• 한국강구조학회 논문집
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• 제25권6호
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• pp.623-634
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• 2013

본 연구에서는 RC 구조 슬래브와 SC 구조 전단벽이 만나는 접합부의 거동특성을 파악하고 RC구조 슬래브-SC구조 전단벽 이질접합부의 전단마찰내력을 평가하고 KEPIC SNG의 접합면 소요전단강도 기준의 안전율을 평가하기 위해 실험연구를 수행하였다. 연구결과, 접합면의 전단마찰내력은 약 300kN으로 나타났고, 변위가 증가할수록 철근의 내력분담이 증가하게 되며, 상부철근보다는 하부철근의 전단내력 분담율이 높은 것으로 나타났다. 하부철근을 구성한 경우에는 하부철근이 없는 실험체에 비해 40% 이상 전단내력이 증가하는 것으로 나타났다.

• Structural Engineering and Mechanics
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• 제52권4호
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• pp.647-661
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• 2014

The use of steel-concrete composite members has been significantly increased as they have the advantages of the reduction of cross sectional areas, excellent ductility against earthquake loadings and a longer life span than typical steel frame members. The increased use of composite members requires an intensive study on the shear resistance evaluation of stud connectors in high strength concrete. However, the applicability of currently available standards is limited to composite members with normal and lightweight strength concrete. In this paper, push-out tests were performed on 24 specimens to investigate the structural behavior and shear resistance of stud connectors in high strength concrete. Test parameters include the existence of shear studs, height to diameter ratio of a shear stud, its diameter and concrete cover thickness. A shear resistance equation of stud connectors is proposed through a linear regression analysis based on the test results. Its accuracy is compared with those of existing shear resistance equations for studs in normal and lightweight concrete.

• Geomechanics and Engineering
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• 제28권2호
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• pp.135-143
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• 2022

Soils are natural granular materials whose mechanical properties differ according to the size and composition of the particles, so soils exhibit an obvious scale effect. Traditional soil mechanics is based on continuum mechanics, which can not reflect the impact of particle size on soil mechanics. On that basis, a matrix-reinforcing-particle cell model is established in which the reinforcing particles are larger-diameter sand particles and the matrix comprises smaller-diameter bentonite particles. Since these two types of particles deform differently under shear stress, a new shear-strength theory under direct shear that considers the stress concentration and bypass phenomena of the matrix is established. In order to verify the rationality of this theory, a series of direct shear tests with different reinforcing particle diameter and volume fraction ratio are carried out. Theoretical analysis and experimental results showed that the interaction among particles of differing size and composition is the basic reason for the size effect of soils. Furthermore, the stress concentration and bypass phenomena of the matrix enhance the shear strength of a soil, and the volume ratio of reinforcing particles has an obvious impact on the shear strength. In addition, the newly proposed shear-strength theory agrees well with experimental values.

• 한국표면공학회지
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• 제34권3호
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• pp.225-230
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• 2001

In this study, the effect of surface treatment of CFRP (Carbon Fiber Reinforced Composites) on the shear strength of CFRP/metal composites was investigated. The surface of 14 plied unidirectional (0-dog ) CFRP was treated by an $Ar^{/}$ + ion beam under an oxygen environment. Shear strength tests were performed using SLS (Single Lap Shear) specimens based on the ASTM D906-94a procedure. The shear strength of the surface-treated CFRP/metal composites was compared with that of the untreated CFRP/metal composites. The results showed that the shear strength of surface-treated CFRP/metal composites was 36% greater than that of untreated CFRP/metal composites.

• International Journal of Concrete Structures and Materials
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• 제11권2호
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• pp.185-197
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• 2017

In this study, we propose a new equation that evaluates the shear strength of beam-column connections in reinforced concrete and steel beam (RCS) composite materials. This equation encompasses the effect of shear keys, extended face bearing plates (E-FBP), and transverse beams on connection shear strength, as well as the contribution of cover plates. Mobilization coefficients for beam-column connections in the RCS composite system are suggested. The proposed model, validated by statistical analysis, provided the strongest correlation with test results for connections containing both E-FBP and transverse beams. Additionally, our results indicated that Architectural Institute of Japan (AIJ) and Modified AIJ (M-AIJ) equations should be used carefully to evaluate the shear strength for connections that do not have E-FBP or transverse beams.

• Geomechanics and Engineering
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• 제12권2호
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• pp.211-221
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• 2017

A laboratory investigation into crude oil contaminated sand-concrete interface behavior is performed. The interface tests were carried out through a direct shear apparatus. Pure sand and sand-bentonite mixture with different crude oil contents and three concrete surfaces of different textures (smooth, semi-rough, and rough) were examined. The experimental results showed that the concrete surface texture is an effective factor in soil-concrete interface shear strength. The interface shear strength of the rough concrete surface was found higher than smooth and semi-rough concrete surfaces. In addition to the texture, the normal stress and the crude oil content also play important roles in interface shear strength. Moreover, the friction angle decreases with increasing crude oil content due to increase of oil concentration in soil and it increases with increasing interface roughness.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2004년도 추계 학술발표회 제16권2호
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• pp.113-116
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• 2004

No specific guidelines are for computing the shear strength of steel coupling beam connections embedded in the reinforced concrete shear wall. In this paper, a theoretical study of the strength of hybrid coupled shear wall connections is achieved. The bearing stress at failure in the concrete below the steel coupling beam section is related to the concrete compressive strength and the ratio of the width of the steel coupling beam section to the thickness of the hybrid coupled shear wall. To revise factor affecting shear transfer strength across connections between coupled shear walls and steel coupling beam, experimental studies are achieved. The main test variables were auxiliary details of stud bolts. In this studies, these proposed equations are shown to be in good agreement with the test results reported in the paper and with other test data in the literature.

• Computers and Concrete
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• 제31권1호
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• pp.33-52
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• 2023

This paper proposes and validates the extension of two models, previously formulated for the evaluation of the shear strength of reinforced concrete members with un-corroded reinforcements, to the case of beams with corroded stirrups. These extended models are based on the plasticity theory (this model has been proposed in the past by one of the authors) and on the simplified modified compression field theory. The response of these models is compared with that of the compression chord capacity model, which has recently been embedded with modifications that simulate the effects of steel corrosion. These latter modifications are first discussed and then introduced into the other two models. An existing database of slender and non-slender beams tested in laboratory by other researchers is revised and improved. Finally, all the considered models are applied to the selected specimens and a comparison is drawn between the shear strength resulting from the considered models and the shear strength resulting from the laboratory tests. The effects of corrosion on some important parameters of the ultimate shear response of the reinforced concrete beams are also discussed.

• Composites Research
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• 제21권2호
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• pp.25-30
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• 2008

A hemispherical microbond specimen adhered onto single carbon fiber has been proposed for evaluating the interfacial shear strength between epoxy and carbon fiber. Hemispherical microbond specimens showed low interfacial shear strength data and its small standard deviation as compared with the droplet one, which seemed to be caused by the reduction of the meniscus effects and of the stress concentration in the region contacting with the tip of pin hole. In comparison with the droplet specimen the hemispherical specimen showed the shear stress distribution similar to the cylindrical one in that low stress concentration arose around the contacting region. Average interfacial shear strength obtained by the hemispherical ones represented a good correlation with the hardness of the epoxy matrix.

• 콘크리트학회논문집
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• 제27권5호
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• pp.489-499
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• 2015

내진 보강 공법의 보강효과 파악을 위해선 이에 대한 이론적 규명이 필요하다. 이에 본 연구는 단부에 기둥 부재를 증타한 단근 배근된 전단벽체를 대상으로 해 보강되는 기둥의 상세와 일체화 거동을 고려한 전단강도 모델을 제안했다. 이 모델은 증타된 기둥부재의 전단변형이 집중되는 길이를 가정해 이를 일체화된 벽체 내에 발생하는 스트럿 두께 산정에 이용했다. 뿐만 아니라 이 길이 내에 집중 발생하는 전단변형률을 유도, 이를 일체화 거동을 고려한 적합성 조건을 기존 전단벽체의 해석 알고리즘에 도입함으로써 증타 보강된 벽체의 해석 알고리즘을 새로이 제안했다. 또한 제안된 알고리즘을 통해 계산된 전단강도로 횡력 저항 메커니즘을 단일 스트럿 화 시켜줌으로써 보강부재의 초기강성을 제안하였다. 본 연구에서 제안한 방법의 타당성을 확인하기 위해 해석 결과 값을 본 연구에서 수행한 증타 보강된 벽체를 대상으로 한 실험뿐만 아니라 기존 RC 골조 내에 RC 전단벽체를 신설해 보강한 실험의 결과와 비교해 본 결과, 기둥부재의 상세를 고려하면서 동시에 기존 기준들에 비해 실험결과에 가깝게 예측할 수 있음을 확인했다.