• Composites Research
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• v.26 no.1
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• pp.66-71
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• 2013

As a fundamental structural element of construction, a pile is constructed to transfer loads from superstructure to foundation. In general, since the pile foundation is constructed in the ground or ground under water, it is difficult to protect from the damages due to moisture and/or salt which create corrosive environment and it is even more difficult to estimate its durability. In this study, in order to enhance the durability and constructibility of the pile foundation, FRP-concrete hybrid composite pile (HCFFT) is suggested. Moreover, equation for the prediction of load carrying capacity of HCFFT circular members under compression is suggested and discussed based on the results of analytical and experimental investigations. In addition, we also conducted the finite element simulation for the structural behavior of new HCFFT composite pile and the result is compared with those of experimental and analytical studies. In addition, the axial loading capacity of new HCFFT composite pile is compared with those of existing PHC pile and hollow circular steel pipe pile, and it was found that the new HCFFT composite pile has advantages over conventional PHC and steel pipe piles.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.4
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• pp.19-27
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• 2011

In this paper, we present a part of results to develop new type hybrid FRP-concrete composite pile (i.e., concrete filled fiber reinforced plastic circular tubes, hybrid CFFT, HCFFT). The purpose of this paper is to evaluate compressive loading capacity through compressive strength test. Before compressive strength test of HCFFT, we investigated mechanical properties of pultruded fiber reinforced plastic (PFRP) and filament winding fiber reinforced plastic (FFRP). For estimating the compressive strength of HCFFT, uni-axial compression strength tests of HCFFT compression members were conducted. The test variables are compressive strengths of concrete and thickness of FFRP. In addition, uni-axial compression strength tests of concrete filled fiber reinforced plastic circular tube (CFFT) except PFRP members were conducted. The test variable in the test is thickness of FFRP. From the test result, the compressive strength of the HCFFT in larger than compressive strength of CFFT as much as 47%. It can be observed that the uni-axial compressive strength of the HCFFT increased if the concrete strength and the thickness of exterior filament winding FRP tube increased. In addition, the finite element analysis result is compared with the experimental result. The difference between the experimental and FEM results is in the range of 0.14% to 17.95%.

• Journal of the Korean Society for Advanced Composite Structures
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• v.5 no.4
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• pp.52-57
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• 2014

Due to the advantageous mechanical properties of the fiber reinforced polymeric plastics(FRP), their application in the construction industries is ever increasing trend, as a substitute of structural steel which is highly vulnerable under hazardous environmental conditions (i.e., corrosion, humidity, etc.). In this study, hybrid FRP-concrete composite pile (HCFFT) connection is suggested. The HCFFT is consisted of pultruded FRP unit module, filament wound FRP which is in the outside of mandrel composed of circular shaped assembly of pultruded FRP unit modules, and concrete which is casted inside of the circular tube shaped hybrid FRP pile. Therefore, pultruded FRP can increase the flexural load carrying capacity, filament wound FRP and concrete filled inside can increase axial load carrying capacity. In the study, connection capacity of HCFFT(small and mid size) is investigated throughout experiments and finite element method. From the results of experiments, we suggested the connection methods about HCFFT pile connection.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.1
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• pp.30-39
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• 2011

In this paper, we persent the results of on experimental investigations pertaining to the structural behavior of new type of concrete filled fiber reinforced plastic circular tubes (i.e., hybrid CFFT, HCFFT) which are suggested in order to mitigate the problems associated with the concrete filled steel-concrete composite tube (CFT) and the concrete filled fiber reinforced plastic tube (CFFT). It is found that when the HCFFT is used in the construction of pile foundation the HCFFT pile can transfer axial as well as flexural loads from the superstructure to the underground effectively in comparison with CFT and CFFT piles.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.2
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• pp.20-28
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• 2010

In this paper, new type CFFT (Concrete Filled FRP Tube) was suggested in order to improve the flexural stiffness. Since the existing CFFT was produced by filament winding process, re-bar for concrete may be necessary in order to ensure structural safety under flexure re-bar. In comparison with existing type CFFT, new type CFFT was reinforced by circular shaped pultrusion FRP without re-bar. Filament winding FRP was attached to the outer layer of pultrusion FRP. Structural behavior of new type CFFT filled with concrete (HCFFT) was investigated by the mechanical property test for the component element and the FE analysis. Furthermore, compressive strength of the HCFFT member based on the equation suggested in previous studies.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.6
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• pp.204-211
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• 2022

In this study, Hollow Concrete Filled FRP Tube Pile(HCFFT Pile) was proposed as a model to utilize the advantages of composite piles and solve the problem of corrosion, which is a disadvantage of CFT piles, and a numerical analysis model was developed to analyze their behavior. The strain compatibility method was applied considering the damage plastic behavior of concrete, the yield plastic behavior of steel, and the elastic behavior of FRP. The flexural strength calculation equation of HCFFT piles was proposed considering the change of the FRP tube section according to the distance from the neutral axis. The flexural strength calculation equation, numerical analysis results, and experimental results were compared and analyzed to verify their adequacy. The results of this study can be used as basic data for the optimal design of various HCFFT piles using FRP.

• Journal of the Korean GEO-environmental Society
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• v.12 no.8
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• pp.59-67
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• 2011

The interaction of the ground deformation and composite piles, which is made of fiber glass, was analyzed for the effective pile application under vertical loads. This study was performed to conduct experimentation test and propose the material characteristics of the new type concrete injection circular FRP pile for the improvement of the defect of CFFT-Concrete composition piles and FRP-Concrete composition piles(FRP reinforced column direction). Additionally, in order to analyze the behaviour characteristics of composite pile and steel pile the numerical analyses were carried out.