GFRP 보강근으로 겹침이음된 휨 부재의 거동에 관한 실험적 연구

최윤철,최현기,최창식,Choi, Yun-Cheul,Choi, Hyun-Ki,Choi, Chang-Sik 대한건축학회 2011 대한건축학회논문집 Vol.27 No.4

The use of glass-fiber-reinforced polymer (GFRP) bars in reinforced concrete (RC) structures has emerged as an alternative to traditional RC due to the corrosion of steel in aggressive environments. Although the number of analytical and experimental studies on RC beams with GFRP reinforcement has increased in recent decades, it is still lower than the number of such studies related to steel RC structures. This paper presents the experimental moment deflection relations of reinforced beam with spliced GFRP bars. Test variables were lab-spliced length of GFRP rebars. The development length was calculated according to the ACI 440 for GFRP rebars in concrete. A total of 6 concrete beams reinforced with steel and GFRP rebar tested. Three concrete beam reinforced with spliced GFRP rebars and 1 reference beams reinforced with non-spliced GFRP rebars were tested. All the specimens had a span of 4000mm, provided with 12.7mm nominal diameter steel and GFRP rebars. All test specimens were tested under 2-point loads so that the spliced region be subject to constant moment. The test results indicated that the modification factor of 1.6 and 1.75 is relatively sufficient for the bond development length of GFRP rebars archiving adequate tension lap splice length.

장스팬 및 층고저감형 와이드 복합보의 휨성능에 관한 연구

최윤철,박금성,이상섭,최현기,Choi, Yun-Cheul,Park, Keum-Sung,Lee, Sang-Sup,Choi, Hyun-Ki 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 논문집 Vol.21 No.6

최근 국내 자동차 보유대수의 급격한 증가로 도심지 주차문제가 복잡해지고 있다. 도심지 주차문제 해결에 있어 공작물 주차장이 주목을 받고 있다. 그러나 공작물 주차장은 전체 높이 8 m 이하로 건설되도록 규정되어 있다. 이에 본 연구에서는 층고절감 및 장스팬화가 가능한 와이드 합성보를 개발하여 휨성능을 평가하였다. 휨 성능 실험 결과, 강재보의 두께가 3 mm 증가($6mm{\rightarrow}9mm$)함에 따라 휨강도는 약 20%가 증가하였다. 보 보강철근(트러스철근)의 형태(삼각형, 사각형)은 휨강도에 영향을 미치지 않았다. 보 보강철근(트러스철근)이 없는 경우는 있는 경우보다 약 10%가량 휨강도가 저하되었다. 또한 하중이 증가할수록 중립축은 상부로 이동하지만 일정하중을 넘어가면 중립축이 다시 하부로 이동하는 결과를 나타내었다. Recently, the parking in downtown area has caused severe problem due to the dramatic increase of possessing automobile in the country. A parking structure has been on the spotlight to solve the parking problem in downtown area. However, the overall height of parking structure is stipulated less than 8 m. Therefore, in this research, 'wide composite beam', which is possible for reducing story height and having long span, is developed and the flexural capacity of the wide composite beam is evaluated. Based on the result of the flexural test, the flexural strength of wide composite beam increased by 20% as the thickness of steel beam increased by 3 mm ($6mm{\rightarrow}9mm$) The shapes of rebar (whether it is triangle or rectangular shape) in the wide composite beam did not affect its flexural strength. The flexural strength of wide composite beam without rebar decreased by 10% compared to that of wide composite beam with rebar. In addition, the neutral axis moved upward as a load increased, but the neutral axis moved downward, when the load exceeded a certain level of load.

U자형 와이드 합성보의 거동특성

최윤철,이상섭,최현기,박금성,Choi, Yun-Cheul,Lee, Sang-Sup,Choi, Hyun-Ki,Park, Keum-Sung 한국구조물진단유지관리공학회 2017 한국구조물진단유지관리공학회 논문집 Vol.21 No.5

도심지 주차문제 해결에 있어 공작물 주차장이 주목을 받고 있다. 그러나 공작물 주차장은 전체 높이 8 m 이하로 건설되도록 규정되어 있다. 이에 본 연구에서는 층고 절감 및 장스팬화가 가능한 와이드 합성보를 대상으로 휨 및 전단성능을 평가하였다. 실험결과 보강철근(트러스 철근)은 휨강도에 영향을 미치지 않았다. 그러나, 보강철근이 없는 실험체의 경우 항복강도의 70%에서 슬립이 발생하여 기계적 부착능력이 저하되었다. 전단부착 실험결과 전단연결재가 없는 모든 실험체는 기계적 부착만으로 충분한 전단부착 성능을 가지지 못하므로, Flat Bar를 최소 2개 이상 설치하여야 한다. A parking structure has been on the spotlight to solve the parking problem in downtown area. However, the overall height of parking structure is stipulated less than 8m. Therefore, in this research, the flexural and shear capacity of 'wide composite beam' which can reduce story height and have long span, is evaluated. Based on test result, the rebar in truss did not affect its flexural strength. However, in the case of the specimen without the rebar, the mechanical bond strength decreased due to slip occurrence at 70% of the flexural yield strength. Based on the test of shear-bond behavior, all specimen without shear connector should be reinforced with 2 or more flat bar, because it did not have enough shear bond strength resisted by the mechanical bond mechanism.

공공기관 건축물의 기후변화에 따른 위험요소 분석

최윤철(Choi, Yun-Cheul),서광덕(Seo, Gwang-Deok) 대한건축학회 2017 大韓建築學會論文集 : 構造系 Vol.33 No.11

Climate change not only affects human shoes, economics, the environment, industries, etc. but also the damage caused by it is increasing Increasingly, if we do not make efforts to respond to climate change, it is expected that serious damage will occur Has been done. Especially when the damage caused by climate change (intense heat, torrential rain, cold wave and heavy snow etc.) as an institution responsible for the provision of public services such as public institutions, the socio-economic spread to the nation and the people The effect is very large. Korea is obliged to formulate climate change adaptation measures up to the basic municipality unit according to Article 38 of the Enforcement Order of the 「Framework act on low carbon, green growth」. In this study, it is very likely that the impact of climate change will cause enormous damage to social infrastructure facilities and national shoes, so it is important to provide public services and fundamental to making adaptation measures against the effects of climate change in public facilities etc. Present the material.

개구부 형태에 따른 전단벽의 거동에 관한 유한요소해석

최윤철(Choi Yun-Cheul),최현기(Choi Hyun-Ki),최창식(Choi Chang-Sik) 대한건축학회 2009 大韓建築學會論文集 : 構造系 Vol.25 No.10

Many engineers find the way of improving the old building’s structural behavior in the remodeling project which is performed using artificial openings for merging two houses. The installation of new opening is necessary for remodeling project which have main plan as house merging. Current code include provisions for the design of symmetric and unsymmetric solid walls; however, it is necessary to provide openings in the walls for doors or windows. There are several researches for shear strength determination however, in order to apply this research results, analysis of stress distribution is mandatory. Therefore, in this study, we carried out analytical study for wall which include openings and connecting elements such as coupling beam. It may be used to evaluation of structural safety and determination of efficient retrofitting methods. Nonlinear analysis was conducted, using ABAQUS, a finite-element analysis program, to obtain data for determining the characteristics of the structural and to allow various parametric analyses for coupling beams according to shape of the openings, the C3D20R element was used, in which concrete element had 20 nodes quadratic brick reduced integration points and each node had 3 degrees of freedom. For the reinforcements, T3D3 element used which is a 3-node quadratic 3-D truss element and these elements embeded in the concrete elements. As a results of analysis, behavior and strength of wall are different according to the existence and size of connecting elements.

개구부 신설에 따른 전단벽의 보강기법 특성

최윤철(Choi Yun-Cheul),최현기(Choi Hyun-Ki),최창식(Choi Chang-Sik) 대한건축학회 2008 大韓建築學會論文集 : 構造系 Vol.24 No.1

Remodeling is also an environmentally-friendly approach that reduces the amount of waste in construction site. Remodeling can sometimes include partial destruction of the structural members of a building. The objective of this paper is to present the test results and structural behavior of RC walls that are perforated and to introduce effective retrofitting methods by evaluating efficacy of passive retrofit and active retrofit. Passive retrofit and active retrofit using carbon fiber sheets, steel plates and wire that are widely used for strengthening the main members of existing buildings. A series of five shear wall specimens was tested under constant axial stress and reversed cyclic lateral loading in order to evaluate the seismic retrofit that had been proposed for the shear wall with the opening. The test results showed that the failed specimens had shear fractures and that two different types of retrofit method had different effects on the strengths of each specimen.

다목적 바닥 레벨조인트 공법의 개발 및 성능평가에 관한 연구

최윤철(Choi, Yun Cheul),서수연(Seo, Soo Yeon),지남용(Jee, Nam Yong),이리형(Lee, Li Hyung) 한국콘크리트학회 2002 한국콘크리트학회 학술대회 논문집 Vol.2002 No.5

정보통신망 건축물의 재난관리를 위한 위험평가 연구

최윤철(Choi, Yun-Cheul),서광덕(Seo, Gwang-Deok) 대한건축학회 2016 大韓建築學會論文集 : 構造系 Vol.32 No.8

The frequency of occurrence of the disaster or large-scale accidents caused by recent hazard have increasingly. This is the sophistication of technology and pointed, due to rapid urbanization, is because the enclosing a variety of hazard and threat. Accordingly, in the present study was to determine the core risk of execution process based on the H building of risk assessment Risk management processes provided by ISO31000, and presents an efficient and systematic risk management scheme through the risk matrix analysis.

PC U형 단면을 사용한 포스트텐션된 넓은 보-기둥 외부접합부의 비탄성 거동

최윤철(Choi Yun-Cheul),임재형(Lim Jae-Hyung),권기혁(Kwon Ki-Hyuk),문정호(Moon Jeong-Ho),이리형(Lee Li-Hyung),김대중(Kim Dae-Joong) 대한건축학회 2004 大韓建築學會論文集 : 構造系 Vol.20 No.12

Post-tensioned precast concrete system(PPS) consists of U-shaped precast wide beams and concrete column The continuity of beam-column joint is provided with the topping concrete on the PC shell beam and post-tensioning The purpose of this paper is to evaluate the response of PPS exterior beam-column joint subjected to cyclic lateral loafing To this end, an experimental investigation was performed with three half-scale exterior connection subassemblages The design parameters were the beam width ratio to column width and the amount of beam reinforcement placed inside the column core The test results showed that specimen cracks were distributed well and plastic hinges spread toward midspan without any significant degradation of strength and ductility And the specimens sufficiently resist up to limiting daft ratio of 0.035 in accordance with the provisional by "Acceptance Criteria for Moment Frames Based on Structural Testing"

GFRP 보강근으로 겹침이음된 휨 부재의 거동에 관한 실험적 연구

최윤철(Choi Yun-Cheul),최현기(Choi Hyun-Ki),최창식(Choi Chang-Sik) 대한건축학회 2011 大韓建築學會論文集 : 構造系 Vol.27 No.4

The use of glass-fiber-reinforced polymer (GFRP) bars in reinforced concrete (RC) structures has emerged as an alternative to traditional RC due to the corrosion of steel in aggressive environments. Although the number of analytical and experimental studies on RC beams with GFRP reinforcement has increased in recent decades, it is still lower than the number of such studies related to steel RC structures. This paper presents the experimental moment deflection relations of reinforced beam with spliced GFRP bars. Test variables were lab-spliced length of GFRP rebars. The development length was calculated according to the ACI 440 for GFRP rebars in concrete. A total of 6 concrete beams reinforced with steel and GFRP rebar tested. Three concrete beam reinforced with spliced GFRP rebars and 1 reference beams reinforced with non-spliced GFRP rebars were tested. All the specimens had a span of 4000mm, provided with 12.7mm nominal diameter steel and GFRP rebars. All test specimens were tested under 2-point loads so that the spliced region be subject to constant moment. The test results indicated that the modification factor of 1.6 and 1.75 is relatively sufficient for the bond development length of GFRP rebars archiving adequate tension lap splice length