On Ground Motion Intensity Indices

2007 ◽  
Vol 23 (1) ◽  
pp. 147-173 ◽  
Author(s):  
Rafael Riddell
Keyword(s):  
Ground Motion ◽  
Seismic Analysis ◽  
Structural Response ◽  
Frequency Range ◽  
Ground Acceleration ◽  
Essential Point ◽  
Sensitive Region ◽  
Peak Ground Motion ◽  
Degradation Models

The characterization of strength of earthquake demands for seismic analysis or design requires the specification of a level of intensity. Numerous ground motion intensity indices that have been proposed over the years are being used for normalizing or scaling earthquake records regardless of their efficiency. An essential point of this study is that a ground motion index is appropriate, or efficient, as long as it can predict the level of structural response. This study presents correlations between 23 ground motion intensity indices and four response variables: elastic and inelastic deformation demands, and input energy and hysteretic energy; nonlinear responses are computed using elastoplastic, bilinear, and bilinear with stiffness degradation models. As expected, no index is found to be satisfactory over the entire frequency range. Indeed, indices related to ground acceleration rank better in the acceleration-sensitive region of the spectrum; indices based on ground velocity are better in the velocity-sensitive region and, correspondingly, generally occur in the displacement-controlled region. Despite frequent criticism, the peak ground motion parameters passed the test successfully. A ranking of indices is presented, thus providing a choice of the most appropriate one for a particular application in the frequency range of interest.

Ground Motion Intensity Measures for Rocking Building Systems

2017 ◽  
Vol 33 (4) ◽  
pp. 1533-1554 ◽  
Author(s):  
Mehrdad Shokrabadi ◽  
Henry V. Burton
Keyword(s):  
Ground Motion ◽  
Structural Response ◽  
Ground Acceleration ◽  
Intensity Measures ◽  
Braced Frame ◽  
Residual Drift ◽  
Engineering Demand Parameter ◽  
Frame System ◽  
Ground Motion Records ◽  
Steel Braced Frame

This paper investigates the effectiveness of various ground motion intensity measures (IMs) in estimating the structural response of two types of rocking systems: (a) a controlled rocking steel braced frame system with self-centering action and (b) a rocking spine system for reinforced concrete infill frames. The IMs are evaluated based on the dispersion in engineering demand parameter (EDP) predictions (efficiency) and the sensitivity of the conditional distributions of EDPs to the distributions of the magnitudes, distances and spectral shape parameter (ε) of ground motion records (sufficiency). The EDPs include maximum transient and residual story drifts and peak floor accelerations. The spectral acceleration averaged over a range of periods (Sa avg) is most effective for predicting transient and residual drift demands and peak ground acceleration (PGA) is generally the best predictor of peak floor accelerations. The proximity of the frequency range most affecting an EDP to that best reflected in an IM is found to be a good indicator of the performance of that IM.

Seismic Hazard Analysis for an NPP Site

2004 ◽  
Author(s):  
A. K. Ghosh ◽  
H. S. Kushwaha
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Hazard Analysis ◽  
Structural Response ◽  
Response Spectra ◽  
Seismic Fragility ◽  
Material Strength ◽  
Ground Acceleration ◽  
Hazard Response

The various uncertainties and randomness associated with the occurrence of earthquakes and the consequences of their effects on the NPP components and structures call for a probabilistic seismic risk assessment (PSRA). However, traditionally, the seismic design basis ground motion has been specified by normalised response spectral shapes and peak ground acceleration (PGA). The mean recurrence interval (MRI) used to be computed for PGA only. The present work develops uniform hazard response spectra i.e. spectra having the same MRI at all frequencies for Kakrapar Atomic Power Station site. Sensitivity of the results to the changes in various parameters has also been presented. These results determine the seismic hazard at the given site and the associated uncertainties. The paper also presents some results of the seismic fragility for an existing containment structure. The various parameters that could affect the seismic structural response include material strength of concrete, structural damping available within the structure and the normalized ground motion response spectral shape. Based on this limited case study the seismic fragility of the structure is developed. The results are presented as families of conditional probability curves plotted against the peak ground acceleration (PGA). The procedure adopted incorporates the various randomness and uncertainty associated with the parameters under consideration.

scholarly journals Engineering characterization of ground motion. Task I. Effects of characteristics of free-field motion on structural response

1984 ◽  
Author(s):  
R.P. Kennedy ◽  
S.A. Short ◽  
K.L. Merz ◽  
F.J. Tokarz ◽  
I.M. Idriss ◽  
...  
Keyword(s):  
Ground Motion ◽  
Free Field ◽  
Structural Response

A Replacement for the 30%, 40%, and SRSS Rules for Multicomponent Seismic Analysis

1998 ◽  
Vol 14 (1) ◽  
pp. 153-163 ◽  
Author(s):  
Charles Menun ◽  
Armen Der Kiureghian
Keyword(s):  
Ground Motion ◽  
Simple Formula ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Structural Response ◽  
General Rule ◽  
Design Codes ◽  
Maximum Value ◽  
Special Cases ◽  
Orthogonal Components

A response spectrum rule for combining the contributions from three orthogonal components of ground motion to the maximum value of a response quantity is presented. This rule, denoted CQC3, is compared to the 30% and 40% rules and the square-root-of-sum-of-squares (SRSS) rule currently specified in many design codes. It is shown that these current rules are special cases of the CQC3 rule, when certain conditions regarding the nature of the ground motion or the structural response are satisfied. Because these conditions are not always satisfied, it is argued that the CQC3 rule should be adopted as a general rule for the multicomponent combination problem. The CQC3 rule additionally offers a simple formula for determining the most critical orientation of the ground motion components for each response quantity of interest. The CQC3 rule is computationally simple and easy to implement in standard dynamic analysis codes.

scholarly journals Probabilistic Seismic Hazard Assessment for Amaravathi Region, Andhra Pradesh

2019 ◽  
Vol 8 (6S4) ◽  
pp. 279-283
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Seismic Analysis ◽  
Response Spectrum ◽  
Seismic Hazard Assessment ◽  
Prediction Equation ◽  
Probabilistic Seismic Hazard Assessment ◽  
Ground Acceleration ◽  
Uniform Hazard Response Spectrum ◽  
Seismic Hazard Map

This article explains an analytical attempt that estimates seismic hazard for Amaravathi city. The present study has been carried out contemplating the available faults and epicentral data within a radius of 300km of the Amaravathi region. The homogenous earthquake catalogue has been prepared for Amaravathi region by Steep’s method. The seismic hazard parameters ―a‖ and ―b‖ for Amaravathi city were evaluated by Gutenberg-Ritcher method. The ―a‖ and ―b‖ values obtained as 4.69, 0.6468 respectively. The total 353 epicenters and 31 faults were considered in this seismic analysis for the estimate of PSHA for Amaravathi. The ground motion produced by the faults at this site has been estimated by using the regionspecific Ground Motion Prediction Equation (GMPE) developed by the raghukanth and lyenger (2007). The probability of occurrence of different magnitude classes was estimated. The hazard curves and mean annual rate of exceedance for Peak Ground Acceleration were calculated by using ground motion estimated in this area. The Uniform Hazard Response Spectrum (UHRS) for the ranging time periods between 0.1 – 4 seconds was prepared. PGA values for Amaravati region was found to be in between 0.001g to 0.3g from seismic hazard map that was prepared in this study

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.

scholarly journals Time-Frequency Energy Distribution of Ground Motion and Its Effect on the Dynamic Response of Nonlinear Structures

2019 ◽  
Vol 11 (3) ◽  
pp. 702 ◽  
Author(s):  
Dongwang Tao ◽  
Jiali Lin ◽  
Zheng Lu
Keyword(s):  
Dynamic Response ◽  
Energy Distribution ◽  
Ground Motion ◽  
Peak Ground Acceleration ◽  
Structural Response ◽  
Ground Acceleration ◽  
Time Frequency ◽  
Plastic Structure ◽  
Perfectly Plastic ◽  
Frequency Components

The ground motion characteristics are essential for understanding the structural seismic response. In this paper, the time-frequency analytical method is used to analyze the time-frequency energy distribution of ground motion, and its effect on the dynamic response of nonlinear structure is studied and discussed. The time-frequency energy distribution of ground motion is obtained by the matching pursuit decomposition algorithm, which not only effectively reflects the energy distribution of different frequency components in time, but also reflects the main frequency components existing near the peak ground acceleration occurrence time. A series of artificial ground motions with the same peak ground acceleration, Fourier amplitude spectrum, and duration are generated and chosen as the earthquake input of the structural response. By analyzing the response of the elasto-perfectly-plastic structure excited by artificial seismic waves, it can be found that the time-frequency energy distribution has a great influence on the structural ductility. Especially if there are even multiple frequency components in the same ground motion phrase, the plastic deformation of the elasto-perfectly-plastic structure will continuously accumulate in a certain direction, resulting in a large nonlinear displacement. This paper reveals that the time-frequency energy distribution of a strong ground motion has a vital influence on the structural response.

Seismic Fragility Analysis of a Water Storage Structure

2004 ◽  
Author(s):  
K. Bhargava ◽  
A. K. Ghosh ◽  
S. Ramanujam
Keyword(s):  
Seismic Analysis ◽  
Water Storage ◽  
Structural Response ◽  
Seismic Fragility ◽  
Material Strength ◽  
Structural Damping ◽  
Ground Acceleration ◽  
Storage Structure ◽  
Hydrodynamic Effects

The present paper is concerned with the seismic response and fragility evaluation of a water storage structure. Seismic analysis has been carried out considering the hydrodynamic effects of the contained water. The various parameters that could affect the seismic structural response include material strength of concrete, structural damping available within the structure and the normalized ground motion response spectral shape. Based on this limited case study; the seismic fragility of the structure is developed as families of conditional probability curves plotted against peak ground acceleration (PGA) at the location of interest. The procedure adopted incorporates the various randomness and uncertainty associated with the parameters under consideration.

Seismic Fragility Analysis of a Water Storage Structure

2005 ◽  
Vol 127 (4) ◽  
pp. 502-507
Author(s):  
Kapilesh Bhargava ◽  
A. K. Ghosh ◽  
S. Ramanujam
Keyword(s):  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Water Storage ◽  
Structural Response ◽  
Seismic Fragility ◽  
Material Strength ◽  
Ground Acceleration ◽  
Storage Structure ◽  
Modes Of Failure ◽  
Hydrodynamic Effects

Probabilistic seismic risk assessment (PSRA) of a structure is essential to identify the seismic vulnerability of structural members associated with the different stages of damage. Seismic fragility evaluation is a widely accepted approach to develop seismic vulnerability information for the structures. The present paper is concerned with the seismic response and fragility evaluation of a water storage structure. Seismic analysis has been carried out considering the hydrodynamic effects of the contained water. For seismic fragility evaluation, the various parameters that could affect the seismic structural response have been identified as material strength of concrete, structural damping available within the structure, and the normalized ground motion response spectral shape. Based on this limited case study, the seismic fragility of the structure is developed as families of conditional probability curves plotted as a function of peak ground acceleration at the location of interest. The paper presents the method adopted for the seismic fragility evaluation that incorporates the various randomness and uncertainty associated with the parameters under consideration. Typical results of fragility have been presented for different stresses, i.e., corresponding to the different modes of failure. The results of the fragility study show that the seismic structural response at the location of interest is quite sensitive to the randomness and uncertainty associated with the variable parameters considered in the present study. These results will be useful for PSRA studies.

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