• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2005년도 봄학술 발표회 논문집(I)
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• pp.399-402
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• 2005

This paper presents shear strength of concrete beam using FRP bars for flexure and shear reinforcements. Generally, the material properties of FRP bar are different from steel reinforcement. So, the shear strength correction factor is proposed through the experimental results.

• Composites Research
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• 제16권3호
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• pp.32-40
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• 2003

최근 철근의 부식과 관련된 철관콘크리트 바닥판의 내구성에 대한 문제점이 증가되면서 부식에 대한 저항성이 크며, 기존 구조용 재료에 비해 여러 가지 물리적, 역학적 장점을 가진 섬유보강플래스틱을 사용한 보강재의 사용성이 증가되고 있다. 본 연구는 GFRP Re-Bar 다발로 보강된 1방향 슬래브의 휨거동에 관한 실험적 연구로서, 국내에서 개발된 GFRP Re-bar의 인장시험을 수행하였으며, GFRP Re-Bar의 보강량을 증가시켜가며 단위 폭을 갖는 1방향 슬래브 실험체를 제작하고 3등분점 재하실험을 수행하였다. 각 실험체에 대한 이론적인 해석은 철근콘크리트 휨부재의 해석 및 설계방법을 수정, 보완하여 개발된 ACI Committee 440에 따라 수행하였으며, 실험결과와 이론적 해석결과를 비교, 분석하였다. 연구결과 ACI Committee 440에 의해 추정한 각 실험체의 하중­처짐 거동은 실험결과와 비교적 잘 일치함을 알 수 있었으며, FRP Re-Bar로 보강된 콘크리트 바닥판의 설계규준을 확립하기 위해서는 강도에 대한 한계상태뿐만 아니라 처짐 등 사용성에 대한 한계상태가 결정되어야 할 것이라 생각된다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2004년도 춘계학술발표대회 논문집
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• pp.13-17
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• 2004

In recent years, the deterioration of reinforced concrete structures has become a serious problem in civil engineering fields. This situation is mainly due to corrosion of steel reinforcing bars embedded in concrete. Recently, there has been a greatly increased demand for the use of FRP (fiber reinforced plastic) in civil engineering field due to their superior mechanical and physical properties. This paper presents an experimental study on the behavior of concrete bridge deck reinforced with FRP Box, FRP Plate, and FRP Re-bar. In tlIe study, mechanical properties of FRP Box, FRP Plate, GFRP Re-bar, and CFRP Grid have been investigated. Full scale one-way deck slab was tested under four point lateral load (equivalent to actual wheel load of DB-24 including impact). Load-deflection and load-strain data were collected through LVDT's and strain gages attached to the specimen.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2000년도 춘계학술발표대회 논문집
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• pp.63-66
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• 2000

This paper describes the need for a ductile Fiber Reinforced Plastic(FRP) reinforcement for concrete structures. Using the material hybrid and geometric hybrid, it is demonstrated that the pseudo-ductility characteristic can be generated in FRP rebar. Ductile hybrid FRP bars were successfully fabricated at 4mm and l0mm nominal diameters using an hand lay up method. Tensile specimens from these bars were tested and compared with behavior of FRP rebar and steel bar

• Structural Engineering and Mechanics
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• 제37권1호
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• pp.95-110
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• 2011

This paper presents a tri-uniform bond stress model for predicting the lap splice strength of reinforcing bar at the critical bond splitting failure. The proposed bond distribution model consists of three zones, namely, splitting zone, post-splitting zone and yielding zone. In each zone, the bond stress is assumed to be constant. The models for bond strength in each zone are adopted from previous studies. Combining the equilibrium, strain-slip relation and the bond strength model in each zone, the steel stress-slip model can be derived, which can be used in the nonlinear frame analysis of the column. The proposed model is applied to derive explicit equations for predicting the strength of the lap splice strengthened by fiber reinforced polymer (FRP) in both elastic and post-yield ranges. For design purpose, a procedure to calculate the required FRP thickness and the number of FRP sheets is also presented. A parametric investigation was conducted to study the relation between lap splice strength and lap splice length, number and thickness of FRP sheets and the ratio of concrete cover to bar diameter. The study shows that the lap splice strength can be enhanced by increasing one of these parameters: lap splice length, number or thickness of FRP sheets and concrete cover to bar diameter ratio. Verification of the model has been conducted using experimental data available in literature.

• Structural Engineering and Mechanics
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• 제77권1호
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• pp.75-87
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• 2021

The present study pertains to the introduction of two new types of grip adaptor for universal testing machines, namely Polyvinyl Chloride (PVC) and Polyoxymethylene (POM) grip adaptors, and their application to tension testing of FRP bars with different fiber and surface finish types. The tabs are connected to the FRP bar sample with the help of mechanical anchors, i.e. bolts. These new adaptors offer vital superiorities over the existing end tab designs (anchors with filling material or mechanical anchorage), including the reduction in the time and labor for production, reusability and the mild nature, i.e. low hardness of the tab material, which retards and even prevents peeling and crushing in the gripping regions of an FRP sample. The methods were successfully applied to FRP bars with different types of fiber (CFRP, GFRP and BFRP) and different types of surface texture (ribbed, wrapped, sand-coated and wound). The test results indicated that the both types of end caps prevented slip of the bar, crushing and peeling in the gripping zone. The mechanical properties from the material tests with the new caps were in perfect agreement with the ones from the material tests with steel tubular caps.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2000년도 춘계학술대회 논문집
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• pp.57-62
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• 2000

This paper describes the need for a ductile Fiber Reinforced Plastic(FRP) reinforcement for concrete structures. Using the material hybrid and geometric hybrid. it is demonstrated that the pseudo-ductility characteristic can be generated in FRP rebar. Ductile hybrid FRP bars were successfully fabricated at 4mm and 10mm nominal diameters using an hand lay up method. Tensile specimens from these bars were tested and compared with behavior of FRP rebar and steel bar

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2009년도 춘계 학술대회 제21권1호
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• pp.505-506
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• 2009

이 논문은 보수 보강 공법으로 쓰이고 있는 FRP bar와 GSP 매입공법의 피로거동에 대한 연구이다. 실험에서 응력비 R는 0.1이고 피로하중 주파수는 1.5Hz이다. 피로실험 결과, S-N 곡선에서 GFRP bar와 GSP 보강보의 피로강도는 각각 정적강도의 58%, 52% 수준임을 얻었다.

• Computers and Concrete
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• 제23권1호
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• pp.49-60
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• 2019

In recent years, multiple experimental studies have been performed on using fiber reinforced polymer (FRP) bars in reinforced concrete (RC) structural members. FRP bars provide a new type of reinforcement that avoids the corrosion of traditional steel reinforcement. In this study, predicting the shear strength of RC beams with FRP longitudinal bars using artificial neural networks (ANNs) is investigated as a different approach from the current specific codes. An ANN model was developed using the experimental data of 104 FRP-RC specimens from an existing database in the literature. Seven different input parameters affecting the shear strength of FRP bar reinforced RC beams were selected to create the ANN structure. The most convenient ANN algorithm was determined as traingdx. The results from current codes (ACI440.1R-15 and JSCE) and existing literature in predicting the shear strength of FRP-RC beams were investigated using the identical test data. The study shows that the ANN model produces acceptable predictions for the ultimate shear strength of FRP-RC beams (maximum $R^2{\approx}0.97$). Additionally, the ANN model provides more accurate predictions for the shear capacity than the other computed methods in the ACI440.1R-15, JSCE codes and existing literature for considering different performance parameters.

• 콘크리트학회논문집
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• 제25권2호
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• pp.187-194
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• 2013

섬유복합체(FRP)는 비부식성 재료라는 특징으로 인해 이상적인 철근 대체재로 주목 받고 있다. 그러나 현재 FRP 보강근은 철근과 달리 일반적으로 수용되는 고정된 형태가 존재하지 않고 다양한 재료와 성분비, 형태 등으로 제작되기 때문에 이에 대한 성능평가 데이터에 근거한 FRP 보강 콘크리트 부재의 거동특성 구명은 상당부분 제한될 수 있다. 더군다나 FRP 보강 콘크리트 부재의 휨거동에 대한 평가는 주로 단기 거동 측면에 집중되어 이루어져 왔다. 이 연구는 GFRP 보강근 및 이를 사용하여 보강된 콘크리트 부재의 장기거동을 평가하기 위한 것으로, 먼저 철근 대체용으로 개발된 GFRP 보강근에 대한 성능평가 결과를 제시하였고, 이의 크리프 거동 특성에 대한 3년간의 계측 결과를 제시하였다. 실험 결과 인장강도의 약 55% 이하의 하중이 지속적으로 재하되는 경우에는 100년 이상의 내구연한을 확보할 수 있는 것으로 나타났다. 또한 GFRP 보강 콘크리트 보의 장기거동을 약 1년간 관찰하였으며 이로부터 FRP 보강 부재의 장기처짐 계산식에 사용되는 수정계수 값 0.73을 도출하였다. 따라서 이 연구로부터 도출된 GFRP 보강근 및 이로 보강된 콘크리트 보의 단기 및 장기 거동 특성값은 FRP 보강 콘크리트 부재의 설계에 유용하게 활용될 수 있을 것으로 사료된다.