• Title/Summary/Keyword: FRP rod

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Development of Estimated Model for Axial Displacement of Hybrid FRP Rod using Strain (Hybrid FRP Rod의 변형률을 이용한 축방향 변위추정 모형 개발)

  • Kwak, Kae-Hwan;Sung, Bai-Kyung;Jang, Hwa-Sup
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.4A
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    • pp.639-645
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    • 2006
  • FRP (Fiber Reinforced Polymer) is an excellent new constructional material in resistibility to corrosion, high intensity, resistibility to fatigue, and plasticity. FBG (Fiber Bragg Grating) sensor is widely used at present as a smart sensor due to lots of advantages such as electric resistance, small-sized material, and high durability. However, with insufficiency of measuring displacement, FBG sensor is used only as a sensor measuring physical properties like strain or temperature. In this study, FRP and FBG sensors are to be hybridized, which could lead to the development of a smart FRP rod. Moreover, developing the estimated model for deflection with neural network method, with the data measured through FBG sensor, could make conquest of a disadvantage of FBG sensor - uniquely used for sensing strain. Artificial neural network is MLP (Multi-layer perceptron), trained within error rate of 0.001. Nonlinear object function and back-propagation algorithm is applied to training and this model is verified with the measured axial displacement through UTM and the estimated numerical values.

The Effects of Salt Water Treating on Dielectric Properties of FRP Composite Insulation Materials (FRP 복합절연재료의 유전특성에 미치는 염수처리의 영향)

  • ;;;;;Ichikawa, K.
    • Electrical & Electronic Materials
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    • v.10 no.1
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    • pp.45-53
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    • 1997
  • The purpose of this paper is to evaluate FRP rod for aging, which exposed to salt water and pure at elevated temperature. Dielectric constant and tan .delta. on time and frequency domain were tested to observe how rapidly the FRP rod aged. Dielectric constants of FRP rods with treating time were slightly increased. That of FRP rods with frequency, However, showed strongly the effects of large relaxation time estimated from interfacial polarization a or ionic. It is obvious that absorbed water affects to dielectric and electric properties of FRP with increasing the treating time.

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Flexural Behavior of Reinforced Concrete Beam with Hybrid FRP Rods (Hybrid FRP Rod로 보강된 철근콘크리트 보의 휨 거동)

  • Kwak, Kae-Hwan;Jang, Hwa-Sup;Yang, Dong-Oun
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.11a
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    • pp.327-330
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    • 2005
  • In this study, the nature of brittleness, one of the main problems of GFRP(Glass Fiber Reinforced Plastic) Re-bar, is improved. Therefore, Hybrid GFRP Rod is developed by attaching FBG sensor to the new GFRP Rod with toughness, essential for flexural reinforcement of the concrete. The test was performed with specimens of Hybrid GFRP Rod. According to the test, data measured by electric gauge sensor are compared with data measured by FBG sensor.

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Characteristics of Flexuarl-Shear Behavior of Beam Using Demonstrated CFRP Rod (국내 시범 생산 CFRP rod를 적용한 보 부재의 휨-전단 특성)

  • Choi, So-Yoeng;Kim, Il-Sun;Choi, Myoung-Sung;Yang, Eun-Ik
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.26 no.5
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    • pp.86-94
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    • 2022
  • Replacement of FRP rod as steel reinforcement has been attracted significantly to prevent the degradation of the concrete structure due to corrosion. So, the technology development to extend the structure's service life by improving FRP properties has been proceeded worldwide. Accordingly, it is necessary to develop Korea's CFRP rod and CFRP grid, including the manufacturing techniques to improve the properties of high-strength and high-stiffness. Moreover, the research should be conducted to evaluate the structural behavior of the beams using the CFRP rod or grid. This study investigates the flexural and shear behavior of reinforced concrete beam using demonstrated CFRP rod as reinforcement according to the reinforcement ratio and shear span to depth ratio. From the results, when the reinforcement ratio is out of a specific range, it is seemed that the effect on performance improvement of the beam using CFRP rod is cancelled or not significant. Meanwhile, when the CFRP rod was used as reinforcement, the possibility of shear failure occurred, even steel stirrups were installed in the beam with CFRP rod as tensile reinforcement according to the Korean Design Standard. Therefore, when the CFRP rod is used as tensile reinforcement in a beam, it should be prepared that a specific limitation of reinforcement ratio and an investigation against shear failure. Also, the ductility of the beam using the CFRP rod is determined by the deformation energy evaluation method. So, the ductility should be investigated by applying the deformation energy evaluation method that reflects the structural behavior of the beam.

An Experimental Study on the Flexural Behavior of Pre-loaded RC Beams Strengthened with CFRP-Rod (선하중(先荷重)을 받은 RC보의 CFRP-Rod 휨보강 효과에 대한 실험적 연구)

  • Ye, Sang-Min;Chun, Woo-Chul;Kang, Joo-Won;Park, Sung-Moo
    • Journal of Korean Association for Spatial Structures
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    • v.7 no.1 s.23
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    • pp.79-85
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    • 2007
  • Steel plate bonding method with epoxy is common applied to repair and strengthen RC structures, but Steel is apt to corrode quickly, hard to manufacture and heavy. To overcome these defects, it is carried out research on strengthening RC structures with FRP(Fibre Reinforced Polyrner/Plastic) FRP is generally used in the shape of Plate or Sheet, but it has weak point such as premature failure, difficult work. To cope with these problem, NSMR(Near Surface Mounted Reinforcement) which uses CFRP in the shape of Rod is proposed and carried out active research on strengthening effect of variables such as quantity, anchorage length and space of CFRP-Rod. Strengthening with CFRP-Rod is carried out under loading to some degree in fact, and so the amount of pre-loading is selected as variable in this research. The amount of pre-loading is chosen in proportion to nominal strength of non-strengthened specimen with CFRP-Rod.

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Tensile Properties of Hybrid FRP Rods with Glass and Carbon Fibers (유리와 탄소섬유로 제작된 하이브리드 FRP 로드의 인장특성에 관한 실험연구)

  • You, Yong-Jun;Park, Ji-Sun;Park, Young-Hwan;Kim, Keung-Hwan
    • Journal of the Korea Concrete Institute
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    • v.18 no.2 s.92
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    • pp.275-282
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    • 2006
  • Recently, Fiber Reinforced Polymers(FRP) has been emerged as an alternative material to solve the corrosion of steel reinforcement in reinforced concrete structures. FRP exhibits higher specific strength and lower weight compared to steel reinforcement. Moreover, good resistance to corrosion of the FRP may be useful in aggressive environments causing deterioration such as chloride environment. However, causes for higher initial cost of FRP than that of steel, little information on the long-term behavior of FRP, and brittle failure make the efforts to apply FRP in civil structures slow. Glass fiber among the fibers used to manufacture FRP can be seen as the most beneficial material with regard to initial costs. But its low elastic modulus, which attains barely a quarter of steel, nay thus lead to excessive deflections when used as reinforcement for flexural members. This research was carried out on the tensile properties of hybrid rods made with glass and carbon fibers to improve those of FRP rod made with glass fiber. Parameters were resin type and the arrangement of glass and carbon fibers. The tensile properties of hybrid rods were compared with those of rods manufactured with only glass or carbon fibers. The results indicated that the tensile properties of hybrid rod were good when the carbon fiber was arranged in the core.

An Experimental Study on the Strengtheing Effect of Reinforced Concrete Beams Strengthened by CFRP Rod (탄소섬유막대로 보강한 철근콘크리트 보의 보강효과에 관한 실험적 연구)

  • Park, Sung-Moo;Kim, Jae-Hun;Park, Kwang-Seob
    • Journal of Korean Association for Spatial Structures
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    • v.4 no.3 s.13
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    • pp.85-91
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    • 2004
  • Rehabilitations of reinforced concrete(RC) structures using advanced fibre-reinfored plastic(FRP) composites has become very popular in last few years. Typical method of strengthening strategy using FRP composite is bonding the CFRP plate or sheet on the surface of existing concrete structures. Many researches, however, have shown that bonding FRP plate or sheet on the surface of concrete has tendancy to debond prematurely induced by stress concentrations at the end of the plate. In order for overcoming the premature failure, the filling-up method which places FRP-rod into the existing concrete sawing groove has been developed. Through filling-up test results, aims of this research is to investigate the efficiencies of the filling-up method and is to determine the availabilities of traditional flexural theories that has provided all over the world.

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Mechanical Properties of Pultruded FRP rod with Wrapping (인발성형 FRP의 Wrapping에 의한 기계적 특성)

  • Park, Hoy-Yul;Kang, Dong-Pil;Han, Dong-Hee;Ahn, Myeong-Sang
    • Proceedings of the KIEE Conference
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    • 2000.07c
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    • pp.1530-1532
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    • 2000
  • The properties of FRP usually depends on the fabricating method. The fiber orientation of FRP is also depends on the fabricating method. The fiber orientation in FRP has a great effect on the strength of FRP because the strength of FRP mainly depends on the strength of fiber. In this study. compressive and bending strength of FRP rods were investigated. Inner part of FRP was made unidirectionally by pultrusion method and outer part of FRP was made by wrapping method. The size effect was also investigated with pultruded FRP rods.

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Self-Diagnosis for Fracture Prediction of Concrete Reinforced by New Type Rib CFGFRP Rod and CF Sheet (신형 리브재 CFGFRP 보강근 및 CF 보강시트로 보강된 콘크리트의 파괴예측 자가진단)

  • Park, Seok-Kyun
    • Journal of the Korean Society for Nondestructive Testing
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    • v.27 no.2
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    • pp.115-123
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    • 2007
  • For investigating self-diagnosis applicability, a method based on monitoring the changes in the electrical resistance of carbon fiber reinforced concrete has been tested. Then after examining change in the value of electrical resistance at each flexural weight-stage of carbon fiber in CFGFRP (carbon fiber and glass fiber reinforcing plastic) with new type rib and carbon sheet for concrete reinforcing, the correlations of electrical resistance and load as a function of strain, deflection were analyzed. As the results, it is clarified that when carbon fiber rod, rib and sheet fracture, the electrical resistance of it increase largely, and specially in case of CFGFRP, afterwards glass fiber tows can be resist the load due to the presence of the hybrid (carbon and glass) reinforced fiber. Therefore, it can be recognized that reinforcing bar and new type rib of CFGFRP and sheet of CF could be applied for self-diagnosis of fracture in reinforced FRP concrete.