• 한국구조물진단유지관리공학회 논문집
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• 제4권3호
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• pp.197-204
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• 2000

Tensile strength (stress) of bar splice is important in the research of mechanical behavior of reinforced concrete structures-beam, column etc.- with bar splice. The purpose of this research is to evaluate the flexural behavior - deflection of beam specimens, strain of main bars - of reinforced concrete beam with Lock Joint Coupler. To make a comparative research, reinforced concrete beam specimens with normal deformed bar and lap splice are tested and analyzed. Test results, Comparing a deflection of three types flexural specimens, a flexural specimen with Lock Joint Coupler is 40% greater than the other flexural specimens. At the center of flexural specimen, the strain of main bar(D29) with lock joint coupler is 50% less, and vice versa, at the point of 14cm far from the center of flexural specimen, the strain of main bar(D29) with lock joint coupler is 9% larger than the strain of main bar(D29) which calculated using the classical flexure theory. A discords, between a deflection behavior of the flexural specimens and a strain of the main bar, are caused by the difference of strain between the lock joint coupler and main bar, near the lock joint coupler. So, additional research is need to verify as stated above discords.

• 한국구조물진단유지관리공학회 논문집
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• 제5권1호
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• pp.237-246
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• 2001

This study is to measure the creep coefficient by 3 days, 7 days and 28 days in the age when loading for the quality assessment of $350kgf/cm^2$ in the high-strength concrete. And it is to analyze the behavior of creep coefficient by applying the experimental data though the compressive strength test, the elastic modulus test and the dry shrinkage test to the ACI-209, AASHTO-94 and CEB/FIP-90, the prediction mode, and the basis of concrete structural design. Also it is to analyze the behavior of short-term creep coefficient during 91 days in the age when loading through the experiment by using the regression analysis, the statistical theory. As applying it to the long-term behavior during 365 days and comparing with the creep prediction mode and examining it, the result from the analysis of the quality of the concrete is as follows. As the result of comparison and analysis about the ACI-209, AASHTO-94 and CEB/FIP-90, the prediction mode, and the basis of concrete structural design, the normal Portland cement class 1 shows the approximate value with the prediction of GEE/PIP-90 and the basis of concrete structural design, but in case of the prediction of ACI-209 and AASHTO-94, there would be worry of underestimation in the application.

• 한국구조물진단유지관리공학회 논문집
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• 제5권3호
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• pp.191-201
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• 2001

In spite of the increasing construction of segmental PSC box girder bridges, the techniques associated with real-time monitoring, construction control and safety assessment during construction have been less developed compared with the construction techniques. Thus, the development of an integrated system including real-time measurement and monitoring, control and safety assessment system during construction is necessary fur more safe and precise construction of the bridges. This study presents a prototype integrated monitoring system for preventing abnormal behavior and accidents under construction stages, that consist of behavior control system for precise construction, reliability-based safety assessment system, and structural analysis. Also, a prototype software system is developed on the basis of the proposed model. It is successfully applied to the Sea-Hae Grand Bridge built by FCM. The integrated system model and software system can be utilized for the safe and precise construction of segmental PSC bridges during construction.

• 한국구조물진단유지관리공학회 논문집
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• 제10권2호
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• pp.191-202
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• 2006

구조물을 설계할 때 사용하는 컴퓨터 프로그램들은 구조물에 작용하는 각각의 조건을 고려한 최적의 설계를 할 수 있도록 도움을 준다. 하지만 컴퓨터 프로그램은 단순화시키고 일반화시킨 조건들을 적용하기 때문에 그 결과들은 실제 구조물의 거동을 정확히 설명할 수 없다. 이러한 문제점들을 극복하기 위해서 도입된 것이 스마트 구조이고 스마트 시스템을 통해 구조물을 상시 계측함으로서 실제 구조물의 정확한 거동을 파악할 수 있다. 본 연구는 실험을 통해 기존의 구조설계방법에 의한 구조물의 거동과 실제 구조물의 거동을 비교하여 계측시스템의 타당성 검토와 함께 앞으로의 발전가능성을 알아보고자 한다.

• 한국구조물진단유지관리공학회 논문집
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• 제14권5호
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• pp.79-86
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• 2010

이 연구에서는 콘크리트 구조물의 섬유보강재인 하이브리드 섬유시트(HFC)와 하이브리드 섬유바(HFB)의 성능을 평가하였다. 실험결과에 의하면, 하이브리드 섬유보강재(시트, 바)로 보강된 보는 무보강보에 비해 약 60%~2배 이상의 높은 보강효과를 보였고 보강된 보는 항복점 이후 연성적인 거동을 보이며 파괴되는 이상적인 파괴모습을 보여주었다. 특히, 하이브리드 섬유바 보강의 경우 하이브리드 섬유바를 에폭시 주입과 접착제로 부착한 보강보는 비슷한 파괴거동을 보여줌으로써 부착방식에 따른 차이가 거의 없는 것으로 나타났다.

• 한국구조물진단유지관리공학회 논문집
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• 제19권2호
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• pp.92-98
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• 2015

최근의 건축물은 복합적인 기능과 형태를 보이고 있으며, 크기가 거대해짐에 따라 구조물 건전성 감시 (Structural Health Monitoring)기술의 수요 또한 증가하고 있다. 구조물마다 고유한 동특성을 가지고 있으며, 다양한 외력의 영향을 받기 때문에 구조물의 건전성을 평가하는 다양한 방법들이 연구되고 있다. 이상거동 시점이란 구조물이 비정상적 (Abnormal)으로 진동하는 시점으로 손상을 명확히 검출하기 위해서는 이상거동의 시점을 기준으로 전과 후를 비교하여야 한다. 즉, 이상거동은 구조물 손상의 이상 징후이며, 정확한 이상거동 시점의 추정은 구조물의 안전과 직결될 수 있다. 이상 거동은 손상을 유발하고 이는 곧 막대한 경제적 피해 및 심각한 인명 피해로 이어지므로 본 연구에서는 시간-주파수 신호분석 기법인 힐버트-황 변환을 이용한 이상거동 시점 추정 기법을 제안하고 진동대를 이용한 모형실험을 통해 제안한 알고리즘의 검증을 수행하였다.

• 한국철도학회논문집
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• 제11권2호
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• pp.165-175
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• 2008

철도판형교에 있어 선받침은 사용 중에 많은 문제를 야기하고 있으며, 구조적으로 불안정하다. 기존 선받침의 문제점을 파악하기 위해 수평저항능력 실험을 수행하였다. 유지보수에 용이하고 들림현상에 저항할 수 있는 개선된 스페리칼받침을 개발하여 기존받침을 교체하였다. 개선된 스페리칼받침의 교체성능 실험과 부반력 저항능력 실험이 수행되어, 유지보수 성능 및 부반력 저항능력이 증명되었다. 선받침 상태 및 스페리칼받침으로 교체된 상태에서 판형교의 동적 거동 및 각 교량받침의 동적 거동을 계측하여 거동의 차이를 분석하였다. 이러한 실험 및 분석을 통하여 개선된 스페리칼받침이 철도 판형교에 교량받침으로 사용하기에 적합함을 알 수 있었다.

• 한국주거학회논문집
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• 제21권5호
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• pp.93-101
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• 2010

The purpose of the study is to investigate the behaviors for ventilation to control indoor air quality and characteristics of the maintenance for ventilation equipments by multi-family housing residents. This study was conducted by the survey in the area of Seoul and Kyungki-do. The results of the study are as follows: the majority of respondents conduct ventilation once a day, below 20 minutes with opening some windows of the inside of the house. The time for ventilation is generally between 9-11 am. and 5-7 pm. Most of the wives are responsible for ventilation activities. In addition, so far building materials and furniture are not seriously considered as the source of indoor air pollution by the respondents. Their satisfaction for indoor air before and after ventilation is perceived as just the level of average. As the mechanical ventilation equipments such as a hood and an exhaust fan, half of the respondents are using them frequently. However, the ventilation equipments are not maintained well. Specially maintenance and checks for exhaust fans are hardly conducted. In conclusion, the frequency of ventilation is very limited and residents show passive attitudes about ventilation and maintenance of ventilation equipments. Therefore, for the actualization of healthy housing, educational programs and guidelines on the way of ventilation targeting the residents should be set up and a certain organization has to check periodically the performance of the ventilation equipments of each house in the multi-family housing complex.

• Steel and Composite Structures
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• 제24권3호
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• pp.383-391
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• 2017

The goal of this study is to investigate structural analysis and behaviors of an innovative aerial work platform truss frame whose ductility is improved by using high strength-steel UL-700. The present space truss frame can move or stop through tunnels for maintenance constructions by automatic facilities and workmanship within standardized limited building lines of tunnel. Most of all, this method overcomes problematic, which is to block cars during construction periods, seriously, of typical methods like as using truck and scaffolds for tunnel maintenance. According to evaluated appropriate design results of space truss frames of numerical examples by using a commercial MIDAS GEN program, it is verified that design parameters such as layered size, cross-sectional size, and steel material of the present space truss frame are determined to depend on characteristics such as lanes or shape of road tunnels.

• Steel and Composite Structures
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• 제24권4호
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• pp.513-521
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• 2017

The goal of this study is to investigate structural analysis and behaviors of an innovative aerial work platform truss frame whose ductility is improved by using high strength-steel UL-700. The present space truss frame can move or stop through tunnels for maintenance constructions by automatic facilities and workmanship within standardized limited building lines of tunnel. Most of all, this method overcomes problematic, which is to block cars during construction periods, seriously, of typical methods like as using truck and scaffolds for tunnel maintenance. According to evaluated appropriate design results of space truss frames of numerical examples by using a commercial MIDAS GEN program, it is verified that design parameters such as layered size, cross-sectional size, and steel material of the present space truss frame are determined to depend on characteristics such as lanes or shape of road tunnels.