• 지질공학
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• 제30권3호
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• pp.279-288
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• 2020

샌드댐이란 하천의 횡단에 보 등을 설치하고 확보된 공간에 모래와 같은 투수성 재료와 물을 함께 채운 후, 공극내의 물을 저장하여 사용하기 위한 구조물이다. 주로 아프리카 케냐를 중심으로 많은 사례가 보고되고 있는 샌드댐에 관해 본 연구에서는 샌드댐의 구조적 안전과 취수량 증대를 위한 설계 방안을 제시하였다. 첫째, 샌드댐의 콘크리트 벽체의 안정성을 확보하기 위해 철근을 가시철근으로 연결, 시공의 편리함을 제시했다. 둘째, 지오텍스타일을 이용하여 증발을 45%에서 8%로 감소시킬 수 있었고 수평방향 투수배출량도 크게 줄일 수 있어 취수량은 기존대비 약 2.4배 증가되는 것을 알 수 있었다. 이 밖에도 수질개선을 위한 침사지 설계로 여과효율을 높였고, 토양수분장력계를 통한 모니터링 방법도 제시하였다.

• KIEAE Journal
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• 제14권6호
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• pp.59-64
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• 2014

The purpose of this study was suggested to establish of student housing by using shipping container. The research method are a study of shipping container and characteristics of student housing by using shipping container, compared typically student housing with student housing by using shipping container. Also there are planning though a case study of various planes and survey based on the student housing city in Amsterdam, Netherland, is called Keetwonen. It is a planning for housing unit to actual build at the part of land to devise master plan The 40FT(High Cube) Shipping Container housing unit are double occupancy room with toilet and balcony. The common areas are the kitchen, laundry facilities, conference room and lounge are available on the first floor with a lightweight steel frame construction method applied for obtain substantive utilization of the space. Considering into the type and scale of site shall be planning in the form of side corridor and central corridor, which is preferable to separate the interior space into two areas by a central corridor to secure personal privacy. Also, planning such as a separate exterior panel, color and landscape design to improve the external image of the container and block the solar radiation heat influx with a pitched roof. Allow 24 college students shall live at the site of Seongnae-dong, Gangdong-gu in Seoul, Korea (site area $330.9m^2$), including common facilities and a lounge with a building that has three stories above ground were established to build plans to target the actual land.

• Structural Engineering and Mechanics
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• 제50권6호
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• pp.755-772
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• 2014

A simplistic approach towards evaluation of complete load deflection response of Reinforced Concrete (RC) flexural members under post fire (residual) scenario is presented in this paper. The cross-section of the RC flexural member is divided into a number of sectors. Thermal analysis is performed to determine the temperature distribution across the section, for given fire duration. Temperature-dependent stress-strain curves for concrete and steel are then utilized to perform a moment-curvature analysis. The moment-curvature relationships are obtained for beams exposed to different fire durations. These are then utilized to obtain the load-deflection plots following pushover analysis. Moreover one of the important issues of modeling the initial stiffness giving due consideration to stiffness degradation due to material degradation and thermal cracking has also been addressed in a rational manner. The approach is straightforward and can be easily programmed in spreadsheets. The presented approach has been validated against the experiments, available in literature, on RC beam subjected to different fire durations viz. 1hr, 1.5hrs and 2hrs. Complete load-deflection curves have been obtained and compared with experimentally reported counterparts. The results also show a good match with the results obtained using more complicated approaches such as those involving Finite element (FE) modeling and conducting a transient thermal stress analysis. Further evaluation of the beams during fire (at elevated temperatures) was performed and a comparison of the mechanical behavior of RC beams under post fire and during fire scenarios is made. Detailed formulations, assumptions and step by step approach are reported in the paper. Due to the simplicity and ease of implementation, this approach can be used for evaluation of global performance of fire affected structures.

• Steel and Composite Structures
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• 제34권6호
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• pp.853-862
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• 2020

In recent years, due to the many advantages cable-stayed bridges have often constructed in medium and long span. These advantages can be listed as an aesthetically pleasing appearance, economic and easy construction, etc. The main structural elements of cable-stayed bridges are listed as deck, pylon, cables and foundation. Perhaps one of the most vital and expensive of these structural elements is stay-cables. Stay-cables ensure the allowable displacement and distribution of bending moments along the bridge deck with prestressing force. Therefore the optimum design of the stay-cables and prestressing force are very important in achieving the performance expected from the cable-stayed bridges. This paper aims to obtain the stay-cables size and prestressing force optimization of the cable-stayed bridge. For this purpose, single pylon and fan type cable configuration Manavgat Cable-Stayed Bridge was selected as an example. The three dimensional (3D) finite element model (FEM) of the bridge was created with SAP2000. Analysis of the 3D FEM of the bridge was conducted under the different combined effects of the self-weight of the structural element, prestressing force of stay-cable and live load. Stay-cable stress and deck displacement were taken into account as constraints for the optimization problem. To optimize this existing bridge a metaheuristic algorithm named Jaya was used in the optimization process. 3D FEM of the selected bridge was repeatedly analyzed by using Open Applicable Programming Interface (OAPI) properties of SAP2000. To carry out the optimization process the developed program which integrates the Jaya algorithm and the required codes for calling SAP2000 is coded in MATLAB. At the end of the study, the total weight of the stay-cables was reduced more than 40% according to existing stay cables under loads taken into account.

• Steel and Composite Structures
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• 제28권3호
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• pp.289-308
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• 2018

Numerous urban seismic vulnerability studies have recognized pounding as one of the main risks due to the restricted separation distance between neighboring structures. The pounding effects on the adjacent buildings could extend from slight non-structural to serious structural damage that could even head to a total collapse of buildings. Therefore, an assessment of the seismic pounding hazard to the adjacent buildings is superficial in future building code calibrations. Thus, this study targets are to draw useful recommendations and set up guidelines for potential pounding damage evaluation for code calibration through a numerical simulation approach for the evaluation of the pounding risks on adjacent buildings. A numerical simulation is formulated to estimate the seismic pounding effects on the seismic response demands of adjacent buildings for different design parameters that include: number of stories, separation distances; alignment configurations, and then compared with nominal model without pounding. Based on the obtained results, it has been concluded that the severity of the pounding effects depends on the dynamic characteristics of the adjacent buildings and the input excitation characteristics, and whether the building is exposed to one or two-sided impacts. Seismic pounding among adjacent buildings produces greater acceleration and shear force response demands at different story levels compared to the no pounding case response demands.

• 한국구조물진단유지관리공학회 논문집
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• 제17권1호
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• pp.133-142
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• 2013

연결보를 가진 전단벽 시스템은 벽체의 개별 강성을 합산한 것보다 훨씬 큰 강성을 확보할 수 있기 때문에 효율적인 횡력저항시스템으로서 40층 이하의 중 고층 건물에 널리 적용되고 있다. 일반적으로 사용되는 철근콘크리트 연결보는 철근배근이 복잡해 시공성이 저하되고, 철골연결보의 경우에는 과도한 스티프너의 사용으로 인해 경제성이 저하된다는 단점을 가지고 있다. 따라서, 이 연구에서는 철근콘크리트와 철골부재를 합성하여 시공성 및 경제성을 개선하고 단면크기를 줄일 수 있는 불연속웨브가 적용된 프리스트레스트 합성연결보를 개발하였다. 개발한 프리스트레스트 합성 연결보의 구조적인 성능을 검증하기 위해서 전단철근비를 주요 변수로 두 개의 실험체를 제작하여 반복하중실험을 수행하였으며, 실험결과는 제안된 연결보의 내진성능을 검증하였다.

• 대한기계학회논문집A
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• 제40권3호
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• pp.245-252
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• 2016

본 논문은 벤드(bend)부의 노후 문제를 경감시키기 위한 대안으로 폼패드를 없앤 이중보온관의 형상 설계를 제안하였다. 전 관경에 대해 유한요소해석을 수행하였으며, 이를 토대로 전단제어링 형상을 결정하였다. 제안된 전단제어링 사양 강화이형관에 대한 현장 시공 시험은 진행하였으며, 온도와 응력 데이터를 취득 및 분석하였다. 강화이형관의 제작과 현장 시범시공을 통하여 강화이형관이 폼패드를 시공하지 않으면서도 강관의 열응력이 허용치 기준내에 있음을 확인하였다. 특히 보온재의 전단강도가 강화되어 폼패드를 적용한 기존 벤드보다 낮은 최대 전단응력이 발생함을 확인함으로써, 강화이형관 적용에 따른 구조 안전성 향상 효과를 확인하였다.

• 한국농공학회논문집
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• 제62권1호
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• pp.117-126
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• 2020

The area of facility horticulture in Korea is increasing rapidly, the single-span pipe house which uses galvanized steel pipe as the main rafters occupies 78.7% of the facility area. Lightweight structures such as the single-span pipe house are vulnerable to meteorological disasters such as strong winds, economic losses of the state, local governments and farmers are continuing as construction does not meet the design standards. In order to minimize economic losses in the horticultural specialty facilities sector, the Rural Development Administration has been operating the horticultural disaster resilient standard for horticultural specialty facilities since April 2007. The only standard for the pipe connector is the disaster resilient standard, there is no standard for the uplift capacity of the house pipe foundation and the research on it is also insufficient. The purpose of this study is to investigate the characteristics of uplift capacity according to the foundation type, compaction ratio and embedded depth through soil box test. The results of the maximum uplift capacity according to the type, compaction ratio and embedded depth can be used as the basic data for the basic design of the pipe house conforming to the disaster resilient standard. Due to the limitation of soil box test, it may be different from the behavior of pipe house installed on site. In the future, the field test and the actual pipe house should be made and supplemented by comparing this result with the field test values.

• 한국구조물진단유지관리공학회 논문집
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• 제18권1호
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• pp.48-58
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• 2014

본 연구에서는 1992년 도로교설계기준의 내진설계도입 이전 규정에 따라 설계, 시공된 교각의 축소 모델을 실험체로 제작하여 원형기둥의 변위비에 따른 횡하중을 변위제어 방식으로 입력하여 준정적 방법을 통해 실험을 실시하였다. 연구에 적용한 보강재는 성능을 향상시킨 무기계 합금강인 Helical Bar로써 원형기둥 외부에 보강 후 실내실험을 통하여 파괴거동, 하중-변위 관계, 연성도 평가 및 에너지 평가를 실시하였다. 실험변수로는 위험단면 내에서 나선으로 보강한 보강재의 단면력의 크기와 나선보강의 간격, 보강형태로 두었으며, 준정적 실험을 통해 보강성능의 차이와 효과를 확인하였다. 실험결과 보강대상 부재의 성능에 따라 적절한 보강재의 단면력 크기결정과 보강간격 및 형식의 선정이 필요하며 기계적 보강재뿐만 아니라 고강도 콘크리트 피복으로의 치환으로도 보강성능이 향상됨을 확인할 수 있었다.

• 한국구조물진단유지관리공학회 논문집
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• 제16권4호
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• pp.116-121
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• 2012

박스형 전력구와 같은 지하구조물의 건설은 점점 증가하고 있는 추세이며, 지상구조물에 비해 보수 및 재시공이 어려운 지하구조물의 수명 연장은 매우 중요한 문제로 대두되고 있다. 콘크리트 구조물에서 이산화탄소에 노출된 환경에서 발생하는 탄산화는 콘크리트 내부의 철근을 부식시켜 수명을 저하시키는 요인이 된다. 이 연구에서는 도심지의 두 박스형 전력구에 대한 탄산화 깊이를 측정하여 탄산화에 의한 내구성을 평가하고, 탄산화 측정결과를 바탕으로 몬테카를로 시뮬레이션 기법을 통해 철근의 부식시기를 예측하였다. 탄산화에 의한 기존 도심지의 두 박스형 전력구의 사용수명은 250년 이상으로 예측되었다.