In 2016, an earthquake occurred at Gyeongju, Korea. At the Wolsong site, the observed peak ground acceleration was lower than the operating basis earthquake (OBE) level of Wolsong nuclear power plant. However, the measured spectral acceleration value exceeded the spectral acceleration of the operating-basis earthquake (OBE) level in some sections of the response spectrum, resulting in a manual shutdown of the nuclear power plant. Analysis of the response spectra shape of the Gyeongju earthquake motion showed that the high-frequency components are stronger than the response spectra shape used in nuclear power plant design. Therefore, the seismic performance evaluation of structures and equipment of nuclear power plants should be made to reflect the characteristics of site-specific earthquakes. In general, the floor response spectrum shape at the installation site or the generalized response spectrum shape is used for the seismic performance evaluation of structures and equipment. In this study, a generalized response spectrum shape is proposed for seismic performance evaluation of structures and equipment for nuclear power plants. The proposed response spectrum shape reflects the characteristics of earthquake motion in Korea through earthquake hazard analysis, and it can be applied to structures and equipment at various locations.

As the number of high-rise buildings increases, a mid-story isolation system has been proposed for high-rise buildings. Due to structural problems, an appropriate isolation layer displacement is required for an isolation system. In this study, the mid-story isolation system was designed and the seismic response of the structure was investigated by varying the yield strength and the horizontal stiffness of the seismic isolation system. To do this, a model with an isolation layer at the bottom of 15th floor of a 20-story building was used as an example structure. Kobe(1995) and Nihonkai-Chubu(1983) earthquake are used as earthquake excitations. The yield strength and the horizontal stiffness of the seismic isolation system were varied to determine the seismic displacement and the story drift ratio of the structure. Based on the analytical results, as the yield strength and horizontal stiffness increase, the displacement of the isolation layer decreases. The story drift ratio decreases and then increases. The displacement of the isolation layer and the story drift ratio are inversely proportional. Increasing the displacement of the isolation layer to reduce the story drift ratio can cause the structure to become unstable. Therefore, an engineer should choose the appropriate yield strength and horizontal stiffness in consideration of the safety and efficiency of the structure when a mid-story isolation system for a high-rise building is designed.

This paper relates to the study of load characteristics applicable to wind turbine generators induced by earthquakes. An artificial design earthquake wave generated through the target spectrum and the envelope function of Richter Magnitude Scale (ML) 7.0 as in ASCE4-98 was created. A simulation of earthquake loads were performed according to the design load cases (DLC) 9.5~9.7 of GL guidelines. Additionally, simulation of seismic loads experienced by Wind Turbines installed in the Gyeongju region were carried out utilizing artificial earthquakes of ML 5.8 simulating the real earthquakes during the Gyeongju Earthquakes of Sept. 2016.

In Korea, the occurrence frequency of earthquakes has recently increased, compared with the past. So, the various damages for cultural properties due to earthquake can be expected, and especially fortress structure is vulnerable to earthquake. Therefore, the resonable seismic characteristics evaluation is required to secure the safety for fortress structure with the various construction and configuration types. Also, we should consider the various applied load conditions as design variables. To this end, this study classifies fortress structures according to the construction and configuration types, and then applies the discrete element method to model and analyze fortress structures. Finally, the seismic characteristics is evaluated through slip condition due to the analysis results considering the various design variables.

서울의 두 평야 지역 4km{\times}4km에 대한 부지 고유의 지진 응답 특성 평가를 위하여 대상 지역내 총 350개의 시추 자료를 활용하였다. 국내 내륙 지역의 공내 탄성파 시험의 자료와 시주 자료를 이용하여 N-V_s 상관관계를 도출하고, 이를 토대로 선정된 350 시추 위치에서의 깊이별 전단파 속도(Vs) 분포를 결정하여 등가선형 기법의 부지 응답 해석을 수행하였다. 현행 지반 분류 기준인 심도 30m까지의 평균 Vs (Vs30)는 대상 지역 내에서 250{\~}550 m/s의 분포를 보였고, 그에 따라 대부분의 부지가 지반 분류 C와 D로 분류되었다. 서울 평야 지역의 부지 고유 주기는 국내 지반 증폭 계수의 근간인 미국 서부 지역에 비해 매우 작은 0.1{\~}0.4초의 분포를 보였다. 비록 몇몇 부지에서 토사 층 내에 연약한 지층이 존재함에 따라 기저 고립 효과가 발생하여 현행 단주기 증폭 계수가 지반 운동을 과대평가하기도 하지만, 미국 서부 지역과의 지반 조건 차이로 인해 전반적으로 서울 평야 지역에서는 현행 국내 내진 설계 기준의 단주기(0.1{\~}0.5초) 증폭 계수(Fa)는 지반 운동을 과소평가하고 중장주기(0.4{\~}2.0초) 증폭 계수(Fv)는 지반 운동을 과대평가하고 있다

전단파속도가 1,050m/sec 이하인 경우의 기초지반에 대한 내진해석에서는 지반-구조물 상호작용해석이 반드시 수행되어야 하며, 이러한 기초지반에서는 강지진동 작용시 지반의 비선형성이 현저하게 나타나므로 내진해석시 지반의 비선형성은 필수적으로 고려되어야 한다. 따라서, 본 연구에서는 입력지진동에 따른 지반의 비선형 거동을 평가하기 위한 방법으로서 기존의 수치해석적인 방법에 비하여 평가절차가 단순하고 신뢰성이 높은 Downhole 지진계측자료에 의한 평가방법을 제안하였다. 대만 화련부지를 대상으로 본 연구에서 제안한 지반의 비선형성 평가방법에 대한 신뢰성을 검증한 결과, 기존의 SHAKE프로그램에 의한 평가결과 및 지진응답 계측결과에 잘 일치하는 높은 수준의 정확성을 보임으로써 그 신뢰성 및 가용성을 확인할 수 있었다.

설비배관은 온도에 의한 신축 및 팽창을 고려한 설계를 하거나, 배관의 자중만을 고려하여 설계되고 제작된다. 그러나 설비배관 행거시스템에 지진 또는 지속적인 외부 진동이 발생하면 그 충격을 감소 및 흡수하지 못하고 2차적인 피해로 이어질 수 있다. 이에 따라 본 연구에서는 내진성능을 고려한 설비배관 행거시스템을 개발하고, 진동대 실험을 통해 지진거동특성을 평가하고자한다.

This study presents the structural modelling method for the seismic behavior characteristics evaluation of flat stone bridge. To this end, we select the representative flat stone bridge according to the construction and configuration types. Also, this study provides the discrete element method for the reasonable seismic modelling of discontinuum structures.

This study presents the structural modelling method for the seismic behavior characteristics evaluation of flat stone bridge. To this end, we select the representative flat stone bridge according to the construction and configuration types. Also, this study provides the discrete element method for the reasonable seismic modelling of discontinuum structures.