• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1370-1376
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• 2009

Reinforcing steel works should be carefully controlled by the construction manager considering the severe fluctuation of the price of reinforcing steel bars and for the safety of structure in building constructions. In particular, preparing rebar placing drawings needs more effort and time than before because of the emergence of higher and more complicated buildings. Moreover, the experience of field engineers or foremen (fabricators or detailers) in preparing placing drawings gives rise to the differences in fabricated bar type and quantity of bars used. To address these problems, this study proposed the support system in preparing placing drawings for reinforcing steel works efficiency. In the near future, if this system can be made available on the web, multiple end-users will be able to share the result; the efficiency of rebar supply chain management will also be improved.

• 한국구조물진단유지관리공학회 논문집
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• 제3권1호
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• pp.171-178
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• 1999

Despite of decrease in shear and moment strengths, most steel structural designers use web openings in beams because of economical benefit and requirement. The purpose of this study is to suggest the method of reinforcement of H-shape steel beams with a rectangular web opening. If shear predominates over bending, it is necessary to consider all possible combinations of shear force and bending moment acting at the opening. In this paper, the ultimate strength and behavior of perforated beams have been investigated according to parameters (ratio of M/V, opening width within opening height ratio D/h, various reinforcing types A/B/C/D/M/N/W). The results of this study are as follows ; 1. Deformation of H-shape steel beams with a rectangular web opening was greatly affected by not only bending but also shear. 2. SB1-2/3 series have little difference in the reinforced efficiency, but SB1-2E/3E series have difference in the reinforced efficiency according to the reinforcement type. 3. Efficiency of SB1-2E/3E series is determined by reinforcing types, which RB1-2E-B/M/C and RB1-3E-M/D/C specimens have good efficient. Reinforcing type of perforated beams chooses efficient method according to ratio of M/V and D/h.

• Current Research on Agriculture and Life Sciences
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• 제31권4호
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• pp.250-255
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• 2013

As a renewable nanomaterial, cellulose nanocrystal (CNC) isolated from wood grants excellent mechanical properties in developing high performance nanocomposites. This study was undertaken to compare the reinforcing efficiency of two different CNCs, i.e., cellulose nanowhiskers (CNWs) and cellulose nanofibrils (CNFs) from hardwood bleached kraft pulp (HW-BKP) as reinforcing agent in polyvinyl alcohol (PVA)-based nanocomposite. The CNWs were isolated by sulfuric acid hydrolysis while the CNFs were isolated by 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-mediated oxidation. Based on measurements using transmission electron microscopy, the individual CNWs were about $6.96{\pm}0.87nm$ wide and $178{\pm}55nm$ long, while CNFs were $7.07{\pm}0.99nm$ wide. The incorporation of CNWs and CNFs into the PVA matrix at 5% and 1% levels, respectively, resulted in the maximum tensile strength, indicating different efficiencies of these CNCs in the nanocomposites. Therefore, these results suggest a relationship between the reinforcing potential of CNCs and their physical characteristics, such as their morphology, dimensions, and aspect ratio.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1997년도 봄 학술발표회 논문집
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• pp.579-584
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• 1997

This experimentation is to apperciation an efficiency of repair for processing crack by corrosion of steel reinforcing, Crack on concrete by corrosion of steel reinforcing is the fact that the first crack appear on the surface of water because of supplying is of oxygen and water. The crack processing is on surface to be contacted by air and to bottom as mainly the vertical direction from a surface of water. The experimentation gives rise to crack in model by electricity. Crack by corrosion of steel reinforcing is more internal crack than external crack. since it is so. crack by corrosion of steel reinforcing have to attention to repair or intermal crack.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.295-297
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• 2013

Reinforcing bar coupling method has a variety of ways including lap-splice method. However, there are problems that need to be improved in terms of constructability, economics analysis. We should be improved about the problems of the existing methods. Accordingly, this study were developed a new type of staggered grip type reinforcing bar coupling. The proposed method show the following effects than existing methods. First, this method can be reduce time through improved workability. Second, increasing safety through the slip removal. Third, improving economic efficiency by reduce the manufacturing costs.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 추계 학술발표회 논문집
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• pp.201-204
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• 2006

The shear resistance of RC beams is subject to the amount of shear-reinforcing bars ($p_w$) and yield strength ($f_{wy}$) as well as their interactive influence ($p_wf_{wy}$). Thus, it is reasonably expected that high-strength steel bars can greatly reduce the necessary amount of shear-reinforcing bars. On the other hand, although the bond strength is influenced by the amount of shear reinforcing bars, it is not affected by the yield strength. Thus, there is often an issue that bond failure occurs before shear failure depending on the arrangement of shear reinforcing bars. It is a common practice to set sub-ties for the transverse confinement of the main re-bars as a method to prevent the bond failure. However, it can also become a factor in decreased work efficiency due to the complexity of the construction. This study experimented with simultaneous use of high-strength transverse reinforcing bars ($f_{wy}=800MPa$) and U-shaped transverse reinforcing bars of regular strength ($f_{wy}=300MPa$) in an attempt to decrease the necessary quantity of shear reinforcing bars. The effect of this attempt was investigated through fundamental experimental research in terms of the improvement in shear resistance and bond strength as well as the ease of construction.

• 한국구조물진단유지관리공학회 논문집
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• 제26권4호
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• pp.81-90
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• 2022

이 연구에서는 일방향 콘크리트 슬래브를 대상으로 하여, 철근을 사용한 경우와 CFRP 보강근을 사용한 경우에 대해 보강근 사용량에 따른 휨강도와 처짐 및 균열폭을 비교하여 평가하였으며, CFRP 보강근 콘크리트 슬래브의 휨설계의 지배적인 성능과 효율적인 휨설계 방안에 대해 검토하였다. CFRP 보강근을 사용한 콘크리트 슬래브는 철근을 사용한 경우에 비해 동일한 보강근량에서 더 큰 설계휨강도를 얻을 수 있는 반면, 처짐 및 균열폭은 상대적으로 훨씬 크게 발생한다. CFRP 보강근을 사용한 콘크리트 슬래브에서는 최대균열폭이 설계의 지배적인 요인으로 작용하는 것으로 확인하였으며, 효율적 휨설계를 위해서는 허용균열폭을 0.7 mm로 완화하여 적용할 필요가 있으며, 작은 직경의 보강근 적용을 검토할 필요가 있음을 제시하였다.

• 한국지반환경공학회 논문집
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• 제9권7호
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• pp.61-71
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• 2008

본 연구에서는 좁게 형성되는 프리캐스트 옹벽 배면에 상재하중을 재하 하였을 경우 마이크로파일의 수평저항 거동에 대한 설치 효율성을 규명하고자 하였다. 이를 확인하기 위한 수단으로 모형시험과 수치해석을 수행 하였다. 실내모형시험은 모형토조에 기초지반 조성 후 모형옹벽을 설치하였으며, 옹벽 배면에 상재하중을 재하 하여 마이크로파일의 설치간격 및 길이 등을 각각 변화시켜 수행하였다. 본 연구에서 보강된 마이크로파일이 프리캐스트 옹벽에 발생하는 수평방향 변형을 효과적으로 억제하는 것으로 나타났다. 마이크로파일의 간격을 좁게 설치하고 파일의 길이가 길어질수록 보강효율이 증가하는 경향을 보이며, 파일의 길이가 0.5H 설치간격은 7D에서 최적의 보강효율을 나타내는 것으로 평가되었다.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1991년도 가을 학술발표회 논문집
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• pp.17-22
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• 1991

An accurate and efficient analytical model describing the bond effect between reinforcing steel and concrete without taking the double nodes is presented. To increase the efficiency of the solution and reduce the number of degrees of freedom, the reinforcing bar elements are considered to be embedded in the connote elements. Relative douses of freedom accounting for the relative slip between reinforcing steel and concrete are condensed out during the stiffness formation phase. However, these degrees of freedom Can be taken into account explicitly by solving the constructed global equilibrium equation for each reinforcing steel. The usefulness of proposed model is established through the comparison with the experimental data subjected on push and push-pull loadings.

• 한국구조물진단유지관리공학회 논문집
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• 제3권3호
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• pp.213-222
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• 1999

On condition that opening located at high shear strength position in H-shaped steel beams with web opening, beams are structurally to be frailed so necessity and efficiency of vertical reinforcement to add horizontal reinforcement already published ahead study. Up to the present study of web opening beams, limited one opening which located in comparatively small shear strength position. But frequently opening area is enlargement by necessity, so width of opening is larger by limit of depth or increasing number of opening. This study carry out experiment to make efficient reinforcing method about strength and deformation of steel beams with web openings. Parameters of this study are openings location, ratio of opening width within opening height and various reinforcing types.