scholarly journals Seismic risk analysis for large dams in West Coast basin, southern Ghana

2021 ◽  
Author(s):  
Stephen A. Irinyemi
Keyword(s):  
High Risk ◽  
Seismic Risk ◽  
Critical Infrastructure ◽  
Active Regions ◽  
Seismic Risk Analysis ◽  
Ground Acceleration ◽  
Seismic Safety ◽  
Risk Class ◽  
Large Dams ◽  
Moderate Seismicity

AbstractDams are parts of the critical infrastructure of any nation, the failure of which would have a high-risk potential on the people and properties within the dam vicinity. Ghana is one of the most seismically active regions in West Africa and has at least 5 large dams across the region, constructed in strategic locations. The area is characterised by low-to-moderate seismicity, yet historical events suggest that major earthquakes that are potentially damaging have occurred in the study basin. This paper summarises the method used to analyse seismic risk and discusses the seismic hazards of three large dams across the study basin based on the seismicity at the dam sites and their risk due to structural properties and the location of each dam. The peak ground acceleration (PGA) values for the dam sites estimated are within the range of (0.31 g and 0.52 g) for 10,000 years return period. The study shows that one large dam has a high-risk class in the basin. This dam should be inspected and analysed for its seismic safety and people’s protection in the downstream paths.

Site effects of the Denis-Perron dam (SM-3): A case study in Eastern North America

2021 ◽  
pp. 875529302110194
Author(s):  
Daniel Verret ◽  
Denis LeBœuf ◽  
Éric Péloquin
Keyword(s):  
North America ◽  
Ground Motion ◽  
Site Effects ◽  
Transfer Functions ◽  
Ground Motions ◽  
Published Data ◽  
Eastern North America ◽  
Ground Acceleration ◽  
Large Dams ◽  
Moderate Seismicity

Eastern North America (ENA) is part of a region with low-to-moderate seismicity; nonetheless, some significant seismic events have occurred in the last few decades. Recent events have reemphasized the need to review ENA seismicity and ground motion models, along with continually reevaluating and updating procedures related to the seismic safety assessment of hydroelectric infrastructures, particularly large dams in Québec. Furthermore, recent researchers have shown that site-specific characteristics, topography, and valley shapes may significantly aggravate the severity of ground motions. To the best of our knowledge, very few instrumental data from actual earthquakes have been published for examining the site effects of hydroelectric dam structures located in eastern Canada. This article presents an analysis of three small earthquakes that occurred in 1999 and 2002 at the Denis-Perron (SM-3) dam. This dam, the highest in Québec, is a rockfill embankment structure with a height of 171 m and a length of 378 m; it is located in a narrow valley. The ground motion datasets of these earthquakes include the bedrock and dam crest three-component accelerometer recordings. Ground motions are analyzed both in the time and frequency domains. The spectral ratios and transfer functions obtained from these small earthquakes provide new insights into the directionality of resonant frequencies, vibration modes, and site effects for the Denis-Perron dam. The crest amplifications observed for this dam are also compared with previously published data for large dams. New statistical relationships are proposed to establish dam crest amplification on the basis of the peak ground acceleration (PGA) at the foundation.

Analysis of Seismic Vulnerability - Case of Buildings of High Seismic Hazard

2014 ◽  
Vol 875-877 ◽  
pp. 416-422
Author(s):  
Abdelheq Guettiche ◽  
Mostefa Mimoune
Keyword(s):  
Seismic Risk ◽  
Seismic Vulnerability ◽  
Housing Stock ◽  
Earthquake Hazard ◽  
Seismic Survey ◽  
Survey Method ◽  
Earthquake Hazards ◽  
Physical Vulnerability ◽  
Seismic Safety ◽  
Moderate Seismicity

Seismic vulnerability of an urban environment is characterized by the ability of buildings and structures to support seismic events (physical vulnerability) and by the ability of people to behave in a consistent and rational face a major event (social vulnerability). Constantine is a city with moderate seismicity but the level of risk is high because of urban concentration and topography of the site. The seismic risk reduction therefore requires assessing the physical vulnerability of its buildings. It is proposed in this paper an analysis of a group of buildings for residential use located west of the city, consisting mainly of relatively high buildings. Following a survey of a portion of the housing stock of this city, a seismic survey method was applied based on "observations" post-seismic. Vulnerability indicators are statistically related to damage through a vulnerability index "IV" to establish curves of damage (or vulnerability). These are used to estimate the level of damage that is likely resulting in damage cards. The goal is to develop an initial database of some of the housing stock in the Constantine city (knowledge of earthquake hazards, construction defects ...) to be used in the estimation of seismic risk and verification of seismic safety of existing buildings. Keywords: Earthquake hazard; Seismic vulnerability; Constantine city; damage.

scholarly journals Seismic Hazard and Total Risk of Existing Large Dams in the Marmara Basin, Turkey

2020 ◽  
pp. 25-36
Author(s):  
Hasan Tosun
Keyword(s):  
High Risk ◽  
Seismic Hazard ◽  
Safety Evaluation ◽  
Active Regions ◽  
Marmara Region ◽  
Total Risk ◽  
The North ◽  
Large Dams ◽  
Hazard Parameters ◽  
Risk Potential

Safety evaluation is a fundamental stage of existing dams and their appurtenant structures, which have a high-risk potential for downstream life and property. Turkey is a country, which seismically settled at one of the most active regions in the world, and earthquakes with high magnitude frequently occur here. There are some regions, which are severely under threatening of earthquakes. One of them is the Marmara region with twenty-four million people. This region, namely the Marmara basin, has at least forty-five large dams with different types. This study considered nineteen of them to relieve their seismic hazard parameters for all dam sites and total risk for each structure. The study area is lying in a seismically, very active part of Turkey. The southern part of the basin is structurally cut by the North Anatolian Fault, which is a famous structural feature that produces deathful earthquakes, and its offshoots. The analyses have indicated that peak acceleration widely ranges for the nineteen dam sites of this basin. The total risk analyses have concluded that most of the dams in the metropolitan area have high-risk classes and a significant effect for public safety.

scholarly journals Total risk analyses for large dams in Kizilirmak basin, Turkey

2010 ◽  
Vol 10 (5) ◽  
pp. 979-987 ◽  
Author(s):  
H. Tosun ◽  
E. Seyrek
Keyword(s):  
High Risk ◽  
Seismic Hazard ◽  
Urban Areas ◽  
Fault System ◽  
Total Risk ◽  
Ground Acceleration ◽  
Large Dams ◽  
Wide Range ◽  
Dam Site ◽  
Kızılırmak Basin

Abstract. Dams located near urban areas have a high risk potential for life and property in downstream. Turkey is one of the most seismically active regions in the world and has at least 1200 large dams with different type. Major earthquakes with the potential of threatening life and property occur frequently here. Kizilirmak basin studied in this article is located in a seismically very active part of Turkey. The northern part of basin is structurally cut by a significant fault system. The shear zone, which is frequently jointed, fractured and faulted at the central part of basin increases total risk of dams within the zone. Consequently, there are so many large dams, which are located close to these faults in the basin. In this paper authors summarize the methods used for the analysis of total risk, discuss the seismic hazards of 36 large dams constructed in the Kizilirmak basin on the basis of the seismic activity of the dam site and their total risk as based on physical properties and the position in the basin. The seismic hazard analyses have indicated that peak ground acceleration changes within a wide range (0.09 g and 0.45 g) for the dam sites of basin. The total risk analyses depending on the seismic hazard rating of dam site and risk rating of the structure have concluded that 23 large dams have high-risk class in the basin.

scholarly journals Shaking table test on the seismic response of the portal section in soft and hard rock junction

2021 ◽  
Vol 104 (3) ◽  
pp. 003685042110313
Author(s):  
Guangyao Cui ◽  
Jianfei Ma
Keyword(s):  
Seismic Response ◽  
Contact Stress ◽  
Hard Rock ◽  
Shaking Table Test ◽  
Soft Rock ◽  
Active Regions ◽  
Shaking Table ◽  
Inertia Force ◽  
Ground Acceleration ◽  
Seismic Safety

Tunnel portal sections located in the soft-hard rock junction are vulnerable to the strong earthquake motions in seismically active regions. The main objective of this paper is to investigate the seismic response of tunnel portals located in the soft-hard rock junction. Taking the Baiyunding tunnel in northeast China as a background, a shaking table test with a geometric scaling ratio of 1:30 was built. Details of test setup and procedures are introduced first and then the test results are presented. The discussion of the results is based on the peak ground acceleration (PGA), the longitudinal, the contact stress, and the safety factor. The results show that the soft section of the soft-hard rock junction suffers remarkable damages under strong seismic motions, while the hard rock section is less affected by earthquakes. The increasing soft rock range causes a rise of the forced displacement of tunnel linings, which, together with the seismic inertia force, leads to the increase of the contact stress of the linings, and ultimately resulting in the deterioration of the tunnel seismic safety. To mitigate the seismic damage of tunnel portals in the soft-hard rock junction, rock grouting, bolt support, and other effective reinforced methods should be considered in the seismic design of the soft section.

Seismic Risk Analysis of an Arch Dam

2013 ◽  
Vol 353-356 ◽  
pp. 2020-2023 ◽  
Author(s):  
Hong Zhong ◽  
Hong Jun Li ◽  
Yan Li Bao
Keyword(s):  
Risk Analysis ◽  
Seismic Risk ◽  
Safety Evaluation ◽  
Numerical Procedure ◽  
Monte Carlo Analysis ◽  
Elastic Vibration ◽  
Arch Dam ◽  
Seismic Risk Analysis ◽  
Seismic Safety ◽  
Seismic Safety Evaluation

Seismic risk analysis is greatly helpful to seismic safety evaluation of dams. A preliminary study on seismic risk analysis of arch dam based on numerical simulation is presented. The numerical procedure approximately takes into account the influence of concrete heterogeneity, it can model the response of the dam from elastic vibration to ultimate failure. Five seismic damage levels including no damage, minor damage, medium damage, serious damage and collapse of dam are defined. Through Monte-Carlo analysis of nonlinear response of the dam, which considers uncertainty persistent in ground motion input as well as material properties of concrete, status of the dam after subjected to earthquakes is obtained. The final seismic risk of the dam, which conforms to the norm distribution, is reached based on data fitting. The results provide meaningful reference to seismic safety evaluation of the dam.

The Basics of Seismic Risk Analysis

1989 ◽  
Vol 5 (4) ◽  
pp. 675-702 ◽  
Author(s):  
Keyword(s):  
Los Angeles ◽  
Risk Analysis ◽  
Seismic Risk ◽  
Future Time ◽  
Seismic Risk Analysis ◽  
Seismic Safety ◽  
Property Owner ◽  
Informed Decisions ◽  
Time Period ◽  
Future Time Period

Seismic risk analysis involves determining the adverse consequences that people and society might suffer as a result of future earthquakes, and estimating the probability of these consequences for some future time period. We review the methods used, and present a simple example for a hypothetical building in Los Angeles. The purpose of a seismic risk analysis is to make informed decisions about seismic safety, and this is illustrated with the Los Angeles example by presenting the implications of several options available for a property owner to accept, insure, or mitigate seismic risk.

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