• Nuclear Engineering and Technology
• /
• 제51권5호
• /
• pp.1470-1476
• /
• 2019

The nuclear power plants in South Korea have been designed in accordance with the U.S. Regulatory Guide 1.60 (R.G 1.60) design spectrum of which the peak frequency range is 2-10 Hz. The characteristics of the earthquakes at the Korea nuclear power plant sites were observed to be closer to that of Central and Eastern United States (CEUS) than the R.G 1.60, which is a lower amplification in a low frequency range, and a higher amplification in a high frequency range. The possibility of failure for sensitive power plant components in the high frequency range has been considered and evaluated. In this study, in order to improve the reliability of nuclear plant and administrative control procedures, seismic tests of an emergency diesel generator (EDG) were conducted using a shaking table under both high and low frequency ranges. From the tests, oil/lubricant leaks from the bolt connections, the fuel filter and the fuel inlet were observed. Therefore, the check list of nuclear plant components after an earthquake should include bolt connections of EDG as well as anchor bolts.

• Nuclear Engineering and Technology
• /
• 제37권2호
• /
• pp.191-200
• /
• 2005

Shaking table tests of the seismic behavior of a steel frame structure model were performed. The purpose of these tests was to estimate the effects of a near-fault ground motion and a scenario earthquake based on a probabilistic seismic hazard analysis for nuclear power plant structures. Three representative kinds of earthquake ground motions were used for the input motions: the design earthquake ground motion for the Korean nuclear power plants, the scenario earthquakes for Korean nuclear power plant sites, and the near-fault earthquake record from the Chi-Chi earthquake. The probability-based scenario earthquakes were developed for the Korean nuclear power plant sites using the PSHA data. A 4-story steel frame structure was fabricated to perform the tests. Test results showed that the high frequency ground motions of the scenario earthquake did not damage the structure at the nuclear power plant site; however, the ground motions had a serious effect on the equipment installed on the high floors of the building. This shows that the design earthquake is not conservative enough to demonstrate the actual danger to safety related nuclear power plant equipment.

• 한국해안해양공학회지
• /
• 제17권1호
• /
• pp.41-46
• /
• 2005

항만구조물의 유체-구조물-지반 상호작용(FSSI)을 고려한 지진응답해석을 수행하였다. 우리나라 동남해안에 위치한 방파제 구조물을 대상으로 장주기 및 단주기파로 구분된 지진을 비롯하여 최근 우리나라에서 발생한 울진지진에 대한 지진응답특성에 대하여 고찰하였다. FSSI 효과를 고려하기 위하여 유체요소는 평면변형해석에 사용하는 4절점 사변형요소를 수정한 요소를 이용하여 모델링 하였다. 그리고 FSSI해석, 진도법, 부가질량법에 의한 지진응답특성을 비교하였다. 고유치해석을 통하여 방파제의 고유주기를 찾고, 기존의 지진 및 최근 우리나라에서 발생한 지진에 대한 지진응답특성 결과로부터 방파제 구조물이 장주기성분에 대한 영향을 더 많이 받는 것을 확인하였다.

• Earthquakes and Structures
• /
• 제7권1호
• /
• pp.83-99
• /
• 2014

This study is devoted to estimate higher-mode effects for multi-story structures with considering soil-structure interaction subjected to decomposed parts of near-fault ground motions. The soil beneath the super-structure is simulated based on the Cone model concept. Two-dimensional structural models of 5, 15, and 25-story shear buildings are idealized by using nonlinear stick models. The ratio of base shears for the soil-MDOF structure system to those obtained from the equivalent soil-SDOF structure system is selected as an estimator to quantify the higher-mode effects. The results demonstrate that the trend of higher-mode effects is regular for pulse component and has a descending variation with respect to the pulse period, whereas an erratic pattern is obtained for high-frequency component. Moreover, the effect of pulse component on higher modes is more significant than high-frequency part for very short-period pulses and as the pulse period increases this phenomenon becomes vice-versa. SSI mechanism increases the higher-mode effects for both pulse and high-frequency components and slenderizing the super-structure amplifies such effects. Furthermore, for low story ductility ranges, increasing nonlinearity level leads to intensify the higher-mode effects; however, for high story ductility, such effects mitigates.

• 한국산업융합학회 논문집
• /
• 제22권6호
• /
• pp.739-748
• /
• 2019

In this study, cyclic triaxial tests were performed for liquefaction characteristics according to earthquake loading frequency. The test period was tested for 0.1Hz, 0.2Hz, 0.5Hz 1.0Hz, 1.5Hz. It was analyzed that the number of earthquake loading increases as the test result frequendy increases. Therefore, additional study of the liquefaction evaluation method was needed considering the local characteristics of the high frequency earthquakes in Korea and the cyclic triaxial test frequency(0.1Hz), which is mainly used in the design.

• 한국수자원학회논문집
• /
• 제30권3호
• /
• pp.195-199
• /
• 1997

지진 발생시 댐에 야기되는 동수압에 대하여 고전이론에서는 이를 정상상태로 취급하였는데 반하여 본 논문에서는 지진운동을 일시적인 현상으로 취급하여 비정상 선형 이론을 가지고 동수압을 검증하였다. 더욱이 지진운동은 불규칙한 수평 및 수직운동으로 구성되어있으며, 이 운동은 일시적인 현상으로 곧 사라짐으로 정상운동이 아니다. 따라서 지진운동에 의한 동수압은 비정상적으로 취급해야하며 불규칙한 지진운동을 그대로 입력하여 동수압을 구해야한다. 고전 이론에서는 지진운동을 수평적이며 단일 Sine 함수로 구성된 정상운동으로 가정하였으며 또한 물을 비압축성 물질로 가정하였으며 지진시 야기되는 수면파는 적다고 가정하여 무시하였다. 이러한 가정들을 모두 본 이론에 적용하였을 시 계산되는 동수압은 고전 이론에서 제시한 결과와 잘 일치함을 보여준다.

• Asian Journal of Business Environment
• /
• 제4권1호
• /
• pp.25-35
• /
• 2014

Purpose - Appropriate project management knowledge as well as its effective application in the construction industry increase construction quality and, therefore, reduce fatalities and destruction. Research design, data, and methodology - This study was conducted through a comparative analysis of earthquake fatalities in Iran, Turkey, Pakistan, Indonesia, China, Haiti, Japan, and the United States of America. The data was analyzed using a frequency study. The analysis contrasts the fatalities of some of the strongest earthquakes around the world between 1960 and 2010. Results - Poor quality construction practices and a lack of effective application of project management knowledge play a major role in the vast destruction, high death toll, and dismal tragedies that are associated with earthquakes, especially in Iran. Conclusions - Despite the history of tragic earthquakes and their continuing recurrence, this study attempts to make governments, companies, and disaster management personnel aware of the dangers of poor quality construction and the deficient application of project management knowledge and, further, accentuates effective ways to prevent the probability of serious damage in future. This study contains valuable information on the effects of project management application towards reducing earthquake fatalities and destruction.

• 한국지반공학회:학술대회논문집
• /
• 한국지반공학회 1999년도 토목섬유 학술발표회 논문집
• /
• pp.69-83
• /
• 1999

Soil-reinforced segmental retaining walls(SRW) have been proven to be high earthquake-resistant structure during recent earthquakes in United States and Japan. The mechanicals behavior of the SRWs under seismic loading, however, has not been fully understood. Although the seismic design issues for the civil engineering structures have gained much attention in Korea due to the increase in frequency of earthquake occurrence, the seismic design for the SRWs has not been being implemented. This study has been undertaken with the aim of developing a more rational seismic design/analysis method for soil-reinforced segmental retaining walls. This paper present fundamentals of current seismic design/analysis method and the results of a comparative study between NCMA and FHWA design guidelines, Practical implications of the findings from this study are discussed in great detail.

• Interaction and multiscale mechanics
• /
• 제6권4호
• /
• pp.339-356
• /
• 2013

This paper investigates the optimized parameters of Tuned Mass Dampers (TMDs) for vibration control of high-rise structures including Soil Structure Interaction (SSI). The Artificial Bee Colony (ABC) method is employed for optimization. The TMD Mass, damping coefficient and spring stiffness are assumed as the design variables of the controller; and the objective is set as the reduction of both the maximum displacement and acceleration of the building. The time domain analysis based on Newmark method is employed to obtain the displacement, velocity and acceleration of different stories and TMD in response to 6 types of far field earthquakes. The optimized mass, frequency and damping ratio are then formulated for different soil types; and employed for the design of TMD for the 40 and 15 story buildings and 10 different earthquakes, and well results are achieved. This study leads the researchers to the better understanding and designing of TMDs as passive controllers for the mitigation of earthquake oscillations.

• 자원환경지질
• /
• 제36권3호
• /
• pp.201-212
• /
• 2003

한반도 남동부의 경상분지에 한국지질자원연구원의 지진관측망을 비롯한 관측소들이 급격히 증가함에 따라, 지진관측의 능력이 최근에 들어 크게 향상되었다. 그러나, 빈번한 중소규모의 화약발파에 의한 진동이 다수 관측되고 있다. 따라서, 이 지역에서 자연지진과 발파에 의한 인공지진의 식별이 중요한 문제로 부상하였다. 이 지역에서의 인공지진과 자연지진의 적절한 식별법을 확립하기 위하여 소규모의 지역지진 43개와 이에 대응되는 인공지진 43개를 선정하였다. 이 연구에서는 주파수 영역에서 Pg파, Sg파 및 Lg파의 스펙트럼 진폭비를 이용하는 기법들이 폭 넓게 검토되었다. 그들 중 Pg/Lg 스펙트럼 진폭비를 이용하는 방법이 가장 좋은 식별법으로 나타났다. 또한, 식별능력을 향상시키기 위하여 Pg/Lg 스펙트럼비에 다변량 판별분석법을 적용하였다. 거리보정이 안된 수직성분에 비하여 거리에 대한 감쇠효과를 보정한 3성분의 Pg/Lg비에 판별분석법을 적용했을 때의 판별능력은 뚜렷한 증가를 보인다. 주파수 대역 4-l4Hz의 범위에서, 거리 보정한 3성분의 Pg/Lg비에 대한 판별분석의 결과 총 분류비율은 0.89%에 불과한 것으로 나타난다.