Quasi-Plane-Hypothesis of Strain Coordination for RC Beam Strengthened with External-Bonded or Near-Surface Mounted Carbon Fiber Reinforced Plastic Strip

2011 ◽  
Vol 255-260 ◽  
pp. 54-58 ◽  
Author(s):  
Zhen Hua Ren ◽  
Xian Tao Zeng
Keyword(s):  
Weight Ratio ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
Superior Performance ◽  
Rc Beam ◽  
Fiber Reinforced ◽  
Near Surface ◽  
Reinforced Plastics ◽  
Steel Rebar ◽  
Near Surface Mounted

Rehabilitation of existing structures with fiber reinforced plastics (FRP) has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high stiffness-to-weight ratio. This paper presents strain coordination results of (two groups)15 reinforced concrete beams strengthened with different methods including external-bonded and near-surface mounted carbon FRP strip in order to investigate the strain coordination of CFRP and steel rebar of RC beam. Because there is relative slipping between RC beam and CFRP, the strain of CFRP and steel rebar of RC beam satisfies the quasi-plane-hypothesis, that is, the strain of longitudinal fiber that parallels to the neutral axis of plated beam within the scope of effective height (h0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis, the strain of FRP and steel rebar satisfies the equation: , the value of is equal to 1.1~1.3 according to the test results.

Quasi-Plane-Hypothesis of Strain Coordination for RC Beam Strengthened with Near-Surface Mounted Carbon Fiber Reinforced Plastic Bar or Helical Rib Bar

2011 ◽  
Vol 243-249 ◽  
pp. 541-545 ◽  
Author(s):  
Xian Tao Zeng ◽  
Zhen Hua Ren
Keyword(s):  
Weight Ratio ◽  
Neutral Axis ◽  
Reinforced Concrete Beams ◽  
Superior Performance ◽  
Rc Beam ◽  
Fiber Reinforced ◽  
Near Surface ◽  
Reinforced Plastics ◽  
Steel Rebar ◽  
Near Surface Mounted

Rehabilitation of existing structures with fiber reinforced plastics (FRP) has been growing in popularity because they offer superior performance in terms of resistance to corrosion and high stiffness-to-weight ratio. This paper presents strain coordination results of (two groups)6 reinforced concrete beams strengthened with different methods including near-surface mounted CFRP bar and helical rib rebar in order to investigate the strain coordination of CFRP bar or HR bar and steel rebar of RC beam. Because there is relative slipping between RC beam and bar, the strain of CFRP or HR bar and steel rebar of RC beam satisfies the quasi-plane-hypothesis, that is, the strain of longitudinal fiber that parallels to the neutral axis of plated beam within the scope of effective height (h0) of the cross section is in direct proportion to the distance from the fiber to the neutral axis, the strain of CFRP or HR and steel rebar satisfies the equation:εCH=βεsteel , the value of β is equal to 1.0～1.2 according to the test results.

Structural Behavior of Reinforced Concrete Beams Strengthened with Carbon Fiber Reinforcement Polymer Plate

2013 ◽  
Vol 302 ◽  
pp. 338-342
Author(s):  
Soo Yeon Seo
Keyword(s):  
Carbon Fiber ◽  
Fiber Reinforcement ◽  
Reinforced Concrete Beams ◽  
Structural Behavior ◽  
Rc Beam ◽  
Near Surface ◽  
Cfrp Plate ◽  
Carbon Fiber Reinforcement ◽  
Externally Bonded ◽  
Near Surface Mounted

This paper presents the study to find retrofit effect in case of Near-Surface-Mounted Retrofit (NSMR) using Carbon Fiber Reinforcement Polymer (CFRP) plate targeting reinforcement concrete (RC) beam by comparing the previous Externally Bonded Retrofit (EBR) method through experimental analytical works. Three RC beam specimens were made and two of them were retrofitted with CFRP plate by using EBR and NSMR. Also Finite Element (FE) analysis was performed in order to simulate the structural behavior of the beams by considering the bond properties between concrete and CFRP. From the study, it was found that the beam retrofitted with EBR hada reduction of bond capacity in the joint while the beam retrofitted with NSMR had perfect bond capacity.

scholarly journals A Parametric Study on the Flexural Strengthening of Reinforced Concrete Beams with Near Surface Mounted FRP Bars

2018 ◽  
Vol 4 (8) ◽  
pp. 1917
Author(s):  
Minu Panahi ◽  
Mohsen Izadinia
Keyword(s):  
Reinforced Concrete ◽  
Concrete Beams ◽  
Weight Ratio ◽  
Bending Moment ◽  
Reinforced Concrete Beams ◽  
Flexural Behavior ◽  
Experimental Investigations ◽  
Near Surface ◽  
Finite Element Software ◽  
Near Surface Mounted

FRP rods as lightweight materials with extraordinary properties of high strength to weight ratio, corrosion resistance, potentially high overall durability, tailor ability and high specific attributes are one of the most favorable materials to strengthen existing reinforced structures. The present study aimed to identify the behavior of reinforced concrete flexural beams strengthened with fiber reinforced polymer (FRP) rods through near surface mounted method (NSM). The results of the current study were based on nonlinear finite element software ABAQUS which can accurately simulate the experimental investigations on flexural behavior of reinforced concrete beams strengthened with NSM FRP rods. Validation of the proposed model was confirmed first by making a comparison with the experimental study presented in the literature. A parametric analysis was conducted on validated specimens to investigate the effect of FRP rod diameters, rod arrangements, FRP materials, as well as rods groove intervals on flexural behavior of strengthened reinforced beams. The numerical results of mid-span bending moment deflection, ultimate bending moment, failure deflection and ductility index were reported. For the sake of simplicity to be used by engineers, the results of the current study were drawn in the form of design charts and tables.

scholarly journals Experimental Evaluation of PSC Structures from FRP with a Prestressing Strengthening Method

Materials ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265
Author(s):  
Tae-Kyun Kim ◽  
Sang-Hyun Kim ◽  
Jong-Sup Park ◽  
Hee-Beom Park
Keyword(s):  
Prestressed Concrete ◽  
Strengthening Effect ◽  
Fiber Reinforced ◽  
Prestress Loss ◽  
Near Surface ◽  
Reinforced Plastics ◽  
Near Surface Mounted ◽  
Fiber Reinforced Plastics ◽  
Flexural Tests ◽  
Strengthening Method

A prestressed concrete (PSC) structure is subject to prestress losses in the long and short terms, and the structure ages over time. The structure is susceptible to corrosion from exposure to environmental factors such as moisture, chloride, and carbonation, thus causing prestress loss. Therefore, strengthening the structure is needed to address this problem. Here, the near surface mounted (NSM) method and the external prestressing (EP) method were selected because they are capable of applying additional prestressing. Further, we used fiber-reinforced plastics or polymers, or carbon fiber-reinforced plastics or polymers because of their high tensile strength and noncorrosive properties. For EP tests, prestressed strands were used. Accordingly, this study performs four-point flexural tests and evaluations for 12 types of specimens fabricated with different PSC methods. All specimens fabricated with the NSM (prestressing, no prestressing) and EP methods achieved stiffness that was 50–60% higher than that of the control PSC specimen. It was observed that the EP method in conjunction with prestressing yielded the best strengthening effect. It is expected that the results of this study will be applied to real structures for strengthening them and improving their performances.

scholarly journals Fatigue Behavior of Concrete Beam with Prestressed Near-Surface Mounted CFRP Reinforcement According to the Strength and Developed Length

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 51 ◽  
Author(s):  
Hee Park ◽  
Jong-Sup Park ◽  
Jae-Yoon Kang ◽  
Woo-Tai Jung
Keyword(s):  
Fatigue Behavior ◽  
Concrete Strength ◽  
Fatigue Loading ◽  
Reinforced Concrete Beams ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Near Surface ◽  
Reinforced Polymer ◽  
Anchoring System ◽  
Near Surface Mounted

The prestressed near-surface mounted reinforcement (NSMR) using Fiber Reinforced Polymer (FRP) was developed to improve the load bearing capacity of ageing or degraded concrete structures. The NSMR using FRP was the subject of numerous studies of which a mere portion was dedicated to the long-term behavior under fatigue loading. Accordingly, the present study intends to examine the fatigue performance of the NSMR applying the anchoring system developed by Korea Institute of Construction and Building Technology (KICT). To that goal, fatigue test is performed on 6.4 m reinforced concrete beams fabricated with various concrete strengths and developed lengths of the Carbon Fiber Reinforced Polymer (CFRP) tendon. The test results reveal that the difference in the concrete strength and in the developed length of the CFRP tendon has insignificant effect on the strengthening performance. It is concluded that the accumulation of fatigue loading, the concrete strength and the developed length of the tendon will not affect significantly the strengthening performance given that sufficient strengthening is secured.

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