• Title, Summary, Keyword: FRP

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Experimental Study of Concrete Beam with FRP Plank as Formwork and Reinforcement (FRP 판을 거푸집 및 보강재로 활용한 콘크리트 보의 실험적 연구)

  • Yoo, Seung-Woon;Bae, Han-Ug;Oliva, Michael;Bank, Lawrence
    • Journal of the Korea Concrete Institute
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    • v.19 no.1
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    • pp.67-74
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    • 2007
  • We perform an experimental study of concrete beam with pultruded fiber reinforced polymer(FRP) plank using as a permanent formwork and the tensile reinforcement. A satisfactory bond at the interface between the smooth surface of the pultruded plank and the concrete must be developed for the FRP plank and the concrete to act as a composite structural member. Two kinds of aggregate were bonded to the FRP plank using a commercially available epoxy. No additional flexural or shear reinforcement was provided in the beams. For comparison we test two types of control specimen. One control did not have any aggregate bonded to the FRP plank and the other control had infernal steel reinforcing bars instead of the FRP plank. The beams were loaded by central patch load to their ultimate capacity. The experimental results were compared to current ACI 318 (2005) and ACI 440 (2006) code predictions. This study demonstrates that the FRP plank has the potential to serve as formwork and reinforcing for concrete structures.

Simulation and Evaluation of Bending Strength of FRP for Insulator According to Winding Angle (와인딩 각도에 따른 절연용 FRP의 굽힘강도 시뮬레이션 및 평가)

  • Park, Hoy-Yul;Kang, Dong-Pil;Ahn, Myeong-Sang;Myung, In-Hae
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.436-439
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    • 2003
  • FRP has been used widely for insulator. FRP consists of fiber and resin. The fiber contributes the high strength and modulus to the composite. 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, FRP was made unidirectionally by pultrusion method. Outer part of the FRP was made by filament winding method to give fiber orientation to the FRP. And outer part of FRP was also made by wrapping method. The bending strength and bending stresses of FRP rods were simulated according to the winding orientation of glass fiber. The bending strength of FRP was also evaluated. The results of simulation and evaluation were compared each other to investigate main stresses which affect the fracture of FRP. The main stresses which had a great effect on the strength of FRP were shear stresses. Bending strength of the FRP was different with the winding angle. The bending strength of $15^{\circ}$ winded FRP was the highest.

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A Proposal of Simplified Bond Stress-Slip Model between FRP Plank and Cast-In-Place Concrete (FRP 판과 현장타설 콘크리트 사이의 단순 부착모델 제안)

  • Yoo, Seung-Woon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.1
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    • pp.65-72
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    • 2008
  • The use of hybrid FRP-concrete structures with a dual purpose of both permanent formwork and reinforcement, has been considered in some studies recently. For the FRP plank and the concrete to act as a composite structural member a satisfactory bond at the interface between the smooth surface of the pultruded plank and the cast-in-place concrete must be developed. Sand was bonded to the pultruded FRP plank using a commercially available epoxy system. In applying general analysis techniques to evaluate the performance of composite structures with FRP stay-in-place forming, it is essential that characteristics of the bond stress-slip relation be identified. In this study I would like to propose a simplified bilinear bond stress-slip model for FRP composite structures.

Interfacial mechanical behaviors of RC beams strengthened with FRP

  • Deng, Jiangdong;Liu, Airong;Huang, Peiyan;Zheng, Xiaohong
    • Structural Engineering and Mechanics
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    • v.58 no.3
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    • pp.577-596
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    • 2016
  • FRP-concrete interfacial mechanical properties determine the strengthening effect of RC beams strengthened with FRP. In this paper, the model experiments were carried out with eight specimens to study the failure modes and the strengthening effect of RC beams strengthened with FRP. Then a theoretical model based on interfacial performances was proposed and interfacial mechanical behaviors were studied. Finite element analysis confirmed the theoretical results. The results showed that RC beams strengthened with FRP had three loading stages and that the FRP strengthening effects were mainly exerted in the Stage III after the yielding of steel bars, including the improvement of the bearing capacity, the decreased ultimate deformation due to the sudden failure of FRP and the improvement of stiffness in this stage. The mechanical formulae of the interfacial shear stress and FRP stress were established and the key influence factors included FRP length, interfacial bond-slip parameter, FRP thickness, etc. According to the theoretical analysis and experimental data, the calculation methods of interfacial shear stress at FRP end and FRP strain at midspan were proposed. When FRP bonding length was shorter, interfacial shear stress at FRP end was larger that led to concrete cover peeling failure. When FRP was longer, FRP reached the ultimate strain and the fracture failure of FRP occurred. The theoretical results were well consistent with the experimental data.

An Experimental Study of Perfobond FRP-Concrete Composite Beam (퍼포본드 FRP-콘크리트 합성보의 실험적 연구)

  • Yoo, Seung-Woon;Kook, Moo-Sung
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.14 no.2
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    • pp.121-127
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    • 2010
  • An experimental study of composite beam with perforated fiber reinforced polymer(FRP) plank as a permanent formwork and the tensile reinforcement was performed. A combined formwork and reinforcement system can facilitate rapid construction of concrete members since no conventional formwork is needed, which requires time consuming assembly and dismantling. In order for a smooth FRP plank to act compositely with the concrete, the surface of the FRP needs to be treated to increase its bond properties. Aggregates were bonded to the FRP plank using a commercially available epoxy and perforated web of plank. No additional flexural or shear reinforcement was provided in the beams. For comparison, two control specimens were tested. One control had no perforated hole in the web of FRP plank and the other had internal steel reinforcing bars instead of the FRP plank. The beams were loaded by central patch load to their ultimate capacity. This study demonstrates that the perforated FRP plank has the potential to serve as a permanent formwork and reinforcing for concrete beam.

Effect of Freezing and Thawing on Adhesion of Cement Concrete with Coarse-sand Coated FRP (규사코팅 FRP와 콘크리트 부착특성에 동결융해가 미치는 영향)

  • Lee, Gyu Phil;Park, Kwang Phil;Hwang, Jae Hong;Kim, Dong Gyou
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.17 no.2
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    • pp.117-123
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    • 2013
  • As fiber reinforced polymer (FRP) material is appled for a curved structure such as tunnel, FRP material must has a curved shape. Until now, the curved FRP material has been producted by hand-lay-up or filament winding work. It is impossible for mass production of the curved FRP material by these methods. Also, the quality of product by these methods is lower than that by pultrusion method. New pultrusion method and equipment had been developed for production of FRP material with steady curvature. The objective of this study is to evaluate the effect of freezing and thawing on adhesion of cement concrete with coarse-sand coated FRP in repair and reinforcement of cement-concrete structure using curved FRP material.

Axial Behavior of Concrete Cylinders Confined with FRP Wires (FRP 와이어 보강 콘크리트 공시체의 압축거동)

  • Cho, Baiksoon;Lee, Jong-Han;Choi, Eunsoo
    • Journal of The Korean Society of Civil Engineers
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    • v.33 no.5
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    • pp.1765-1775
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    • 2013
  • The application of FRP wire as a mean of improving strength and ductility capacity of concrete cylinders under axial compressive load through confinement is investigated experimentally in this study. An experimental investigation involves axial compressive test of three confining amounts of FRP wire and three concrete compressive strengths. The effectiveness of FRP wire confinement on the concrete microstructure were examined by evaluating the internal concrete damage using axial, circumferential, and volumetric strains. The axial stress-strain relations of FRP wire confined concrete showed bilinear behavior with transition region. It showed strain-hardening behavior in the post-cracking region. The load carrying capacity was linearly increased with increasing of the amount of FRP wire. The ultimate strength of the 35 MPa specimen confined with 3 layer of FRP wire was increased by 286% compared to control one. When the concrete were effectively confined with FRP wire, horizontal cracks were formed by shearing. It was developed from sudden expansion of the concrete due to confinement ruptures at one side while the FRP wire was still working in hindering expansion of concrete at the other side of the crack. The FRP wire failure strains obtained from FRP wire confined concrete tests were 55~90%, average 69.5%, of the FRP wire ultimate uniaxial tensile strain. It was as high as any other FRP confined method. The magnitude of FRP wire failure strain was related to the FRP wire effectiveness.

Feasibility Verification for the Basic Shape of FRP Bridge Decks Using Optimization Algorithm (최적설계 알고리즘을 이용한 교량용 FRP바닥판의 기본 단면형상 제안)

  • Park, Ki Tae;Hwang, Yoon Koog;Lee, Young Ho;Jeong, Jin Woo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.11 no.2
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    • pp.93-102
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    • 2007
  • A large number of FRP decks are already in service worldwide because the lighter FRP-based bridge decks are ideal for rapid construction to reduce the dead load of superstructures. And the proper design process is demanded for the effective FRP deck application. In this paper, to get the basic prototype of FRP bridge decks, the ratio of individual parameters, which compose the specification of FRP bridge decks, are determined by a finite element analysis. In addition, optimum FRP deck shapes are determined considering complex constraints and material properties of bi-directional characteristics. Upon these results, the prototype of FRP bridge decks is validated.

Evaluation on Strengthening Capacities and Rebound Rate of Structures with Sprayed FRP (분사식 FRP에 의한 구조물의 보강 성능 및 반발률 평가)

  • Han, Seung-Chul;Yang, Jun-Mo;Yoon, Young-Soo
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.12 no.1
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    • pp.193-202
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    • 2008
  • This paper investigates experimentally the confining effect, strengthening capacity and rebound rate of sprayed Fiber-Reinforced-Polymer (SFRP). From the method, resin and chopped fibers are sprayed separately from the nozzle with high pressure, and then they are attached to the concrete surface, so structure could be repaired. To evaluate the strengthening effect of sprayed FRP, cylindrical specimens and beam specimens were strengthening with SFRP. As main material of FRP, glass fiber and polyester resin are used. To investigate the optimum condition of sprayed FRP, the effects of fiber length, coating thickness, fiber volume ratio and concrete strength were examined. Capacities of sprayed FRP method were also compared to the FRP sheet method. In case of the sprayed FRP, rebound rate is important parameter considering economical efficiency and constructibility, so rebound rate of was discussed. From the test results, optimum conditions of sprayed FRP were determined. SFRP method showed superior strengthening capacities than FRP sheet method.

New Practical and Eco-friendly Recycling method of FRP Boats (FRP선박의 재처리시스템과 활용성 연구)

  • Yoon, Koo-Young
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.10 no.3
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    • pp.181-186
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    • 2007
  • Despite of environmental problems(safety hazards), mechanical recycling of FRP boats, which involves shredding and grinding of the scrap FRP in a new product. is one of the simpler and more technically proven methods than incineration or reclamation ones. Because FRP is made up of reinforced fiber glass, it is very difficult to break into pieces. It also occurs secondary problem such as air pollution and unacceptable shredding noise level. The another urgent problem which is a serious barrier to FRP recycling is very limited reusable applications. This study is to propose a new method which is efficient and environment friendly waste FRP regenerating system. And it also have shown the polymer cement and fiber-reinforced concrete applications with the waste FRP.

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