이동하중에 의한 교량의 공진현상은 차량의 속도와 유효타격간격에 의해 결정되는 이동하중의 운행진동수와 교량의 고유진동수가 일치할 경우 발생하게 된다. 철도교의 경우에는 정해진 열차만 통행하게 되므로 이러한 유효타격간격이 정량적으로 정해져있다 본 연구에서는 고속전철하중을 받는 교량의 지간장 변화에 따른 교량의 공진현상과 공진소멸현상을 분석하고자 한다. 강합성형 철도교에 대하여 판요소와 공간뼈대요소의 조합에 의한 3차원 모델링을 적용하였으며 또한 고속전철하중은 이동집중하중 모델과 3차원 모델링 두가지 방법을 사용하였다 수치예제로서 지간장 변화에 따른 수직처짐의 동적확대계수 상판의 최대수직가속도 단부회전각 등의 동적응답 분석을 통하여 고속철도 교량의 동적안정성에 적합한 지간장 설계기준에 대하여 논의 하였다.

오하이오 중부에서 풍속이 0.5m.s-1인 경우는 매우 드물었으며, 5년 평균 풍속은 약 2.5 m.s-1인 것으로 나타났다. 최고 기온이 35t인 오하이오주의 대표적인 여름에 온실 내의 여섯 곳에서 측정된 기온의 최대범위는 1.7℃, 온실 내외 기온의 최대차는 3.5℃인 것으로 나타났다. CFD 모델에서의 온도 분포를 분석한 결과, 온실의 환기 회수가 0.9 회/분 이상일 때 실내 공기가 외부 기온을 2.8℃이상 초과하는 경우는 없었던 것으로 예측되었다. 풍향과 풍속에 따라서 각각의 환기구들의 효율성이 영향을 받는 것으로 나타났으며, 특히 환기창을 통해 유입되는 강한 바람에 의하여 발생하는 공기의 소용돌이들은 지붕창들의 효율성에 많은 영향을 미치는 것으로 예측되었다. CFD model은 서쪽에서와 동쪽에서 불어오는 바람이 각각 2.1 m.s-1와 3.5 m.s-1이상일 때 이 연동형 온실은 적정한 자연 환기량을 취할 수 있다고 예측하였다. 측면창 바로 옆에 위치한 식물군과 벤취에 의해 측면창을 통한 자연적인 공기의 유입이 방해를 받기 때문에, 바람이 서쪽에서 불어올 때 식물군이 없을 때보다 평균 12%의 환기량의 감소 결과를 가져오는 것으로 예측되었다. 식물군은 공기의 유입창의 위치보다 약간 낮은 곳에 위치하여야 하며, 유입창을 너무 높이 설치하면 측면창을 통해 유입되는 공기는 가장 근접한 지붕창을 통해 대부분이 배출되는 것으로 예측되었다. 연동형 자연환기식 온실에 있어서 바람이 불어오는 쪽의 측면창들과 바람의 반대쪽을 향한 지붕창들의 혼합형이 가장 효율적인 온실 설계인 것으로 예측되었다.

이동제한장치는 내진분리된 교량 또는 교각에 소서인지가 발생하는 다경간연속교에 있어서 지진에 의한 교축방향 최대변위 및 잔류변위를 제한함에 있어 매우 효과적이다 교축방향의 수평변위가 이동제한장치에 의해 제한되는 경우 상부구조의 최대변위를 예측하기 위해서 비선셩동적해석을 설계에 실무적으로 사용하기에는 시간소요 및 해석상 어려움이 있다 본 연구에서는 등가탄성해석방법과 가속도-변위 스펙트럼을 이용한 간단한 이동제한장치 설계절차를 제시하였다 여기서 제시된 방법은 이동제한 장치의 설치위치 및 이격거리를 결정함에 있어 매우 효율적으로 사용할 수 있을 것이다.

온실의 동방위 및 지붕경사각, 구조물의 재원, 설치 지역의 위도 등이 단동형 유리 온실내의 직달 및 산란일사 투과에 미치는 효과를 분석하고자 컴퓨터 시뮬레이션 모형이 개발되었다. 개발된 모형은 년중 일수, 온실의 방위 및 설치된 지점의 윈도, 지붕경사각이 서로 다른 단동 및 연동 온실에 대하여 적용할 수 있다. 본 연구에서 수행된 온실의 동방위가 온실내의 직달 및 산란일사 투과율에 미치는 영향에서 얻어진 결과를 요약하면 다음과 같다. 1. 단동의 유리온실에서 계산된 산란일사의 투과율은 60.4％로서, 동방위에 무관하게 일정한 값을 갖는 것으로 나타났다. 2. 겨울철에 직달일사의 투과율은 동서동에서 67∼69％ 정도이고, 남북동의 경우 51∼55％ 정도로서 동서동에서 14∼16％ 정도 높게 나타났다. 3. 여름철에 직달일사의 투과율은 동서동에 서보다 남북동에서 높게 나타났다. 4. 직달일사의 투과율에 미치는 국내 지역간의 차이는 거의 없는 것으로 나타났다.

Subsea pipelines are exposed to several potential risks of damage due to wave, soil instability and other hazards. Structural failure of the steel pipelines will result in serious consequences such as release of transported hydrocarbons, pollution to the ocean environment and heavy costs due to repair. This paper examines the safety of subsea pipelines with free span which is one of high potential damages. The variation of an allowable length of static free span is examined for different boundary conditions and is given in a curve which is useful for the dsign of the subsea pipeline with a free span.

One of the most destructive forces around greenhouses is wind. Wind loads can be obtained by multiplying velocity pressure by dimensionless wind force coefficient. Generally, wind force coefficients can be determined by wind tunnel experiments. The wind force coefficient distribution on a single - span arched greenhouse was estimated using experimental data and compared with reported values from various countries. The results obtained are as follows : 1. The coefficients obtained from this study agree with the values proposed by G. L. Nelson except about 0.5 of difference in the middle region of roof section. This discrepancy is mainly attributed to the dissimilarity of experimental conditions (or wind tunnel test such as Reynolds number, type of terrain, surface roughness of model, location of the lapping and measuring methods. 2. Considering that the wind force coefficients are varied along the height of a wall at wind direction perpendicular to wall, structural analysis using subdivided wind force coefficient distribution is more resonable for wall. 3. It is recommendable that wind force coefficient distribution on a roof should take more subdivision than the existing four equal divisions for more accurate structural design. 4. Structural design using wind forces close to real values is more advantageous in safety and expense.

The wind pressure distributions were analyzed through the wind tunnel experiment to provide fundamental criteria for the structural design on the three-span arched house according to the wind directions. In order to investigate the wind force distribution, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated from the experimental data. The results obtained are as follows : 1. The variation of the wind force with the wind directions on the side walls was the greatest at the upwind edge of the walls. The change of pressure from the positive to the negative on the side walls occurred at the wind direction of 30˚ in the first house and 60˚ in the third house. 2. The maximum negative wind force along the length of the roof appeared at the length ratio of 0-0.2, when the wind directions were 90˚ in the first house, 60˚ in the second house and 30˚ in the third house. 3. The maximum negative wind force along the width of the roof appeared at the width ratio and the wind direction of 0.4 and 0˚ in the first house, 0.4-0.6 and 30˚ in the second house and 0.6 and 30˚ in the third house, respectively. 4. The maximum mean positive and negative wind forces occurred at the wind direction of 60˚ and 30˚, respectively, on the side walls of the first house, and the maximum mean negative wind force on the roof occurred at the wind direction of 30˚ in third house. 5. The maximum drag and lift forces occurred at the wind direction of 30˚, and the maximum lift force appeared in the third house. 6. The parts to be considered for the local wind forces were the edges of the walls, the edges of the x-direction of the roofs, and the locations of the width ratio of 0.4 of the first and third house and the center of the width of the second house for the y-direction of the roofs.

The wind pressure distributions were analyzed to provide fundamental criteria for the structural design on the two-span arched house according to the wind directions through the wind tunnel experiment. In order to investigate the wind force distributions, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated using the experimental data. The results obtained are as follows : 1. The variation of the wind force with wind directions on the side walls was the greatest at the upwind edge of the walls. 2. The maximum negative wind force along the length of the roof appeared at the upwind edge at the wind direction of 60˚. 3. The maximum negative wind force along the width of the roof appeared at the width ratio and wind direction of 0˚ and 0.4 in the first house and 0.6 and 30˚ in the second house, respectively. 4. The mean negative wind force on the side walls of the first house at the wind direction of 0˚ was far greater than that of the second house, and the maximum negative wind force on the roof occurred at the wind direction of 30˚. 5. The maximum lift force appeared on the second house at the wind direction of 30˚, but the lift force on the first house was far greater than that on the second house at the wind direction of 0˚. 6. The parts to be considered for the local wind forces were the edges of the walls, and the edges of the x-direction and the width ratio, 0.4 of the y-direction in the roofs.

The wind pressure distributions were analyzed to provide fundamental criteria for the structural design on e single-span arched house according to the wind directions through the wind tunnel experiment. In order to investigate the wind force distributions, the variation of the wind force coefficients, the mean wind force coefficients, the drag force coefficients and the lift force coefficients were estimated by using the experimental data. The results obtained are as follows: 1. When the wind direction was normal to the wall, the maximum positive wind pressure along the height of the wall occurred approximately at two-thirds of the wall height because of the effects of boundary layer flow. 2. When the wind direction was 30˚ to the wall, the maximum positive wind force occurred at the windward edge of the wall. When the wind direction was parallel to the wall, the maximum negative wind force occurred at the windward edge of the wall. 3. The maximum negative wind force along the width of the roof appeared around the width ratio, 0.4, and that along the length of the roof appeared around the length ratio, 0.5. 4. According to the results of the mean wind force coefficients analysis, the maximum negative wind force occurred on the roof at the wind direction of 30˚. 5. The wind forces at the wind direction of 30˚ instead of 0˚ are recommended in the structural design of supports for a house. 6. To prevent partial damage of a house structure by wind forces, the local wind forces should be considered to the structural design of a house.

In this study, strawberry cultivation environment in a greenhouse located in Jeonju was monitored and internal environmental parameters were analyzed. Temperature, humidity, RAD, and PPF sensors were installed to monitor environmental conditions in the test greenhouse. Data were collected every 10 minutes during four winter months from sensors placed across the greenhouse to assess its permeability and environmental uniformity. Temperature and humidity inside the greenhouse were relatively uniform with negligible deviations among the center, south, and north; however, it was judged that further analysis of gradients of these parameters f rom the east to t he w est of t he g reenhouse w ould b e needed. Both R AD (Total solar radiation) a nd P PF (Photosynthetic photon flux) had high values on the south and were low on the north and the reduction rate of these parameters was 54% and 61%, respectively, indicating that a significant amount of light could not be transmitted. This implied a significant decrease in the amount of light entering the greenhouse during winter. Therefore, it is concluded that environmental control devices and auxiliary lighting are needed to achieve uniform greenhouse environment for efficient strawberry cultivation.

In this study, nonlinear time history analysis was performed using OpenSEES, a general structural analysis program, after selecting the target bridges. The degree of damage was classified by the damage status definition proposed by Alkex(2008). The seismic evaluation of the target bridges was carried out through the analysis results.

In this study, flexural test of the 2-span arch deck specimen was conducted. In load-displacement test , a load carrying capacity of the specimen was approximately 2.4 times higher than the design ultimate load. Strain of Rebars was structurally stable until the maximum load was reached. The overall results showed that the specimens had excellent structural performance due to the structural advantages of the arch shape. Overall, the precasted arch deck is expected to be useful for long span PSC girder bridges as wide span decks..

This paper is to clarify the boundary condition of the joint connection in the multi-span vinyl greenhouse. It is carried out that experiments for the rotational stiffness of the joint connectors used in both the field and the guidelines of the greenhouse constructions.

본 연구에서는 만 2세 영아들의 언어발달과 언어표현력, 주의집중에 증강현실 그림책이 미치는 영향에 대해 알아보았다. G시에 소재한 어린이집 2곳 21명을 연구대상으로 선정하여 전통적 교수방법 집단, 증강현실 기반 교수방법 집단, 전통적 교수와 증강현실 기반 교수방법을 함께 사용한 집단으로 구분하였다. 실험은 4주간 16회를 실시하였으며 언어발달을 측정하기 위해 PRES를 사용하였고, 주의집중 분석을 위해 비디오 촬영을 실시하여 시간 표집법을 활용하였다. 연구 결과 전통적 교수와 증강현실 기반 교수방법을 함께 사용한 집단은 다른 교수 방법 집단에 비해 언어발달과 주의집중에서 유의한 향상을 보였으나, 표현력 향상에서는 유의한 차이가 나지 않았으며, 증강현실 기반 교수 방법만 받은 집단은 전통적 교수방법을 받은 집단과 유의한 차이가 나지 않았다. 본 연구의 결과를 보면 증강현실 기반을 적용한 언어발달 교육프로그램이 만 2세 영아의 언어발달과 주의집중 향상에 효과적으로 사용될 수 있음을 시사한다.

In the military and civil area a long-span temporary bridge for rapid construction is recently in demand. In this study the current state of technology and market is investigated as part of the planning research. The results show that the existing temporary bridges consist mainly of about 20m long span, and it takes 6 to 8 weeks to complete the construction. For an emergency restoration project in a short period a long-span temporary bridge for rapid construction requires the high-performance materials and the latest construction technology

기존 PSC I형 거더는 콘크리트의 자중, 정착구 및 긴장방식 등의 영향으로 장경간화의 적용성이 불리하였다. 이를 극복하기 위하여 PSC 거더의 복부에 중공을 도입하고 다단계 긴장을 도입함으로써 50∼70m 경간에 적용 가능한 중공 웨브 PSC I형 거더를 개발하고 실교량으로 시공하였다. 본 연구는 중공 웨브 PSC I형 거더교 현장에서 정적재하시험을 통하여 계측을 한 결과와 대상 구조물의 유한요소해석 결과를 바탕으로 비교, 분석하여 중공 웨브 장경간 PSC 거더교의 공용내하력과 안전성을 평가하였다. 본 교량의 정적재하시험과 수치해석 결과가 유사하게 나타났으며 중공 웨브 PSC I형 거더의 거동을 잘 모사하는 것으로 나타났다. 교량의 모든 거더는 설계 활하중 하에서 충분한 내하력을 확보하는 것으로 평가되었고 안전성을 확보하여 시공 결과의 적절성을 확인하였다.

The purpose of this paper is to clarify the boundary condition of the joint members in the multi-span greenhouse. It is carried out that experiments for the rotational stiffness of the joint members used in both the field and the standards of the greenhouse constructions.

In this study, the natural frequencies of long-span truss bridges with LRB were analyzed and compared. As a result of the mode analysis, a similar mode shape was shown irrespective of whether LRB was applied or not. The natural frequency analysis using the measurement data, the natural frequencies of the first to third transverse modes could not be analyzed due to the small dynamic response, and the natural frequency of the fourth vertical mode was analyzed to be similar to the mode analysis results. As a result of comparing the natural frequency of the vertical direction mode of 18 truss bridges in the past, the bridge with LRB was analyzed to have smaller natural frequency than the bridge without LBR.

케이블지지교량에서 케이블은 하중을 지지하는 주요 부재로, 케이블 장력은 교량의 건전성과 안전도 평가에 있어서 매우 중요한 변수이다. 케이블의 장력을 추정하는 기법으로, 로드셀 및 유압잭 등을 이용하여 케이블의 응력을 직접 측정하는 직접법과 케이블의 형상조건과 계측된 동특성을 활용하여 장력을 역산하는 진동법이 가장 많이 활용되고 있다. 최근 들어 케이블 내부 강재의 응력변화로 인하여 유발되는 자기장 변화를 탐지하는 EM 센서의 연구 및 활용이 증가하고 있다. 본 연구에서는 리프트오프 테스트, EM 센서 및 진동법(Vision-based System, Accelerometer)을 적용하여 장력을 측정하고 그 결과를 비교 분석하였다.

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 (6 mm → 9 mm) 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.