• International Journal of Highway Engineering
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• v.15 no.1
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• pp.23-36
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• 2013

PURPOSES: The problem under this circumstance is that the erosion not only drops strength of the steel dowel bar but also comes with volume expansion of the steel dowel bar which can reduce load transferring efficiency of the steel dowel bar. To avoid this erosion problem, alternative dowers bars are developed. METHODS: In this study, the bearing stresses between the FRP tube dowel bar and concrete slab are calculated and compared with its allowable bearing stress to check its structural stability in the concrete pavement. These comparisons are conducted with several cross-sections of FRP tube dowel bars. Comprehensive laboratory tests including the shear load-deflection test on a full-scale specimen and the full-scale accelerated joint concrete pavement test are conducted and the results were compared with those from the steel dowel bar. RESULTS: In all cross-sections of FRP tube dowel bars, computed bearing stresses between the FRP tube dowel bar and concrete slab are less than their allowable stress levels. The pultrusion FRP-tube dowel bar show better performance on direct shear tests on full-scale specimen and static compression tests at full-scale concrete pavement joints than prepreg and filament-winding FRP-tube dowel bar. CONCLUSIONS: The FRP tube dowel bars as alternative dowel bar are invulnerable to erosion that may be caused by moisture from masonry joint or bottom of the pavement system. Also, the pultrusion FRP-tube dowel bar performed very well on the laboratory evaluation.

• Proceedings of the KSR Conference
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• 2009.05b
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• pp.665-670
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• 2009

From the result of preceding study, there is no reinforcement such as dowel bar or etc. in Joint system of floating slab. Length of floating slab in preceding study is short than one of this study. If there is no reinforcement in the joint of long slab span, fracture of slab is predicted by difference between two slabs. Therefore using of dowel bar is demanded. In this study, General characteristic and preceding technology of dowel bar is researched for data of analysis study. And it is considered application of dowel bar in floating slab system.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.101-114
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• 2007

Dowel bars in the jointed concrete pavement are used to both provide load transfer across pavements joints and prevent the joint faulting leading to longer service life. On the contrary, the misplacement of dowel bar can provide negative results including the joint freezing(locking) that may cause the joint spatting and unexpected mid-slab cracking. The dowel bar can be placed using the assembly or dowel bar inserter (DBI) during the concrete pavement construction. In the domestic practice of the concrete pavement construction, the dowel bar is placed using the assembly method. This study primarily focuses on the comparison of these two dowel placement methods using the field data from the KHC test road in which both dowel placement methods have been applied to a certain length of the concrete pavement. The field data regarding the alignment of the dowel bars placed by both methods was collected using MIT-SCAN2, a nondestructive measuring equipment, and processed to compute Joint Score and Running Ave. Joint Score which are used as indicators of the dowel bar performance. The comparison of the methods for the dowel bar placement using these indicators shows that the DBI method provided much better alignment of the dowel bars reducing the risk of joint freezing than the assembly method. In order to improve the quality of the dowel bar placement using the assembly method, the current weak points of the assembly method including the fabrication, storage, and installation of dowel bar assembly were investigated and the solution was suggested. The improved dowel bar sets based on the suggested solution have been applied to an actual practice of the concrete pavement construction. The field data shows that the improved assembly method suggested in this study can highly reduce the risk of joint freezing.

• Magazine of the Korea Concrete Institute
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• v.7 no.6
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• pp.216-223
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• 1995

This research is aimed to investigate the influence of the structural parameters on dowel action of reinforcing bars in reinforced concrete members. I~ollowing the previous research, $^{(3.6)}$ a total of forty two specimens were tested to scrutinize the dowel action of reinforcing bars. Concrete cover, reinforcing bar size and bar distance were taken as main test variables for constant compressive strength of concrete. ]+om the test results, the structural behavior of all specimens was almost linear up to failure load. It is seen that dowel force increases as concrete cover increases. Reinforcing bar size and bar distance hardly affects dowel force. It is found that the dowel forces obtained by this experimental research is relatively close to that of regression analysis results and White's equation.

• International Journal of Highway Engineering
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• v.11 no.4
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• pp.79-85
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• 2009

Dowel-bar in the jointed concrete pavement has been designed and constructed by Foreign standard and experience in Korea. Timoshenko solution was evaluated for dowel bar design. However, various assumptions, Timoshenko solution evaluated only single dowel bar. Therefore, This study object is evaluated the guide line dowel size and arrangement that using the 3Dimensional Finite Element Method. Dowel bar behavior, Timoshenko solution and 3D FEM estimated used result. Dowel allowable stress and Friberg bearing stress estimated using result. The effects of Dowel Group Action were analyzed using Timoshenko range and Friberg range and 3D FEM.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.2D
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• pp.135-141
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• 2010

Dowel bar in the jointed concrete pavement has been designed and constructed by Foreign standard and experience in Korea. The behavior of dowel bar is explored based in analyze of 3-Dimension Finite Element Method. To evaluate behavior of dowel bar compared Timoshenko theory and 3-Dimensional Finite Element Method. Based on the 3-Dimension Finite Element Method analyze the dowel-bar optimum position that can reduce deflections of slabs by considering wheel path distributions was suggest in this study.

• International Journal of Highway Engineering
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• v.13 no.3
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• pp.21-30
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• 2011

As well known, dowel bars are used to transfer traffic load acting on one edge to another edge of concrete slab in concrete pavement system. The dowel bars widely used in South Korea are round shape steel bar and they shows satisfactory performance under bending stress which is developed by repetitive traffic loading and environment loading. However, they are not invulnerable to erosion that may be caused by moisture from masonry joint or bottom of the pavement system. Especially, the erosion could rapidly progress with saline to prevent frost of snow in winter time. The problem under this circumstance is that the erosion not only drops strength of the steel dower bar but also comes with volume expansion of the steel dowel bar which can reduce load transferring efficiency of the steel dowel bar. To avoid this erosion problem in reasonable expenses, dowers bars with various materials are being developed. Fiber reinforced plastic(FRP) dower that is presented in this paper is suggested as an alternative of the steel dowel bar and it shows competitive resistance against erosion and tensile stress. The FRP dowel bar is developed in tube shape and is filled with high strength no shrinkage. Several slab thickness designs with the FRP dowel bars are performed by evaluating bearing stress between the dowel bar and concrete slab. To calculated the bearing stresses, theoretical formulation and finite element method(FEM) are utilized with material properties measured from laboratory tests. The results show that both FRP tube dowel bars with diameters of 32mm and 40mm satisfy bearing stress requirement for dowel bars. Also, with consideration that lean concrete is typical material to support concrete slab in South Korea, which means low load transfer efficiency and, therefore, low bearing stress, the FRP tube dowel bar can be used as a replacement of round shape steel bar.

• International Journal of Highway Engineering
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• v.11 no.2
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• pp.141-149
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• 2009

This study was conducted to investigate the causes that induce the T-shape cracks at the joints in the jointed concrete pavements(JCPs). The finite element models of JCP including dowel bars were developed and the stress distribution in the slab was investigated under environmental loads. To investigate the effect of dowel bars on the transverse stresses at the joints that induce the T-shape cracks, the slab curling behavior was analyzed with and without dowel bars. In addition, the stress concentration was investigated when the dowel bar was not installed at the mid-depth of the slab. The results of this study showed that the transverse stresses were not affected by the dowel bars if the dowel bars were installed at the mid-depth of the slab. However, if the dowel bars were not installed at the mid-depth, the transverse stresses were concentrated at the dowel bar locations when the slab curled. The stress concentration was dependent on the contact characteristics between the dowel bar and concrete, and was significantly large when the dowel bar not installed at the mid-depth was located far from the edge of the slab. Therefore, to mitigate T-shape cracking in JCP, dowel bars should be very carefully installed and leveled at the proper locations.

• Computers and Concrete
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• v.21 no.5
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• pp.593-605
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• 2018

A nonlinear finite element modeling approach is developed to assess the behavior of a dowel bar embedded on a single concrete block substrate, subjected to monotonic loading. In this approach, a discrete representation of the steel reinforcing bar is considered, using beam finite elements with nonlinear material behavior. The bar is connected to the concrete embedment through nonlinear Winkler spring elements. This modeling approach can only be used if a new constitutive model is developed for the spring elements, to simulate the deformability and strength of the concrete substrate. To define this constitutive model, an extensive literature review was conducted, as well as 3 experimental tests, in order to select the experimental data which can be used in the calibration of the model. Based on this data, an empirical model was established to predict the global dowel response, for a wide range of bar diameters and concrete strengths. This empirical model provided the information needed for calibration of the nonlinear Winkler spring model, valid for dowel displacements up to 4 mm. This new constitutive model is composed by 5 stages, in order to reproduce the concrete substrate response.

• Magazine of the Korea Concrete Institute
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• v.6 no.3
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• pp.215-220
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• 1994

Results of an experimental investigation on the bearing strength and stiffness of concrete under dowel bars are summarized. The effects of concrete strength bar diameter, and location of the bar on concrete were studied. Based on test results, empirical equations are proposed to predict the, concrete bearing strength and stiffness under reinforcing bars. Cornparisions of analytical arid experimental results are presented.