• Title, Summary, Keyword: GFRP

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A Study on the Static Behavior of GFRP Bridge Deck (GFRP 교량 바닥판의 정적거동에 관한 연구)

  • Ji, Hyo Seon
    • Journal of the Korea institute for structural maintenance and inspection
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    • v.15 no.3
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    • pp.163-170
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    • 2011
  • A concept of Modular GFRP(Glass Fiber Reinforced Polymer) deck panel was proposed for bridge decks. The modular GFRP bridge deck system is comprised of main unit module and connector unit module with GFRP flanges and web. Its structural performance under static loading was evaluated and compared with the LUSAS finite element predictions. It was found that the presented GFRP modular panel was very efficient for use in bridges. The failure mode of the proposed GFRP deck was similar when compared with that of commercial other GFRP decks developed.

Long-Term Performance Evaluation of a GFRP Slab Bridge (GFRP 슬래브 교량의 장기성능 평가)

  • Ji, Hyo-Seon
    • Journal of Korean Society of Steel Construction
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    • v.24 no.3
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    • pp.349-360
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    • 2012
  • This paper describes a detailed assessment of the structural safety, serviceability, capacity rating and long-term performance of a glass fiber-reinforced polymer (GFRP) slab bridge superstructure. This first all-GFRP slab bridge was installed in Korea on May 2002. The GFRP slab bridge is a simply supported, its length is 10.0 m, and is designed to carry two-lane traffic and has an overall width of 8.0m. The GFRP slab bridge is a sandwich structure with a corrugated core, fabricated by hand lay-up process with E-glass fibers and vinyl ester resins. The assessment of long-term performance for the GFRP slab bridge in 2004, 2011 includes a field load testing identical to that performed in 2002. The assessment indicates that the GFRP slab bridge has no structural problems and is structurally performing well in-service as expected. The assessment may provide a baseline data for the capacity ratings assessment of the GFRP slab bridge and also serve as part of a long-term performance of all-GFRP bridge superstructure.

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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    • 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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Bending strength of GFRP for Insulator according to Winding Angle (전기절연물용 GFRP의 winding 각도에 따른 굽힘강도)

  • Park, Hoy-Yul;Kang, Dong-Pil;Ahn, Myeong-Sang;Lee, Tae-Joo
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • pp.429-432
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    • 2004
  • The demand for electric power keeps growing, and tends to be more effective. Polymer insulators have been manufactured for almost twenty years and the excellent insulation performance of polymer insulators is attractive. Polymeric materials are now widely used as a replacement for inorganic materials such as porcelain or glass for the outdoor insulation of high voltage insulation. GFRP has been used widely as a core materials for polymer insulators. This paper reports the mechanical properties of GFRP for insulators. The bending strength was simulated and evaluated according to the winding angle. The fiber orientation in GFRP has a great effect on the strength of GFRP because the strength of GFRP mainly depends on the strength of fiber. Results of simulated and evaluated strength of GFRP were compared each other. The simulated strength of GFRP rod was different from the evaluated strength. It was caused that the shear stress had a great effect on the strength of GFRP although the stress of parallel direction of GFRP was much higher.

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Service and Ultimate Load Behavior of Bridge Deck Reinforced with GFRP Rebars (GFRP 보강근으로 보강된 교량 바닥판의 성능과 사용성에 관한 실험연구)

  • Yu, Young Jun;Park, Young Hwan;Park, Ji Sun
    • Journal of The Korean Society of Civil Engineers
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    • v.28 no.5A
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    • pp.719-727
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    • 2008
  • The tensile and bond performance of GFRP rebar are different from those of conventional steel reinforcement. It requires some studies on concrete members reinforced with GFRP reinforcing bars to apply it to concrete structures. GFRP has some advantages such as high specific strength, low weight, non-corrosive nature, and disadvantage of larger deflection due to the lower modulus of elasticity than that of steel. Bridge deck is a preferred structure to apply FRP rebars due to the increase of flexural capacity by arching action. This paper focuses on the behavior of concrete bridge deck reinforced with newly developed GFRP rebars. A total of three real size bridge deck specimens were made and tested. Main variables are the type of reinforcing bar and reinforcement ratio. Static test was performed with the load of DB-24 level until failure. Test results were compared and analyzed with ultimate load, deflection behavior, crack pattern and width.

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Comparison of Shear Strength Equation for Flat Plates with GFRP Plate (GFRP 판으로 보강된 플랫 플레이트의 전단강도식에 관한 규준의 비교 분석)

  • Kim, Min Sook;Hwang, Seung Yeon;Kim, Heecheul;Lee, Young Hak
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.27 no.4
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    • pp.247-254
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    • 2014
  • In this study, shear test performed to investigate the shear behavior of flat plate that reinforced by embedded GFRP(glass fiber reinforced polymer) plate with openings. Shape of the GFRP shear reinforcement is a plate with several openings to ensure perfect integration with concrete. The test parameters include the distance between the column face and the first line of GFRP plate and number of GFRP plate vertical strip. The result of test showed that when number of GFRP plate vertical strip was increased, shear strength improved. The shear strength for flat plate reinforced GFRP plate in various codes including ACI 318, BS 8110, EUROCODE 2, and KCI were compared to provide more rational approach for reinforced concrete flat plates with GFRP plate.

A Comparison of Residual Tensile Properties of GFRP Reinforcing Bar at High Temperature and after Exposure to High Temperature (고온과 고온노출 후 GFRP 보강근의 잔존인장성능 비교)

  • Kim, Seongdo;Moon, Doyoung
    • Journal of The Korean Society of Civil Engineers
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    • v.35 no.1
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    • pp.77-84
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    • 2015
  • Tensile tests were conducted on the GFRP reinforcement exposed to high temperature. The exposure condition for this study was below $200^{\circ}C$ for about 3 minutes. This conditioning is minor compared with that presented in experimental program conducted by other researchers. The residual tensile strength and elastic modulus of GFRP reinforcing bars at high temperature and after exposure to high temperature were compared. In results, tensile properties were decreased at high temperatures, but those after exposure to high temperature were recovered to pre-heating level almost completely. These results could be valuable for evaluating GFRP reinforced structure damaged by fire accident.

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.

A Study on the Basic Development Length of GFRP Rebar With Ribs (이형 GFRP 보강근의 기본정착길이에 대한 연구)

  • Moon, Do Young
    • Journal of The Korean Society of Civil Engineers
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    • v.30 no.5A
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    • pp.485-493
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    • 2010
  • GFRP rebar with ribs resemble those of deformed steel rebar was developed in 2005. It was reported that ribs of the GFRP rebar were sheared off due to the lower shear strength of polymer. In this study, the basic development length of the GFRP rebar was investigated through pull-out tests, models specified in ACI440.1R-03 and -06, and empirical model derived by Cosenza et al. (2002). As a results of pull-out tests, the critical embeddment length, which is defined as the length when failure mode is changed from pull-out to bar fracture, was 20 times of bar diameter for GFRP rebar and was 15 times for steel rebar. It is believed that the basic development of the GFRP rebar is 21 times of bar diameter, which is determined from the application of average bond strength into the model equation specified in ACI440.1R-03. Compared to the model equation in ACI440.1R-06, that in ACI440.1R-03 is recommendable for design purpose. The Cosenza et al.'s model underestimates the basic development length of the GFRP rebar.

Behavior of GFRP reinforced decks with various reinforcement ratio (GFRP 보강근으로 보강된 바닥판의 보강비에 따른 거동 실험)

  • You, Young-Jun;Park, Ji-Sun;Park, Young-Hwan;Kim, Hyeong-Yeol;Kim, Keung-Hwan
    • Proceedings of the Korea Concrete Institute Conference
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    • pp.49-52
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    • 2008
  • The tensile and bond performance of GFRP rebar are different from those of conventional steel reinforcement. It requires some studies on concrete members reinforced with GFRP reinforcing bars to apply it to concrete structures. GFRP has some advantages such as high specific strength, low weight, non-corrosive nature, and disadvantage of larger deflection due to the lower modulus of elasticity than that of steel. Bridge deck is a preferred structure to apply FRP rebars due to the increase of flexural capacity by arching action. This paper focuses on the behavior of concrete bridge deck reinforced with newly developed GFRP rebar. A total of three real size bridge deck specimens were made and tested. Main variable was reinforcement ratio of GFRP rebar. Static test was performed with the load of DB-24 level until failure. Test results were compared and analyzed with ultimate load, deflection behavior.

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