• Earthquakes and Structures
• /
• 제8권3호
• /
• pp.511-539
• /
• 2015

The main objective of this study is to analytically investigate the effectiveness of different strengthening solutions in upgrading the seismic performance of existing reinforced concrete (RC) buildings in Nepal. For this, four building models with different structural configurations and detailing were considered. Three possible rehabilitation solutions were studied, namely: (a) RC shear wall, (b) steel bracing, and (c) RC jacketing for all of the studied buildings. A numerical analysis was conducted with adaptive pushover and dynamic time history analysis. Seismic performance enhancement of the studied buildings was evaluated in terms of demand capacity ratio of the RC elements, capacity curve, inter-storey drift, energy dissipation capacity and moment curvature demand of the structures. Finally, the seismic safety assessment was performed based on standard drift limits, showing that retrofitting solutions significantly improved the seismic performance of existing buildings in Nepal.

• Earthquakes and Structures
• /
• 제18권3호
• /
• pp.391-405
• /
• 2020

The use of passive energy dissipation devices has been widely used in the construction industry to minimize the probability of damage occurred under intense ground motion. In this study, collapse margin ratio (CMR) and fragility curves are the main parameters in the assessment to characterize the collapse safety of the structures. The assessment is done on three types of RC frame structures, incorporating three types of dampers, viscoelastic, friction, and BRB dampers. The Incremental dynamic analyses (IDA) were performed by simulating an array of 20 strong ground motion (SGM) records considering both far-field and near-field seismic scenarios that were followed by fragility curves. With respect to far-field ground motion records, the CMR values of the selected frames indicate to be higher and reachable to safety margin more than those under near-field ground motion records that introduce a high devastating impact on the structures compared to far-field excitations. This implies that the near field impact affects the ground movements at the site by attenuation the direction and causing high-frequency filtration. Besides that, the results show that the viscoelastic damper gives better performance for the structures in terms of reducing the damages compared to the other energy dissipation devices during earthquakes.

• 환경영향평가
• /
• 제21권6호
• /
• pp.927-939
• /
• 2012

Cool roofs are currently being emerged as one of important mechanism to save energy in relation to the building. Although green roof has already gained nation-wide recognition as a typical method of energy saving in the roof, this approach did not provide a realistic evidence that is economically feasible in terms of installation cost. This research is primarily intended to compare installation cost between the two techniques. This research proposes a comparative evaluation framework in a more objective and quantitative way for an installation cost between the two techniques. Kyungpook National University (KNU) was selected as a survey objective and an exhaustive and realistic comparison of installation cost between the two techniques was conducted, based on Life Cycle Cost analysis (initial investment cost, maintenance cost, dismantling and waste disposal expense). It was possible to identify that installation cost of cool roofs is 4.7 times cheaper than that of green roof. Also present value based on probabilistic approach was identified as 0.25 (4.95) higher than the installation cost on the assumption of constant price and interest. It is expected that much more installation cost for the large scale green roof will be required since small-size green roof selected as a survey objective in this study could be operated under less initial installation and maintenance condition.

• Journal of Radiation Protection and Research
• /
• 제20권1호
• /
• pp.53-64
• /
• 1995

월성 원자력발전소 2,3,4 호기의 보조건물 주요 지역에서 냉각재 다량상h7사고 (large LOCA) 후의 방사선장을 평가하였다. 핵분열 생성물의 총량은 ORIGEN2 코드를 사용하여 계산하였고 선원항은 2중고장 시나리오, 즉 LOCA 사고후 비상노심냉각 (ECC) 계통의 고장이 결부된 사고시의 방사능 방출에 근거하였다. 원자로건물, 보조건물 및 ECC 계통의 구조모형을 QAD-CG 모델에 포함하여 계산하였다. 사고시점부터 90일 경과시까지 시간대 별로 선량율과 누적선량을 계산하였다. 결과적으로, 연속출입이 요구되는 중요지역에서의 방사선장은 충분히 낮은 것으로 평가되었다. 그러나, 일부구역에서는 제한적인 출입을 허용할 정도로 상대적으로 높은 방사선장을 나타내었다.

• Journal of Construction Engineering and Project Management
• /
• 제2권4호
• /
• pp.20-24
• /
• 2012

Construction while being an economic activity that provides facilities and infrastructure, it is beneficial to man in some aspects and detrimental in others. There have been environmental concerns related to construction activities globally which mainly focus on atmospheric emissions, depletion of natural resources and energy issues. This study was carried out to assess the impacts of construction activities on the environment in Iganga Municipality and to propose measures for their mitigation. The methodology included: review of relevant literature, observations of the general environmental effects of construction activities, focus groups and a survey conducted among construction industry role players to determine their perceptions and opinions regarding environmental impact of construction activities. The collected data was presented in tabular form and analysed by description of responses to questions. The study revealed that forests were the most greatly degraded due to high demand of timber for construction followed by wetlands degradation. The findings of this study will be useful to architects, designers and builders in order to carefully design buildings and other infrastructure that are environmentally friendly and sustainable. Construction materials and their mode of acquisition are harmful threats to the environment. There is need to reduce the consumption of these materials through recycling and reusing wastes to reduce on waste generation, use of virgin materials and the subsequent waste of energy used in new material production.

• 분석과학
• /
• 제31권4호
• /
• pp.149-160
• /
• 2018

국내에서는 많은 수의 친환경 및 건강 증진을 목적으로 하는 기능성 생활제품이 생산되고 있으며 이러한 제품 제조 시 원료물질에 존재하는 모나자이트, 토르말린 등 방사능 농도가 높은 물질이 가공제품 내에 함께 유입 될 수 있어 원료물질과 함께 국민 생활과 밀접한 가공제품의 관리가 필수적이다. 이를 위해서 정확한 방사능 농도 분석 자료 및 유효성이 검증된 분석방법의 이용 및 개발이 필수적이다. 본 연구에서는 천연방사성 물질의 신속 스크리닝을 위한 ED-XRF 분석법과 정밀분석의 목적으로 ICP-MS를 이용하여 실내 건축자재 및 생활제품 내의 천연방사성핵종($^{238}U$, $^{232}Th$)의 농도를 정량분석하고 비교 및 평가하였다. 타일, 시멘트, 페인트, 벽지, 석고보드 등 총 47 종의 실내 건축자재와 건강제품, 섬유제품, 광물질 등 총 47 종의 생활 가공제품의 실제시료를 분석한 결과, ED-XRF 및 ICP-MS의 결과값은 전체적으로 1:1의 선형성을 보였으며 ED-XRF를 이용한 신속 스크리닝의 적용성과 ICP-MS를 이용한 정량분석법의 유효성을 확인하였다. 한편, 가공제품 중의 $^{238}U$, $^{232}Th$ 방사능 농도는 생활제품에 비해서 건축자재에서 상대적으로 매우 낮은 수준이었으며 특히 생활제품은 47 개 중 6 개의 제품이 원료물질의 관리기준치($1.0Bq{\cdot}g^{-1}$)를 초과(최대 $8.2Bq{\cdot}g^{-1}$)하는 것으로 평가되었다.

• 한국태양에너지학회 논문집
• /
• 제31권2호
• /
• pp.47-52
• /
• 2011

Currently, Exterior wall's U-value about building envelope is 0.36 W/$m^2K$(Central Region), but window's one is 2.1 W/$m^2K$ according to air gap of glazing, filling gas, coating and type of windows. The door"s one is 1.6~5.5 W/$m^2{\cdot}K$ depending on material and configuration of door. As such, energy loss per unit of door is considerably larger like windows. The door for the recognition was relatively low because energy loss through the door is relatively small compared to window area. In this paper, thermal performance was analyzed through simulation targeting the door which has thermal break that can improve the insulation performance and doesn't have one. As a results of simulations, case1 was calculated as the average of 1.63 w/m2k and case 2 was calculated as the average of 4.14 w/m2k. The thermal performance of door depends on the type and condition of insulations. As a results of final simulations, Case1 was calculated as 1.06 w/m2k and Case2 was calculated as 1.27 w/m2k. As a results of the experiments, thermal performance of case 1 was measured as 1.28 w/m2k. Error between experiments and simulations is considered problems encountered when creating the samples. The effect of door frame on the overall thermal performance is slight because it's a small proportion of the door frame.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 추계학술대회 초록집
• /
• pp.59.2-59.2
• /
• 2011

This study presents a new method for coupling ArcGIS (popular GIS software) with TRaNsient SYstems Simulation (TRNSYS, reference software for researchers and engineers around the world) to use capabilities of the 4 and 5-parameter PV array performance models within the ArcGIS environment. Using the validated and industry-proven solar energy simulation models implemented in TRNSYS and other built-in ArcGIS functionalities, dynamic characteristics of distributed PV potential in terms of hourly, daily or monthly power outputs can be investigated with considerations of diverse options in selecting and mounting PV panels. In addition, the proposed method allows users to complete entire procedures in a single framework (i.e., a preliminary site survey using 3D building models, shading analyses to investigate usable rooftop areas with considerations of different sizes and shapes of buildings, dynamic energy simulation to examine the performances of various PV systems, visualization of the simulation results to understand spatially and temporally distributed patterns of PV potential). Therefore tedious tasks for data conversion among multiple softwares can be significantly reduced or eliminated. While the programming environment of TRNSYS is proprietary, the redistributable executable, simulation kernel and simulation engine of TRNSYS can be freely distributed to end-users. Therefore, GIS users who do not have a license of TRNSYS can also use the functionalities of solar energy simulation models within ArcGIS.

• 설비공학논문집
• /
• 제14권11호
• /
• pp.972-980
• /
• 2002

This work is aimed at estimating the effects of various factors on the energy consumption of Korean-style apartment houses using TRNSYS. The factors considered here include the nominal size of floor area, type of remodeling, azimuth, sidewall insulation, and window type. Based on some assumptions, an actual apartment house is simplified into a model that is used for thermal load calculations. The simplified model is validated by showing a good agreement with the actual one in the predicted result. Remodeling balconies into unconditioned buffer spaces yields a favorable thermal performance in comparison with the original type regardless of the nominal size. Incorporating balconies into a conditioned indoor space leads to sharp increases in thermal loads, which must be avoided in view of energy conservation as well as structural problem. A quantitative assessment on the azimuthal effect indicates that the heating energy can be saved up to 16％ by taking the south or southeast direction. Reduction in the heating load with enhancing the sidewall insulation is gradual, so that a cost-effectiveness analysis may be needed when amending the regulations concerned. Glazing appears to significantly affect the heat transfer through window. A typical case illustrates that the heating load is decreased about 25％ by simply adopting triple glazing instead of double glazing.

• Nuclear Engineering and Technology
• /
• 제55권6호
• /
• pp.1959-1965
• /
• 2023

The objective of this study was the establishment of clearance method that can ensure radiological safety and reasonably minimize radioactive waste when demolishing contaminated buildings at KRR-1&2. By reviewing Korean and international laws related to decommissioning, the method for clearance of contaminated buildings presented in this study is to first decontaminate the building and then conduct a radiological safety assessment, such as measuring residual radioactivity, to determine whether the radiation dose criteria for clearance are satisfied. The measurement results meet the radiation dose criteria, the contaminated buildings are regarded as clearance and can be converted into the general buildings. The demolition of the cleared buildings is carried out using conventional demolition methods. The waste generated during the demolition is classified as general construction waste and is disposed of according to relevant laws. The proposed method significantly optimized the number of samples analyzed and reduced the time and cost associated with the decommissioning. The established method will be applied to the ongoing decommissioning of contaminated buildings at KRR-1&2, and its application will be verified by regulatory bodies. The study suggests that this method could be used for the decommissioning of contaminated buildings at other Korean nuclear facilities in the future.