• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2001년도 가을 학술발표회 논문집
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• pp.1003-1008
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• 2001

It is recently reported that bond failure can be initiated in the region where maximum bending moment and shear force is acted by accompanying shear deformation after flexural crack in full-scale RC beams strengthened by CFRP. Such a shear deformation effect causing bond failure is relatively little in the case of small-scale specimens. So, additional reinforcing details to the critical beam section where maximum moment and shear were acted is required to prevent the bond failure caused by the shear deformations. The U-type wrapping methods by CFRP to the critical beam section is proposed and tested in this paper. Also, the applicability of design bond strength derived from the tests of small-scale beam was investigated by the full-scale RC beam strengthened by CFRP.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 가을 학술발표회 논문집
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• pp.221-229
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• 1996

An analytical method based on the nonlinear layered finite element method is used to simulate the load-deflection behavior of strengthened beam. Beams considered in this study are the ones strengthened either with external steel plate or Carbon Fiber Reinforced Plastic (CFRP) sheets bonded to the overlay soffit or with reinforcing rebars in the overlay. The theoretically obtained load-deflections and strains of the strengthened beam are compared to the corresponding experimental values. Comparing the approximate measures on the cumulative slips, efficiencies of the repairing techniques are evaluated. Parametric studies are, then, peformed using the developed model to investigate the effects of design variables on the overal flexural behavior of the strengthened beam. Simply supported beams under monotonically increasing symmetrical loads are considered exclusively.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.326-329
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• 2006

Strengthening method using CFS have been developed for the rehabilitation of structures. However, it is very difficult to estimate their resistance capacity after retrofit. Therefore, damage information for strengthened structure with CFS investigated and the estimation method structural capacity by using the damage information is developed. The final objective of this research work is to propose the guideline and method for resistance capacity estimate of structure. In this paper, experimental study result with test parameters of number of carbon fiber sheets and bonding ratio is introduced.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.106-109
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• 2006

It has been shown that many reinforced concrete(RC) structures designed without seismic details have experienced brittle shear failures in the beam-column joint area and may result in large permanent deformations and structural collapse. In this study, experimental investigations for RC beam-column joints strengthened with the carbon fiber-reinforced polymer(CFRP) under cyclic loadings were presented. The use of CFRP in the joint was varied to determine the effective way of improving the structural performances of RC joints. Ten RC beam-column joints were designed and tested with cyclic loadings. The experimental results showed that the use of CFRP in RC joints would be very effective solutions to improve the seismic performances of the non-seismic RC joints. All of the non-seismic design specimens strengthened with CFRP sheets showed the significant increase of strength and ductility.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계학술발표회 논문집(I)
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• pp.234-237
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• 2006

A series of three shear wall specimens was tested under constant axial stress and reversed cyclic lateral loading in order to evaluate the seismic retrofit that had been proposed for the shear wall with the opening induced by remodeling. One of these specimens was tested in the as-built condition and the other two were retrofitted prior to testing. The retrofit involved the use of carbon fiber sheets and steel plates (thickness of 3mm) over the entire face of the wall. The test results show that the ultimate failure modes of the specimens were found to be shear fracture of the wall around the opening and two difference types of retrofitting strategy make the different effects of a rise in the strength of each specimen.

• Structural Engineering and Mechanics
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• 제60권1호
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• pp.163-173
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• 2016

Nowadays using Carbon Fiber Reinforced Polymer (CFRP) has been expanded in strengthening steel structures. Given that few studies have taken about strengthening of steel hollow pipe sections using CFRP, in present study, the effects of CFRP sheets using two layers as well as in combination with additional reinforcing strips has been assessment. Strengthening of five specimens was carried out in laboratory tests. As well as numerical simulation was performed for all specimens by Finite Element Method (FEM) using ABAQUS software and high correlation between the results of numerical models with experimental data indicate the power of FEM in this field. The results of both laboratory and simulated specimens showed that load-bearing capacity of circular cross-sections can be significantly increased using CFRP retrofitting technique. Also, application of additional CFRP reinforcing strips and layers caused more strength for the strengthened specimens.

• Computers and Concrete
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• 제19권4호
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• pp.405-411
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• 2017

Carbon Fiber Reinforced Plastic (CFRP) has commonly been used to strengthen existing RC structures. Wrapping the whole component with CFRP is an effective method and simple to execute. Besides, specific configuration of CFRP sheets (L, X and T shape) has also been considered in some experiments to examine CFRP effects in advance. This study aimed to provide an optimal CFRP configuration to effectively retrofit the beam-column connection using continuous material topology optimization procedure. In addition, Moved and Regularized Heaviside Functions and penalization factors were also considered. Furthermore, a multi-material procedure was also used to compare with the results from the single material procedure.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2073-2079
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• 2008

This study aims to investigate the residual strength of sandwich composites with Al honeycomb core and carbon fiber face sheets after the quasi-static indentation damage by the experimental investigation. The 3-point bending test and the edge-wise compressive strength test were used to find the mechanical properties. The quasi-static point load and damaged hole was applied to introduce the simulated damage on the Each damaged specimens were finally assessed by the 3-point bending test and the compressive strength test. The investigation results revealed the residual strength of the damaged specimens due to the quasi-static indentation.

• 한국구조물진단유지관리공학회 논문집
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• 제11권3호
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• pp.105-115
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• 2007

리모델링의 증가로 보수보강에 대하여 많은 관심을 갖게 되었다. 탄소섬유시트의 사용은 철근콘크리트 구조의 강성을 증가시키기 위하여 많이 쓰이고 있다. 따라서 새로운 보강방법으로 외부 부착에 의한 강성이 증가된 RC구조의 휨거동을 알아보기 위하여 실험과 분석 연구를 수행하였다. 또한 본 연구는 실험에 의한 피로하중을 받도록 한 FRP패널 보강방법에 대하여 살펴보는데 그 목적이 있다.

• 항공우주시스템공학회지
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• 제4권1호
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• pp.23-26
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• 2010

In this study, it was performed damage assesment of small scale composite aircraft developing. This aircraft adopted the sandwich structure to skin of wing. This study aims to investigate the residual strength of sandwich composites with Nomex honeycomb core and carbon fiber face sheets after the open hole damage by the experimental investigation. The 4-point bending tests were used to find the bending strength, and the open hole was applied to introduce the simulated damage on the specimen. The bending strength test results after open hole was compared with the results of no damaged specimen test. The FEM analysis is assessed via an experimental 4-point bending test.