• 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.4 no.4
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• pp.1-8
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• 2013

Pile foundations constructed by the fiber reinforced polymer plastic piles have been used in coastal and oceanic regions in many countries. Generally, fiber reinforced polymer plastic piles are consisted of filament winding FRP which is used to wrap the outside of concrete pile to increase the axial load carrying capacity or pultruded FRP which is located in the core concrete to resist the bending moment arising due to eccentric loading. In this paper, the analytical procedures of hybrid concrete filled FRP tube flexural members are suggested based on the CFT design method. Moreover, the analytical results are compared with the experimental results to obtained by the previous researches. The results of comparison analyses are performed to estimate the accuracy of the analytical procedure for hybrid FRP-concrete composite compression test, members under eccentrical loading.

• Journal of the Korean Society for Advanced Composite Structures
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• v.1 no.3
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• pp.10-16
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• 2010

In construction industries, new construction materials are needed to overcome some problems associated with the use of conventional construction materials due to the change of environmental and social requirements. Accordingly, the requirements to be satisfied in the design of civil engineering structures are diversified. As a new construction material in the civil engineering industries, fiber reinforced polymeric plastic (FRP) has a superior corrosion resistance, high specific strength/stiffness, etc. Therefore, such properties can be used to mitigate the problems associated with the use of conventional construction materials. Nowadays, new types of bridge piers and marine piles are being studied for new construction. They are usually made of concrete filled fiber reinforced polymeric plastic tubes (CFFT). In this paper, a new type of FRP-concrete composite pile which is composed of reinforced concrete filled FRP tube (RCFFT) is proposed to improve compressive strength as well as flexural strength. The load carrying capacity of proposed RCFFT compression member is discussed based on the result of experimental and analytical investigations.

• 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.

• Advances in concrete construction
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• v.9 no.2
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• pp.125-137
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• 2020

As confining materials for concrete, steel and fibre-reinforced polymer (FRP) composites have important applications in both the seismic retrofit of existing reinforced concrete columns and in the new construction of composite structures. We present a comprehensive review of the axial stress-strain behaviour of the FRP-confined concrete column. Next, the mechanical performance of the hybrid FRP-confined concrete-steel composite columns are comprehensively reviewed. Furthermore, the results of FRP-confined concrete column experiments and FRP-confined circular concrete-filled steel tube experiments are presented to study the interaction relationship between various material sections. Finally, the combinations of material sections are discussed. Based on these observations, recommendations regarding future research directions for composite columns are also outlined.

• 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.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%.