Geologic and seismic setting pertinent to dam safety review of Duncan Dam

1994 ◽  
Vol 31 (6) ◽  
pp. 919-926 ◽  
Author(s):  
Tim E. Little ◽  
Alan S. Imrie ◽  
John F. Psutka
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Probabilistic Methods ◽  
Dam Safety ◽  
Embankment Dam ◽  
Seismic Ground Motion ◽  
Time Histories ◽  
Peak Horizontal Acceleration ◽  
Design Earthquake ◽  
Selection Of

Duncan Dam is a B.C. Hydro facility constructed on the Duncan River in southeastern British Columbia, Canada, between 1965 and 1967. The dam was founded on a complex sequence of more than 380 m of glacial drift and glaciofluvial sediments, some of which are pervious and compressible. Some sandy units are potentially liquefiable, in particular a sand layer (unit 3c) up to 23 m thick. Current B.C. Hydro seismic guidelines for dams require that Duncan Dam should be able to withstand the Maximum Credible Earthquake (MCE) without catastrophic release of the reservoir. This paper describes the geologic and seismic setting of the region around the dam and the selection of seismic ground motion parameters. Probabilistic methods were applied to develop MCE ground motions, which were estimated to consist of a firm ground peak horizontal acceleration of 0.12 g, which could be caused by a M 6.5 earthquake at a distance of about 50 km. Several time histories with characteristics similar to this design earthquake were selected for dynamic soil analyses. Key words : dam safety, embankment dam, liquefaction, sand, seismicity, seismic ground motion.

scholarly journals Selection of Compatible Ground Motions with the Seismic Characteristics of Erbil City, the Capital of the Kurdistan Region of Iraq

2020 ◽  
Vol 10 (1) ◽  
pp. 110-120
Author(s):  
Zina A. AbdulJaleel ◽  
Bahman O. Taha
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Risk Evaluation ◽  
Ground Motions ◽  
Imperial Valley ◽  
Engineering Research ◽  
Ground Motion Selection ◽  
Seismic Characteristics ◽  
Time Histories ◽  
Selection Of

Erbil city characterized by the risk of earthquakes generated by Zagros-Taurus Belt. The central objective of this study is to obtain a compatible input ground motion within the seismicity of Erbil city since which is considered an essential component of seismic risk evaluation and vulnerability studies. The real records obtained from the online database Pacific Earthquake Engineering Research Next Generation Attenuation. Four sets of ground motion selection and modification methods proposed to obtain fifteen records, where each record scaled and matched with the defined target spectra and seismic characteristics in Erbil city. Based on the greatest number of repetition and different events, ten compatible ground motions with earthquake name and NGA record number are selected: Gazli_Ussr (#126), Imperial Vally_06 (#183), El Mayor-Cucapah_Maxico (#5827), Christchurch_New Zealand (#8124), Imperial Valley (#6), Darfield_NewZealand (#6893), Duzce Turkey (#1602), Northridge_01 (#1082), Loma Prieta (#761), and Spitak_Armenia (#730). Seismosoft application utilized to obtain the graphs of acceleration, velocity, and displacement time histories for three components, in addition to determine the important parameters to characterize the amplitude, frequency content, and duration of the selected ground motion.

On the characteristics of local geology and their influence on ground motions generated by the Loma Prieta earthquake in the San Francisco Bay region, California

1992 ◽  
Vol 82 (2) ◽  
pp. 603-641 ◽  
Author(s):  
Roger D. Borcherdt ◽  
Gary Glassmoyer
Keyword(s):  
Ground Motion ◽  
San Francisco ◽  
San Francisco Bay ◽  
Ground Motions ◽  
Loma Prieta Earthquake ◽  
Franciscan Complex ◽  
Horizontal Acceleration ◽  
Geological Conditions ◽  
Peak Horizontal Acceleration ◽  
Loma Prieta

Abstract Strong ground motions recorded at 34 sites in the San Francisco Bay region from the Loma Prieta earthquake show marked variations in characteristics dependent on crustal structure and local geological conditions. Peak horizontal acceleration and velocity inferred for sites underlain by “rock” generally occur on the transverse component of motion. They are consistently greater with lower attenuation rates than the corresponding mean value predicted by empirical curves based on previous strong-motion data. Theoretical amplitude distributions and synthetic seismograms calculated for 10-layer models suggest that “bedrock” motions were elevated due in part to the wide-angle reflection of S energy from the base of a relatively thin (25 km) continental crust in the region. Characteristics of geologic and geotechnical units as currently mapped for the San Francisco Bay region show that average ratios of peak horizontal acceleration, velocity and displacement increase with decreasing mean shear-wave velocity. Ratios of peak acceleration for sites on “soil” (alluvium, fill/Bay mud) are statistically larger than those for sites on “hard rock” (sandstone, shale, Franciscan Complex). Spectral ratios establish the existence of predominant site periods with peak amplifications near 15 for potentially damaging levels of ground motion at some sites underlain by alluvium and fill/bay mud. Average spectral amplifications inferred for vertical and the mean horizontal motion are, respectively, (1,1) for sites on the Franciscan Complex (KJf), (1.4, 1.5) for sites on Mesozoic and Tertiary rocks (TMzs), (2.1, 2.0) for sites on the Santa Clara Formation (QTs), (2.3, 2.9) for sites on alluvium (Qal), and (2.1, 4.0) for sites on fill/Bay mud (Qaf/Qhbm). These mean values are not statistically different at the 5% significance level from those inferred from previous low-strain data. Analyses suggest that soil amplification and reflected crustal shear energy were major contributors to levels of ground motion sufficient to cause damage to vulnerable structures at distances near 100 km in the cities of San Francisco and Oakland.

Evaluation of Hybrid Broadband Ground Motion Simulations for Response History Analysis and Design

2015 ◽  
Vol 31 (3) ◽  
pp. 1691-1710 ◽  
Author(s):  
Lynne S. Burks ◽  
Reid B. Zimmerman ◽  
Jack W. Baker
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Spectral Response ◽  
Analysis And Design ◽  
History Analysis ◽  
Response History Analysis ◽  
Simulated Ground Motions ◽  
Broadband Ground Motion ◽  
New Buildings ◽  
Selection Of

Chapter 16 of ASCE 7 governs the selection of ground motions for analysis of new buildings and requires recordings that meet specified criteria. If a sufficient number of recordings cannot be found, it allows the use of “appropriate simulated ground motions,” but does not provide further guidance. This paper outlines a procedure for generating and selecting a set of “appropriate” hybrid broadband simulations and a comparable set of recordings. Both ground motion sets are used to analyze a building in Berkeley, California, and the predicted structural performance is compared. The structural behavior resulting from recordings and simulations is similar, and most discrepancies are explained by differences in directional properties such as orientation of the maximum spectral response. These results suggest that when simulations meet the criteria outlined for recordings in ASCE 7 and properties such as directionality are realistically represented, simulations provide useful results for structural analysis and design.

Selection of the Test Specimens for Seismic Tests of Air-Operated Valve Actuators for Nuclear Power Plants

2019 ◽  
Author(s):  
Nobuo Kojima ◽  
Yoshitaka Tsutsumi ◽  
Yoshinao Matsubara ◽  
Koji Nishino ◽  
Yasuyuki Ito ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Power Plants ◽  
Nuclear Power Plants ◽  
Ground Motions ◽  
Test Results ◽  
Earthquake Ground Motions ◽  
Dynamic Function ◽  
Design Earthquake ◽  
Seismic Tests ◽  
Selection Of

Abstract The soundness for the function of air-operated valves in nuclear power plants during earthquake has been investigated via seismic test results and so forth. Since the seismic response acceleration has increased more and more with a recent reassessment of design earthquake ground motions conducted according to the revised Japanese nuclear safety regulation, it is necessary to evaluate the soundness for the function of various valves subject to large acceleration beyond design basis. The air-operated valves currently installed in the nuclear power plants in Japan play the important roles in the sever accident events. In this study, we classified them based on the valve type, manufactures and the previous test results. Furthermore, we proposed the strategy for evaluating the seismic-proof and the seismic test condition for examining the soundness of the dynamic function. Here, the dynamic function is defined as the function required under and after earthquakes.

Shake table tests on the out-of-plane response of unreinforced masonry wallsThis article is one of a selection of papers published in this Special Issue on Masonry.

2007 ◽  
Vol 34 (11) ◽  
pp. 1381-1392 ◽  
Author(s):  
C. S. Meisl ◽  
K. J. Elwood ◽  
C. E. Ventura
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Unreinforced Masonry ◽  
Rigid Bodies ◽  
Shake Table ◽  
Shake Table Tests ◽  
Out Of Plane ◽  
Wall Construction ◽  
Selection Of

Given sufficient anchorage to the diaphragms, out-of-plane walls in unreinforced masonry (URM) buildings have been shown to crack above midheight and then rock as two rigid bodies. This study investigates the sensitivity of the rocking response to the type of ground motion and the quality of the wall construction. Shake table tests were conducted on four full-scale multi-wythe walls, all with a height to thickness (h/t) ratio of 12 but of varying construction quality and subjected to three different ground motions. All walls experienced cracking at less than one half of the 2005 National Building Code of Canada (NBCC) level for Vancouver, but exhibited a stable rocking behaviour without collapse beyond a ground motion 1.5 times the 2005 NBCC level.

Disaggregation of seismic hazard

1999 ◽  
Vol 89 (2) ◽  
pp. 501-520 ◽  
Author(s):  
Paolo Bazzurro ◽  
C. Allin Cornell
Keyword(s):  
Seismic Hazard ◽  
Ground Motion ◽  
Hazard Analysis ◽  
Seismic Source ◽  
Source Effects ◽  
Motion Time ◽  
Time Histories ◽  
Definition Of ◽  
Rupture Mechanism ◽  
Selection Of

Abstract Probabilistic seismic hazard analysis (PSHA) integrates over all potential earthquake occurrences and ground motions to estimate the mean frequency of exceedance of any given spectral acceleration at the site. For improved communication and insights, it is becoming common practice to display the relative contributions to that hazard from the range of values of magnitude, M, distance, R, and epsilon, ɛ, the number of standard deviations from the median ground motion as predicted by an attenuation equation. The proposed disaggregation procedures, while conceptually similar, differ in several important points that are often not reported by the researchers and not appreciated by the users. We discuss here such issues, for example, definition of the probability distribution to be disaggregated, different disaggregation techniques, disaggregation of R versus ln R, and the effects of different binning strategies on the results. Misconception of these details may lead to unintended interpretations of the relative contributions to hazard. Finally, we propose to improve the disaggregation process by displaying hazard contributions in terms of not R, but latitude, longitude, as well as M and ɛ. This permits a display directly on a typical map of the faults of the surrounding area and hence enables one to identify hazard-dominating scenario events and to associate them with one or more specific faults, rather than a given distance. This information makes it possible to account for other seismic source characteristics, such as rupture mechanism and near-source effects, during selection of scenario-based ground-motion time histories for structural analysis.

Compatible ground-motion time histories for new national seismic hazard maps

1998 ◽  
Vol 25 (2) ◽  
pp. 305-318 ◽  
Author(s):  
Gail M Atkinson ◽  
Igor A Beresnev
Keyword(s):  
British Columbia ◽  
Seismic Hazard ◽  
Ground Motion ◽  
Ground Motions ◽  
Hazard Maps ◽  
Probability Level ◽  
Seismic Hazard Maps ◽  
Motion Time ◽  
Time Histories ◽  
Canadian Council

Ground-motion time histories which are compatible with the uniform hazard spectra (UHS) provided by the new national seismic hazard maps of the Geological Survey of Canada (GSC) are simulated. Time histories are simulated for the following cities: Halifax, La Malbaie, Québec, Montreal, Ottawa, Toronto, Prince George, Tofino, Vancouver, and Victoria. The target UHS for the time history simulations are the GSC 5% damped horizontal-component spectra for "firm ground" (Class B) sites for an annual probability of 1/500. The Canadian Council on Earthquake Engineering is currently considering the adoption of these maps as the seismological basis for the earthquake design requirements for future editions of the National Building Code of Canada. It is therefore useful to have compatible time histories for these spectra, in order that dynamic analysis methods requiring the use of time histories can be employed. The simulated records provide a realistic representation of ground motion for the earthquake magnitudes and distances that contribute most strongly to hazard at the selected cities and probability level. For each selected city, two horizontal components are generated for a moderate earthquake nearby, and two horizontal components are generated for a larger earthquake farther away. These records match the short- and long-period ends of the target UHS, respectively. These simulations for local and regional crustal earthquakes are based on a point-source stochastic simulation procedure. For cities in British Columbia, records are also simulated for a scenario M8.5 earthquake on the Cascadia subduction zone, using a stochastic finite-fault simulation model. Four different rupture scenarios are considered. The ground motions for this scenario event are not associated with a specific probability level, but current information suggests that their probability of occurrence is comparable to that of the 1/500 UHS (the probabilistic analyses performed for the national hazard maps do not explicitly include the Cascadia subduction event). Thus it would be reasonable to conduct engineering analyses for cities in British Columbia using both the simulated crustal-event motions and the simulated Cascadia-event motions for the Cascadia event. The time histories simulated for this study are available free of charge to all interested parties.Key words: compatible time-histories, seismic hazard, ground motions.

scholarly journals Stochastic Simulation of Strong Ground Motions From Two M > 5 Uttarakhand Earthquakes

2021 ◽  
Vol 9 ◽  
Author(s):  
Nitin Sharma ◽  
D. Srinagesh ◽  
G. Suresh ◽  
D. Srinivas
Keyword(s):  
Ground Motion ◽  
Ground Motions ◽  
Plate Boundary ◽  
Response Spectra ◽  
Site Effect ◽  
Vital Role ◽  
Frequency Range ◽  
Waveform Data ◽  
Ground Motion Parameter ◽  
Time Histories

Many studies based on the geodetic data and statistical analysis of seismicity have pointed out that sufficient amount of stress accumulated in the Himalayan plate boundary may host a big earthquake. Consequently, high seismic activities and infrastructural developments in the major cities around Himalayan regions are always of major concern. The ground motion parameter estimation plays a vital role in the near real time evaluation of potentially damaged areas and helps in mitigating the seismic hazard. Therefore, keeping in mind the importance of estimation of ground motion parameters, we targeted two moderate-size earthquakes that occurred recently within a gap of 10 months in Uttarakhand region with M > 5.0 on 06/02/2017 and 06/12/2017. The ground motions are simulated by adopting a stochastic modeling technique. The source is assumed as ω−2, a circular point source (Brune’s model). The average value of reported anelastic attenuation from various studies, the quality factor, Qs = 130.4*(f0.996), and stress drop values obtained through iterative procedure are considered for simulations. The stochastic spectra are generated between 0.1 and 10 Hz of frequency range. The site effect is also estimated by using the H/V method in the same frequency range. The synthetic spectra are compared with the observed Fourier amplitude spectra obtained from the recorded waveform data and converted back to the time histories. The stochastic time histories are compared with the observed waveforms and discussed in terms of amplitude (PGA). The simulated and observed response spectra at different structural periods are also discussed. The mismatch between the observed and simulated PGA values along with the GMPE existing for shallow crustal earthquakes is also discussed in the present work.

The SMART I Accelerograph Array (1980-1987): A Review

1987 ◽  
Vol 3 (2) ◽  
pp. 263-287 ◽  
Author(s):  
N. A. Abrahamson ◽  
B. A. Bolt ◽  
R. B. Darragh ◽  
J. Penzien ◽  
Y. B. Tsai
Keyword(s):  
Ground Motion ◽  
Earthquake Engineering ◽  
Ground Motions ◽  
Near Field ◽  
Strong Motion ◽  
Response Spectra ◽  
Transform Faults ◽  
Engineering Research ◽  
Motion Data ◽  
Time Histories

SMART 1 is the first large digital array of strong-motion seismographs specially designed for engineering and seismological studies of the generation and near-field properties of earthquakes. Since the array began operation in September 1980, it has recorded over 3000 accelerogram traces from 48 earthquakes ranging in local magnitude ( ML) from 3.6 to 7.0. Peak ground accelerations have been recorded up to 0.33g and 0.34g on the horizontal and vertical components, respectively. Epicentral distances have ranged from 3 km 200 km from the array center, and focal depths have ranged from shallow to 100 km. The recorded earthquakes had both reverse and strike-slip focal mechanisms associated with the subduction zone and transform faults. These high quality, digital, ground motions provide a varied resource for earthquake engineering research. Earthquake engineering studies of the SMART 1 ground motion data have led to advances in knowledge in several cases: for example, on frequency-dependent incoherency of free-surface ground motions over short distances, on response of linear systems to multiple support excitations, on attenuation of peak ground-motion parameters and response spectra, on site torsion and phasing effects, and on the identification of wave types. Accelerograms from individual strong-motion seismographs do not, in general, provide such information. This review describes the SMART 1 array and the recorded earthquakes with special engineering applications. Also, it tabulates the unfiltered peak array accelerations, displays some of the recorded ground motion time histories, and summarizes the main engineering research that has made use of SMART 1 data.

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