Towards a new base shear format in future NBCC seismic provisions

1994 ◽  
Vol 21 (4) ◽  
pp. 682-695 ◽  
Author(s):  
A. C. Heidebrecht ◽  
N. Naumoski ◽  
A. Rutenberg
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Velocity Ratio ◽  
Degree Of Freedom ◽  
Peak Ground Velocity ◽  
Base Shear ◽  
Ground Acceleration ◽  
Direct Evaluation ◽  
Design Spectra ◽  
Time Histories

Recent trends in the specifications of earthquake design forces are moving away from spectral amplification of ground motion towards direct evaluation of spectral values. Also, the 1988 Saguenay earthquake produced strong evidence for the need to modify the present provisions for low period structures in eastern North America. A new database consisting of 75 time histories was assembled and an extensive parametric study was undertaken to prepare new seismic response factors (S curves) for the National Building Code of Canada (NBCC). These time histories were divided into five categories (15 time histories each) on the basis of their frequency content as measured by their peak ground acceleration to peak ground velocity ratios, ranging from very high (≈3) to very low (≈0.5). Mean and mean + one standard deviation response spectra for one-degree-of-freedom and multi-degree-of-freedom systems were computed for the five categories using several normalizing (scaling) rules for the time histories. The results were compared and spectral amplification factors are presented. Spectra based on peak spectral velocity scaling were compared with spectra based on the present peak ground velocity scaling approach, and some differences are noted. Also, comparisons with the design spectra given in the 1991 edition of the National Earthquake Hazard Reduction Program provisions are presented. On the basis of this study, new S curves are proposed for consideration in the development of future editions of the NBCC. Key words: earthquake engineering, design spectra, building codes, amplification, ground motion, acceleration, velocity, ratio.

scholarly journals Seismic Hazard Assessment for the Tianshui Urban Area, Gansu Province, China

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Zhenming Wang ◽  
David T. Butler ◽  
Edward W. Woolery ◽  
Lanmin Wang
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Design ◽  
Hazard Analysis ◽  
Seismic Hazard Assessment ◽  
Gansu Province ◽  
Mitigation Measures ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Acceleration Time Histories

A scenario seismic hazard analysis was performed for the city of Tianshui. The scenario hazard analysis utilized the best available geologic and seismological information as well as composite source model (i.e., ground motion simulation) to derive ground motion hazards in terms of acceleration time histories, peak values (e.g., peak ground acceleration and peak ground velocity), and response spectra. This study confirms that Tianshui is facing significant seismic hazard, and certain mitigation measures, such as better seismic design for buildings and other structures, should be developed and implemented. This study shows that PGA of 0.3 g (equivalent to Chinese intensity VIII) should be considered for seismic design of general building and PGA of 0.4 g (equivalent to Chinese intensity IX) for seismic design of critical facility in Tianshui.

scholarly journals An approach to quantify the influence of ground motion uncertainty on elastoplastic system acceleration in incremental dynamic analysis

2017 ◽  
Vol 20 (11) ◽  
pp. 1744-1756 ◽  
Author(s):  
Peng Deng ◽  
Shiling Pei ◽  
John W. van de Lindt ◽  
Hongyan Liu ◽  
Chao Zhang
Keyword(s):  
Dynamic Analysis ◽  
Ground Motion ◽  
Earthquake Engineering ◽  
Structural Response ◽  
Incremental Dynamic Analysis ◽  
Degree Of Freedom ◽  
Maximum Acceleration ◽  
Single Degree Of Freedom ◽  
Single Degree ◽  
Performance Based Earthquake Engineering

Inclusion of ground motion–induced uncertainty in structural response evaluation is an essential component for performance-based earthquake engineering. In current practice, ground motion uncertainty is often represented in performance-based earthquake engineering analysis empirically through the use of one or more ground motion suites. How to quantitatively characterize ground motion–induced structural response uncertainty propagation at different seismic hazard levels has not been thoroughly studied to date. In this study, a procedure to quantify the influence of ground motion uncertainty on elastoplastic single-degree-of-freedom acceleration responses in an incremental dynamic analysis is proposed. By modeling the shape of the incremental dynamic analysis curves, the formula to calculate uncertainty in maximum acceleration responses of linear systems and elastoplastic single-degree-of-freedom systems is constructed. This closed-form calculation provided a quantitative way to establish statistical equivalency for different ground motion suites with regard to acceleration response in these simple systems. This equivalence was validated through a numerical experiment, in which an equivalent ground motion suite for an existing ground motion suite was constructed and shown to yield statistically similar acceleration responses to that of the existing ground motion suite at all intensity levels.

NGA-Subduction research program

2021 ◽  
pp. 875529302110560
Author(s):  
Yousef Bozorgnia ◽  
Norman A Abrahamson ◽  
Sean K Ahdi ◽  
Timothy D Ancheta ◽  
Linda Al Atik ◽  
...  
Keyword(s):  
Ground Motion ◽  
Research Program ◽  
Epistemic Uncertainty ◽  
Specific Model ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Motion Data ◽  
Motion Models ◽  
Aleatory Variability ◽  
Adjustment Factors

This article summarizes the Next Generation Attenuation (NGA) Subduction (NGA-Sub) project, a major research program to develop a database and ground motion models (GMMs) for subduction regions. A comprehensive database of subduction earthquakes recorded worldwide was developed. The database includes a total of 214,020 individual records from 1,880 subduction events, which is by far the largest database of all the NGA programs. As part of the NGA-Sub program, four GMMs were developed. Three of them are global subduction GMMs with adjustment factors for up to seven worldwide regions: Alaska, Cascadia, Central America and Mexico, Japan, New Zealand, South America, and Taiwan. The fourth GMM is a new Japan-specific model. The GMMs provide median predictions, and the associated aleatory variability, of RotD50 horizontal components of peak ground acceleration, peak ground velocity, and 5%-damped pseudo-spectral acceleration (PSA) at oscillator periods ranging from 0.01 to 10 s. Three GMMs also quantified “within-model” epistemic uncertainty of the median prediction, which is important in regions with sparse ground motion data, such as Cascadia. In addition, a damping scaling model was developed to scale the predicted 5%-damped PSA of horizontal components to other damping ratios ranging from 0.5% to 30%. The NGA-Sub flatfile, which was used for the development of the NGA-Sub GMMs, and the NGA-Sub GMMs coded on various software platforms, have been posted for public use.

Ground Motion Estimation Using Front Site Wave Form Data Based on RVM for Earthquake Early Warning

2015 ◽  
Vol 10 (4) ◽  
pp. 667-677
Author(s):  
Yincheng Yang ◽  
◽  
Masato Motosaka ◽  
Keyword(s):  
Ground Motion ◽  
Early Warning ◽  
Warning System ◽  
Earthquake Early Warning ◽  
Peak Ground Velocity ◽  
Wave Form ◽  
Source Information ◽  
Ground Acceleration ◽  
P Waves ◽  
Earthquake Early Warning System

The use of the earthquake early warning system (EEWS), one of the most useful emergency response tools, requires that the accuracy of real-time ground motion prediction (GMP) be enhanced. This requires that waveform information at observation points along earthquake wave propagation paths (hereafter, front-site waveform information) be used effectively. To enhance the combined reliability of different systems, such as on-site and local/regional warning, we present a GMP method using front-site waveform information by applying a relevant vector machine (RVM). We present methodology and application examples for a case study estimating peak ground acceleration (PGA) and peak ground velocity (PGV) for earthquakes in the Miyagi-Ken Oki subduction zone. With no knowledge of source information, front site waveforms have been used to predict ground motion at target sites. Five input variables – earthquake PGA, PGD, pulse rise time, average period and theVpmax/Amaxratio – have been used for the first 4 to 6 seconds of P-waves in training a regression model. We found that RVM is a useful tool for the prediction of peak ground motion.

Empirical Correlations between Generalized Ground-Motion Intensity Measures for Earthquakes in China

2020 ◽  
Author(s):  
Kun Ji ◽  
Yefei Ren ◽  
Ruizhi Wen
Keyword(s):  
Ground Motion ◽  
Correlation Coefficients ◽  
Parametric Models ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Vibration Period ◽  
Significant Duration ◽  
Cumulative Absolute Velocity ◽  
Spectrum Intensity

ABSTRACT This study used earthquake records from China to investigate comprehensively the correlation coefficients between various intensity measures (IMs), including peak ground acceleration, peak ground velocity, spectral acceleration, spectrum intensity, acceleration spectrum intensity, Arias intensity, cumulative absolute velocity, and significant duration. After collection of metadata information, 681 three-component ground-motion recordings with magnitudes of Mw 4.9–6.9 were carefully processed and extracted from the China National Strong-Motion Observation Network System dataset (2007–2015). The applicability of both the Next Generation Attenuation (NGA)-West2 ground-motion model (GMM) and of other GMMs was verified for different IMs, regarding the China dataset. Then, empirical correlation coefficients between different IMs were computed, considering the uncertainty due to the different sample sizes of the observational data using the bootstrap sampling method and Fisher z transformation. Finally, the median values of the correlation coefficients were fitted as a continuous function of the vibration period in the range of 0.01–10.0 s and compared with the results of similar studies developed for shallow crustal regions worldwide. The developed region-specific correlation coefficient prediction model yielded tendencies approximately like those reported in other studies. However, obvious differences were found in long-period ranges of amplitude-based IMs, cumulative effect IMs, and significant duration. These results suggest the necessity of using region-specific correlation coefficients for generalized IMs in China. The presented results and parametric models could be easily implemented in a generalized IM ground-motion selection method or a vector-based probability seismic hazard analysis procedure for China.

3D Nonlinear Ground‐Motion Simulation Using a Physics‐Based Method for the Kinburn Basin

2019 ◽  
Author(s):  
Amin Esmaeilzadeh ◽  
Dariush Motazedian ◽  
Jim Hunter
Keyword(s):  
Shear Wave ◽  
Ground Motion ◽  
Seismic Waves ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Low Frequencies ◽  
Wave Velocities ◽  
Shear Wave Velocities ◽  
Nonlinear Viscoelastic ◽  
Finite Fault

Abstract We used a finite‐difference modeling method, developed by Olsen–Day–Cui, to simulate nonlinear‐viscoelastic basin effects in a spectral frequency range of 0.1–1 Hz in the Kinburn bedrock topographic basin, Ottawa, Canada, for large earthquakes. The geotechnical and geological features of the study area are unique: loose, postglacial sediments with very low shear‐wave velocities (<200  m/s) overlying very firm bedrock with high shear‐wave velocities (>2000  m/s). Comparing records and simulated velocity time series showed regular viscoelastic simulations could model the ground motions at the rock and soil sites in the Kinburn basin for the Ladysmith earthquake, a local earthquake occurred on 17 May 2013 with Mw 4.7 (MN 5.2). The Ladysmith earthquake was scaled to provide a strong level of shaking for investigating the nonlinear behavior of soil; therefore, a new nonlinear‐viscoelastic subroutine was introduced to the program. A modeled stress–strain relationship associated with ground‐motion modeling in the Kinburn basin using a scaled Ladysmith earthquake event of Mw 7.5 followed Masing’s rules. Using nonlinear‐viscoelastic ground‐motion simulations significantly reduced the amplitude of the horizontal component of the Fourier spectrum at low frequencies and the predicted peak ground acceleration and peak ground velocity values compared with regular linear viscoelastic simulations; hence, the lower soil amplification of seismic waves and the frequency and amplitude spectral content were altered by the nonlinear soil behavior. In addition, using a finite‐fault model to simulate an earthquake with Mw 7.5 was necessary to predict the higher levels of stresses and strains, which were generated in the basin. Using a finite‐fault source for the nonlinear‐viscoelastic simulation caused decreases in the horizontal components because of the shear modulus reduction and increase of damping.

Chile Strong Ground Motion Flatfile

2016 ◽  
Vol 32 (4) ◽  
pp. 2549-2566 ◽  
Author(s):  
Nicolas Bastías ◽  
Gonzalo A. Montalva
Keyword(s):  
Ground Motion ◽  
Plate Boundary ◽  
Peak Ground Velocity ◽  
South American ◽  
Ground Acceleration ◽  
Data Set ◽  
Intensity Measures ◽  
South American Plate ◽  
Rupture Plane ◽  
Illapel Earthquake

The Nazca-South American plate boundary produces large-magnitude events (Mw > 8) every 20 years on the coast of Chile. This work describes a public ground motion database that contains 3,572 records from 477 earthquakes and 181 seismic stations, which includes the recent 2015 Mw 8.3 Illapel earthquake. The data set is controlled by subduction interface and inslab events. The oldest event included is Valparaiso (1985), and the magnitude span is 4.6–8.8 Mw. The source-to-site distance metrics reported are the closest distance to the rupture plane ( R rup), epicentral ( R epi) and hypocentral ( R hyp) distances, with a range for R rup from 20 to 650 km. Site characterization is based on V S30, ranging from 110 to 1,951 m/s. Intensity measures included are peak ground acceleration, spectral acceleration values from 0.01 to 10 s, Arias intensity, and peak ground velocity. Each record was uniformly processed component by component. A flatfile with the related metadata and the spectral accelerations from processed ground motions is available at NEEShub ( http://doi.org/10.17603/DS2N30J ; Bastías and Montalva 2015 ).

scholarly journals New Ground Motion to Intensity Conversion Equations for China

2021 ◽  
Vol 2021 ◽  
pp. 1-21
Author(s):  
Xiufeng Tian ◽  
Zengping Wen ◽  
Weidong Zhang ◽  
Jie Yuan
Keyword(s):  
Ground Motion ◽  
Correction Term ◽  
Strong Motion ◽  
Seismic Intensity ◽  
Peak Ground Velocity ◽  
Ground Acceleration ◽  
Strong Earthquakes ◽  
Hypocentral Distance ◽  
Peak Ground Motion ◽  
Pseudo Spectral

In this study, we use the strong motion records and seismic intensity data from 11 moderate-to-strong earthquakes in the mainland of China since 2008 to develop new conversion equations between seismic intensity and peak ground motion parameters. Based on the analysis of the distribution of the dataset, the reversible conversion relationships between modified Mercalli intensity (MMI) and peak ground acceleration (PGA), peak ground velocity (PGV), and pseudo-spectral acceleration (PSA) at natural vibration periods of 0.3 s, 1.0 s, 2.0 s, and 3.0 s are obtained by using the orthogonal regression. The influence of moment magnitude, hypocentral distance, and hypocentral depth on the residuals of conversion equations is also explored. To account for and eliminate the trends in the residuals, we introduce a magnitude-distance-depth correction term and obtain the improved relationships. Furthermore, we compare the results of this study with previously published works and analyze the regional dependence of conversion equations. To quantify the regional variations, a regional correction factor for China, suitable for adjustment of global relationships, has also been estimated.

A Ground-Motion Prediction Model for Shallow Crustal Earthquakes in Greece

2020 ◽  
Author(s):  
David M. Boore ◽  
Jonathan P. Stewart ◽  
Andreas A. Skarlatoudis ◽  
Emel Seyhan ◽  
Basil Margaris ◽  
...  
Keyword(s):  
Prediction Model ◽  
Ground Motion ◽  
Site Response ◽  
Epistemic Uncertainty ◽  
Peak Ground Velocity ◽  
Motion Prediction ◽  
Ground Motion Prediction ◽  
Ground Acceleration ◽  
Magnitude Scaling ◽  
Nonlinear Site Response

ABSTRACT Using a recently completed database of uniformly processed strong-motion data recorded in Greece, we derive a ground-motion prediction model (GMPM) for horizontal-component peak ground velocity, peak ground acceleration, and 5% damped pseudoacceleration response spectra, at 105 periods ranging from 0.01 to 10 s. The equations were developed by modifying a global GMPM, to account for more rapid attenuation and weaker magnitude scaling in the Greek ground motions than in the global GMPM. Our GMPM is calibrated using the Greek data for distances up to 300 km, magnitudes from 4.0 to 7.0, and time-averaged 30 m shear-wave velocities from 150 to 1200  m/s. The GMPM has important attributes for hazard applications including magnitude scaling that extends the range of applicability to M 8.0 and nonlinear site response. These features are possible because they are well constrained by data in the global GMPM from which our model is derived. An interesting feature of the Greek data, also observed previously in studies of mid-magnitude events (6.1–6.5) in Italy, is that they are substantially overpredicted by the global GMPM, which may be a repeatable regional feature, but may also be influenced by soil–structure interaction. This bias is an important source of epistemic uncertainty that should be considered in hazard analysis.

scholarly journals Empirical Correlations between Peak Ground Velocity and Spectrum-Based Intensity Measures

2012 ◽  
Vol 28 (1) ◽  
pp. 17-35 ◽  
Author(s):  
Brendon A. Bradley
Keyword(s):  
Ground Motion ◽  
Peak Ground Velocity ◽  
Strongly Correlated ◽  
Correlation Equations ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Ground Motion Selection ◽  
Crustal Earthquakes ◽  
Short Period ◽  
Spectrum Intensity

Empirical correlation equations between peak ground velocity ( PGV) and several spectrum-based ground motion intensity measures are developed. The intensity measures examined in particular were: peak ground acceleration ( PGA), 5% damped pseudo-spectral acceleration ( SA), acceleration spectrum intensity ( ASI), and spectrum intensity ( SI). The computed correlations were obtained using ground motions from active shallow crustal earthquakes and four ground motion prediction equations. Results indicate that PGV is strongly correlated (i.e., a correlation coefficient of [Formula: see text]) with SI, moderately correlated with medium to long-period SA (i.e., [Formula: see text] for vibration periods 0.5-3.0 seconds), and also moderately correlated with short period SA, PGA and ASI ([Formula: see text]). A simple example is used to illustrate one possible application of the developed correlation equations for ground motion selection.

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