• Title/Summary/Keyword: 탄소섬유시트

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The Performance of Shear Strengthened Reinforced Concrete Columns with Carbon Fiber Sheets (탄소섬유시트로 전단 보강된 철근콘크리트 기둥의 성능 평가)

  • 강경원;하상수;나정민;이용택;이리형
    • Proceedings of the Korea Concrete Institute Conference
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    • 1999.10a
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    • pp.733-736
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    • 1999
  • R/C columns, one of the main structural members of reinforced concrete structures, usually sustain the axial forces of combined dead loads and live loads. When subjected to lateral loads, however, they are repeatedly subjected to bending moment, shearing forces and brittle failure such as shear failure can occur. This failure mode is not desirable and extra reinforcement is usually needed to induce a ductile failure. The design equation which is used to evaluate the maximum shear strength of a R/C column is still unsatisfactory. The objective of this study was, therefore, to evaluate the hysteretic strengthening effect and the maximum shear strength of R/C columns strengthened using carbon fibers on the seismic performance of the R/C columns under anti-symmetrical by acting moment. According to this study, it may be suggested that the shear of the strengthened R/C column were adequate to induce ductile failures.

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FEM Analysis of RC Beams Strengthened with CFS on Loading Situation (재하상태에서 탄소섬유시트로 보강된 RC보부재의 유한요소해석)

  • ;Kanetou Masayoshi
    • Proceedings of the Korea Concrete Institute Conference
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    • 2001.11a
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    • pp.1181-1184
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    • 2001
  • This study was performed FEM analysis of RC beams strengthened with CPS, in order to verify the effect strengthened of the loading situation. By load-deflection curve, It was not different that max capacity of RF2-L0 strengthened with CFS on the sound and RF2-L60 strengthened with on the 60% loading situation of service load. When RC beam was shortly strengthened with CFS, bond element of beam on the end was ripped off. Because stress was concentrated on bond element of beam on the end.

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A Study on the Failure Behavior of Carbon Fiber Sheet Reinforced Mortar Using Acoustic Emission Technique (AE를 이용한 탄소섬유시트 강화 모르타르의 파괴거동에 관한 연구)

  • 이진경;이준현;장일영
    • Journal of the Korea Concrete Institute
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    • v.12 no.3
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    • pp.67-75
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    • 2000
  • It was well recognized that the damages associated mainly with the aging of civil infrastructures were one of very serious problems for assurance of safety and reliability. Recently carbon fiber sheet(CFS) has been widely used for reinforcement and rehabilitation of damaged concrete beam. However, the fundamental mechanism of load transfer and its load-resistant for carbon fiber sheet reinforced concrete are not fully understood. In this study, three point bending test has been carried out to understand the damage progress and the micro-failure mechanism of CFS reinforced mortars. For this purpose, four different types of specimens are used, that is, mortar, steel bar reinforced mortar, CFS reinforced mortar, and steel bar and CFS reinforced morter. Acoustic Emission(AE) technique was used to evaluate the characteristics of damage progress and the failure mechanism of specimens. in addition, two-dimensional AE source location was also performed to monitor crack initiation and propagation processes for these specimens.

Considerations in the Safety Evaluation of the Lateral Structural Members Reinforced with Steel Plate or CFRP Sheet (강판 또는 탄소섬유시트 보강된 수평 구조 부재의 안전성 평가시 고려사항)

  • 강석원;박형철;오보환
    • Proceedings of the Korea Concrete Institute Conference
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    • 2003.11a
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    • pp.331-334
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    • 2003
  • Since regulation or specification for the reinforcing method are quite ambiguous, structural design for the reinforcement can be subjectively and arbitrarily conducted. Thus, reasonable limitation and guide for the quantity of the reinforcement are required for the safe use of the structure after repair. In order to guarantee the safety of the structural member several items should be considered; reinforcing limit to avoid the brittle failure, least required strength of the existing member before reinforcement in order not to fail under the new serviceability load condition when reinforcing steel plates or CFRP sheets are harmed or subjected to fire.

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A Study on the Shear Capacity of Reinforced Concrete Beams Strengthened with Carbon Fiber Sheets (탄소섬유시트(CFS)로 보강된 철근콘크리트 보의 전단내력에 관한 연구)

  • Gwon, Chul-Sung;Kim, Ha-Yong;Gwon, Woo-Hyun;Baek, Seung-Min;Kwak, Yoon-Keun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.259-262
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    • 2005
  • This paper deals with the shear strengthening effect of RC beams strengthened with carbon fiber sheets. Fifteen strengthened RC beams(including control beam) were experimentally evaluated to determine improvements in shear strength. The major parmeters of experiment variables are fiber sheet strengthening ratios and strengthening methods of fiber sheet(I-S, I-W, U-S, U-W type). Reinforced concrete beams strengthened with carbon fiber sheets were tested under the combined control of load. Considering strengthening ratios and strengthening methods of fiber sheet, shear capacity and failure mode of test specimens were evaluated. The results show that shear capacity of beams strengthened with fiber sheet is about $28.82\%$ in IS type, $20.49\%$ in IW type, $26.04\%$ in US type, $28.70\%$ in UW type higher than the strength of control beam.

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Study on the Monitoring Method of Concrete Structure Repaired by Carbon Sheets with Optical Fiber Sensors (콘크리트구조물의 탄소섬유시트에 의한 구조 보강시 광섬유 센서를 이용한 모니터링기법에 관한 연구)

  • Kim, Ki-Soo
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2005.11a
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    • pp.149-152
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    • 2005
  • In order to extend the life time of building and civil infra-structure, nowadays, patch type carbon sheets are widely used as repairing meterials. Repaired concrete columns and beams with carbon sheets gain their stiffness and strength, but they lose toughness and show brittle failure behaviors. Usually, the cracks of concrete structures are visible with naked eyes and the status of the structure in the life cycle is estimated with visible inspection. After repairing of the structure, crack visibility is blocked by repaired carbon sheets. Therefore, structural monitoring after repairing is indispensible and self diagnosis method with optical fiber sensor is very useful. In this paper, peel-out effects is detected with optical fiber sensors and the strain difference between main structure and repaired carbon sheets when they separate each other.

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An Experimental Study on Flexural Repair of Reinforced Concrete Beams with the CFRP Sheet (탄소섬유시트를 사용한 철근콘크리트 구조물의 휨 보강에 관한 실험적 연구)

  • 박정원;박상렬;민창식
    • Proceedings of the Korea Concrete Institute Conference
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    • 2000.04a
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    • pp.781-786
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    • 2000
  • This paper presents the behavior and strenghening effect of reinforced concrete rectangular beams strengthened sing CFRP sheets with different strengthening level. In general, normally strengthened beams are failed by interfacial shear failure (delamination) within concrete, instead of by tensile failure of the CFRP sheets. The delamination occurred suddenly and the concrete cover cracked vertically by flexure was spalled off due to the release energy. The ultimate load considerably increased with an increase of strengthening level, while the ultimate deflection significantly decreased. The tensile force of CFRP sheets and average shear stress of concrete at delamination failure were curvilinearly proportional to the strengthening level. Therefore, the increment of ultimate load obtained by strengthening was curvilinearly proportional to th strengthening level.

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Study on the Self Diagnosis of Reinforced Concrete Beam Repaired by Patch Type Composite with Optical Fiber Sensors (광섬유 센서를 이용한 패치형 복합재료 보강 구조물에서의 진단기법에 관한 연구)

  • Lee, Jeong-Geun;Han, Seong-Do;Um, Jin-Seong;Lee, Jeong-Gyu;Jeong, Cheol;Kim, Gi-Su
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.1-4
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    • 2003
  • 사회기반기설을 구축하는 다양한 토목·건축 분야의 주요 콘크리트 구조부재에 탄소섬유시트를 비롯한 섬유복합재료를 이용하여 보수·보강하는 공법은 최근에 세계적으로 많이 활용되고 있는 신공법 중에 하나이다. 기존의 보수·보강재료에 비해 섬유 복합재료에 의한 시공방법의 장점은 구조부재의 내하력을 증가시킬 수 있고 기존에 발생한 균열을 구속하는 효과를 얻을 수 있다. (중략)

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FEM Analysis of Reinforced Concrete Columns Shear Strengthened with Carbon Fiber Sheets (탄소섬유시트로 전단 보강된 철근콘크리트 기둥의 유한요소해석)

  • Lee, Yong-Taeg;Na, Jung-Min;Lee, Li-Hyung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.6 no.3
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    • pp.111-118
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    • 2002
  • In this paper, FEM analysis is performed in order to estimate the behavior of RC columns retrofitted with Carbon Fiber Sheet(CFS). Two node truss element and four node isometric plate bond element are used for modeling the CFS and the adhesion between concrete and CFS, respectively. Five specimens with different quantity of CFS are analyzed and compared with experimental results. From the comparison, analytical results show a good agreement with the test results. Therefore, it is advisable to use the FEM used in this paper to predict the behavior of columns with CFS.

Shear Failure Behaviour of Reinforced Concrete Deep Beam Strengthened by Carbon Fiber Sheets (탄소섬유시트로 보강된 춤이 큰 철근콘크리트 보의 전단파괴거동(剪斷破壞擧動))

  • Cho, Su-Je;Son, Sung-Hun;Park, Sung-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.3 no.4
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    • pp.145-153
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    • 1999
  • The major objective of this study is to investigate experimentally the shear strengthening effect of carbon fiber sheets upon reinforced concrete deep beam and shear failure behavior variation of reinforced concrete deep beam strengthened by carbon fiber sheets. Tests are carried out with 6 specimens were shear failure at first loading tests, and with parameters including the types of shear strengthening of carbon fiber sheets (I type, S type, U type), and plies of sheets (2 ply and 1 ply). From the results of test, analyzed load-deflection of midspan, strain variation of main bars and transverse reinforcement, maximum load capacity of strengthened specimens, and compared with the previous test results.

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