• 한국건축시공학회지
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• 제8권2호
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• pp.71-79
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• 2008

The rebar work is very related to the safety and durability of the building. Recently, the rebar work is produced some serious problems due to the lack of skillful crafts-man and the rising cost of rebar materials. Many papers have dealt with the rebar work of the manufacturing system in plants with a view to improvement those problems. But, the research on the rebar work of the manufacturing system in field is in a insignificant condition. This study presents the following improvement schemes as a result. First, the education strengthening for evaluation on practical affairs, second, the reinforcement of drawing & management in shop drawing and finally the simplification of apartment rebar work in slab. Also, this paper aims at advancing apartment rebar work by the actual condition survey in slab work. The further research will be needed about the whole structure parts such as foundation, wall, girder and rebar truss-deck plate as one of the improvement methods.

• 한국건설관리학회논문집
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• 제10권6호
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• pp.58-66
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• 2009

최근 국내 건설업은 기능인력의 부족, 건설경기의 침체 등으로 인하여 원가절감 등을 통한 수익성 확보의 필요성이 증대되고 있다. 철근공사는 구조물의 안전성과 내구성에 많은 영향을 미치고 원가측면에서도 매우 중요한 공사임에도 불구하고, 노동 집약적인 특성을 그대로 유지하고 있어 철근 자재의 손실에 따른 원가 상승의 문제가 매우 심각하다고 할 수 있다. 철근공장 가공은 철근의 절단 및 절곡작업을 자동화 시설을 갖춘 공장에서 실시하여 현장에 반입하는 것으로 가공된 철근의 품질이 우수하고, 철근 자재의 손실도 절감할 수 있는 장점이 있다. 그러나 이와 같은 기대효과에도 불구하고 철근 공장가공 방식은 1990년대 중반에 국내에 도입된 이후 현재까지 활성화되지 못한 실정이다. 본 연구에서는 철근 가공 공장에 대한 실태조사를 수행하고, 그 조사결과를 토대로 철근공장가공 정착을 위한 방안으로 철근 가공 표준을 제안하였다.

• 한국건축시공학회지
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• 제5권4호
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• pp.99-106
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• 2005

With labor shortage and high-wage, the construction cost is rising and the construction-business is dull, demanding the construction environment of Korea to raise profitability through major cost savings and rationalization of construction management. Therefore, in this study, to improve many problems found in calculating rebar quantity for capital expenditure programming which is considered the beginning stage of rebar work. and to improve problems such as no grasping of rebar loss due to lack of systematic management in order/purchase stage and construction management stage, a rebar information-management-system was found and preyed. The relation database was designed for the rebar information management system by analyzing work process of a rebar manufacturing plant, as the rebar information that is necessary in a rebar manufacturing plant if similar to that of a purchasing department of general construction company. The Proposed rebar information management system was implemented in two large rebar production plants. The implementation of the proposed system showed that the system increased work efficiency, reduced the management manpower, and improved the project-integrated management

• 한국구조물진단유지관리공학회 논문집
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• 제16권1호
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• pp.110-119
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• 2012

최근 고부식 환경에 놓여 있는 철근 콘크리트 구조물의 철근 부식 문제를 해결할 수 있는 방안 중 하나로 뛰어난 내부식성을 가진 섬유복합체(Fiber Reinforced Polymer, FRP)로 제작된 보강근이 주목받고 있다. 유리섬유복합체로 제작된 보강근이 상용화된 상태이나 가격, 철근보다 낮은 탄성계수, 취성파괴 특성 등의 이유로 사용 실적은 많지 않은 것이 현실이다. 이러한 문제점을 해결하기 위한 방편 중 하나는 유리섬유복합체 보강근의 성능을 고도화하는 것이다. 성능 고도화를 통해 강도 대비 가격을 낮출 수 있으며, 인장성능을 향상시킬 수 있다. 본 연구는 주어진 재료와 조건 하에서 보강근 성능에 영향을 미치는 인자들의 효율성 향상을 통한 고인장 성능 유리섬유복합체 보강근의 개발에 관한 것이다. 이를 위해 구성재료와 제작방법 등 유리섬유복합체 보강근의 인장성능에 영향을 미치는 인자들에 대해 분석을 수행하여 개선 방안을 제안하였으며, 이를 통해 보강근의 주재료인 유리섬유의 성능을 기존 제품보다 더욱 효율적으로 활용하는 보강근을 제작하였으며, 다양한 변수에 대한 인장시험을 통하여 그 성능을 비교 분석함으로써 개선 방안의 적절성을 검증하였다.

• 한국건설관리학회논문집
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• 제13권1호
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• pp.106-117
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• 2012

최근 국내에서 정착되고 있는 철근 공장가공은 절단손실 감소, 정밀도 향상 등의 장점과 도심지공사 증가, 숙련공 감소 등의 외부 요인으로 향후 비중이 증가할 것으로 예상된다. 그러나 공장가공을 하더라도 정척철근 (Straight rebar)을 사용하면 손실 발생 및 그로 인한 CO2배출 같은 환경 문제가 발생할 수밖에 없다. 이를 해결하기 위한 대안의 일환으로 코일철근(Bar in coil) 도입이 제안되었으나, 코일철근은 국내 미생산, 고가의 장비비 등의 이유로 국내 적용이 거의 전무하다. 또한 코일철근은 완전 자동화에 가까운 방식으로 가공되기 때문에 향후 높은 손실저감률과 가품질이 우수하여 국내 적용이 확대될 것으로 예상되나, 적용타당성 분석에 대한 연구가 부족한 실정이다. 따라서 본 연구에서는 최근 국내 생산이 시작된 코일철근의 특성과 코일철근 도입이 철근가공 산업에 미치는 영향을 분석, 철근가공 산업 선진화를 위한 기초연구로서 진행한다. 이를 위해 국내 철근가공 산업의 현황을 조사하고, 코일철근 도입시 산업적 측면에서 적용성과 경제적 측면에서 이해관계자의 손익 타당성을 분석하고 향후 연구방향을 제시한다.

• 한국농공학회논문집
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• 제46권3호
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• pp.73-81
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• 2004

FRP reinforcing bars(rebars) are produced through a variety of manufacturing process includes pultrusion, and filament winding and braiding etc. Each manufacturing method produces a different surface condition of FRP rebar. The surface properties of FRP rebar is an important property for mechanical bond with concrete. Current methods of providing surface deformation to FRP rebars include helical wrapping, surfaces and coating and rib molding. The problem with the helical wrapping method is that it can not provide enough surface deformation for good bond and it can be easily sheard off from the FRP rebars. Sand coating and rib molding provide surface deformation only to the outer FRP skins. Therefore, FRP rebar has about 60% of bond strength of steel rebar. The main objective was to evaluate the bond properties of FRP rebar after environmental exposure. Five types of FRP rebar includes CFRP ISO, GFRP Aslan, AFRP Technora CFRP(Korea), and GFRP(Korea) rebars performed direct bond tests. Also, FRP rebar bond specimens were subjected to exposure conditions including alkaline solution, acid solution, salt solution and deionized water etc. According to bond test results, CFRP(Korea) and CFRP(Korea) rebars were found to have better bond strength with concrete than previous FRP rebars. Also, FRP(Korea) rebar had more than about 70% in bond strength of steel rebar.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2002년도 가을 학술발표회 논문집
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• pp.63-67
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• 2002

The induced chemical and salt solution in water or admixture are originated to the corrosion process of the steeo rebar. These liquids penetrate into concrete as the accompanied by the chemical reaction and cause to attack the steel rebar in concrete. Concrete surfaces which it exposed to deicing, water and sea water is allowed to enter the chlorides in the structures. To prevent from the source of corrosion and deterioration Is subjected to put an end to corrode or reduce to contaminate on the steel rebar. As this reason the MCI 2022 products are applied to the surface of concrete and steel rebar. The concrete samples were made of to the kind of four, i.e. RF, MR, MS, and MM. Corrosion inhibitor is applied to coat on the surface of concrete after it had been cured for 28days. Specimen were immersed in a 3.5％ sodium chloride solution. Concrete specimen were tested to determine the changes of the resistance polarization, Rp, over a 22 weeks period. MCI 2022 is significantly shown the corrosion inhibition of steel rebar in 3.5% NaCl solution. In the each different concrete sample, MS and MM is seemed to be better than others. The results are proofed that MCI 2022 is promised to maintain the inhibition of corrosion with high resistance polarization of the steel rebar in concrete.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2013년도 춘계학술대회 논문집
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• pp.469-470
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• 2013

• 한국기계가공학회지
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• 제14권2호
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• pp.75-80
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• 2015

The rebar factory production process involves the repetitive bending of rebars. Therefore, the fatigue failure of the rebar bending machine needs to be considered. In this paper, fatigue analysis of the rebar machine was performed using the commercial software DAFUL, which is based on MFBD (Multi Flexible Body Dynamics). The rotating roller, fixing roller and rebar were modeled by the finite element method. The rebar bending process is simulated and the mechanical stresses on the rollers are calculated. Structural analysis of the rebar bending roller was performed using the maximum bending angle of $180^{\circ}$ and maximum processing rebar diameter of ${\Phi}19mm$. Then, for fatigue analysis, the S-N curve of STD-11 was. The fatigue life of rollers is estimated by modified Goodman diagram. The fatigue life range of the rotating roller is $2.99961{\times}10^5{\sim}1{\times}10^8$ while that of the fixed roller is $2.53142{\times}10^5{\sim}1{\times}10^8$. STD-11 has an infinite life cycle after $1{\times}10^8$. Therefore, the rollers of the rebar bending machine may be expected to suffer fatigue failure. Thus, we performed a parameter study of fatigue life according to various axial radii of the fixed roller and rotating roller, and redesign of the rebar bending machine. Consequently, the axial radius of the fixed roller and rotating roller was found to be 35~37.5mm and 30~35mm, respectively, and an infinite life cycle was confirmed at these.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 추계학술발표대회 논문집
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• pp.199-205
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• 2001

This paper describes the design methodology, manufacturing process, rebar tensile and bending properties. Braidtrusion is a direct Composite fabrication technique utilizing an in-line braiding and pultrusion process. The produced Composite rebar exhibits ductile stress-strain behavior similar to that of conventional steel bar. Various rebar diameters ranging from modeling scale(3m) to full-scale prototype of 9.5mm have been produced Glass Fiber Reinforced Plastics(GFRP) rebar were successfully fabricated at $\phi$8.5mm and $\phi$9.5mm nominal diameters of soild and hollow type using a braidtrusion process. Tensile and bending specimens were tested and compared with behavior of stress-strain of GFRP rebar and steel bar.