• 제목/요약/키워드: Reinforcing technology

검색결과 594건 처리시간 0.024초

탄소섬유쉬트에 의해 휨보강된 RC보의 휨강도 추정 (An Estimate of Flexural Strength for Reinforce Concrete Beams Strengthened with CFRP Sheets)

  • 박종섭;정우태;유영준;박영환
    • 콘크리트학회논문집
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    • 제17권2호
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    • pp.213-220
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    • 2005
  • 탄소섬유쉬트를 이용한 철근콘크리트 교량의 보강은 재료의 높은 중량-강도비, 중량-강성비, 내부식성 및 시공의 편리성 등과 같은 여러 가지 장점으로 인하여 최근 그 사용이 급증하고 있다. 본 연구의 목적은 탄소섬유쉬트로 휨보강된 철근콘크리트보의 보강성능을 비교하고, 그 특성을 고려한 보강설계식을 제안하기 위함이다. 철근비 및 보강비에 따른 철근콘크리트보의 보강성능을 검토하기 위하여 3m 경간의 단순보에 대한 실험을 수행하였으며, 파괴모드, 최대하중 및 단면 내에서의 변형률분포에 비중을 두고 결과를 분석하였다. 실험 결과, 보강된 보는 단면 내에서의 변형률이 선형으로 분포하지 않는 것으로 나타났으며, 본 연구에서는 이러한 실험결과를 바탕으로 보강설계식을 제안하고 국내외 여러 실험결과들과의 비교를 통해 제안된 보강설계식이 타당함을 나타내었다.

기술연관분석을 통한 중소기업형 전략적 기술개발과제의 우선순위 도출 (Selection of the Strategic R&D Field Satisfying SMEs' Specific Needs by Technology Relevance/Cluster Analysis)

  • 고병열;홍정진;손종구;박영서
    • 기술혁신학회지
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    • 제6권3호
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    • pp.373-390
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    • 2003
  • With limited resources, proper allocation of the national R&D budget is very crucial matter for reinforcing the national competence, and the importance of selecting strategic R&D fields have been increasingly emphasized by technology policy-makers and CTOs. This paper deals with technology relevance/cluster analysis, which measures technological dependency and relevancy among technologies, and how it can be used for selecting the strategic R&D fields especially satisfying SMEs(small and medium enterprises)' specific needs. As a result of this study, technology-product tree composed of 7 major technology fields, 22 clusters, 41 groups, 335 core-need technologies and hundreds of related business items are produced that can be used for designing SMEs' R&D/business portfolio as well as R&D investment decision-making of the Ministry of Small and Medium Business Administration.

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문화산업에서 창조인력, R&D 기술수준 및 관용성의 역동적인 관계성 (Dynamic Relationship in Creative Manpower, R&D Technology Level, and Tolerance in the Culture Industry)

  • 최해옥;이만형
    • 한국시스템다이내믹스연구
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    • 제10권2호
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    • pp.81-102
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    • 2009
  • Based on various employment and technology data in the cultural sector from the mid-1990s to the mid-2000s in Seoul, Korea, this research examines whether technology- and human resource-oriented programs exert significant impact on creative manpower, R&D technology level and tolerance. After briefly introducing Seoul's trends in the culture industry, it tries to explain major reinforcing and balancing loops. The stock-flow diagram of the culture industry in Seoul is applied to estimate relative effectiveness of technology- and human resource-oriented cultural programs cultural programs. Judging from a series of simulated experiments, technology-oriented cultural programs are essential to increase creative manpower and R&D technology level in the short term. For the first half of research period, this research finds that human resource-oriented cultural programs put forth minimal impact, if they even exist at all. The trends, however, are reversed in the long term: Both size of creative manpower and R&D technology level absolutely depend on human resource-oriented cultural programs in the second half.

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Predictions of Seismic Behavior of Reinforced Concrete Bridge Columns

  • 김태훈;김운학;이광명;신현목
    • 콘크리트학회논문집
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    • 제16권3호
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    • pp.441-450
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    • 2004
  • The objectives of this study are to investigate the seismic behavior of reinforced concrete bridge columns and to provide the data for developing improved seismic design criteria. The accuracy and objectivity of the assessment process can be enhanced by the use of sophisticated nonlinear finite element analysis program. A computer program, named RCAHEST (Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The low-cycle fatigue damage of both concrete and reinforcing bars has been also considered in order to predict a reliable seismic behavior. The proposed numerical method for the prediction of seismic behavior of reinforced concrete bridge columns is verified by comparison with the reliable experimental results.

A Study on the Loss Reduction Method of Reinforcing Bar through Case Study

  • Park, U-Yeol;Jung, Hyeon-Ok;Kang, Tai-Kyung;Cho, Hun-Hee
    • 한국건축시공학회지
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    • 제10권4호
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    • pp.123-132
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    • 2010
  • Rebar work accounts for approximately 30% of the total construction costs for rebars and concrete. Recently, the high rising prices of rebars have become one of the principle factors of rising construction costs. Therefore, construction companies are putting much effort into loss reduction of rebars. Consequently, in this study, we wished to present loss reduction methods of rebars before the preparation of the placing drawings. To devise such methods, we collected previous case studies and analyzed methods that were applied for loss reduction. As a result of the analysis, we were able to find the following methods for loss reduction of rebars: method of reducing the number of splices at the mat foundation, method of reducing splice length at the internal columns or walls of the underground parking lot, method of reducing cap-ties of internal beams of basement floors excluding perimeter beams, and method of reducing anchorage length at the internal column or wall of the underground parking lot. Based on those analysis results, we presented our own loss reduction methods of rebars. Applying our methods resulted in considerable loss reduction.

Galvanic Sensor System for Detecting the Corrosion Damage of the Steel in Concrete

  • Kim, Jung-Gu;Park, Zin-Taek;Yoo, Ji-Hong;Hwang, Woon-Suk
    • Corrosion Science and Technology
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    • 제3권3호
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    • pp.118-126
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    • 2004
  • The correlation between sensor output and corrosion rate of reinforcing steel was evaluated by laboratory electrochemical tests in saturated $Ca(OH)_2$ with 3.5 wt.% NaCl and confirmed in concrete environment. In this paper, two types of electrochemical probes were developed: galvanic cells containing of steel/copper and steel/stainless steel couples. Potentiodynamic test, weight loss measurement, monitoring of open-circuit potential, linear polarization resistance (LPR) measurement and electrochemical impedance spectroscopy (EIS) were used to evaluate the corrosion behavior of steel bar embedded in concrete. Also, galvanic current measurements were conducted to obtain the charge of sensor embedded in concrete. In this study, steel/copper and steel/stainless steel sensors showed a good correlation in simulated concrete solution between sensor output and corrosion rate of steel bar. However, there was no linear relationship between steel/stainless steel sensor output and corrosion rate of steel bar in concrete environment due to the low galvanic current output. Thus, steel/copper sensor is a reliable corrosion monitoring sensor system which can detect corrosion rate of reinforcing steel in concrete structures.

실내요소실험에 의한 압축형 앵커의 정착부 보강효과 분석 (Analysis on Reinforcing Effect at Fixed Part of Compression Anchor by Laboratory Element Tests)

  • 홍석우
    • 한국해양공학회지
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    • 제16권5호
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    • pp.49-55
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    • 2002
  • The compression anchor is characterized by decrement of progressive failure, simple site work, economy and durability compared with tension anchor. In this paper, compression anchor is analysed through the laboratory element tests. The formula to be estimate the grout strength in fixed part of compression anchor and the effective reinforcement method for several types of soil were suggested. The following conclusions were made from this study : (1) A formula, which is able to calculate the grout strength in the fixed part of the compression anchor, is suggested. (2) The strength increment ratios( $R_{si}$) are 100%, 132%, 147%, 217% according to the reinforcement method of grout. The reinforcement method is Non, Outside spiral, Inside-Outside spiral, Steel pipe, respectively. (3) The strength increment ratios( $R_{si}$) by reinforcing can be 8.23 times the strength increment effect according to the reinforcement types and ground confining pressure. (4) The steel pipe reinforcement is most effective in decomposed soil while, in the case of hard rock ground, high confining pressure is exerted on the grout, so there is no need to use reinforcements.

준설토 재활용을 위한 무보강 및 보강 경량토의 압축거동특성 비교 (Comparison of Compressive Behavior Characteristics between Unreinforced and Reinforced Lightweight Soils for Recycling of Dredged Soils)

  • 김윤태;권용규;김홍주
    • 한국해양공학회지
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    • 제19권6호통권67호
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    • pp.44-49
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    • 2005
  • This paper investigates strength characteristics and stress-strain behaviors of unreinforced and reinforced lightweight soils. Lightweight soil, composed of dredged soil, cement, and air-foam, was reinforced by a waste fishing net, in order to increase its compressive strength. Test specimens were fabricated by various mixing conditions, such as cement content, initial water content, air content, and waste fishing net; then, unconfined compression tests were carried out on these specimens. From the test results, it was shown that reinforced lightweight soil had different behavior after failure, even though it had similar behavior as unreinforced lightweight soil before failure. The test results also showed that stress became constant after peak strength in reinforced lightweight soil, while the stress decreased continuously in unreinforced lightweight soil. It was observed that the strength was increased due to reinforcing effect by the waste fishing net for most cases, except high water content greater than $218\%$. In the case of high water content, a reinforcing effect is negligible, due to slip between waste fishing net and soil particles. In reinforced lightweight soil, secant modulus (E50) was increased, due to the inclusion of waste fishing net.

Experimental and FE simulations of ferrocement columns incorporating composite materials

  • Shaheen, Yousry B.I.;Mahmoud, Ashraf M.;Refat, Hala M.
    • Structural Engineering and Mechanics
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    • 제64권2호
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    • pp.155-171
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    • 2017
  • This paper presents a proposed method for producing reinforced composite concrete columns reinforced with various types of metallic and non metallic mesh reinforcement. The experimental program includes casting and testing of twelve square columns having the dimensions of $100mm{\times}100mm{\times}1000mm$ under concentric compression loadings. The test samples comprise all designation specimens to make comparative study between conventionally reinforced concrete column and concrete columns reinforced with welded steel mesh, expanded steel mesh, fiber glass mesh and tensar mesh. The main variables are the type of innovative reinforcing materials, metallic or non metallic, the number of layers and volume fraction of reinforcement. The main objective is to evaluate the effectiveness of employing the new innovative materials in reinforcing the composite concrete columns. The results of an experimental investigation to examine the effectiveness of these produced columns are reported and discussed including strength, deformation, cracking, and ductility properties. Non-linear finite element analysis; (NLFEA) was carried out to simulate the behavior of the reinforced concrete composite columns. The numerical model could agree the behavior level of the test results. ANSYS-10.0 Software. Also, parametric study is presented to look at the variables that can mainly affect the mechanical behaviors of the model such as the change of column dimensions. The results proved that new reinforced concrete columns can be developed with high strength, crack resistance, and high ductility properties using the innovative composite materials.

자동차 도어 경량화를 위한 판재형 사이드 임팩트 빔 개발 프로세스 (Development Process of Side Impact Beam for Automotive Light-Weighting Door using Sheet Type)

  • 이인철;이태규;장동환
    • 소성∙가공
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    • 제24권2호
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    • pp.130-137
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    • 2015
  • This paper presents the development process of automotive side door impact beam for passenger cars. Weight reduction while maintaining functional requirements is one of the major goals in the automotive industry. In this study, thin-walled side door beam using quenchable boron steel was designed to reduce the weight of conventional side door tubular one. In order to estimate design for the proposed side door beams, the static side impact protection tests(FMVSS 214) were conducted using the finite element method. Based on the simulation results, geometry modification of the side door beam has been performed via creating new reinforcing ribs. Furthermore, the manufactured frontal impact beam was mounted on the real side door of a passenger car, and then static impact protection test carried out. It is concluded that the presented test results can provide significant contribution to the stiffness of side door impact beams and light-weighting door research.