CFRP Rebar로 보강한 콘크리트 보의 휨 거동 = Flexural Behavior of Concrete Beams Reinforced with CFRP rebars

국문 초록 (Abstract)

철근의 부식을 해결하기 위해 철근의 대체 재료로 적용 가능한 FRP에 대한 연구의 적용성이 대두되었다. 그러나 취성적인 성질과 탄성계수가 낮은 단점을 가지고 있어, FRP rebar로 보강된 휨 부재의 사용성 평가 즉 처짐에 대한 연구가 필요하다. 본 연구에서는 보강비를 변수로 한, CFRP rebar로 보강된 콘크리트 보의 휨 실험을 수행하였다. 실험 결과, CFRP rebar로 보강된 실험체는 보강비가 증가함에 따라 내력 및 강성이 증가하는 양상을 보였으며, 철근 실험체와 동일한 단면성능을 발휘하기 위해서는 약 1.3배의 보강비가 요구되는 것으로 나타났다. 또한 유효단면2차모멘트에 대한 기존 제안식의 비교 결과, Bischoff & Scanlon이 제안한 식이 가장 정밀해에 가까운 처짐을 예측하였다.

다국어 초록 (Multilingual Abstract)

To address the problems caused by the corrosion of steel rebar, active research has recently been carried out on members where fiber-reinforced polymer (FRP) is used in place of rebar. As FRP bar is highly brittle and has a low modulus of elasticity, further research is needed on the evaluation of serviceability, in other words on the deflection of flexural concrete members reinforced with FRP rebars. Taking the reinforcement ratio as a variable, this paper analyzes the flexural capacity of concrete beams reinforced with CFRP rebar. The test results of specimens reinforced with CFRP rebar show an increase in stiffness and resisting force along with an increase in the reinforcement ratio. A reinforcement ratio of about 1.3 is needed for the member reinforced with CFRP rebar to show same section property of a steel member. Through a comparison for the value of an effective moment of inertia, the equation suggested by Bischoff & Scanlon predicted values closest to the actual results.

참고문헌 (Reference)

1 Nayal, R, "Tension Stiffening Model for Concrete Beams Reinforced with Steel and FRP Bars" 18 (18): 831-841, 2006

2 Scanlon, A., "Shrinkage Restraint and Loading History Effects on Deflection of Fiber-Reinforced Polymer Reinforced Beams" 105 (105): 498-506, 2008

3 ACI Committee 440, "Guide for the Design and Construction of Structural Concrete Reinforced with FRP Bars(ACI 440.1R-06)" Farmington Hills 2006

4 Benmokrane, B, "Flexural Response of Concrete Beams Reinforced with FRP Reinforcing Bars" 91 (91): 46-55, 1995

5 Habeeb, M. N., "Flexural Behavior of Continuous GFRP Reinforced Concrete Beams" 12 (12): 115-124, 2008

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7 Bischoff, P. H., "Effective Moment of Inertia for Calculating Deflections of Concrete Members Containing Steel Reinforcement and Fiber-Reinforced Polymer Reinforcement" 104 (104): 68-75, 2007

8 Bischoff, P. H, "Deflection Calculation of FRP Reinforced Concrete Beams Based on Modifications to the Existing Branson Equation" 11 (11): 4-14, 2007

9 ACI Committee 435, "Control of Deflection in Concrete Structures(ACI 435R-95)" Farmington Hills 1995

10 이영학, "CFRP 보강근의 부착강도에 대한 실험적 연구" 대한건축학회 24 (24): 53-60, 2008

11 ACI Committee 318, "Building Code Requirement for Structural Concrete(ACI 318-05)" Farmington Hills 2005

12 Rashid, M.A, "Behavior of Aramid Fiber-Reinforced Polymer Reinforced High Strength Concrete Beams Under Bending" 9 (9): 117-127, 2005

13 Rafi, M. M, "Aspects of behaviour of CFRP reinforced concrete beams in bending" 22 : 277-285, 2008