• Computers and Concrete
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• v.20 no.2
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• pp.215-227
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• 2017

A finite element model (FEM) for predicting early-age behavior of reinforced concrete (RC) bridge deck slabs with fiber-reinforced polymer (FRP) bars is presented. In this model, the shrinkage profile of concrete accounted for the effect of surrounding conditions including air flow. The results of the model were verified against the experimental test results, published by the authors. The model was verified for cracking pattern, crack width and spacing, and reinforcement strains in the vicinity of the crack using different types and ratios of longitudinal reinforcement. The FEM was able to predict the experimental results within 6 to 10% error. The verified model was utilized to conduct a parametric study investigating the effect of four key parameters including reinforcement spacing, concrete cover, FRP bar type, and concrete compressive strength on the behavior of FRP-RC bridge deck slabs subjected to restrained shrinkage at early-age. It is concluded that a reinforcement ratio of 0.45% carbon FRP (CFRP) can control the early-age crack width and reinforcement strain in CFRP-RC members subjected to restrained shrinkage. Also, the results indicate that changing the bond-slippage characteristics (sand-coated and ribbed bars) or concrete cover had an insignificant effect on the early-age crack behavior of FRP-RC bridge deck slabs subjected to shrinkage. However, reducing bar spacing and concrete strength resulted in a decrease in crack width and reinforcement strain.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.76-82
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• 2006

The concrete shear strength of FRP Bar reinforced concrete beam according to the variation of flexural reinforcement ratio was investigated. A number of experimental result showed that the concrete shear strength was lower than that of RC beam, but it was increased according to the increasement of reinforcement ratio. Shear strength correction factors considering the kind and reinforcement ratio of FRP Bar was proposed using the proposed formula in the literature and regression analysis of the experimental result.

• Proceedings of the KSR Conference
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• 2010.06a
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• pp.1486-1491
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• 2010

Recently, the frequency and magnitude of the earthquake have increased. The structural safety of the public facilities such as bridges and tunnels etc. which were not concerned for earthquake resistant design are increased. Fiber reinforcement polymer that has been frequently studied for seismic retrofit has advantage as seismic reinforcement material, but it has disadvantage of the brittleness. Therefore, the investigation of safety and seismic reinforcement are required. In this study, new FRP-ductile material layered composites proposed to seismic performance reinforced of subway tunnel. Tensile test of FRP-ductile material layered composites showed that Maximum tensile force of FRP-ductile using Aluminum is similar to existing FRP reinforcement material and maximum strain was increased. In case of application of domestic subway tunnel which need ductility, layered composites of FRP-Aluminum is estimated effectively for increase of seismic performance.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.3A
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• pp.259-266
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• 2009

This study is to develop equations that consider the elastic modulus ratio of FRP bar and steel reinforcement, shear span to depth ratio, and flexural reinforcement ratio of FRP bar, to determine concrete shear strength of FRP reinforced concrete beams without shear reinforcement. As experimental parameters, 2 types of FRP bar, 3 types of shear span to depth ratio, and 3 types of flexural reinforcement were used. Experimental results for two of shear span to depth ratio were quoted from previous study to evaluate effect of shear span to depth ratio in more detail. Shear strength correction factors needed for evaluating concrete shear strength were proposed from regression analysis using above experimental results. Equations suggested from this study and other codes were examined and compared with 31 experimental results available in the literature. From this comparison, it could be known that the equation suggested from this study gives the most approaching result to experimental results.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.309-312
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• 2006

An experimental study for bond slip behavior of concrete and a FRP plank was used as the both formwork and the tensile reinforcement for a concrete structural member is described. 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 FRP and the concrete must be developed. This study focuses on investigation of the bond slip behavior of sand coated interface between FRP and cast-in-place concrete experimentally.

• International Journal of Concrete Structures and Materials
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• v.1 no.1
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• pp.45-55
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• 2007

Ten beams bonded with glass fiber reinforced polymer (GFRP) laminates were tested under cyclic loading with the load range and the FRP reinforcement ratio as test parameters. The maximum load level during cyclic loading was 55%, 65% and 75% of the static flexural strength while the minimum load level was kept constant at 35%. Deflections of the beams at the end of 525000 cycles were found to increase by 16% and 44% when the maximum load level was increased from 55% to 65% and 75% of the static flexural strength, respectively. Beams with FRP reinforcement ratios of 0.64% and 1.28% were found to exhibit lesser deflections of about 15% and 20%, respectively, compared to a similar beam without FRP reinforcement. An analytical approach based on cycle-dependent effective moduli of elasticity of concrete and FRP reinforcement is presented and found to predict the deflections of the test beams well.

• Journal of Korean Association for Spatial Structures
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• v.22 no.1
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• pp.59-66
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• 2022

In this paper, the flexural capacity equation of FRP-bar reinforced concrete beams was verified by comparing the experimental results and flexural capacity obtained according to the ACI procedure. And, also the economic feasibility of FRP-bar reinforced concrete beams was analyzed by comparing nominal moment capacity of beams. The results of analysis were as follows, 1) GFRP concrete beams have lower flexural performance than reinforced concrete beams, whereas CFRP concrete beams have similar flexural performance to reinforced concrete beams under the same reinforcement ratio 2) Although the design moment increased as the compressive strength of concrete increased, the flexural performance of GFRP reinforced concrete beams was found to be lower than the reinforced concrete beams for all reinforcement ratios.

• Computers and Concrete
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• v.20 no.4
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• pp.391-407
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• 2017

Fiber reinforced polymer (FRP) bars have been recently used to reinforce concrete members in flexure due to their high tensile strength and especially in corrosive environments to improve the durability of concrete structures. However, FRPs have a low modulus of elasticity and a linear elastic behavior up to rupture, thus reinforced concrete (RC) components with such materials would exhibit a less ductility in comparison with steel reinforcement at the similar members. There were several studies showed the behavior of concrete beams with the hybrid combination of steel and FRP longitudinal reinforcement by adopting the experimental and numerical programs. The current study presents a numerical and analytical investigation based on the data of previous researches. Three-dimensional (3D) finite element (FE) models of beams by using ANSYS are built and investigated. In addition, this study also discusses on the design methods for hybrid FRP-steel beams in terms of ultimate moment capacity, load-deflection response, crack width, and ductility. The effects of the reinforcement ratio, concrete compressive strength, arrangement of reinforcement, and the length of FRP bars on the mechanical performance of hybrid beams are considered as a parametric study by means of FE method. The results obtained from this study are compared and verified with the experimental and numerical data of the literature. This study provides insight into the mechanical performances of hybrid FRP-steel RC beams, builds the reliable FE models which can be used to predict the structural behavior of hybrid RC beams, offers a rational design method together with an useful database to evaluate the ductility for concrete beams with the combination of FRP and steel reinforcement, and motivates the further development in the future research by applying parametric study.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.3
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• pp.105-115
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• 2007

Repair and Reinforcement are subjected change to increasing of remodelling. The usage of carbon fiber sheets is increasing for the strengthening of reinforce concrete structures. Therefore experimental and analytical studies are carry out to investigate the flexural behaviors of the strengthened RC structures by the external bonding of the new reinforcement method. Also the aim of this study is to investigate reinforcing method of FRP panel deal with fatigue loading through experiments.

• Proceedings of the Korea Concrete Institute Conference
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• 1990.10a
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• pp.163-168
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• 1990

This study shows both through experiment and based on theory the reinforcement effectiveness when using FRP(Fiber Reinforced Plastics) as a means of reinforcing the concrete of the deteriorated concrete. Non-deteriorated concrete and deteriorated concrete which is deteriorated by freezing and thawing are made three type specimens (non-reinforced) concrete beam, one layer FRP reinforced concrete beam, two layer FRP reinforced concrete beam) for this purpose. Bending strength and cracking load ratio is measured by bending test.