• Journal of the Korean earth science society
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• v.43 no.1
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• pp.151-164
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• 2022

According to the records of historical and instrumental earthquakes, the southeastern part of the Korean Peninsula is considered the highest seismic activity area. Owing to recent reports of numerous Quaternary faults along the Yangsan and Ulsan fault zones, paleoseismological studies are being actively conducted in these areas. The study area is located in the central part of the Ulsan fault zone, where the largest number of active faults have been reported. Based on lineament and geomorphic analysis using LiDAR images and aerial photographs, fault-related landforms showing topographic relief were observed and a trench survey was conducted. The trench length 20 m, width 5 m, depth 5 m is located approximately 300 m away to the northeast from the previously reported Malbang fault. From the trench section, we interpreted the geometric and kinematic characteristics of the fault based on the deformed features of the Quaternary sedimentary layers. The attitude of the reverse fault, N26°W/33°NE, is similar to those of the reported faults distributed along the Ulsan fault zone. Although a single apparent displacement of approximately 40 cm has been observed, the true displacement could not be calculated due to the absence of the slickenline on the fault plane. Based on the geochronological results of the cryogenic structure proposed in a previous study, the most recent faulting event has been estimated as being earlier than the late Wurm glaciation. We interpreted the thrust fault system of the study area as an imbrication structure based on the previous studies and the fault geometry obtained in this additional trench. Although several previous investigations including many trench surveys have been conducted, they found limited success in obtaining the information on fault parameters, which could be due to complex characteristics of the reverse fault system. Additional paleoseismic studies will contribute to solving the mentioned problems and the comprehensive fault evolution.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.6
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• pp.152-161
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• 2023

In general, large-capacity hydrogen storage vessels, typically in the form of vertical cylindrical vessels, are constructed using steel materials. These vessels are anchored to foundation slabs that are specially designed to suit the environmental conditions. This anchoring method involves pre-installed anchors on top of the concrete foundation slab. However, it's important to note that such a design can result in concentrated stresses at the anchoring points when external forces, such as seismic events, are at play. This may lead to potential structural damage due to anchor and concrete damage. For this reason, in this study, it selected an vertical hydrogen storage vessel based on site observations and created a 3D finite element model. Artificial seismic motions made following the procedures specified in ICC-ES AC 156, as well as domestic recorded earthquakes with a magnitude greater than 5.0, were applied to analyze the structural behavior and performance of the target structures. Conducting experiments on a structure built to actual scale would be ideal, but due to practical constraints, it proved challenging to execute. Therefore, it opted for an analytical approach to assess the safety of the target structure. Regarding the structural response characteristics, the acceleration induced by seismic motion was observed to amplify by approximately ten times compared to the input seismic motions. Additionally, there was a tendency for a decrease in amplification as the response acceleration was transmitted to the point where the centre of gravity is located. For the vulnerable components, specifically the sub-system (support columns and anchorages), the stress levels were found to satisfy the allowable stress criteria. However, the concrete's tensile strength exhibited only about a 5% margin of safety compared to the allowable stress. This indicates the need for mitigation strategies in addressing these concerns. Based on the research findings presented in this paper, it is anticipated that predictable load information for the design of storage vessels required for future shaking table tests will be provided.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.4
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• pp.108-118
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• 2006

The purpose of this study is to investigate the effectiveness of a LQG Hybrid controller to suppress the earthquake disturbance for the building structure. The ground acceleration of N-S component of El-Centro earthquake was scaled to confirm that the building behaved within the elastic range. The tuned mass damper(TMD) on the top floor regulated by LQG algorithm was designed to control the floor displacements. The displacement responses of the hybrid control were compared with those obtained from an active control along with a passive control. The results showed that the LQG hybrid control used approximately 50% less input forces than an active control to satisfy the performance criteria.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.4
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• pp.43-50
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• 2004

A large concrete dam, of which construction work had not been continued for more than 20 years because of social problem, was investigated with emphasis on its seismic performance. Mechanical properties of the concrete dam material were estimated by performing uniaxial compression tests for obtained the samples from dam body. Borehole image Processing System (BIPS) was used to investigate the susceptible faults developed in the interface between old an new concretes. Using the results of several laboratory and field tests earthquake response analysis for the dam were done, The results of such investigation show that its physical and mechanical conditions are in a good condition, and the results earthquake response analysis imply that the dam, even it consists of two different concretes, show good seismic performance.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.28-34
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• 2011

Because strong urban earthquakes must produce huge losses of both life and property, examinations about the effect of huge earthquakes for tall buildings are very required. The goal of this report is examining model safety and compare the behavior of 2-D tall models under huge seismic loads. This report examines high-rise models designed KBC2009 codes using 1) seismic loads regulated by KBC2009 and 2) amplified seismic loads assumed to strong earthquakes. And observing for more realistic behavior of tall buildings under huge earthquakes, this report takes two analysis methods - response spectrum analysis and non-linear time history analysis considering P-delta effect.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.6 s.46
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• pp.1-12
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• 2005

For a shear-deformable beam-column element subjected io non-conservative forces, equations of motion and a finite element formulation are presented applying extended Hamilton's principle. The influence of non-conservative force's direction parameter, internal and external damping forces, and shear deformation and rotary inertia effects on divergence and flutter loads of Beck's columns are intensively investigated based on element stiffness, damping and mass matrixes derived for the non-conservative system.

• Journal of the Earthquake Engineering Society of Korea
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• v.15 no.6
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• pp.81-90
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• 2011

The purpose of this study was to investigate the seismic performance of reinforced concrete bridge columns with interlocking circular hoops. Three interlocking columns were tested under a constant axial load and a quasistatic, cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology) was used for the analysis of reinforced concrete structures. The used numerical method gives a realistic prediction of performance throughout the loading cycles for several test specimens investigated. Based on the experimental and analytical results, design recommendations are presented to improve the existing practice in the design and construction of reinforced concrete bridge columns with interlocking circular hoops.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.51-62
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• 2010

The purpose of this study was to investigate the performance of hollow precast segmental PSC bridge columns. The proposed system can reduce work at a construction site and makes construction periods shorter. Shortened construction times, in turn, lead to important safety and economic advantages when traffic disruption or rerouting is necessary. Two hollow precast segmental PSC bridge columns were tested under a constant axial load and a quasistatic, cyclically reversed horizontal load. A computer program, RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures, was used. The proposed numerical method gives a realistic prediction of performance throughout the loading cycles for several test specimens investigated.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2012.07a
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• pp.152-154
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• 2012

2011년 3월 11일 일본 혼슈 센타이 부근 해역에서 발생한 규모 9.0의 지진에 의한 쓰나미로 동북부 지역에 엄청난 피해가 발생함에 따라 우리나라에서도 지진을 비롯한 각종 대규모 자연재해 대비를 위해 재난방송에 대한 체계를 전반적으로 재점검해야 한다는 의견이 나오고 있다. 지금까지 우리는 재난이 발생하면 TV나 라디오 등 전통적인 매체에 의존하고 있으며 실제 이러한 매체는 지금까지 국민들에게 신속하게 재난정보를 알리는 중요하고도 충실한 역할을 담당해 오고 있다. 그러나 지난해 일본의 쓰나미와 같이 인간의 능력으로 감당하기 힘든 대규모 재난이 발생하였을 경우 이러한 전통적인 재난 방송 매체만으론 역 부족이 될 수 있고, 실제로 일본에서 효과를 나타낸 것은 인터넷 전화(VoIP)와 SNS(Social Network Service) 등 뉴미디어로 구글, 페이스 북과 국내의 NHN, 다음 등은 실종자 정보와 피난처 정보를 제공하고 피해자의 안위를 확인할 수 있는 서비스 하는 등 필요한 정보를 실시간으로 알리는 새로운 매체로 큰 역할을 했다는 평가를 받았다. 본 논문에서는 뉴미디어를 재난방송 전달 매체로 활용하기 위해 현재 운영되고 있는 재난방송 체계 및 시스템의 조사를 통해 개선되어야 할 사항을 도출한다.

• Proceedings of the KAIS Fall Conference
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• 2010.05b
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• pp.653-656
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• 2010

개착식 구조물의 내진성능 예비평가는 설계자료나 현장조사를 토대로 지진도 그룹, 취약도 지수, 영향도 지수를 산정하여 내진성능 상세평가의 시행여부를 판단하는 근거가 되어왔다. 내진성능 예비평가를 적용했던 사례를 분석한 결과 평가항목 산정 시 근거가 미약하고, 내진성능 상세평가 대상으로 분류되지 않은 그룹에 대해 구조적 내진성능 확보가 불확실하여 내진성능 예비평가를 개정하였다. 개정한 내진성능 예비평가는 지진도 그룹, 취약도 지수, 영향도 지수를 적용하는 기존의 틀은 유지하면서 평가항목을 산정하는 근거를 명확하게 하였으며, 내진성능 상세평가를 실시하지 않는 그룹에 대해서도 간략하게 구조적 내진성능 확보여부를 검토할 수 있는 전단변형각을 도입하였다. 본 연구에서는 개정한 내진성능 예비평가를 기존 사례에 적용하여 결과를 도출하였으며, 기존의 적용 사례와 비교 분석하였다.