• Proceedings of the Korean Society For Composite Materials Conference
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• 2005.04a
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• pp.180-183
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• 2005

Application of the soil nailing system is continuously extended to stabilize excavations and slopes. Although there are many applications in the construction site, the system is still needed to improve its mechanical performance and durability. So, the use of FRP for this system can be an alternative for the conventional system. Recently, there has been a greatly increased demand for the use of FRP (fiber reinforced plastic) in civil engineering applications due to their superior mechanical and physical properties. This paper presents an experimental and theoretical study on the flexural behavior of FRP plate to develop fabricated permanent soil nailing system. In this study, mechanical properties of FRP plate have been investigated. Rectangular FRP plates that is simply supported and uniformly loaded over the area of a circle at the center of plate are analyzed by experiment, classical plate theory, and finite element method. From the results of analysis we can determine the shape of curved FRP plate which will exert certain amount of prestressing force in soil nail.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.245-246
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• 2010

The purpose of this research is to investigate the nonlinear shear characteristics of Glass Fiber Reinforced Polymer(GFRP). FRP shear tests are conducted to determine the nonlinear shear behavior in accordance with ASTM specifications. The results obtained by these tests provides the exact shear properties and finally will be used to predict the long-term performance of RC structures applied by shear force.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.1-10
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• 2012

In spite of high resistant to corrosion and its strength, over the last two decades, concerns still remain about the durability of FRP materials under severe environmental and thermal exposures. In this paper, authors experimentally examine the combined degradation by thermal and chemical attacks in heterogeneous FRP rebar be made up with various fibers and resins. Five types of Carbon, Glass and Hybrid FRP rebars had manufactured by different process and surface patterns are adopted for the experiments such as weight change, interlaminar shear strength, SEM and FT-IR analysis. FRP specimens were immersed in alkaline or distilled solution up to 150 days and then thermal exposed on 60, 100, 150 and $300^{\circ}C$ for 30 minutes. From the test results, the degradation of FRP bars are influnced by the resin type and manufacturing process as well as the fiber, and ILSS of exposed FRP bar in solutions is slightly increased in initial stage and then decresed with the passing of immersed time. But, in this test, it is observed that the discrepancy of ILSS between degraded by alkaline solution and distilled water is negligible value.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2004.04a
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• pp.143-146
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• 2004

Fiber reinforced plastic material should be inspected in fabrication process in order to enhance quality by prevent defects such as delamination and void. Generally, ultrasonic technique is widely used to evaluate FRP. In conventional ultrasonic techniques, transducer should be contacted on FRP. However, conventional contacting method could not be applied in fabrication process and novel non-contact evaluating technique was required. Laser-based ultrasonic technique was tried to evaluate FRP plate. Laser-based ultrasonic waves propagated on CFRP were received with various transducers such as accelerometer and AE sensor in order to evaluated the properties of waves due to the variation of frequency. Velocities of laser-based ultrasonic waves were evaluated for various fiber orientation.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.04a
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• pp.27-27
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• 1999

본 연구에서는 초음파 Immersion법을 이용하여 복합재 연소관내에 존재하는 결함을 검출하는 방법에 대하여 연구하였으며, 이를 위하여 FRP의 delamination, FRP-EPDM간의 미접착을 모사한 모의 결함 시편을 제작하여 시험하였다. 먼저 복합재료에 대한 초음파 시험방법을 최적화하기 위하여 가장 검출 감도가 좋은 탐촉자의 적용 주파수조건 및 물거리를 구하였으며, 이들 최적 조건으로 모의 결함 시편을 A, B, C-Scan하여 결함을 검출 분석하였다. 그리고 시험 자료를 바탕으로 데이터 값을 분석함으로써 복합재료에서의 음파 속도, 음향 임피던스, 반사율 및 투과율 등 복합재료의 초음파 특성을 산출하였으며, 동 시편에 대한 X-ray 필름을 촬영하여 그 결과를 초음파 시험 결과와 비교 분석하였다.

• Composites Research
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• v.18 no.4
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• pp.66-74
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• 2005

This paper reports new repair and strengthening mathod using improved material. This mathod have two type according to covering thickness of reinforcement. One type is near surface mounted FRP rod. Anther type is overay. Fiber Reinforced Plastic (FRP) materials has become very popular in recent years. FRP material used to rehabilitate many types of structures with superior characteristics such as high strength and stiffness and corrosion resistance. This strengthening mathod were used FRP rod which have better bond and shear strangth than current FRP rod. Development of FRP rod due to 3-D winding system. In addition, Ductile hybrid FRP has a certain plastic deformation and an elongation greater than 3% at maximum load is usually required for steel reinforcement in concrete structures. Moerover this mathod can be effective repair of base concrete by sprayed polymer mortar.

• Composites Research
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• v.27 no.3
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• pp.103-108
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• 2014

Fiber reinforced polymer plastic (FRP) structural members are recently available in construction industries due to various material properties such as high specific strength and stiffness, light-weight, and corrosionresistance. The floating PV generation structure can also be an illustration for applying FRP in construction applications. The floating PV generation structure has been recently issued as a representative item for the low carbon and green growth campaign and many related studies have been conducted for the structural safety and commercial viability. Moreover, the floating PV generation structures for the commercial purpose have been constructed. In this paper, the investigation and development processes of elements for the floating PV generation structure are presented during commercialization.

• Journal of the Korean Society for Advanced Composite Structures
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• v.4 no.1
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• pp.40-46
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• 2013

This paper presents the design, fabrication and performance of a reinforced concrete beam strengthened by GFRP box plate and its possibility for structural rehabilitations. The load capacity, ductility and failure mode of reinforced concrete structures strengthened by FRP box plate were investigated and compared with traditional FRP plate strengthening method. This is intended to assess the feasibility of using FRP box plate for repair and strengthening of damaged RC beams. A series of four-point bending tests were conducted on RC beams with or without strengthening FRP systems the influence of concrete cover thickness on the performance of overall stiffness of the structure. The parameters obtained by the experimental studies were the stiffness, strength, crack width and pattern, failure mode, respectively. The test yielded complete load-deflection curves from which the increase in load capacity and the failure mode was evaluated.

• Journal of the Korea institute for structural maintenance and inspection
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• v.17 no.5
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• pp.136-145
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• 2013

Social interest in the seismic retrofit of the structure is growing massive earthquake that occurred recently. The brittle fracture of Non-seismically designed Columns lead to full collapse of the building. In the past, cross-sectional expansion method, a steel plate reinforcing method is applied mainly in recent years, fiber-reinforced method utilizing the advantages of the composite material are preferred. However, the reinforcement methods such as this, there is a drawback to induce physical damage to structures, and time consuming work space is large. IIn this study, FRP seismic reinforcement was developed using the Aluminum connector and the composite material (Glass Fiber Reinforced Polymer). Then, the optimum quantities of FRP seismic reinforcement was determined using a nonlinear finite element analysis program. Finally, the quantity decision process through the design and analysis of FRP reinforcement was suggested.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.40 no.2
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• pp.147-156
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• 2016

In this paper, optimal designs of bicycle frame were studied for weight reduction of bicycle using carbon-fiber-reinforced plastic (CFRP), glass-fiber-reinforced plastic (GFRP) and Kevlar-fiber-reinforced plastic (KFRP), respectively. Based on the anisotropic properties of FRP material, stacking angle and thickness optimization were performed under the safety reference of European committee for standardization (CEN) to ensure the stability of bicycle frame. Finally, performances of FRP bicycle frame was evaluated by digital logic method based on the optimized results of weight, strength properties and cost. Then, the optimized bicycle frame composed of each FRPs were evaluated and ranked by total performance values.