鐵筋콘크리트 휨部材의 前斷力에 關한 硏究

郭桂煥 원광대학교 공업기술개발연구소 1982 工業技術開發硏究誌 Vol.2 No.-

This study is to make researches on the problems of sheardesign by comparing the differences of reinforced concrete bending beam in WSD between the present and the old project of Korean Society of Civil Engineers .

교량 내하력의 동적거동에 관한 연구

곽계환,박종건,정명덕 圓光大學校 環境建設硏究所 1992 環境建設論文集 Vol.1 No.-

This study analyzed the dynamic behavior of Structural Proof Stress by means of computer simulation so as to investigate the stability of bridge structure. It also analyzed the numerical values and the propriety of impact coefficient showed on the present road bridge specifications and measured values. Thus, this study aimed to discover in advance the bridge damage that had happened on account of existing bridge amount of dynamic materials and the freqency of vehicle traffic, to prevent the damage, to maintain bridge structure and to repair them.

PDA와 광섬유 센서를 이용한 교량의 무선계측 시스템 개발

곽계환,황해성,장화섭,김우종,김희옥 한국구조물진단유지관리공학회 2009 한국구조물진단유지관리공학회 논문집 Vol.13 No.1

본 연구에서는 FBG 센서 및 PDA를 이용하여 새로운 안전관리 시스템인 무선 계측 시스템을 개발하기 위해 FBG 센서를 이용하여 광섬유 변위(FBG-LVDT) 센서, 광섬유 변형률(FBG-STRAIN) 센서, 광섬유 온도(FBG-TEMP) 센서 그리고 광섬유 가속도(FBG-ACC) 센서를 특별 제작하였다. 또한, 신호처리 시스템에는 적용된 FBG 센서들의 무선송신 시스템이 가능하도록 신호처리 시스템을 구성하였으며, PDA를 이용하여 원격 거리에서도 display가 가능할 수 있도록 프로그램을 개발하였다. 개발된 FBG 센서들과 무선계측 모니터링 시스템의 현장 적용성, 정확성 및 활용 가능성을 검증하고자 현장 교량에서 정적, 동적 재하시험을 실시하였다. 또한, FBG-LVDT 센서, FBG-ACC 센서에 의하여 측정된 동적 데이터들은 Meister의 진동등감각 곡선에 적용시킴으로서 교량의 진동에 대한 사용성 평가를 실시하였고 교량의 진동 사용성을 고려하여 진동 제한 기준을 제시하여 대상 교량의 진동 평가를 위한 방법을 마련하였다. This study proposes a wireless measurement system that is a new safety management system by using an FBG sensor and a PDA. The sensor part has many advantages of implementing a wireless measurement system, and the study emploies an FBG-LVDT sensor, FBG-STRAIN sensor, FBG-TEMP sensor, and FBG-ACC sensor, using FBG sensors. Also, the study show a configuration of a signal process system for operating a wireless transmission system of FBG sensors applied to the signal process system, and engrafted the cutting edge information technology industry in order to display from a remote distance using a PDA. In order to verify the applicability of the developed FBG sensors and wireless measurement monitoring system to the field, their accuracy, and usability, the study has conducted a static and dynamic test to a bridge in the field. The study made an assessment of service for the vibration of the bridge by applying dynamic data measured by an FBG-LVDT sensor and FBG-ACC sensor to Meister’s curve and prepared methods for assessing the vibration of the bridge by proposing a standard of vibration limitation given the service of vibration of the bridge. As a follow up for this study, it would be necessary to set up an overall model for the standard of service assessment established in this study.

강섬유의 형상비와 혼입률에 따른 강섬유 보강 콘크리트 보의 역학적 특성 추정 모형 개발

곽계환,황해성,성배경,장화섭,Kwak, Kae-Hwan,Hwang, Hae-Sung,Sung, Bai-Kyung,Jang, Hwa-Sup 한국농공학회 2006 한국농공학회논문집 Vol.48 No.3

Practially useful method of steel fiber for construction work is presented in this study. The most important purpose of this study is to develop a model which can predict mechanical behavior of the structure according to aspect ratio and volume fraction of steel fiber. Experiments on compressive strength, elastic modulus, and splitting strength were performed with self-made cylindrical specimens of variable aspect ratios and volume fractions. The experiment showed that compressive strength was not in direct proportion to volume fraction which doesn't seem to have great influence over compressive strength. However, splitting strength showed almost direct proportion to aspect ratio and volume fraction. Improvement of optimal efficiency was confirmed when the aspect ratio was 70. Experiments on flexural strength, fracture energy, and characteristic length were carried out with self-manufactured beams with notch. As a result, increases of flexural strength, fracture energy, and characteristic length according to increase of volume fraction tend to be prominent when aspect ratio is 70. The steel fiber improves concrete to be more ductile and tough. Moreover, regression analysis was the performed and predictable model was developed after determining variables. With comparison and analysis of suggested estimated values and measured data, reliance of the model was verified.

신경망 기법을 이용한 강섬유 혼입 콘크리트의 전단강도 추정 모형 개발

곽계환,황해성,김우종,장화섭,강신묵,Kwak, Kae-Hwan,Hwang, Hae-Sung,Kim, Woo-Jong,Jang, Hwa-Sup,Kang, Shin-Muk 한국농공학회 2007 한국농공학회논문집 Vol.49 No.2

This study, the present study wishes to develop a model that estimates shear strength characteristics of steel fiber reinforced concrete using artifical neural network models. Neural network models, developed as mathematical models, are being widely used not only in its original purpose of pattern recognition, but also in application fields by the function's nonlinear loaming and interpolar ability Neural network has a repetitive rotation algorithm that can cyclically and repeatedly estimate system conditions and parameter ideal values, and it can be used in the modeling of the nonlinear system by nonlinear characteristic functions that construct the system.

폴리머-강섬유를 혼인합 고강도 콘크리트 보의 보수.보강

곽계환,김원태 한국구조물진단유지관리공학회 2002 한국구조물진단유지관리공학회 논문집 Vol.6 No.2

콘크리트 충진 FRP 거더의 전단재하 실험에 관한 연구

곽계환,장화섭,김우종,김회옥,Kwak, Kae-Hwan,Jang, Hwa-Sup,Kim, Woo-Jong,Kim, Hoi-Ok 한국전산구조공학회 2008 한국전산구조공학회논문집 Vol.21 No.4

섬유복합재료(Fiber Reinforced Polymer, FRP)는 경량성, 높은 설계기준강도, 비전기 비자성 및 내부식성의 특징 등으로 인하여 최근 건설분야에서 많은 연구가 진행되고 있다. 그 중 GFRP(Glass Fiber Reinforced Polymer)는 가격 경쟁성에서 우수하여 일반적으로 많이 사용되고 있다. 그러나 GFRP는 상대적으로 낮은 탄성계수를 가지고 있어 처짐이 과대하게 발생함으로 구조부재 단면으로서 활용되기 위해서는 단면이 커야하며, 설계시 사용하중에 의한 처짐 제한에 대한 검토를 실시해야 한다. 이에 본 연구에서는 언급된 기술적인 문제점을 해결하기 위하여 대형 단면의 적용이 가능하도록 모듈형식의 단면을 제안하였다. 그리고 FRP의 낮은 강성을 확보하군 위하여 콘크리트를 충진하는 새로운 FRP+콘크리트 합성 거더 형상을 개발하였다. 개발된 FRP)콘크리트 합성 거더의 전단지간비와 콘크리트 충진 여부에 따른 전단강도 및 처짐, 중립축 변화를 확인하고자 전단실험을 실시하였다. Fiber Reinforced Polymer, FRP has a light weight, a high tensile strength based on design, non-electronic, non-magnetic, and rust-resistant feature, etc and many researches are being conducted recently on FRP in the construction area. Among them, GFRP (Glass Fiber Reinforced Polymer) is excellent in price competitiveness and is widely being used. However, since GFRP has a relative low modulus of elasticity and causes excessive deflection, the section must be large to be used as a structural component and an investigative review must be carried out in design to set the limit for deflection by the use load. Therefore, in order to solve the mentioned technical problems, this study suggested a section of a module form such that application of a large-scale section is possible. Also, to secure the low rigidity of FRP, this study developed a new FRP+ concrete composite girder form that confined the concrete. To identify the structural movement of the developed FRP+ concrete composite girder, shear strength test was carried out.

FRP 모듈형 박스 부재의 연결 시스템에 관한 실험적 연구

곽계환,장화섭,양동운,김호선,Kwak, Kae-Hwan,Jang, Hwa-Sup,Yang, Dong-Woon,Kim, Ho-Sun 한국농공학회 2009 한국농공학회논문집 Vol.51 No.4

This is a basic experimental study to apply FRP modular box member to a variety of construction structures exposed to flexural strength, such as a slab and a girder. Applying FRP modular box member to a real structure requires a large section. FRP box member was made into modular systems. Tests were conducted under various conditions in order to analyze jointing performance of the developed FRP modular box member as a large section. For the methods of jointing FRP modular box member, synthetic resins connection, mechanical connection, and a combination of both were used to test both length and breadth connection. As a result of the test, using urethane + two bolts + sheets was the most efficient method of connecting FRP modular box member. It is expected that the proposed joint system in this study will contribute to the increase of failure load and synthesis behavior of FRP modular box member.

휨을 받는 조립형 FRP 박스부재의 최적단면검토

곽계환,김경숙,김호선,Kwak, Kae-Hwan,Kim, Kyung-Suk,Kim, Ho-Sun 한국농공학회 2011 한국농공학회논문집 Vol.53 No.3

Fiber Reinforced Polymer (FRP)s have various advantages for construction material in that they are noncorrosive and very strong. FRPs are economical and effective for management and maintenance when applied to footbridge, beam or deck of the bridge, girder, and marine structure. For safety, optimal design for standard modulation of the cross section is necessary. Conditions of optimum are possibilities of domestic production, modular assembly, and structure materials cast in compressed area.

前 龜裂을 준 鋼纖維 콘크리트보의 破壞特性

곽계환,박종건,박세웅,Kwark, Kae-Hwan,Park, Jong-Gun,Park, Sai-Woong 한국농공학회 1992 韓國農工學會誌 : 전원과 자원 Vol.34 No.2

In our researches we made mix-design, with the mixing ratio and pre-cracked ratio of steel fibrous different from each other, building the steel fibrous concrete beam which had pre-cracks. To obtain the fracture characteristics of steel fibrous reinforced concrete, series of experiment were conducted on pre-cracked beam subjected to 3-point bending. Thus, we carried out experiments on the destructive characteristics of its pre-crack and post-crack and the result is as follows. 1. The compressive strength of steel fibrous concrete beam increased more slightly than plane beam, and the tensile strength increased 37%, 59%, 94% and 121% respectively when the amount of fibrous was 0.5%, 0.1% 1.5%, and 1.75% respectively. 2. As the amount of steel fibrous mixing increased ant the steel fibrous inhibited the crack growth, the crack condition of steel fibrous concrete beam was retarded irregularly, and this increased fracture load. 3. The defiance of destruction was reduced in the ratio of 1.35 times and 1.22 times respectively when the length of pre-crack was each 2cm and 4cm in comparison with the case of being without the length, and was similar to that of plane beam when the amount of steel fibrous mixing was below 1.0%, and increased linearly when it as above 1.0%. 4. The experimental formula seeking fracture energy was follows and thus we found that the value of fracture energy depended upon tensile strength and the size of speciment. $G_f=K\;{\cdot}\;f_f^'{\cdot}$da/Ec 5. We observed that in the load-strain curve of steel fibrous concrete beam the progress of the crack became slow, compared with plane beam because the crack condition became long to the extent of about 10 times. Concrete was faultiest brittleness fracture through the study, it was known ductile.