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공항 콘크리트 포장 구조해석을 위한 3차원 유한요소 모형 개발
박해원,심차상,임진선,조남현,정진훈 한국도로학회 2017 한국도로학회논문집 Vol.19 No.6
PURPOSES: In this study, a three-dimensional nonlinear finite element analysis (FEA) model for airport concrete pavement was developed using the commercial program ABAQUS. Users can select an analysis method and set the range of input parameters to reflect actual conditions such as environmental loading.METHODS : The geometrical shape of the FEA model was chosen by considering the concrete pavement located in the third-stage construction site of Incheon International Airport. Incompatible eight-node elements were used for the FEA model. Laboratory test results for the concrete specimens fabricated at the construction site were used as material properties of the concrete slab. The material properties of the cement-treated base suggested by the Federal Aviation Administration(FAA) manual were used as those of the lean concrete subbase. In addition, preceding studies and pavement evaluation reports of Incheon International Airport were referred for the material properties of asphalt base and subgrade. The kinetic friction coefficient between the concrete slab and asphalt base acquired from a preceding study was used for the friction coefficient between the layers. A nonlinear temperature gradient according to slab depth was used as an input parameter of environmental loading, and a quasistatic method was used to analyze traffic loading. The average load transfer efficiency obtained from an Heavy falling Weight Deflectomete(HWD) test was converted to a spring constant between adjacent slabs to be used as an input parameter. The reliability of the FEA model developed in this study was verified by comparing its analysis results to those of the FEAFAA model.RESULTS : A series of analyses were performed for environmental loading, traffic loading, and combined loading by using both the model developed in this study and the FEAFAA model under the same conditions. The stresses of the concrete slab obtained by both analysis models were almost the same. An HWD test was simulated and analyzed using the FEA model developed in this study. As a result, the actual deflections at the center, mid-edge, and corner of the slab caused by the HWD loading were similar to those obtained by the analysis.CONCLUSIONS : The FEA model developed in this study was judged to be utilized sufficiently in the prediction of behavior of airport concrete pavement.
박해원,문기훈,서진석,이찬희,정진훈 한국도로학회 2019 한국도로학회논문집 Vol.21 No.4
PURPOSES : It is well known that low temperature cracking is one of the most serious distresses on asphalt pavement, especially for northern U.S. (including Alaska), Canada and the northern part of south Korea. The risk of thermal cracking can be numerically measured by estimating thermal stress of a given asphalt mixture. This thermal stress can be computed by low temperature creep testing. Currently, in-direct tensile (IDT) mixture creep test mentioned in AASHTO specification is used for measuring low temperature creep properties of a given asphalt mixture. However, IDT requires the use of expensive testing equipment for performing the sophisticated analysis process, however, very few laboratories utilize this equipment. In this paper, a new and simple performance test (SPT) method: bending beam rheometer (BBR) mixture creep testing equipment is introduced, and the estimated experimental results were compared with those of conventional IDT tests. METHODS: Three different asphalt mixtures containing reclaimed asphalt pavement (RAP) and roofing shingles were prepared in the Korea Expressway Corporation (KEC) research laboratory. Using the BBR and IDT, the low temperature creep stiffness data were measured and subsequently computed. Using a simple power-law function, the creep stiffness data were converted into relaxation modulus, and subsequently compared. Finally, thermal stress results were computed from relaxation modulus master curve using Gaussian quadrature approach with condierations of 24 Gauss number. RESULTS: In the case of the conventional asphalt mixture, similar trends were observed when the relaxation modulus and thermal stress results were compared. In the case of RAP and Shingle added mixtures, relatively different computation results were obtained. It can be estimated that different experimental surroundings and specimen sizes affected the results. CONCLUSIONS: It can be said that the BBR mixture creep test can be a more viable approach for measuring low temperature properties of asphalt mixture compared to expensive and complex IDT testing methods. However, more extensive research and analysis are required to further verify the feasibility of the BBR mixture creep test.
아마추어 골퍼의 자아정체감과 자아탄력성 및 대인관계의 관계
박해원 한국골프학회 2021 골프연구 Vol.15 No.2
[목적] 이 연구는 아마추어 골퍼를 대상으로 자아정체감, 자아탄력성, 대인관계의 관계를 규명하는데 연구의 목적 이 있다. [방법] 아마추어 골퍼를 연구대상으로 선정한 후 자아정체감, 자아탄력성, 대인관계를 측정하였다. 측정 후 수집된 자료는 상관관계분석과 구조방정식모형을 적용하여 연구 변인들 간의 관계를 규명하였다. [결과] 연구 의 결과 자아정체감은 자아탄력성과 대인관계에 통계적으로 유의한 정적 영향을 미치는 것으로 나타났다. 자아탄 력성은 대인관계에 통계적으로 유의한 정적 영향을 미치는 것으로 나타났다. 자아정체감과 대인관계의 영향관계 에서 자아탄력성은 매개변인으로 작용하는 것으로 나타났다. [결론] 아마추어 골퍼의 대인관계를 높이기 위해서는 적절한 자아정체감과 자아탄력성이 중요한 역할을 수행할 것이라 판단된다. [Purpose] The purpose of this study is to investigate the relationship between self-identity, self-elasticity, and interpersonal relationships for amateur golfers. [Method] After selecting an amateur golfer as the subject of the study, self-identity, self-elasticity, and interpersonal relationships were measured. The data collected after measurement were analyzed by correlation analysis and structural equation model to clarify the relationship between the research variables. [Result] As a result of the study, it was found that self-identity had a statistically significant positive effect on self-elasticity and interpersonal relationships. It was found that self-elasti ci ty had a stati sti cally si gni fi cant posi ti ve effect on i nterpersonal relati onshi ps. In the relati onship between self-identity and interpersonal relations, self-empowerment was found to act as a mediating variable. [Conclusion] In order to enhance the interpersonal relationship of amateur golfers, it is judged that proper self-identity and self-elasticity will play an important role.
유한요소해석 모형을 이용한 공항콘크리트 포장의 건조수축 발생 경향 분석
박해원,김동혁,이종훈,임진선,조남현,정진훈 한국도로학회 2017 한국도로학회 학술대회 발표논문 초록집 Vol.2017 No.10
콘크리트에 발생하는 건조수축은 콘크리트 구조체 내부에 존재하는 수분의 이동에 의해 발생하며 강도발현시점 이후부터 점진적으로 그 크기가 커진다. 콘크리트에 발생할 수 있는 건조수축의 크기는 골재나 시멘트 등의 특성에 따라 다르나 약 40-1000 의 범위에서 발생하므로 그 크기는 무시할 수 없는 수준이다. 많은 연구자들은 콘크리트의 건조수축의 약 20-25%가 재령 2주내에, 약 50-60%가 3개월 내에, 80% 이상이 재령 1년 이내에 발생하는 것으로 판단하고 있다. 다만 콘크리트 포장에서는 깊이에 따라 건조수축의 발생의 진행정도가 다르며 이로 인해 포장체 상부와 하부에서의 수축차이가 생기는 부등건조수축이 발생하므로 단순히 구조체 전체가 동등하게 수축한다고 가정할 수 없다. 본 연구는 공항 콘크리트포장을 대상으로 한 유한요소해석 모형에 실제 현장에서 약 9개월간 계측한 슬래브 깊이별 실측 온도를 적용하여 계절적 온도변화에 의한 포장체의 거동을 해석하였다. 유한요소해석 결과와 실제 현장에서 계측한 슬래브 위치별, 깊이별 변형률을 비교 분석하였으며, 온도의 영향만을 반영하여 해석을 실시한 결과와 건조수축이 발생하는 실제 슬래브의 거동사이에 차이가 발생함을 확인하였다. 상대적으로 재령 초기에 건조수축의 발생이 작은 슬래브 바닥면을 기준으로 보정계수를 추정하여 해석결과를 보정하였으며 슬래브의 재령에 따른 깊이별 건조수축의 발생 경향을 확인할 수 있었다.
박해원,김동혁,정진훈 한국도로학회 2018 한국도로학회논문집 Vol.20 No.4
PURPOSES : The purpose of this study is to analyze the magnitude of shoving of asphalt pavement by junction type between airport concrete and asphalt pavements, and to suggest a junction type to reduce shoving. METHODS : The actual pavement junction of a domestic airport, which is called airport “A”was modified by placing the bottom of the buried slab on the top surface of the subbase. A finite element model was developed that simulated three junction types: a standard section of junction proposed by the FAA (Federal Aviation Administration), an actual section of junction from airport “A”and a modified section of junction from airport“ A”. The vertical displacement of the asphalt surface caused by the horizontal displacement of the concrete pavement was investigated in the three types of junction. RESULTS: A vertical displacement of approximately 13 mm occurred for the FAA standard section under horizontal pushing of 100 mm, and a vertical displacement of approximately 55 mm occurred for the actual section of airport “A”under the same level of pushing. On the other hand, for the modified section from airport“ A”a vertical displacement of approximately 17 mm occurred under the same level of pushing, which is slightly larger than the vertical displacement of the FAA standard section. CONCLUSIONS: It was confirmed that shoving of the asphalt pavement at the junction could be reduced by placing the bottom of the buried slab on the top surface of the subbase. It was also determined that the junction type suggested in this study was more advantageous than the FAA standard section because it resists faulting by the buried slab that is connected to the concrete pavement. Faulting of the junctions caused by aircraft loading will be compared by performing finite element analysis in the following study.
기상과 재료 특성에 의한 공항 콘크리트 포장 팽창줄눈 간격의 적정성 검토
박해원,정진훈 한국도로학회 2018 한국도로학회논문집 Vol.20 No.3
PURPOSES : In this study, the propriety of expansion joint spacing of airport concrete pavement was examined by using weather and material characteristics. METHODS: A finite element model for simulating airport concrete pavement was developed and blowup occurrence due to temperature increase was analyzed. The critical temperature causing the expansion of concrete slab and blow up at the expansion joint was calculated according to the initial vertical displacement at the joint. The amount of expansion that can occur in the concrete slab for 20 years of design life was calculated by summing the expansion and contraction by temperature, alkali-silica reaction, and drying shrinkage. The effective expansion of pavement section between adjacent expansion joints was calculated by subtracting the effective width of expansion joint from the summation of the expansion of the pavement section. The temperature change causing the effective expansion of pavement section was also calculated. The effective expansion equivalent temperature change was compared to the critical temperature, which causes the blowup, according to expansion joint spacing to verify the propriety of expansion joint applied to the airport concrete pavement. RESULTS: When an initial vertical displacement of the expansion joint was 3mm or less, the blowup never occurred for 300m of joint spacing which is used in Korean airports currently. But, there was a risk of blow-up when an initial vertical displacement of the expansion joint was 5mm or more due to the weather or material characteristics. CONCLUSIONS: It was confirmed that the intial vertical displacement at the expansion joint could be managed below 3mm from the previous research results. Accordingly it was concluded that the 300m of current expansion joint spacing of Korean airports could be used without blowup by controling the alkali-silica reaction below its allowable limit.
초등학교 태권도 수련생의 사회적 친밀성이 학교생활적응에 미치는 영향
박해원,손원일 대한무도학회 2022 대한무도학회지 Vol.24 No.4
이 연구는 초등학교 태권도 수련생의 사회적 친밀성이 학교생활적응에 미치는 영향을 검증하는데연구의 목적이 있다. 초등학교 태권도 수련생을 연구대상으로 선정하였으며, 사회적 친밀성과 학교생활적응을 측정할 수 있는 척도를 본 연구에 맞게 수정하여 설문조사를 실시하고 자료를 수집하였다. 수집된 자료는 탐색적 요인분석과 크론바흐 알파 계수를 이용하여 적합도와 신뢰도를 검증하였다. SPSS 26.0 프로그램을 이용하여 사회적 친밀성이 학교생활적응에 미치는 영향을 검증하였다. 통계분석은 상관관계분석과 회귀분석을 실시하였으며, 모든 통계적 유의수준은 .05로 설정하였다. 연구 결과첫째, 사회적 친밀성은 학교생활적응과 통계적으로 유의한 상관이 있는 것으로 나타났다. 둘째, 사회적 친밀성은 학교생활적응에 통계적으로 유의한 영향을 미치는 것으로 나타났다.