• Magazine of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.13-25
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• 2003

• Magazine of the Korean Society of Hazard Mitigation
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• v.3 no.4 s.11
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• pp.39-40
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• 2003

• Journal of the Korea institute for structural maintenance and inspection
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• v.28 no.3
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• pp.91-99
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• 2024

Piping systems are crucial facilities used in various industries, particularly in areas related to daily life and safety. Piping systems are fixed to the main structures of buildings and facilities but do not support external loads and serve as non-structural elements performing specific functions. Piping systems are affected by relative displacements owing to phase differences arising from different behaviors between two support points under seismic loads; this can cause damage owing to the displacement-dominant cyclic behavior. Fittings and joints in piping systems are representative elements that are vulnerable to seismic loads. To evaluate the seismic performance and limit states of fittings and joints in piping systems, a high-stroke actuator is required to simulate relative displacements. However, this is challenging because only few facilities can conduct these experiments. Therefore, element-level experiments are required to evaluate the seismic performance and limit states of piping systems connected by fittings and joints. This study proposed a method to evaluate the seismic performance of an elbow specimen that includes fittings and joints that are vulnerable to seismic loads in vertical piping systems. The elbow specimen was created by connecting straight pipes to both ends of a 90° pipe elbow using flexible groove joints. The seismic performance of the elbow specimen was evaluated using a cyclic loading protocol based on deformation angles. To determine the margin of the evaluated seismic performance, the limit states were assessed by applying cyclic loading with a constant amplitude.

• 한국방재학회:학술대회논문집
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• 2008.02a
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• pp.253-256
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• 2008

지하 토사 조건 및 지질 구조는 지진 시 지반 운동의 증폭에 관련된 부지 효과에 매우 큰 영향을 미친다. 본 연구에서는 국내 홍성 지역을 대상으로 시추 조사와 현장 탄성파 시험을 포함한 현장 조사 및 지표 부근지질 정보를 획득하기 위한 부지 답사를 통해 부지 효과를 확인하였다. 홍성 지역은 1978년 계기 지진이 발생한 지역으로서 기반암 상부에 최대 약 50 m 두께의 풍화대 지층이 분포한다. 연구 대상 지역의 공간 지층 구조를 효율적으로 확인하기 위하여 지리정보시스템(GIS) 기법 기반의 지반 정보 시스템(GTIS)의 구축하였으며, 홍성 지역은 분지는 얕고 넓은 형상임을 확인하였다. 홍성 지역의 부지 지진 응답을 평가하기 위하여 대표 단면에 대한 2차원 유한 요소 해석을 수행하였다. 도출된 지진 응답으로부터 지반 운동이 기반암 상부 토사층을 통해 전단파가 전파되면서 증폭되고 분지 형상에 따른 전단파의 상호 작용으로 생성된 표면파로 인해 분지 경계 부근 진동 지속 시간이 증가됨을 확인하였다. 뿐만 아니라, 분지 내의 선정된 토사 부지들에 대해서 추가적인 1차원 유한 요소 지진 응답 해석을 수행하였으며, 본 연구 대상 분지가 매우 얕고 넓음에 따라 분지 경계 부근을 제외하고는 분지 내 대부분의 위치에서 2차원 지진 응답과 유사한 결과를 보였다.

• Journal of the Korean Society of Hazard Mitigation
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• v.11 no.2
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• pp.171-177
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• 2011

Tsunami forces acting on coastal structures have not been relatively much paid attention by researchers. However, they should be appropriately reflected in design of coastal and harbor facilities. The temporary and permanent tsunami shelters have to be chosen to resist stably against unexpected tsunami forces. There have been only few numerical studies on the tsunami forces acting on coastal and harbor structures. In this study, a practical prediction of tsunami forces is carried out by using a two-dimensional numerical model.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.4
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• pp.135-143
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• 2008

During the last decades several devastating tsunamis have been occurred. Recently, there have been increasingly concerned about tsunamis around the Korean Peninsula since the 2004 Sumatra Tsunami occurred on December 26, 2004. In general, the Korean Peninsula is not safe against potential tsunami attacks. The 1983 Central East Sea Tsunami and the 1993 Hokkaido Tsunami caused considerable damage to the Eastern Part of the Peninsula. Thus, a prediction of damage due to tsunamis must be required at the Eastern Part of the Peninsula. In this study, numerical simulation of tsunamis at Pohang New Port, one of the most important ports in the Eastern Part of Korea, is conducted for three different tsunami events. Numerical simulation is focused on inundation on the port and run-down around an intake structure which supplies cooling water to the porthinterland. The computed results show that Pohang New Port is damaged by the most dangerous tsunami which can be generated in the East Sea. Thus, it is required to set up a counter-measure against tsunami attacks at Pohang New Port.

• Journal of the Korean Society of Hazard Mitigation
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• v.5 no.4 s.19
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• pp.95-105
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• 2005

Korea is located away from plate boundaries which are not safe from earthquakes. However, having witnessed the large-scale earthquake in the Tangshan region in 1976 deemed as a safe plate, it should not be assured that Korea is absolutely safe from earthquakes. In addition, many seismologists have claimed that there indeed is a high possibility of earthquakes above mid scale that would occur in Korea. Because it is impossible to prevent earthquake, studies on seismic design and earthquake disaster control system are widely being conducted. However, studies on early response to earthquakes or recovery process are still very limited, and only a few studies for establishing earthquake damage evaluation system are being conducted. Thus, this study aimed to present essential data for establishing earthquake damage evaluation system that takes into account the real situation of structures in Korea. In this study, a nonseimically reinforced concrete apartment structure in Gangnamgu was selected as an standard type of such structures and its earthquake damage was estimated. The result of damage evaluation based on the derivation of vulnerability function and realtive story displacement was compared to that abtained using HAZUS Program Vulnerability Function.

• Journal of the Korean earth science society
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• v.43 no.1
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• pp.176-187
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• 2022

Due to recent mid-scale earthquakes in the Korean Peninsula, the Korean central and local governments are preparing new measures for earthquake hazard mitigation. Geological and geotechnical information is essential for earthquake hazard assessment. Thus, related data have been collected and assimilated as DBs by various national organizations. However, several problems arise when local governments intend to use this information to establish earthquake hazard mitigation measures. In the case of the geological information, small-scale geological maps make it difficult to acquire detailed information, whereas lithofacies and faults do not often match at the boundaries of large-scale geological maps. Significant geotechnical information is lost due to lack of digitalization. Present study proposes four policy plans for geological and geological information management. First, it is necessary to link industry-academictechnology fields to use the information that has already been or to be produced more efficiently and professionally. Second, local government regulations are required to be enacted and revised to accumulate a lot of geological and geotechnical information. Third an expert system should be prepared to improve the quality of the information. Fourth, it is necessary to establish a dedicated department and expand budget support for efficient information management.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.33-41
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• 2023

The application of seismic separation joints that can improve the deformation capacity of piping is an effective way to improve seismic performance. Seismic separation joints capable of axial expansion and bending deformation are installed where deformation is expected and used for the purpose of safely protecting the piping. Bellows are flexible and have low stiffness, so they can be used as seismic separation joints because they have excellent ability to respond to relatively large deformation. In this study, the seismic performance and limit state for bending deformation of 2-ply and 3-ply bellows specimens were evaluated. Seismic performance was evaluated by applying an increasing cyclic load to consider low-cycle fatigue due to seismic load. In order to confirm the margin for the limit state of the evaluated seismic performance, an experiment was conducted in which a cyclic loading of constant amplitude was applied. As a result of the experiment, it was confirmed that the bellows specimen was made of stainless steel and had a high elongation, so that the 2-ply bellows specimen had the limit performance of resisting within 3 cycles even at the maximum forced displacement of the 3-ply bellows specimen.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
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• 1992.08a
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• pp.22-22
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• 1992

지진 해일(진파, Tsunami)에 대한 방재 대책을 검토할 때, 제일 중요시하여야 할 사항은 내습시간, Tsunami 규모 및 피해 예상범위 등이다. 이 문제를 논할 때 지진 예지가 어려운 현시점에서 가장 기본이 되는 자료는 역사적인 사료라 할 수 있다. 유사이래 지진해일로 인하여 한국 연안에 어느 정도의 피해가 있었는가를 연구하는 것은, 앞으로 발생할 수 있는 지진해일 피해의 척도가 될 수 있기 때문에 대단히 중요하다.(중략)