• Structural Engineering and Mechanics
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• 제25권4호
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• pp.445-466
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• 2007

As the LNG (Liquefied Natural Gas) tank contains cryogenic liquid, realistic thermal analyses are of a primary importance for a successful design. The structural details of the LNG tank are so complicated that some strategies are necessary to reasonably predict its temperature distribution. The proposed heat transfer model can consider the beneficial effects of insulation layers and a suspended deck on temperature distribution of the outer concrete tank against cryogenic conditions simply by the boundary conditions of the outer tank model. To this aim, the equilibrium condition or heat balance in a steady state is utilized in a various way, and some aspects of heat transfer via conduction, convection and radiation are implemented as necessary. Overall thermal analysis procedures for the LNG tank are revisited to examine some unjustifiable assumptions of conventional analyses. Concrete and insulation properties under cryogenic condition and a reasonable conversion procedure of the temperature-induced nonlinear stress into the section forces are discussed. Numerical examples are presented to verify the proposed schemes in predicting the actual temperature and stress distributions of the tank as affected by the cryogenic LNG for the cases of normal operation and leakage from the inner steel tank. It is expected that the proposed schemes enable a designer to readily detect the effects of insulation layers and a suspended deck and, therefore, can be employed as a useful and consistent tool to evaluate the thermal effect in a design stage of an LNG tank as well as in a detailed analysis.

• 교육시설 논문지
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• 제23권6호
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• pp.27-34
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• 2016

Although the scale and number of university facilities have increased, the maintenance of these facilities has not been efficient as maintenance costs incurred during facility operation periods, as well as management time, have not been sufficiently considered. In this study, the maintenance record data of national universities was compared and analyzed to analyze factors that incur maintenance costs according to the uses and costs of the facilities. According to the results, the number of cases of maintenance and repair work for basic educational facilities was shown to be the largest, accounting for 79%. The number of maintenance and repair work occurred according to work type was examined. According to the results, the highest ratio of maintenance and repair work occurred in the field of construction, specifically, the maintenance costs required for facility supplementation accounted for the highest ratio. Maintenance costs per unit area decreased over time in the newer university facilities, while showing a tendency to increase in older university facilities. However, there were cases where maintenance costs did not show any trends due to factors such as the limited maintenance budgets owing to the characteristics of public service facilities and facilities in the stage of deterioration or destruction after the stage of stabilization. This study is considered to be helpful for efficient university facility maintenance plans and budget calculations.

• 한국CDE학회논문집
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• 제21권2호
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• pp.130-142
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• 2016

BIM library, as a systematic collection of BIM objects where the building information is stored, is a vital factor to construct the BIM based work environment. However, construction business is faced the problems relating BIM library such as the absence of the standard for establishing BIM library, the discontinuity of BIM library's compatibility and the lack of practice applicable BIM library. These problems cause the decreasing work efficiency and the recreating BIM model, by delivering inefficient information required in each stage and application field. The purpose of this study is to suggest the integrated management system for property information of BIM library in order to minimize the reworking and to manage information of each stage and application field when exchanging and sharing information. To achieve this, the BIM information classification, the criteria of property requirements for information exchange in BIM application field and the BIM library management system are developed. This study could contributes to ensuring the reliability and accuracy of results of BIM based analysis and to enhancing the speed of business process with sharing and exchanging building information utilizing a single BIM model.

• 환경영향평가
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• 제11권3호
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• pp.129-143
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• 2002

This study was executed environmental assessment to determine whether or not the national landuse planning change on the reserved area for a rope way in the ice valley(Eoreurngol) of Miryang. The selected survery area is $1,633,442m^2$ and assessed with flora, actual vegetation, degree of green naturality(DGN), sere stage and wild birds. The flora was summarized as 132 taxa which is 90 genera, 117 species, 12 varieties and 3 forms. The actual vegetation was classified 24 types and nature forests like Quercus and deciduous-broad leaf community was distrubuted broadly. Especially Quercus and deciduous-broadleaf communities were assessed high rarity value in Miryang. From the analysis of DGN, it were found out that DGN 8 is 72.5% and DGN 9 is 3.9%. At the analysis of sere stage, the communities were divided 4 with Quercus mongolica, Pinus densiflora, Carpinus laxiflora and deciduous-broadleaf community. Wildbirds was observated as 30 species and 161 ea and Aix galericulata (natural monument no. 327) especially inhabited there. From the above nature ecosystem assessment, the survey area has high quality naturalness, so it was turned out that a rope way construction might be not suitable in survery area.

• 한국건설관리학회논문집
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• 제23권6호
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• pp.101-110
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• 2022

최근 세계 건설시장은 2025년까지 연 평균 4.8%씩 성장할 것으로 예상하고 있으며, 이에 따른 해외건설 리스크도 증가할 것으로 전망하고 있다. 특히, 국내 건설업체들은 EPC(Engineering, Procurement, Construction)/Turnkey 사업에 집중적으로 참여하였지만, 계약적 리스크에 대응하지 못한 결과, 2013년부터 수조원대의 해외사업 손실을 입은 경험이 있다. 그럼에도 불구하고, 지금까지 EPC/Turnkey의 계약적 핵심 리스크 세부조항 도출에 대한 연구는 많지 않았다. 따라서 본 연구에서는 국제컨설팅엔지니어링연맹(FIDIC)에서 발행한 2017년 Silver Book 계약조건을 대상으로 핵심 리스크 세부조항을 연구하였다. 이를 위해서 국제건설계약 경험이 10년 이상인 30인의 전문가를 패널로 구성하여 FIDIC Silver Book 21개 조항 170개 세부조항을 델파이 설문조사를 실시하여 62개의 주요 리스크 세부조항을 도출하였다. 또한, 최종적으로 FMEA(Failure Mode and Effect Analysis)기법을 활용하여 RPN(Risk Priority Number)을 산정하였으며, Critical Risk 범위에 속하는 25개의 핵심 리스크 세부조항을 도출하였다. 본 연구 결과를 통하여 실무관점에서는 해외건설사업에서 입찰 및 계약체결 단계에서 주의 깊게 검토해야 할 계약조항들에 대해 참조할 수 있게 해주고, 학문관점에서는 해외건설 EPC/Turnkey 사업에서 사용되는 계약분야에 대해 어떤 방식으로 연구해야 할지의 방향성과 기초적 지식을 제공하고 있다.

• 한국CDE학회논문집
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• 제20권2호
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• pp.124-132
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• 2015

When Building Information Modeling (BIM) was introduced at the early stage, it was only utilized as a three-dimensional visualization tool. Nowadays, however, BIM is being studied for increasing design productivity and managing enormous information on building life cycle. One of the representative research is developing 'common prototype BIM libraries'. BIM data made of common prototype libraries should be utilized in various ways, quantity takeoff, code checking, energy analysis and so on. However, common prototype BIM libraries are not enough to estimate accurate cost. For example, composite wall libraries should be divided into several single objects, wall structure and finishes, for the quantity takeoff and construction cost calculation. In this paper, we are suggesting an automated division algorithm of composite wall and developing a system prototype for it. This study is expected to reduce extra modeling work and contribute to fast and accurate cost calculation in the construction.

• 한국건축시공학회지
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• 제8권1호
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• pp.83-90
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• 2008

The reinforcing steel process is composed of the development of placing drawing, cutting and bending, and the placement and fabrication of the reinforcement, and is participated in by reinforcement detailer, the fabricator and placer. Because the reinforcing steel process-from estimating and rebar detailing, to production, material tracking, billing, and general accounting-is conducted by many participant, reinforcement details based on building code and reinforcing bar detailing standards are essential. The process, however, holds some problems. Building code has been revised recently, and the utilization of placing drawings was proved to be low, and the reinforcement estimating in early stage of the process is below what is required for placement. Therefore, in this study, a survey was conducted to the reinforcement detailer, the fabricator and placer of domestic construction industry. According to the analysis of the survey, the reinforcement details on site was not standardized. The improvement in reinforcing steel detailing standards was sought by analyzing the results of the survey including reinforcement constructability.

• 한국건축시공학회지
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• 제12권3호
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• pp.291-298
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• 2012

For cold weather concreting, frost damage at early age is generated in the concrete, and problems such as delaying of setting and hardening and lowering of strength manifestation emerge due to the low outside air temperature at the early stage of pouring, making the selection of an effective curing method critically important. Unfortunately, the tent sheet currently used as the curing film for heating insulation at work sites, not only has the problems of inferior permeability and extremely deteriorated airtightness, but a phenomenon of continuous fracturing is also generated along the direction of fabric of the material itself, presenting difficult circumstances for maintaining adequate curing temperature. The aim of this study was to develop an improved bubble sheet type curing film for heating insulation of cold weather concrete by combining mesh-tarpaulin, which has excellent tension properties, with bubble sheet, which offers superior insulation performance. The analysis showed that the improved curing film in which BBS1 is stacked to MT was a suitable replacement for curing films currently in use, as it has better permeability, tension property, and insulation performance than the T type film used at work sites today.

• 한국건설관리학회논문집
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• 제7권1호
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• pp.55-63
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• 2006

건설프로젝트에서 설계VE는 그 적용효과가 크므로 체계적 절차에 따른 분석이 요구되며, 그 중 가장 중요한 부분은 우수한 아이디어를 창출하기 위한 창조 단계이다. 하지만 현행 아이디어 창출 방법인 브레인스토밍, 델파이 등을 비롯한 기법들은 아이디어 창출에 많은 시간이 소요되고 우수한 아이디어를 고안한다는 것이 쉽지가 않다. 이는 설계VE에 참가하는 대부분의 전문가들이 아이디 어 창출의 효율성이 떨어지는 방법으로 접근하는데 그 원인이 있는 것으로 판단된다. 이에 본 연구에서는 VE의 효율적 수행을 위한 방법으로 창의적 아이디어 발상기법인 ASIT(Advanced Systematic Inventive Thinking) 적용을 제안하고자 한다. ASIT는 아이디어 고안을 체계적 절차에 따라 수행하도록 지원하여 단기간에 효과적 아이디어를 창출하는데 기여할 것으로 판단된다.

• 한국지열·수열에너지학회논문집
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• 제9권1호
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• pp.15-19
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• 2013

In this Study, effect of core position, area ratio and orientation of building on energy load is examined using TRNSYS17. This parameters are major parameters of the conceptual design stage. Reference model is square floor plan($1,444m^2$), centered core and 29% core area ratio. As the results, without considering the building orientation, the annual heating load of central building with 1:1 area ratio is lowest ($10.33kWh/m^2yr$) and the annual cooling load of off-central building with 1:1 area ratio is lowest ($59.27kWh/m^2yr$). As area ratio is bigger, cooling load is lower and heating load is higher. But if we consider building orientation, orders of heating load and cooling load are changed for area ratio and orientation.