• Title/Summary/Keyword: 이영학

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Experimental Investigation of the Flexural Behavior of Lightweight Aggregate Concrete Beams (경량 콘크리트 보의 휨 거동에 관한 실험적 연구)

  • Byon, Eun-Hyuk;Cho, Jang-Se;Lee, Young-Hak;Kim, Hee-Cheul
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 2010.04a
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    • pp.441-444
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    • 2010
  • 대공간 구조물과 초고층 빌딩에 있어 건축물의 자중 감소에 대한 요구가 늘어나고 있으며 이에 대한 가장 효과적인 방법 중 하나는 경량 콘크리트를 사용하는 것이다. 본 연구는 최외단 철근의 순인장 변형률에 따른 경량콘크리트 보의 휨 거동 및 휨 성능을 평가하는 것에 그 목적이 있다. 크기와 형상이 동일한 보통중량 콘크리트 보 1개와 경량 콘크리트 보 4개의 총 5개 시험체를 제작하여 최외단 철근의 순인장 변형률을 변수로 실험을 수행하였으며 이를 통해 순인장 변형률에 따른 경량콘크리트 보의 강도와 연성의 변화를 분석하였다. 실험 결과 최외단 철근의 순인장 변형률이 증가할수록 시험체의 연성비는 증가하였으며 최대하중과 강성은 감소하였다. 특히 순인장 변형률 0.005 이상에서 연성지수 2 이상을 확보할 수 있었다.

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Nonlinear finite element analysis of Concrete Filled Carbon Tube Columns Using Plasticity Theory (축하중을 받는 콘크리트 충전 탄소섬유튜브 기둥의 소성 이론을 적용한 비선형 유한요소해석)

  • Kim, Heecheul;Seo, Sang Hoon;Lee, Young Hak
    • KIEAE Journal
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    • v.7 no.6
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    • pp.119-126
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    • 2007
  • In the field of composite structures, the use of carbon tube for the confinement of concrete has been arisen since 1990's. However, experimental and analytical studies were limited to those of reinforced concrete and concrete filled steel tube. The carbon tube provides excellent confinement capabilities for concrete cores, enhancing compressive strength and ductility of concrete significantly. The carbon tube has high tensile strength, light weight, corrosion immunity and high fatigue strength properties. Since carbon fiber is an anisotropic material, carbon tube could be optimized by adjusting the fiber orientation, thickness and the number of different layers. In this study, both experimental and analytical studies of axial and lateral behavior of full-scale CFCT (Concrete Filled Carbon Tube) columns subjected to monotonic axial load were carried out using Drucker-Prager theory. And, based on comparison results between experiment results and analytical results, k factor estimation was proposed for effective analysis.

Current Status and Improvement Plan for Records Management at Research and Management Institutions: Focused on Core Research Records (연구관리 전문기관 기록물관리 현황 및 개선 방안: 핵심 연구기록물을 중심으로)

  • Kim, Hye-mi;Lee, Young-hak
    • Journal of Korean Society of Archives and Records Management
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    • v.19 no.2
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    • pp.173-191
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    • 2019
  • A research and management institution plays a middleman role between government departments and research institutes. Research records collected from research institutes are important not only as evidence for research tasks but also for knowledge and information sharing. In this study, the key research records collected by research management institutions are identified, and problems are analyzed to present efficient measures to improve key research management.

Bursting Force Equation for Design in Unbonded Post-Tensioned Anchorage Zone (비부착 포스트텐션 정착구역 설계를 위한 파열력 산정 방법)

  • Ro, Kyong Min;Lee, Young Hak
    • Journal of the Architectural Institute of Korea Structure & Construction
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    • v.34 no.12
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    • pp.21-26
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    • 2018
  • For evaluating equations of bursting force in different codes, comparative study of the formulas was conducted. Because the equations does not consider variables such as shape of anchorages and duct, a relation between the bursting forces and the variables has to be analyzed. In this paper, the bursting forces equation was proposed by finite element analysis. As evaluation through comparison of the proposed equation with the previous ones and an experiment, it was figured out that bursting force computed by the proposed equation could be used for design of reinforcement in the anchorage zone.

Seismic Performance of Replaceable Steel Brace System Subjected to Combined Loadings (복합하중을 고려한 교체 가능한 강재 브레이스 시스템의 내진성능)

  • Ro Kyong Min;Kim Yoon Sung;Kim Min Sook;Lee Young Hak
    • Journal of Korean Association for Spatial Structures
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    • v.23 no.4
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    • pp.43-50
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    • 2023
  • This study aims to assess the seismic performance of retrofitted reinforced concrete columns using a Replaceable Steel Brace (RSB) system, subjected to combined axial, lateral, and torsional loadings. Through experimental testing, one non-retrofitted concrete column specimen and two retrofitted specimens with variable sliding slot lengths were subjected to eccentric lateral loads to simulate realistic seismic loading. The retrofitted specimens with RSBs exhibited enhanced resistance against shear cracking, effective torsional resistance, and demonstrated the feasibility of easy replacement. The RSB system substantially improved seismic performance, achieving approximately 1.7 times higher load capacity and 3.5 times greater energy dissipation compared to non-retrofitted column, thus validating its efficacy under combined loading conditions.

Performance Evaluation of Welded Joints for Single-Layer Latticed Domes through Joint Rigidity Test (단층 래티스 돔에 적용 가능한 용접 접합부의 휨실험을 통한 성능 평가)

  • Lee, Young Hak;Seo, Sang Hoon;Kim, Min Sook;Kim, Hee Cheul;Lee, Sung Min
    • Journal of Korean Society of Steel Construction
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    • v.20 no.5
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    • pp.601-608
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    • 2008
  • Joints of single-layer latticed domes show various flexural behaviors according to their shapes and connecting methods. Ball joints are relatively easy to apply and build while their rigidities are relatively small and have disadvantage in long span. Welded joints have many advantages in rigidity, internal force and long span. However few experimental studies have been performed. In this paper, improved welded joint for the single layer latticed domes was proposed through both analytical and experimental analyses. Length of inserted plates, thickness of inserted plates and hole of sub steel pipes were selected as parameters for experimental comparisons and defining the effects of the selected variables.

3D Face Recognition using Projection Vectors and Surface Curvatures (투영 벡터와 표면 곡률을 이용한 3차원 얼굴 인식)

  • Park, Rocky;Lee, Yeung-Hak;Yi, Tai-Hong
    • Journal of KIISE:Software and Applications
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    • v.33 no.1
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    • pp.130-137
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    • 2006
  • The depth information in the face represents personal features in detail. In particular, the surface curvatures extracted from the face contain the most important personal facial information. This surface curvature and together with grouped projection vector which reduces the dimensions resulting less computations are collaborated into the proposed 3D face recognition algorithm. The maximum and minimum curvature are calculated from the surface curvature image, which are grouped into projected vectors for recognition. The minimum curvature showed the best recognition rate among the surface parameters.

Experimental Study on Shear Strength of Concrete Deep Beam Reinforced FRP Bars (FRP Bar로 보강된 콘크리트 깊은보의 전단강도에 관한 실험적 연구)

  • Cho, Jang-Se;Kim, Min-Sook;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.24 no.1
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    • pp.23-31
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    • 2011
  • This study carried out shear experiment for concrete deep beam reinforced FRP(Fiber Reinforced Polymers) bar to investigate shear strength of deep beam. The test conducted for 15 specimens, and the variables were shear span-to-depth ratio, reinforcement ratio, effective depth, reinforcement components of shear strength. crack, deflection are investigated based on shear experimental. We compared shear strength using ACI 318-08 STM with proposed equations that considered arching action according to shear span-to-depth ratio. Consequently shear strength of deep beam reinforced FRP bar presented higher shear strength than steel bar. ACI STM's predictions are better accurate than other predicting equations.

Analytical Study on Punching Shear of Reinforced Concrete Flat Plates (철근콘크리트 플랫 플레이트의 뚫림전단 거동에 관한 해석적 연구)

  • Kim, Min-Sook;Lee, Young-Hak;Kim, Hee-Cheul
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.23 no.4
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    • pp.409-415
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    • 2010
  • A finite element model for punching shear of flat plate structures is presented. A parametric study also has been conducted to verification of influence of several parameters in terms of the flexural reinforcement ratio, slab thickness. Reisnner-Mindlin assumptions are adopted to consider of shear deformation. Layered shell element is considered for the material non-linearities. The finite element model of this study was verified comparing with existing experimental results. The model is able to predict the capacity of the flat plate structures. The punching shear of flat plate structures varied depending on the flexural reinforcement ratio, slab thickness.

Reliability Analysis of Concrete Filled Carbon Composite Tube (탄소 섬유관으로 구속된 콘크리트 부재의 신뢰성 해석)

  • Kim, Hee-Cheul;Lee, Kyoung-Hun;Hong, Won-Kee;Lee, Young-Hak;Eom, Chul-Hwan
    • Journal of the Earthquake Engineering Society of Korea
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    • v.10 no.5 s.51
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    • pp.1-9
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    • 2006
  • In this study, axial and lateral loading experiments for both circular and square plain concrete columns confined with carbon fiber tube manufactured by carbon filament winding technique were performed. Based on the test results, reliability analyses to estimate strength reduction factors were carried out by utilizing Monte Carlo technique. CASE I was for plain concrete columns confined with the carbon tubes, CASE II was for reinforced concrete columns confined with the carbon tubes. As results, the strength reduction factors, ${\phi}$, were estimated as 0.7 for CASE I and 0.85 for CASE II respectively.