• Title/Summary/Keyword: GFRP-concrete

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Governing Design Factors of GFRP-Reinforced Concrete Bridge Deck (GFRP 근 보강 콘크리트 교량 바닥판의 설계지배인자)

  • Cho, Jeong-Rae;Park, Young Hwan;Park, Sung Yong;Cho, Kunhee;Kim, Sung Tae
    • Journal of the Korean Society of Safety
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    • v.30 no.6
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    • pp.70-77
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    • 2015
  • In this study, the governing design factors of GFRP-reinforced concrete bridge deck are analyzed for typical bridges in Korea. The adopted bridge deck is a cast-in-situ concrete bridge deck for the prestressed concrete girder bridge with dimensions of 240 mm thickness and 2.75 m span length from center-to-center of supporting girders. The selected design variables are the diameters of GFRP rebar, spacings of GFRP rebars and concrete cover thicknesses, Considering the absence of the specification relating GFRP rebar in Korea, AASHTO specification is used to design the GFRP-reinforced concrete bridge deck. The GFRP-reinforced concrete bridge deck is proved to be governed by the criteria about serviceability, especially maximum crack width, while steel reinforced concrete bridge deck is governed by the criteria on ultimate limit state. In addition, GFRP rebars with diameter of 16 mm ~ 19 mm should be used for the main transverse direction of decks to assure appropriate rebar spacings.

Local Bond Stress-Slip Model of GFRP Rebars (GFRP 보강근의 부착응력-미끄럼 모델)

  • Cheong, Yeon-Geol;Yi, Chong-Ku;Lee, Jung-Yoon
    • Proceedings of the Korea Concrete Institute Conference
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    • 2008.11a
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    • pp.133-136
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    • 2008
  • The cost of repairing the deterioration of concrete structures due to corrosion of the reinforcement steel has been the prominent figure in the maintenacne of the reinforced-concrete infrastructures. As an alternative material to steel reinforcement, the use of Glass Fiber Reinforced Polymer (GFRP) bar in concrete is being actively studied for the high resistance of chemical environment and high strength to weight ratio properties of GFRP. However, there remain various aspects of GFRP properties that still need to be studied before the standard design criteria can be established. One of the imminent issues is the bond between GFRP and concrete. In this study, the bond-behavior of GFRP bars in concrete is investigated via the pullout test with varying parameters: surface condition of GFRP bars and concrete compression strength. And the local bond-stress model of GFRP rabars with applying monotonc load was also derived from the present test.

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Direct Tensile Test of GFRP Bar Reinforced Concrete Prisms

  • Choi Dong-Uk;Lee Chang-Ho;Ha Sang-Su
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05a
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    • pp.323-326
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    • 2005
  • Uniaxial tension test of Glass Fiber Reinforced Polymer (GFRP) bar reinforced concrete prisms was performed. The objective was to investigate the adequate cover thickness of the GFRP rebars. The tension stiffening effect of GFRP bar reinforced concrete was also studied. The test variables included rebar types (conventional steel rebar and two different GFRP rebars) and cover thicknesses (five different cover thicknesses ranging between 1-3db). Normal strength concrete was used. Cracking patterns on concrete surface and cracking loads were careful1y observed during the direct tensile test. The test results indicated that the adequate cover thickness of the GFRP rebars may even be larger than that of the steel rebars and that the cover thickness of 2db commonly specified for the GFRP rebars may not be large enough. The tension stiffening effect of the GFRP rebars was also quantified and documented from the test results.

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Flexural behaviour of GFRP reinforced concrete beams under cyclic loading

  • Murthy, A. Ramachandra;Gandhi, P.;Pukazhendhi, D.M.;Samuel, F. Giftson;Vishnuvardhan, S.
    • Structural Engineering and Mechanics
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    • v.84 no.3
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    • pp.361-373
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    • 2022
  • This paper examines the flexural performance of concrete beams reinforced with glass fibre-reinforced polymer (GFRP) bars under fatigue loading. Experiments were carried out on concrete beams of size 1500×200×100 mm reinforced with 10 mm and 13 mm diameter GFRP bars under fatigue loading. Experimental investigations revealed that fatigue loading affects both strength and serviceability properties of GFRP reinforced concrete. Experimental results indicated that (i) the concrete beams experienced increase in deflection with increase in number of cycles and failed suddenly due to snapping of rebars and (ii) the fatigue life of concrete beams drastically decreased with increase in stress level. Analytical model presented a procedure for predicting the deflection of concrete beams reinforced with GFRP bars under cyclic loading. Deflection of concrete beams was computed by considering the aspects such as stiffness degradation, force equilibrium equations and effective moment of inertia. Nonlinear finite element (FE) analysis was performed on concrete beams reinforced with GFRP bars. Appropriate constitutive relationships for concrete and GFRP bars were considered in the numerical modelling. Concrete non linearity has been accounted through concrete damage plasticity model available in ABAQUS. Deflection versus number of cycles obtained experimentally for various beams was compared with the analytical and numerical predictions. It was observed that the predicted values are comparable (less than 20% difference) with the corresponding experimental observations.

Behaviour of Lightweight Concrete Slab Reinforced with GFRP Bars under Concentrated Load (집중하중을 받는 GFRP 보강근 경량콘크리트 슬래브의 거동)

  • Son, Byung-Lak;Kim, Chung-Ho;Jang, Heui-Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.19 no.4
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    • pp.57-66
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    • 2015
  • This paper is a preliminary study to apply the lightweight concrete slabs reinforced with GFRP (glass fiber reinforced polymer) bars to the bridge deck slabs or some other concrete structures. So, some different behaviors between the conventional steel reinforced concrete slab and the lightweight concrete slab reinforced with GFRP bars were investigated. For this purpose, a number of slabs were constructed and then the three point bending test and numerical analysis for these slabs were performed. The flexural test results showed that the lightweight concrete slabs reinforced with GFRP bars were failed by the shear failure due to the over-reinforced design. The weight and failure load of the GFRP bar reinforced lightweight concrete slabs were 72% and 58% of the steel reinforced concrete slab with the same dimensions, respectively. Results of the numerical analysis for these slabs using a commercial program, midas FEA, showed that the load-deflection curve could be simulated well until the shear failure of the slabs, but the applied loads and the deflections continuously increased even beyond the shear failure loads.

Evaluation of Load Capacity and Toughness of Porous Concrete Blocks Reinforced with GFRP Bars (GFRP 보강 다공성 콘크리트 블록의 내력 및 인성 평가)

  • Jung, Seung-Bae;Yang, Keun-Hyeok
    • Journal of the Korea Institute of Building Construction
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    • v.17 no.5
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    • pp.403-409
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    • 2017
  • In this study, mix proportioning of porous concrete with compressive strength and porosity exceeding 3MPa and 30%, respectively, was examined and then load capacity and flexural toughness of the porous concrete block were evaluated according to the different arrangements of the GFRP bars. To achieve the designed requirements of porous concrete, it can be recommended that water-to-cement ratio and cement-to-coarse aggregate ratio are 25% and 20%, respectively, under the aggregate particle distribution of 15~20mm. The failure mode of porous concrete blocks reinforced with GFRP bars was governed by shear cracks. As a result, very few flexural resistance of the GFRP was expected. However, the enhanced shear strength of porous concrete due to the dowel action of the GFRP bars increased the load capacity and toughness of the blocks. The porous concrete blocks reinforced with one GFRP bar at each compressive and tensile regions had 2.1 times higher load capacity than the companion non-reinforced block and exhibited a high ductile behavior with the ultimate toughness index ($I_{30}$) of 43.4.

Experimental study on hollow steel-reinforced concrete-filled GFRP tubular members under axial compression

  • Chen, B.L.;Wang, L.G.
    • Steel and Composite Structures
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    • v.32 no.1
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    • pp.59-66
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    • 2019
  • Hollow steel-reinforced concrete-filled GFRP tubular member is a new kind of composite members. Firstly set the mold in the GFRP tube (non-bearing component), then set the longitudinal reinforcements with stirrups (steel reinforcement cage) between the GFRP tube and the mold, and filled the concrete between them. Through the axial compression test of the hollow steel-reinforced concrete-filled GFRP tubular member, the working mechanism and failure modes of composite members were obtained. Based on the experiment, when the load reached the ranges of $55-70%P_u$ ($P_u-ultimate$ load), white cracks appeared on the surface of the GFRP tubes of specimens. At that time, the confinement effects of the GFRP tubes on core concrete were obvious. Keep loading, the ranges of white cracks were expanding, and the confinement effects increased proportionally. In addition, the damages of specimens, which were accompanied with great noise, were marked by fiber breaking and resin cracking on the surface of GFRP tubes, also accompanied with concrete crushing. The bearing capacity of the axially compressed components increased with the increase of reinforcement ratio, and decreased with the increase of hollow ratio. When the reinforcement ratio was increased from 0 to 4.30%, the bearing capacity was increased by about 23%. When the diameter of hollow part was decreased from 55mm to 0, the bearing capacity was increased by about 32%.

Application of GFRP Re-bar in Concrete Bridge Deck Construction (교량 바닥판 콘크리트의 시공을 위한 GFRP근의 활용)

  • 김지홍;주형중;김병석;윤순종
    • Proceedings of the Korean Society For Composite Materials Conference
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    • 2003.04a
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    • pp.152-156
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    • 2003
  • In this paper, we present the results of an experimental research on the load-deflection characteristics of full-scale concrete bridge decks reinforced with GFRP re-bars. Similar researches have been conducted in many countries to extend the service life of concrete bridge decks, which are under harsh environmental condition. Concrete bridge decks are one of the major concerns for the maintenance of bridges. GFRP re-bar available in the domestic construction market was investigated and the concrete deck reinforced with GFRP re-bars was tested under flexure to investigate the applicability of GFRP re-bar on the bridge deck construction.

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A Fundamental Study for the Behavior of Lightweight Aggregate Concrete Slab Reinforced with GFRP Bar (GFRP bar를 휨보강근으로 사용한 경량골재콘크리트 슬래브의 거동에 관한 기초적 연구)

  • Jeon, Sang Hun;Shon, Byung Lak;Kim, Chung Ho;Jang, Heui Suk
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.16 no.3
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    • pp.99-108
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    • 2012
  • In this paper, to intend anticorrosive effect and weight reduction of conventional reinforced concrete slab, lightweight concrete slab reinforced with glass fiber reinforced polymer(GFRP) bar was considered and some basic behaviour of the slab were investigated. Measurement of splitting tensile strength and fracture energy of the concrete, a number of flexural experiment of the slab, numerical analysis using nonlinear finite element analysis, and comparison of the experimental results to the numerical analysis, were conducted. As a result, even the weight of the lightweight concrete slab could be reduced by about 28% than the normal concrete slab, failure load of the lightweight concrete slab was 36% smaller than the normal concrete slab. Such a thing can be attributed to the lower axial stiffness and lower bond strength of GFRP bar. In the numerical analysis, to consider decreasing property of bond strength of the lightweight concrete, interface element was used between the concrete and the GFRP bar elements and this method was shown to be a better way for the numerical analysis to approach the experimental results.

Finite element modelling of GFRP reinforced concrete beams

  • Stoner, Joseph G.;Polak, Maria Anna
    • Computers and Concrete
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    • v.25 no.4
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    • pp.369-382
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    • 2020
  • This paper presents a discussion of the Finite Element Analysis (FEA) when applied for the analysis of concrete elements reinforced with glass fibre reinforced polymer (GFRP) bars. The purpose of such nonlinear FEA model development is to create a tool that can be used for numerical parametric studies which can be used to extend the existing (and limited) experiment database. The presented research focuses on the numerical analyses of concrete beams reinforced with GFRP longitudinal and shear reinforcements. FEA of concrete members reinforced with linear elastic brittle reinforcements (like GFRP) presents unique challenges when compared to the analysis of members reinforced with plastic (steel) reinforcements, which are discussed in the paper. Specifically, the behaviour and failure of GFRP reinforced members are strongly influenced by the compressive response of concrete and thus modelling of concrete behaviour is essential for proper analysis. FEA was performed using the commercial software ABAQUS. A damaged-plasticity model was utilized to simulate the concrete behaviour. The influence of tension, compression, dilatancy, mesh, and reinforcement modelling was studied to replicate experimental test data of beams previously tested at the University of Waterloo, Canada. Recommendations for the finite element modelling of beams reinforced with GFRP longitudinal and shear reinforcements are offered. The knowledge gained from this research allows for the development of a rational methodology for modelling GFRP reinforced concrete beams, which subsequently can be used for extensive parametric studies and the formation of informed recommendations to design standards.