• Title/Summary/Keyword: earthquake safety

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Strain-Based Structural Integrity Evaluation Methods for Nuclear Power Plant Piping under Beyond Design Basis Earthquake (설계기준초과지진 하의 원전 배관 구조건전성 평가를 위한 변형률 기반 방법)

  • Lee, Dae Young;Park, Heung Bae;Kim, Jin Weon;Ryu, Ho Wan;Kim, Yun-Jae
    • Transactions of the Korean Society of Pressure Vessels and Piping
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    • v.12 no.2
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    • pp.66-70
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    • 2016
  • Following the 2011 Fukushima Nuclear Power Plant accident, the IAEA has issued a revised version of the Nuclear Safety Standard for beyond design basis earthquake to consider the core meltdown accident. In Korea, relevant laws and regulations were also revised to consider beyond design basis earthquake to nuclear components. In this paper, CAV, an seismic damage factor that determines the restart of nuclear power plant after operating breakdown earthquake, is proposed for extension to the beyond design basis earthquake. For pipings not satisfying the beyond design basis earthquake condition, several evaluation methods are suggested, such as strain-based evaluation methods, simple nonlinear analysis method and cumulative damage evaluation method.

Damage Potential of a Domestic Metropolitan Railway Bridge subjected to 2016 Gyeongju Earthquake (2016년 경주지진에 의한 국내 도시철도 교량의 잠재적 손상평가)

  • Lee, Do Hyung;Shim, Jae Yeob;Jeon, Jong-Su
    • Journal of the Earthquake Engineering Society of Korea
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    • v.20 no.7_spc
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    • pp.461-472
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    • 2016
  • Damage potential has been investigated for a domestic metropolitan railway bridge subjected to 2016 Gyeongju earthquake which has been reported as the strongest earthquake in Korea. For this purpose, nonlinear static pushover analyses for the bridge piers have been carried out to evaluate ductility capacities. Then, the capacities have been compared with those suggested by Railway Design Standards of Korea. This comparison shows that all piers possess enough safety margins. Nonlinear dynamic time-history analysis has also been conducted to estimate both displacement and shear force demands for the bridge subjected to ground motions recorded at stations in near of Gyeongju. Maximum demands reveal that response under the ground motions remains essentially in elastic. In addition, for a further assessment of the bridge under the Gyeongju earthquake, fragility analyses have been performed using those ground motions. The fragility results indicate that the recorded earthquakes do not significantly affect the damage exceedance probability of the bridge piers.

Earthquake-induced Liquefaction Areas and Safety Assessment of Facilities (지진으로 인한 액상화 지역 및 시설물 안정성 평가)

  • Jeon, Sang-Soo;Heo, DaeYang;Lee, Sang-Seung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.7
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    • pp.133-143
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    • 2018
  • Liquefaction is one of secondary damages after earthquake and has been rarely reported until earthquake except Mw = 5.4 15 November 2017 Pohang earthquake in Korea. In recent years, Mw = 5.8 12 September 2016 Gyeongju earthquake and Mw = 5.4 15 November 2017 Pohang earthquake, which induced liquefaction, occurred in fault zone of Yangsan City located at south-eastern part of Korea. This explains that Korea is not safe against liquefaction induced by earthquake. In this study, the distance between the centroid of administrative district and the epicenter located at Yangsan fault, peak ground velocity (PGA) induced by both Mw = 5.0 and 6.5, and liquefaction potential index (LPI), which is calculated by using groundwater level and standard penetration test results of 274 in the area of Gimhae city located in adjacent to Nakdong river and across Yangsan fault, have been estimated and then kriging method using geographical information systems has been used to evaluate liquefaction effects on the damage of facilities. This study presents that Mw = 5.0 earthquake induces a small and low level of liquefaction resulting in slight damage of facilities but Mw = 6.5 earthquake induces a large and high level of liquefaction resulting in severe damage of facilities.

The design considerations of steel braced frame for seismic retrofit through increasing the lateral strength of existing RC buildings (철골브레이스에 의한 기존 RC건축물의 강도상승형 내진보강을 위한 설계고려사항)

  • Ahn, Choong Weon;Yoon, Jeong Hwan;Song, Dong Yub;Chang, Buhm Soo;Min, Chan Gi
    • Journal of the Earthquake Engineering Society of Korea
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    • v.17 no.6
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    • pp.293-303
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    • 2013
  • This paper deals with steel braced frame as increasing the lateral strength and ductility in order to seismic retrofit of existing buildings and discusses the designing criteria and calculation method of retrofitted buildings. The addition of steel braced frame can be effective for increasing the lateral strength and ductility of existing buildings. However, There is a problem in utilizing this method. It is the approach to provide an adequate connection between the existing RC frame and the installed steel braced frame, because global strength by failure mode(three type) depends on detail of connection and strength of existing RC frame. So, the designer must be confirmed if it satisfies the required performance or not. Failure mode of type I is the most appropriate for increasing the lateral strength and ductility. Seismic performance evaluation and strength calculation of seismic retrofit are performed by guideline by KISTEC(Korea Infrastructure Safety & Technology)'s "seismic performance evaluation and rehabilitation of existing buildings" and Japan Building Disaster Prevention Association. Buildings are modeled and non-linear pushover analysis are performed using MIDAS program.

Evaluation of Degradation and Safety of Small Agricultural Reservoir (소규모 농업용 저수지의 노후도 및 안전도 평가 -고삼 저수지에 대한 사례 연구-)

  • 장병옥;박영곤;우철웅
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.40 no.1
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    • pp.49-56
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    • 1998
  • Ths study was peformed to evaluate the degree of degradation and safety of a small agricultural reservoir, Kosam Reservoir, in Kyungki Province. Evaluation was done by the program developed by the authors. Results of the study are as follows: 1) Although many burrows were found in downstream side of embankment and cracks were found in wall joining spillway, it appeared that degree of degradation of embankment was in good conditions. 2) Compressive strengths of concrete of crest, side channel, chute floor of spillway were in poor condition. But it appeared that overall degree of degradation of structures was in medium condition based on the criteria of the evaluation system 3) From the analysis of slope stability, safety factor of downstream slope was over 3.3 for the worst condition, such as flood and high water level and that of upstream slope was also over 3.6 for rapid drawdown. In case of earthquake, safety factors were over 2.5 for all conditions. Therefore embankment slopes of Kosam Reservoir were very stable for normal and earthquake condition. 4) As upon assumed failure of embankment of Kosam Reservoir, degree of damage was estimated to be very serious because of many loss of life and properties in the downstream area. 5) Overall grade of safety of Kosam Reservoir was in good condition. Therefore safety was considered to be "No problems" at the present time but further degradation may be proceeded partly and continuously as time goes by.e goes by.

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Seismic Response Analysis of the Concrete Face Rockfill Dam (콘크리트표면차수벽령 석괴댐의 지진응답해석)

  • 오병현;임정열;이종옥
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2001.09a
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    • pp.147-154
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    • 2001
  • In this study, comprehensive seismic performance analysis were performed for the concrete face rockfill dam(CFRD) designed seismic coefficient method(0. 10g). The static and pseudo-static FEM analysis, limited equilibrium method and dynamic FEM analysis were used for the dam safety analysis. The results of the seismic analysis were that the minimum factor of safety of down slope was 1.2 and horizontal displacement increased 8cm and vertical displacement increased 1.2cm at dam crest rather than those of static condition. The model dam did not show any serious tai lure in seismic stabi1ity for 0.13g. And much more research is still necessary in seismic safety of CFRD.

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A Study on the Management of Construction Project for Preventing Accidents of Reclamation : basic on the collapse of Sangdo Kindergarten (도심지 소규모 재개발·재건축공사시 흙막이가시설 사고예방을 위한 건설사업관리 방안 연구 : 상도유치원 붕괴사고 중심으로)

  • Oh, Se-kil;Park, Joo-Moon
    • Journal of Urban Science
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    • v.8 no.1
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    • pp.33-44
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    • 2019
  • The purpose of this study is to investigate the cause of repeated accidents through the investigation and analysis of the collapse cases of domestic earthquakes in order to prevent the earthquake disaster in the urban redevelopment and reconstruction. It is designed and constructed to draw out various problem factors and to find solutions to these problems. And the contents related to various laws and systems of the construction project management stage. Especially. In the management of the construction management centered on the safety management and quality control of the technical aspect design, supervision, construction phase through the cause of the accident and improvement measures based on the investigation report of the collapse of the construction site near Sangdo Kindergarten in Seoul. Supervisor. And constructors should be settled on the responsibility and responsibility of God. In order to achieve the purpose of the project, a system is established to link worker-centered occupational safety and health management with technology-based safety construction management, and analysis of how the quality control of the earthquake prevention affects safety construction management The purpose of this study is to prepare the optimum management plan of construction business.As a result of this study, it is aimed to accomplish the purpose of small scale redevelopment and reconstruction construction project by providing optimization method in the stage of construction project management in order to prevent collapse caused by differences in design,Is expected.

A Study on Risk Mitigation Measures of NaTech Damage Effect of Hazardous Chemical Storage Tank - Focus on Triggered by Earthquake - (화학물질 저장탱크의 NaTech 피해영향 저감방법 연구 - 지진으로 인한 사고 중심으로 -)

  • Lee, Tae-Hyung;Lee, Hyun-Seung;Yoo, Byung-Tae
    • Journal of the Korean Institute of Gas
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    • v.22 no.5
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    • pp.79-88
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    • 2018
  • This study presents an evaluation method to estimate the damage scale of chemical storage tank of petrochemical plant due to the earthquake that is likely to occur among NaTech damage types. Based on this, the risk for damage reduction of chemical storage tanks was evaluated. As a result of the study, the risk of the storage tank increased greatly considering the earthquake, and the risk was greatly reduced as a result of evaluating the proposed measures to mitigate the damage impact on the earthquake. This study is expected to contribute to the research on the reduction of NaTech damages such as typhoons and thunderstorms as well as earthquakes, and to establish an emergency response plan. In the future, it is necessary to systematically study and institutionalize the risk reduction measures considering earthquakes.

Improving Information Service for Earthquake Using Rapid ShakeMap

  • Hwang, Jinsang;Ha, Ok-Kyoon
    • Journal of the Korea Society of Computer and Information
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    • v.26 no.5
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    • pp.95-101
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    • 2021
  • In this study, we present how to improve the current seismic disaster information service by utilizing Shake, which can express the effects of earthquakes in the form of isolines. Using ShakeMap software provided by the U.S. Geological Survey, an automated rapid ShakeMap generation system was implemented, and based on this, an earthquake disaster information service improvement model was presented to identify earthquake risk in the form of intensity or peak ground acceleration. In order to verify the feasibility and effectiveness of the improved model, the seismic disaster information service app. was developed and operated on a trial basis in Pohang, Gyeongsangbuk-do. As a result of the operation, it was found that more detailed seismic risk information could be provided by providing information using rapid ShakeMap to induce users' safety behavior more effectively.

Comparative analysis of existing reinforced concrete buildings damaged at different levels during past earthquakes using rapid assessment methods

  • Sezer Aynur;Hilal Meydanli Atalay
    • Structural Engineering and Mechanics
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    • v.85 no.6
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    • pp.793-808
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    • 2023
  • Türkiye is located in a region where destructive earthquakes are frequently experienced due to its geological characteristics and geographical location. Therefore, considering the possibility of a devastating earthquake at any time, determining the reinforced concrete (RC) building seismic safety, constructed before or after the current seismic buildings code, is one of the most important issues to be completed firstly. For this purpose, rapid assessment methods developed to quickly determine the seismic safety of buildings are available in the literature. Comparison of the principles of Principles of the Determination of Risky Structures-2019, Column and Wall Index Method, P25 Scoring Method and Improved Discriminant Analysis Method, which are among these methods, have been aimed within the scope of this study. Within the scope of this paper, a total of 43 buildings in the Yalova/Çınarcık region of Türkiye that the damage level was determined by street observation method immediately after the 1999 Kocaeli (Izmit) Earthquake; 15 buildings with heavy damage and 28 buildings with moderate damage were examined by rapid assessment methods. Although the risk detection difference was not separated as a clear line in any of the methods used, the results obtained from the rapid assessment methods are evaluated as being compatible with the detected after earthquake structural seismic behavior of the buildings. The PDRS-2019 and column and wall index method gave the most approximate results. In the results obtained from the analyzes; structural features such as number of floors, frame continuity, soft/weak story irregularity, effective shear strength area, existence of heavy overhangs in plan, type of structural system have been found to be significantly effective on the earthquake behavior of buildings.