• 한국전산구조공학회논문집
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• 제24권1호
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• pp.43-53
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• 2011

철근 콘크리트 부재에서 부착강도는 콘크리트와 보강근 사이에 중요한 요소 중 하나이다. 본 실험에서는 인공경량골재를 사용한 경량콘크리트와 이형철근의 부착강도의 특성을 확인하기 위하여 인발실험을 수행하였다. 콘크리트의 압축강도, 이형철근의 직경과 묻힘길이를 변수로 하는 144개의 인발실험 시험체가 사용되었다. 보통콘크리트와의 비교를 위하여 물/시멘트 비 50%의 보통콘크리트의 인발실험을 수행하였으며, 실험을 통해서 부착응력-미끌림 관계와 파괴형상을 평가하였다. 물/시멘트 비에 따른 콘크리트의 압축강도가 증가할수록 부착강도는 증가하였다. 또한 인발실험을 토대로 회귀분석을 실시하여 경량 콘크리트의 부착응력에 대한 산정식을 제안하였다.

• 한국지진공학회논문집
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• 제13권1호
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• pp.9-16
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• 2009

철근 콘크리트 부재에서 부착강도는 콘크리트와 보강근 사이에 중요한 요소 중 하나이다. 본 연구는 인발실험을 통해 AFRP 보강근의 부착강도에 대하여 실험하고, AFRP 보강근과 이형철근의 부착특성을 비교하여 나타내었다. 묻힘 길이와 보강근의 직경이 실험의 변수로 사용되었으며, 실험을 통해서 AFRP 보강근의 부착응력-미끌림 관계 및 파괴양상을 평가하였다. AFRP 보강근의 부착응력-미끌림 관계는 이형철근과 비슷한 양상을 보였으며, 보강근의 직경이 증가할수록 인발하중은 증가하나 부착응력은 비슷한 결과를 보였다. AFRP 보강근의 부착강도는 이형철근의 약 54%에 달하는 것으로 나타났다.

• KCI Concrete Journal
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• 제14권3호
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• pp.102-110
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• 2002

Results of an experimental study on the pullout behavior of the headed reinforcement are presented. A total of 48 pullout tests was performed to evaluate pullout strengths and load-displacement behaviors in pullout of the headed bars. The square steel heads had gross area of 4 $A_{b}$ and thickness of $d_{b}$ The test program consisted of three pullout test groups: Simple and Edge pullout tests using plain concrete slabs, comparison of pullout performances between the standard hooks and the headed reinforcement, and pullout tests of headed reinforcement using reinforced concrete columns. Test variables included concrete strengths ( $f_{c}$' = 27.1MPa, 39.1MPa), reinforcing bar diameters (D16~D29), embedment depths (6 $d_{b}$~12 $d_{b}$), edge conditions, column reinforcement, and single-vs.-multiple bar pullout. Test results revealed that the heads effectively provided the pullout resistances of the deformed bars in tension. The load-displacement behaviors were similar between the 90-degree hooks and the headed reinforcement. When a multiple number of headed bars installed with small head-to-head spacings was pulled out, reinforcement designed to run across the concrete failure surface in a direction parallel to the headed bars helped improve the pullout performances of the headed reinforcement.t.ement.t.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1991년도 봄 학술발표회 논문집
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• pp.41-48
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• 1991

In recent years, conskderable interest has developed in the fatigue strength of reinforced concrete members subjected to cyclic loading for the wide-spread adoption of ultimate strength design poecedures, the higher strength materials and the new recognition of the effect of repeated loading on structures such as bridges, concrete pavementes and offshore structures. In this study, a series of experiments is carried out to investigate the fatigue characteristics of deformed bars and underreinforced simply supported beams. The 69 reinforcing bar specimens with grade SD30 and designation of D16, D22, D25, and 24 beam specimens with D16 bars are prepared for this study. From these series of tests, it is found that I) a decrease of the bar deameter result in increased fatigue life, ii) the fatigue life of the bars embedded as main reinforcement within a concrete is more than that of bars in the air. iii) the fatigue strength at 2$\times$106 cycles of beams with steel ratio of 0.61% and 1.22% is 64.5% and 63.2% of the yielding strength, restectively. It is concluded that the low steel ratio has no significant effect on fatigue strength of underreinforced beams and the fatigue life of underreinforced concrete beams can be predicted conservatively by the fatigue life lf reinforcing bar.

• 한국산학기술학회논문지
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• 제18권12호
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• pp.118-125
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• 2017

본 논문은 FRP Hybrid Bar의 최적 부착 성능 도출을 위한 실험 결과를 나타낸다. FRP Hybrid Bar는 이형 철근의 부식문제를 해결하기 위하여 이형 철근 외측에 유리섬유를 감싸 만들어졌다. 콘크리트와의 부착 성능 향상을 위해 매끈한 FRP Hybrid Bar 표면에 수지와 규사를 이용하여 코팅하였고 수지의 종류 및 점도, 그리고 규사의 크기를 실험 변수로 하여 FRP Hybrid Bar의 부착 성능을 실험적으로 평가하였다. FRP Hybrid Bar의 부착 성능 평가를 위해 한 변의 길이가 200 mm인 정육면체 콘크리트 블록에 FRP Hybrid Bar를 매립하였고, 인발 실험을 통하여 FRP Hybrid Bar와 콘크리트의 계면에서의 최대 하중과 슬립을 측정하였다. 실험 결과로부터, 각 실험 변수에 따른 최대 하중 및 부착 강도를 산정하였고 FRP Hybrid Bar의 부착 성능이 가장 우수한 수지 종류 및 점도, 그리고 규사 크기를 도출하였다. 에폭시 수지와 5호 규사를 사용한 실험체의 최대부착강도는 이형철근의 최대부착강도 대비 약 35% 정도 증가되었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2010년도 춘계 학술발표회
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• pp.240-247
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• 2010

The soil nailing system is becoming common as reinforcement method of slope face in soil. It has application to obtain slope stability method and scaffolding system. It has some troubles when the soil nailing system is applied to the downtown because it could be invaded someone's private area. Thus, in this paper, wedge type removable soil nailing system which can easily remove deformed bar in final excavation step is developed. Field pull-out test is performed to evaluate deformed bars removal and pullout resistance characteristics. According to this result, application of Wedge Type Removable Soil Nailing System is performed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.273-275
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• 2013

If the mechanical development is applied to the Nuclear Power Plant Structures instead of the standard hook development, the problem of overcrowding re-bars in the anchorage zone can be solved and the construction quality of the concrete work will be improved. But there are some problems in applying it to the NPP structures because of the restriction on the yield strength and diameter of the re-bar. After the performance evaluation test for the mechanical development, we can develop the new design equation of the mechanical development length in order to solve the limitation and apply it to NPP structures.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 봄 학술발표회 논문집
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• pp.325-330
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• 1995

Three types of model concrete with different mix ratios for 1/10 scale reinforced concrete model were made and tested to find the best solution for the simulation of mechanical characteristics of prototype concrete. Scaled reinforcing materials in diameter(D1.8) having similar con-figuration and mechanical properties with commercial deformed bars(D19) were prepared for 1/10 scale model tests of reinforced concrete structures. Two types of model test using D1.8 model reinforcing bars and model concrete, monotonic simple beam test and cyclic cantilever beam test, were performed to ensure and check the similitude of bond behavior between 1/10 scale model and prototype. The test results showed that the flexural behavior of 1/10 scale models can be simulated with accuracy enough for practical use in monotonic and cyclic loading test.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1995년도 가을 학술발표회 논문집
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• pp.299-305
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• 1995

In this study the influcence of the lateral pressure on bond behavior of reinforcing barshas been investigaed experimentally. A total of 36 specimens has been tested at the laboratory. The tests have been carried out for the uniaxial and biaxial pressures of the intensities of 0, 5, 10, 20 and 40kg/$\textrm{cm}^2$. the compressive strengths of the specimens are either 360 or 520 kg/$\textrm{cm}^2$, and two kinds of bars, round and deformed, have been used. Based on the test results, linear regression equations have been proposed, and the comparisons between test results and the regression calculations have been made.

• 건축역사연구
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• 제23권6호
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• pp.39-46
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• 2014

In this study, we evaluated the chemical and physical properties of structural steel, which is the most basic material for steel structures and reinforcement concrete structures in modern period. We theorized the technical data for the research of technical history of modern heritage structures by analyzing the product system and its quality control of structural steel used in modern historical heritages. The results of this study are as follow; first, the rounded bars were used in most of modern heritage structures. But in the case of Waegwan railroad bridge, the deformed bars were used in spit of not using in Japan after the great earthquake of Kantou. Second, the structural steel was good in terms of quality control, but It has brittle properties because it was not manufactured by heat treatment process.