• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.56.2-56.2
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• 2009

• Journal of Korean Society of Steel Construction
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• v.22 no.3
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• pp.229-239
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• 2010

As a new structural system, the diagrid system resists both gravity and lateral loads with diagonal columns. In current seismic design provisions, however, the response modification factor for a new structural system is not provided yet. ATC-63 provides a new methodology for defining various seismic performance factors, including the response modification factor. ATC-63 includes the collapse margin ratio in modifying the response modification factor, which can vary with many structural systems. In this paper, a non-linear static analysis and a dynamic analysis were conducted for four different diagrid models with 4-to 36-story heights. From these analyses, the response modification factor of the diagrid system was evaluated.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2009.04a
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• pp.506-512
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• 2009

최근 건설 중인 금정터널(총 연장 20.3km)이나 부산-거제간 침매터널은 화재 발생시 구조체의 강도저하로 인한 붕괴 및 사회기반시설인 교통망을 장시간 끊어놓은 등 큰 피해를 야기시킬 수 있다. 이러한 초장대터널이나 침매터널은 다른 터널보다 밀폐된 공간이므로 화재 시 단시간에 급격하게 온도상승이 일어날 수 있으며 이로 인해 구조물의 주재료인 콘크리트의 폭렬이 발생하고 구조물 내부까지 고온이 전달되어 경우에 따라 구조체의 붕괴의 원인이 되기도 한다. 따라서 본 연구에서는 콘크리트 구조체의 내화성능을 확보하기 위해 유럽에서 사용되고 있는 터널내화용 보드와 모르타르를 적용한 콘크리트의 내화성능 확보방안을 위한 시험을 수행하였다. 실험에 대한 내화성능 평가는 ITA(International Tunneling Association)에서 정한 화재 손상범위를 평가기준으로 하였고 터널화재 시나리오는 네덜란드의 TNO에 의해 실행된 실험결과를 따른 RWS 화재곡선을 이용하여 수행하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.3
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• pp.219-226
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• 2012

Columns are the key elements supporting load in structure. Column failure causes the structure to collapse. It is important to evaluate residual strength for damaged columns under blast load for preventing progressive collapse. In this paper, columns were investigated to compare the blast resistance on the change of the number of steel bars within the range of reinforcement ratio. And this study was carried out 4 different analytical models to evaluate effects of aspect ratio. The results indicate that the vertical strain was unaffected by the number of steel bars and aspect ratio. As the number of steel bars facing blast load increase, the blast resisting capacity of the columns was improved in the lateral strain. Also, the analysis results showed that a large moment of inertia of area, as compared to a small one would be superior in residual strength as well as force of restitution.

• Composites Research
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• v.20 no.3
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• pp.8-16
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• 2007

Bending collapse of light-weight square tubes used for vehicle structure components is a dominant failure mode in oblique collision and rollover of vehicles. In this paper bending performances of aluminum-GFRP hybrid tube beams were evaluated in relation with bending deformation behavior and energy absorption characteristics. Aluminum/GFRP hybrid tube beams fabricated by inserting adhesive film between prepreg and metal layer were used in the bending test. Failure mechanisms of hybrid tubes under a bending load were experimentally investigated to analyze the bending performance as a function of ply orientation and composite layer thickness. Ultimate bending moments and energy absorption capacity of hybrid tube beams were obtained from the measured load-displacement corves. It was found that aluminum/GFRP hybrid tubes could be converted to rather stable collapse mode showing excellent energy absorption capacity in comparison to the pure aluminum tube beams. In particular, the hybrid tube beam with $[0^{\circ}/90^{\circ}]s$ composite layer showed a large improvement by about 78% in energy absorption capacity and by 29% in specific energy absorption.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.3
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• pp.28-39
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• 2013

The most common housing type in Korea is low-rise buildings with unreinforced masonry walls (UMWs) that have been known as a vulnerable seismic-force-resisting system (SFRS) due to the lack of ductility capacities compared to high lateral stiffness of an UMW. However, there are still a little experimental investigation on the shear strength and stiffness of UMWs and on the seismic performance of buildings using UMWs as a SFRS. In Korea, the shear strength and stiffness of UMWs have been evaluated with the equations suggested in FEMA 356 which can not reflect the structural and material characteristics, and workmanship of domestic UMW construction. First of all, this study demonstrates the differences in shear strength and stiffness of UMWs obtained from between FEMA 356 and test results. The influence of these differences on the seismic performance of UMW buildings is then discussed with incremental dynamic analyses results of a prototype UMW building that were selected by the site survey of more than 200 UMW buildings and existing test results of UMWs. The seismic performance assessment of the prototype UMW building are analyzed based on collapse margin ratios and beta values repesenting uncertainty of seismic capacity. Analysis results show that the seismic performance of the UMW building estimated using the equations in FEMA 356 underestimates both a collapse margin ratio and a beta value compared to that estimated by test results. Whatever the estimation is carried out two cases, the seismic performance of the prototype building does not meet the criteria prescribed in a current Korean seismic code and about 90% collapse probability presents for more than 30-year-old UMW buildings under earthquakes with 2400 return years.

• Journal of Korean Society of Steel Construction
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• v.18 no.5
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• pp.585-596
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• 2006

This study focuses on the seismic behavior of 3-, 9-, and 20-story steel moment resisting frame (MRF) structures designed in accordance with the 2000 International Building Code using different Response Modification factors (R factors), i.e., 8, 9, 10, 11, and 12. For a detailed case study, 30 different structures were evaluated for 20 ground motions representing the hazard level, which is equal to a 2% probability in 50 years (2% in 50 years). The results showed that the current R factors provide conservative designs for the 3- and 9-story buildings for the Collapse Prevention performance objective. the 20-story buildings, which were designed without using the minimum requirement of spectral acceleration CS prescribed in IBC 2000, did not satisfy the seismic performance for Collapse Prevention performance.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.168-168
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• 2017

기후변화로 인한 집중호우 및 태풍의 발생빈도 증가로 인하여 댐 및 저수지 붕괴 우려가 증대되고 있으며, 이에 따른 주변지역 주민들의 불안감도 고조되고 있다. 특히 2017년 2월 미국에서 가장 높은 위치에 있는 캘리포니아주 오로빌 댐은 집중호우로 인해 범람할 가능성이 커지면서 지역민 19만여명을 대피하는 상황이 발생되었다. 국내에서는 기후변화와 댐 안전, 노후화된 댐 성능개선 및 재개발, 유지관리 효율화 증대 방안 등의 다양한 대비책 마련이 제시되고 있으나, 아직까지 기후변화에 따른 수문학적, 구조적 안전성 등 다양한 인자를 고려한 댐 재개발 평가에 대한 정량적 연구가 미흡한 실정이다. 따라서 본 연구에서는 기후변화의 영향과 댐 시설물의 고령화 등에 따른 복합적인 댐 안전성 문제 등에 대비하기 위하여 기후변화를 고려한 댐 재개발 평가 기준 개발/개선하였으며, 국내 다목적댐, 발전용댐, 농업용 저수지댐 1종 시설물을 대상으로 평가를 실시하였다. 또한, 유역경계, 댐, 저수지, 도로 등의 지형데이터베이스와 수자원이용율, 유역면적, 수질, 문화재수 등의 댐 재개발 평가항목들의 속성자료를 검색할 수 있으며, 댐 구역별 기후변화 영향과 수문학적 안전성 평가 정보를 확인 할 수 있는 댐 재개발 평가시스템을 개발하였다. 본 연구성과는 댐 재개발계획 수립을 위한 의사결정 도구로 객관적이고 정량적인 의사결정 판단자료를 제공할 것이며, 댐 붕괴로 발생하는 경제, 사회, 인명 손실을 사전에 예방할 수 있을 것으로 기대된다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.450-453
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• 2009

본 논문에서는 지진하중을 고려하여 충분한 연성거동이 가능하도록 배근한 철근콘크리트 횡하중 저항 골조(내진상세)와 고정하중과 적재하중만을 고려하여 설계한 중력하중 저항 골조(일반상세)를 대상으로 외부기둥과 내부기둥에 연결된 보의 연쇄붕괴 거동을 평가하기 위한 실험을 수행하였다. 일방향 가력실험 결과에 따르면 내진상세의 경우 대변형 상태에서 보의 하단철근의 파단이후 상단 압축철근이 인장력을 부담하면서 전체 보 부재는 축인장력이 작용을 하면서 힘-변위 곡선은 상승하는 현수작용이 발현되었다. 그러나 일반상세의 경우 충분한 현수작용이 발현되기 전에 보의 주근이 정착된 외부기둥 접합부의 파괴로 인하여 저항내력이 감소하였다.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.1
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• pp.27-35
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• 2014

In this study, an improved energy-based nonlinear static analysis method are proposed to be used for more accurate evaluation of progressive collapse potential of steel moment frames by reflecting the contribution of a double-span floor slab. To this end, the behavior of the double-span floor slab was first investigated by performing material and geometric nonlinear finite element analysis. A simplified energy-absorbed analytical model by idealizing the deformed shape of the double-span floor slab was developed. It is shown that the proposed model can easily be utilized for modeling the axial tensile force and strain energy response of the double-span floor slab under the column-removal scenario.