scholarly journals Effect of Characteristics of Ground Motion on Seismically Induced Sliding Surface of Slopes

2021 ◽  
Vol 11 (12) ◽  
pp. 5319
Author(s):  
Muhammad Irslan Khalid ◽  
Yonggook Lee ◽  
Yong-Hee Lee ◽  
Hak-Sung Kim ◽  
Duhee Park
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Nonlinear Finite Element ◽  
Sliding Surface ◽  
Strength Parameters ◽  
The Mean ◽  
Motion Characteristics ◽  
Definition Of ◽  
Input Motion ◽  
Steep Slopes

The seismic performance of slopes is typically evaluated with a pseudo-static method using equivalent horizontal load or with Newmark sliding block analysis. In both procedures, the definition of the potential sliding surface is a required input. The sliding surface has been reported to be marginally influenced by the input ground motion and, therefore, is most often assumed from a pseudo-static procedure. In this study, extensive series of two-dimensional dynamic nonlinear finite element analyses are performed to evaluate the sensitivity of the sliding surface on the slope geometry, soil strength parameters, and input ground motion characteristics. It is demonstrated that the sliding surface may vary with the intensity and frequency characteristics of the input motion. Slopes with inclination angle equal or less than 35° are shown to be marginally influenced by motion intensity if the mean period (Tm) < 0.3 s. However, slopes inclined at 45° are revealed to be more sensitive to the motion intensity and Tm. For motions with Tm > 0.3 s, the sliding surface is demonstrated to widen with an increase in the intensity of the input ground motions. The degree of widening increases proportionally with an increase in Tm. It is, therefore, recommended to derive sliding surfaces from a dynamic analysis for steep slopes.

scholarly journals The 30 October 2020 Samos (Eastern Aegean Sea) Earthquake: effects of source rupture, path and local-site conditions on the observed and simulated ground motions

2021 ◽  
Author(s):  
Aybige Akinci ◽  
Daniele Cheloni ◽  
AHMET ANIL DINDAR
Keyword(s):  
Ground Motion ◽  
Structural Damage ◽  
Ground Motions ◽  
Aegean Sea ◽  
Peak Ground Velocity ◽  
Ground Shaking ◽  
Local Site ◽  
Eastern Aegean ◽  
Motion Characteristics ◽  
Eastern Aegean Sea

Abstract On 30 October 2020 a MW 7.0 earthquake occurred in the eastern Aegean Sea, between the Greek island of Samos and Turkey’s Aegean coast, causing considerable seismic damage and deaths, especially in the Turkish city of Izmir, approximately 70 km from the epicenter. In this study, we provide a detailed description of the Samos earthquake, starting from the fault rupture to the ground motion characteristics. We first use Interferometric Synthetic Aperture Radar (InSAR) and Global Positioning System (GPS) data to constrain the source mechanisms. Then, we utilize this information to analyze the ground motion characteristics of the mainshock in terms of peak ground acceleration (PGA), peak ground velocity (PGV), and spectral pseudo-accelerations. Modelling of geodetic data shows that the Samos earthquake ruptured a NNE-dipping normal fault located offshore north of Samos, with up to 2.5-3 m of slip and an estimated geodetic moment of 3.3 ⨯ 1019 Nm (MW 7.0). Although low PGA were induced by the earthquake, the ground shaking was strongly amplified in Izmir throughout the alluvial sediments. Structural damage observed in Izmir reveals the potential of seismic risk due to the local site effects. To better understand the earthquake characteristics, we generated and compared stochastic strong ground motions with the observed ground motion parameters as well as the ground motion prediction equations (GMPEs), exploring also the efficacy of the region-specific parameters which may be improved to better predict the expected ground shaking from future large earthquakes in the region.

Effects of Seismic Incident Directionality on Ground Motion Characteristics and Responses of a Single-Mass Bi-Degree-of-Freedom System

2021 ◽  
pp. 2150119
Author(s):  
Jun Gong ◽  
Xudong Zhi ◽  
Feng Fan ◽  
Shizhao Shen ◽  
Da Qaio ◽  
...  
Keyword(s):  
Ground Motion ◽  
Large Scale ◽  
Seismic Analysis ◽  
Ground Motions ◽  
Propagation Distance ◽  
Degree Of Freedom ◽  
Different Types ◽  
Single Mass ◽  
Motion Characteristics ◽  
The Impact

To investigate the variability of ground motion characteristics (GMC) with the angle of seismic incidence (ASI) and the impact of seismic incident directionality on structural responses, first, a large-scale database of recorded ground motions was used to analyze the causes of GMC variability due to the seismic incident directionality effect (SIDE). Then a single-mass bi-degree-of-freedom system (SM-BDOF-S) with different types of symmetrical sections was selected to explore the influence mechanism of SIDE on the seismic responses. The results illustrated that the GMC has substantial variability with the ASI, which is independent of the earthquake source, propagation distance, and site condition, and exhibits complex random characteristics. Additionally, a classification method for ground motions is proposed based on this GMC variability to establish a criterion for selecting ground motions in seismic analysis considering the SIDE. Moreover, for an SM-BDOF-S, the response spectral plane is proposed to explain the transition behavior of spectral responses that are very similar among different stiffness ratios, but divergent for different types of ground motions. The influence of SIDE on structures is determined by their stiffness and stiffness ratio in the [Formula: see text]- and [Formula: see text]-directions, as well as the type of ground motion.

Exploring the Proximity of Ground-Motion Models Using High-Dimensional Visualization Techniques

2010 ◽  
Vol 26 (4) ◽  
pp. 1117-1138 ◽  
Author(s):  
Frank Scherbaum ◽  
Nicolas M. Kuehn ◽  
Matthias Ohrnberger ◽  
Andreas Koehler
Keyword(s):  
Ground Motion ◽  
Hazard Analysis ◽  
Ground Motions ◽  
High Dimensional ◽  
Logic Tree ◽  
Motion Models ◽  
Metric Set ◽  
Motion Characteristics ◽  
Visualization Techniques ◽  
Ground Motion Models

Logic trees have become a popular tool to capture epistemic uncertainties in seismic hazard analysis. They are commonly used by assigning weights to models on a purely descriptive basis (nominal scale). This invites the creation of unintended inconsistencies regarding the weights on the corresponding hazard curves. On the other hand, for human experts it is difficult to confidently express degrees-of-beliefs in particular numerical values. Here we demonstrate for ground-motion models how the model and the value-based perspectives can be partially reconciled by using high-dimensional information-visualization techniques. For this purpose we use Sammon's (1969) mapping and self-organizing mapping to project ground-motion models onto a two-dimensional map (an ordered metric set). Here they can be evaluated jointly according to their proximity in predicting similar ground motions, potentially making the assignment of logic tree weights consistent with their ground motion characteristics without having to abandon the model-based perspective.

scholarly journals Structure and Motion of Severe-Wind-Producing Mesoscale Convective Systems and Derechos in Relation to the Mean Wind

2017 ◽  
Vol 32 (2) ◽  
pp. 423-439 ◽  
Author(s):  
Matthew A. Campbell ◽  
Ariel E. Cohen ◽  
Michael C. Coniglio ◽  
Andrew R. Dean ◽  
Stephen F. Corfidi ◽  
...  
Keyword(s):  
Large Scale ◽  
Mean Flow ◽  
Convective Systems ◽  
Structure And Motion ◽  
Mesoscale Convective ◽  
The Mean ◽  
Wind Events ◽  
Motion Characteristics ◽  
Definition Of ◽  
Convective Vortices

Abstract The goal of this study is to document differences in the convective structure and motion of long-track, severe-wind-producing MCSs from short-track severe-wind-producing MCSs in relation to the mean wind. An ancillary goal is to determine if these differences are large enough that some criterion for MCS motion relative to the mean wind could be used in future definitions of “derechos.” Results confirm past investigations that well-organized MCSs, including those that produce derechos, tend to move faster than the mean wind, exhibiting a significantly larger degree of propagation (component of MCS motion in addition to the component contributed by the mean flow). Furthermore, well-organized systems that produce shorter-track swaths of damaging winds likewise tend to move faster than the mean wind with a significant propagation component along the mean wind. Therefore, propagation in the direction of the mean wind is not necessarily a characteristic that can be used to distinguish derechos from nonderechos. However, there is some indication that long-track damaging wind events that occur without large-scale or persistent bow echoes and mesoscale convective vortices (MCVs) require a strong propagation component along the mean wind direction to become long lived. Overall, however, there does not appear to be enough separation in the motion characteristics among the MCS types to warrant the inclusion of a mean-wind criterion into the definition of a derecho at this time.

The Stability of Ground Motions Randomly Synthesized for an Engineering Site

2013 ◽  
Vol 477-478 ◽  
pp. 1069-1074
Author(s):  
Hai Ming Liu ◽  
Xiaxin Tao ◽  
Li Yuan Wang
Keyword(s):  
Ground Motion ◽  
Response Spectrum ◽  
Ground Motions ◽  
Source Models ◽  
The Mean ◽  
The Stability

The ground motions at two rock stations where motions were recorded during the great Wenchuan earthquae are randomly synthsized for 10 times. The mean response spectrum and mean PGA of each synthesis and the general mean spectrum and PGA after each synthesis are calculated. The result shows the fact that the general mean spectrum after 10 syntheses, and the general mean PGA could be improved just a little. It means that it is not necessary to synthsize ground motion many times for an engineering site in practice, if the mean spectrum and PG are taken from the syntheses by 30 source models.

Ground Motion Selection for Liquefaction Evaluation Analysis of Earthen Levees

2012 ◽  
Vol 28 (4) ◽  
pp. 1331-1351 ◽  
Author(s):  
Adda Athanasopoulos-Zekkos ◽  
Mustafa Saadi
Keyword(s):  
Ground Motion ◽  
Cross Sections ◽  
Ground Motions ◽  
Cyclic Stress ◽  
Cyclic Stress Ratio ◽  
Ground Motion Selection ◽  
Liquefaction Susceptibility ◽  
Wide Range ◽  
Dynamic Analyses ◽  
The Mean

Guidelines for selecting ground motions for liquefaction evaluation analysis of earthen levees are proposed. These guidelines were developed based on results from dynamic analyses of characteristic earthen levee cross sections using a wide range of ground motions (~1,500). The effect of a number of ground motion parameters on the dynamic response of the levees in terms of liquefaction susceptibility was studied, and the parameters that correlated best to the response were identified. For the liquefaction triggering evaluation, the mean period of the ground motion ( Tm) is best correlated to the cyclic stress ratio (CSR). Regression relationships between CSR and Tm are proposed for a series of levee types and shaking intensities.

Seismic Fragilities of High-Voltage Substation Disconnect Switches

2019 ◽  
Vol 35 (4) ◽  
pp. 1559-1582
Author(s):  
Bai Wen ◽  
Mohamed A. Moustafa ◽  
Dai Junwu
Keyword(s):  
Seismic Vulnerability ◽  
Fragility Curves ◽  
Ground Motions ◽  
Incremental Dynamic Analysis ◽  
Nonlinear Finite Element ◽  
Power Grids ◽  
Finite Element Models ◽  
Severe Damage ◽  
Substation Equipment ◽  
Motion Characteristics

Electrical substations and vital components, e.g., disconnect switches, experienced severe damage that caused blackouts during past earthquakes. To improve the seismic resiliency of power grids and use probabilistic decision-making frameworks, comprehensive fragility data for the different substation equipment are needed. The objective of this study is to investigate the seismic performance of and develop component and system fragility curves for a critical substation component: disconnect switches. The seismic vulnerability of two common switch types was evaluated and two operational configurations were considered. Detailed nonlinear finite element models for the full switches were calibrated using previous experimental data and used to conduct incremental dynamic analysis and carry out the fragility assessment. A total of 160 triaxial ground motions representing four sets of different ground motion characteristics were used. The switches’ fragility curves were developed and presented to be readily used for new substation design, prioritizing retrofit/maintenance activities and reliability assessment of power grids.

scholarly journals Ground-motion relations for eastern North America

1995 ◽  
Vol 85 (1) ◽  
pp. 17-30 ◽  
Author(s):  
Gail M. Atkinson ◽  
David M. Boore
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Response Spectra ◽  
Model Parameters ◽  
Eastern North America ◽  
Motion Model ◽  
Ground Acceleration ◽  
Ground Motion Model ◽  
Definition Of ◽  
Validation Of Results

Abstract Predictive relations are developed for ground motions from eastern North American earthquakes of 4.0 ≦ M ≦ 7.25 at distances of 10 ≦ R ≦ 500 km. The predicted parameters are response spectra at frequencies of 0.5 to 20 Hz, and peak ground acceleration and velocity. The predictions are derived from an empirically based stochastic ground-motion model. The relations differ from previous work in the improved empirical definition of input parameters and empirical validation of results. The relations are in demonstrable agreement with ground motions from earthquakes of M 4 to 5. There are insufficient data to adequately judge the relations at larger magnitudes, although they are consistent with data from the Saguenay (M 5.8) and Nahanni (M 6.8) earthquakes. The underlying model parameters are constrained by empirical data for events as large as M 6.8.

scholarly journals Representative ground-motion ensembles for several major earthquake scenarios in New Zealand

2014 ◽  
Vol 47 (4) ◽  
pp. 231-252 ◽  
Author(s):  
Karim Tarbali ◽  
Brendon A. Bradley
Keyword(s):  
New Zealand ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Ground Motions ◽  
Conditional Intensity ◽  
Intensity Measure ◽  
Earthquake Scenarios ◽  
Major Earthquake ◽  
The Mean ◽  
Representative Ground

In this paper, representative ground motion ensembles for several major earthquake scenarios in New Zealand are developed. Cases considered include representative ground motions for the occurrence of Alpine, Hope and Porters Pass earthquakes in Christchurch city, and the occurrence of Wellington, Wairarapa and Ohariu fault ruptures in Wellington city. For each considered scenario rupture, ensembles of 20 and 7 ground motions are selected using the generalized conditional intensity measure (GCIM) approach, ensuring that the ground motion ensembles represent both the mean and distribution of ground motion intensity which such scenarios could impose. These scenario-based ground motion sets can be used to complement ground motions which are often selected in conjunction with probabilistic seismic hazard analysis, in order to understand the performance of structures for the question “what if this fault ruptures?”

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