• Title, Summary, Keyword: confinement

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Effect of Edge Confinement on Deformation Capacity in the Isolated R/C Structural Walls (전단벽의 단부보강효과에 따른 변형능력의 평가)

  • 이희동;한상환;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.525-528
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    • 1998
  • This paper reports on tests of reinforced concrete shear walls for wall-type apartment structure under axial loads and the cyclic reversal of lateral loads with different confinement of the boundary elements. Confinement of the extreme element by U-stirrups and tie hooks seems to be as effective as closed stirrups. The shear strength capacity seems not to be increased by the confinement but deformation capacity improved.

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Confinement Effectiveness on Compressive Zone of RC Walls (철근콘크리트 벽체 압축단부의 구속효과)

  • 김장훈;안상훈
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.459-464
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    • 2001
  • A great level of strength and deformability on compressive zone of RC wall is essentially required when subjected to high axial and in-plane lateral loading due to earthquakes. One of the best ways to handle this situation is to provide the confinement effectiveness to the compressive zone by reinforcing steel. For this a series of design charts were constructed to evaluate the confinement effectiveness for a given steel configuration in accordance with a well-known model and part of them are presented in this paper. Using the chart, designers can choose a desirable steel arrangement in flexural compressive zone of RC walls for a prescribed confinement factor.

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Phase Transition of Confined Gold Nanoparticles: Replica Exchange Molecular Dynamics Study

  • Kim, Hyun-Sik;Li, Feng-Yin;Jang, Soon-Min
    • Bulletin of the Korean Chemical Society
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    • v.33 no.3
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    • pp.929-932
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    • 2012
  • The classical molecular dynamics simulation was used to study the phase transition of gold nanoparticles under confinement using Sutton-Chen (SC) potential. Metal gold nanoparticles with different number of atoms are subject to replica exchange molecular dynamics simulation for this purpose. The simulation showing the solidto-liquid melting temperature largely remains unaffected by confinement, while the confinement induces characteristic pre-melting at very low temperature depending on atom number in nanoparticles.

A Study on the Axial Behavior of the Concrete Cylinders Confined by Carbon Fiber Sheets (탄소섬유쉬트로 횡구속된 콘크리트 공시체의 압축 거동에 관한 연구)

  • Hwang, Jin-Seog
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.4 no.4
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    • pp.141-148
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    • 2000
  • Recently the Carbon Fiber Sheet(CFS) is widely used for strengthening damaged RC structures. Strengthening compression members such as column can increase ductility and strength due to the confinement effect. In this experiment, the behavior of concrete cylinders confined by CFS was examined. The confinement pressure is increased linearly as axial stress is increased in low axial stress, and the confinement effect of CFS was rapidly developed after near maximum axial stress, thus axial strength and ductility was improved. As the ratio of CPS is increased, concrete cylinders failed due to local fracture of CFS. The confinement effect of circular section is more efficient than that of rectangular section. And significant improvement of axial strength, axial strain, transverse strain at failure is observed in circular section. This is because in rectangular section the local fracture of CFS near corner may be occured, thus the strain efficiency ratio must be considered for RC structures with CFS.

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Relationship between Ductility and Confinement Steel of RC Bridge Columns (철근콘크리트 교각의 연성도와 심부구속철근량의 상관관계)

  • 손혁수;한상엽;이재훈
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.141-146
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    • 2002
  • The purpose of this study is to develop a reasonable design for transverse confinement reinforcement considering ductility and required transverse confinement reinforcement of RC bridge columns. In order to develop relationships between the curvature ductility and required transverse confinement reinforcement for design purpose, the analysis using the computer program NARCC have been carried out for parametric studies. Based on the results from the parametric studies, an equation for calculating the required transverse confinement reinforcement based on ductility demand was developed for seismic design of RC bridge columns. The equations proposed by this study will provide more reasonable and more effective design guidelines for performance-based seismic design of RC bridge columns.

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Experimental Study of Structural Capacity Evaluation of RC T-shape Walls with the Confinement Effect (단부구속 효과에 따른 철근콘크리트 T형 벽체의 구조성능 평가에 관한 실험적 연구)

  • 하상수;윤현도;최창식;오영훈;이원호;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.191-196
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    • 2001
  • The structural performance of a shear wall subjected to lateral loads is influenced by many factors, such as sectional shape, aspect ratio, vertical and horizontal reinforcement, lateral confinement and axial compression, etc. This experimental research is focusing to investigate the structural performance of T-shaped walls with different confining reinforcement. Experimental results show that all specimens finally failed by the crushing of the concrete in the compression zone. Although the location and content of the lateral confinement is different, the results are very similar during the negative loading direction where the flange is compressed. However, when flange is subjected to tension, the location and content of the lateral confinement results in a large difference in the structural performance of T-shaped walls. Therefore, selection of location and content of the lateral confinement would be important aspect in the design of the nonsymmetric structural walls.

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Shear Strenhth and Ductility of Steel-Fiber Reinforced High Strength Concrete Beams with Shear Confinement (전단보강이 있는 강섬유 보강 고강도 철근콘크리트 보의 전단 및 연상에 관한 연구)

  • 오정근;이광수;권영호;신성우
    • Magazine of the Korea Concrete Institute
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    • v.2 no.4
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    • pp.53-60
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    • 1990
  • Investigations on the behavior of steel fiber reinforced high strength concrete beams with shear confinement are accomplished to determine their ultimate shear strength including diagonal tension strength. The parameters varied were the shear confinement ratio(Ps), and fiber volume fraction(Vs). Ultimate shear strength increased significantly in steel fiber reinforced concrete beam without shear confinement. In steel- fiber reinforced high strength concrete beams with shear confinement, there is no increase of ultimate shear strength but shows much beneficial effects of Ductility Capacity.

Axial behavior of steel-jacketed concrete columns

  • Rupp, J.;Sezen, H.;Chaturvedi, S.
    • Steel and Composite Structures
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    • v.16 no.1
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    • pp.59-75
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    • 2014
  • A new concrete confinement model is developed to predict the axial load versus displacement behavior of circular columns under concentric axial load. The new confinement model is proposed for concrete filled steel tube columns as well as circular reinforced concrete columns with steel tube jacketing. Existing confinement models were evaluated and improved using available experimental data from different sets of columns tested under similar loading conditions. The proposed model is based on commonly used confinement models with an emphasis on modifying the effective confining pressure coefficient utilizing the strength of the unconfined concrete and the steel tube, the length of the column, and the thickness of the steel tube. The proposed model predicts the ultimate axial strength and the corresponding strain with an acceptable degree of accuracy while also highlighting the importance of the manner in which the steel tube is used.

Proposed Design Provisions for Bond and Development Length Considering Effects of Confinement (횡구속 영향을 고려한 부착 및 정착길이 설계 개선 안)

  • 최완철;김상준
    • Journal of the Korea Concrete Institute
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    • v.11 no.5
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    • pp.61-68
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    • 1999
  • Confinement is one of the major concepts for bond of reinforcing steel to concrete. Cover distance, and lateral reinforcement are the key factors for current provisions for development and splices of reinforcement. However, the current provisions still being complicated to calculate major variables need to be developed in the process of design. In this study, an experimental work was performed to examine the behavior of bond using beam end specimens. The test results and previous available data are analyzed to isolate the effects of confinement on bond strength. From this reevaluation, new provisions for development and splice of reinforcement are proposed. The provisions also propose some limits for confinement index. The new provisions will help engineers to decide easily the simple but conservative way for manual calculations or the exact approach for computerized design.

Mechanical Behavior of Slender Concrete-Filled Fiber Reinforced Polymer Columns

  • Choi Sokhwan;Lee Myung;Lee Sung-Woo
    • Journal of the Korea Concrete Institute
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    • v.16 no.4
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    • pp.565-572
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    • 2004
  • The mechanical behavior of concrete-filled glass fiber reinforced polymer columns is affected by various factors including concrete strength, stiffness of tube, end confinement effect, and slenderness ratio of members. In this research the behavior of slender columns was examined both experimentally and analytically. Experimental works include 1) compression test with 30cm long glass fiber composite columns under different end confinement conditions, 2) uni-axial compression test for 7 slender columns, which have various slenderness ratios. Short-length stocky columns gave high strength and ductility revealing high confinement action of FRP tubes. The strength increment and strain change were examined under different end confinement conditions. With slender columns, failure strengths, confinement effects, and stress-strains relations were examined. Through analytical work, effective length was computed and it was compared with the amount of reduction in column strength, which is required to predict design strength with slender specimens. This study shows the feasibility of slender concrete-filled glass fiber reinforced polymer composite columns.