studies, the Arias intensity-based definition of strong-motion duration is adopted here. This paper shows that, if the same definitions of strong-motion duration and modeling assumptions are used for time history and RVT computations, then the same result can be expected. This is illustrated by application to a simplified model of a reactor building.

scholarly journals Unique Method for Generating Design Earthquake Time Histories

2008 ◽  
Author(s):  
R. E. Spears
Keyword(s):  
Response Spectrum ◽  
Low Frequency ◽  
Time History ◽  
Response Spectra ◽  
Cumulative Energy ◽  
Time Histories ◽  
Displacement Response Spectra ◽  
Unique Method ◽  
Design Earthquake ◽  
Velocity Response Spectrum

A method has been developed which takes a seed earthquake time history and modifies it to produce given design response spectra. It is a multi-step process with an initial scaling step and then multiple refinement steps. It is unique in the fact that both the acceleration and displacement response spectra are considered when performing the fit (which primarily improves the low frequency acceleration response spectrum accuracy). Additionally, no matrix inversion is needed. The features include encouraging the code acceleration, velocity, and displacement ratios and attempting to fit the pseudo velocity response spectrum. Also, “smoothing” is done to transition the modified time history to the seed time history at its start and end. This is done in the time history regions below a cumulative energy of 5% and above a cumulative energy of 95%. Finally, the modified acceleration, velocity, and displacement time histories are adjusted to start and end with an amplitude of zero (using Fourier transform techniques for integration).

Smooth Acceleration Spectra for Pulse-Like Ground Motions

2020 ◽  
Vol 110 (6) ◽  
pp. 2755-2765
Author(s):  
Cuihua Li ◽  
Guofeng Xue ◽  
Zhanxuan Zuo
Keyword(s):  
Seismic Design ◽  
Amplification Factor ◽  
Response Spectrum ◽  
Ground Motions ◽  
Response Spectra ◽  
Acceleration Response ◽  
Constant Acceleration ◽  
Step Procedure ◽  
Acceleration Response Spectrum ◽  
Smooth Acceleration

ABSTRACT Idealization of acceleration response spectra is the basis for construction of target spectra for seismic design and assessment of structures. The adequacy of current methods to reasonably idealize (or smooth) the acceleration spectra of pulse-like and nonpulse-like ground motions is examined in this study. The influence of separated pulses on different regions of acceleration response spectrum is first investigated using wavelet transform. One representative method is selected as the benchmark to examine the effectiveness of the Newmark–Hall-based methods to smooth the acceleration spectra of pulse-like and nonpulse-like ground motions. Presented are some important insights into why the plateau (or amplification factor) associated with the constant-acceleration branch may be underestimated and the ending cutoff period Tg be overestimated by Newmark–Hall-based methods. This study highlights the intrinsic characteristics and the importance of the constant-acceleration branch, based on which a two-step procedure is proposed to idealize the acceleration spectra. The results show that the proposed methodology can accurately identify the constant-acceleration branch regardless of the influence of pulses on the descending branch of acceleration spectra.

Drift Spectrum vs. Modal Analysis of Structural Response to Near-Fault Ground Motions

2001 ◽  
Vol 17 (2) ◽  
pp. 221-234 ◽  
Author(s):  
Anil K. Chopra ◽  
Chatpan Chintanapakdee
Keyword(s):  
Earthquake Engineering ◽  
Response Spectrum ◽  
Ground Motions ◽  
Structural Response ◽  
Response Spectra ◽  
Engineering Practice ◽  
Drift Spectrum ◽  
Combination Rules ◽  
Near Fault ◽  
Far Fault

A new measure of earthquake demand, the drift spectrum has been developed as an adjunct to the response spectrum, a central concept in earthquake engineering, in calculating the internal deformations of a structure due to near-fault ground motions with pronounced coherent pulses in the velocity and displacement histories. Compared in this paper are certain aspects of the elastic structural response to near-fault and far-fault ground motions. It is demonstrated that (1) the difference between drift and response spectra are not unique to near-fault ground motions; these differences simply reflect higher-mode response, which is larger due to near-fault ground motions; (2) response spectrum analysis (RSA) using existing modal combination rules can provide an estimate of structural response that is accurate to a useful degree; (3) these modal combination rules are similarly accurate for near-fault and far-fault ground motions although the underlying assumptions are not satisfied by near-fault excitations; and (4) RSA is preferable over the drift spectrum in computing structural response because it represents standard engineering practice and is applicable to a wide variety of structures.

Sign in / Sign up

Export Citation Format

Share Document