• Journal of the Korea Institute of Building Construction
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• v.10 no.1
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• pp.39-47
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• 2010

Fly ash has the advantages, among others, of improving the characteristics of concrete, reducing the price of concrete products, improving the durability, and reducing hydration heat. However, when added in mass, it leads to problems such as insufficient concrete intensity, increase of AE use, and others, resulting in a limitation of the use volume. Therefore, this study is undertaken to solve the problems associated with themass use of fly ash through the high concentration powder ($4000{\sim}8000cm^2/g$) of fly ash, curing method, the addition of an alkali stimulation agent and others for the purpose of increasing the added value of the fly ash. The research showed that the intensity manifestation has an outstanding status, with the hydrates reaching a very stable condition if the rate of addition of a stimulation agent is appropriately used with the heightening of the fineness of the fly ash in the temperature range of $40^{\circ}C$, and if the applicable study is continued, it is likely to result ineffective value generation on the massive replacement of fly ash.

• Journal of the Korea Institute of Building Construction
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• v.19 no.1
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• pp.47-57
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• 2019

The purpose of this study is to evaluate the improvement effect of adhesion in tension and flexure of polymer cement mortars that have widely used as a repair-reinforcement material in construction field according to adding of polymer dispersions depending on different three types test methods. From the test results, the adhesion performance is improved with a raise in polymer-cement ratio irrespective of the type of polymer. The maximums of A type adhesion in tension, B type adhesion in tension and adhesion in flexure show 1.90 times, 2.17 times and 1.83 times, respectively that of plain cement mortar. The relative strength ratios, B type adhesion in tension and adhesion in flexure of polymer cement mortars to tensile and flexural strengths of plain mortar respectively are in ranges of 50.1% to 101.7% and 73.8% to 132.9% compared to 46.9% of plain mortar. It is apparent that polymer cement mortars with EVA and polymer cement ratios of 10% to 15% are recommended considering its adhesion performance and cost as a repair-reinforcement material in construction field.

• Journal of the Korea Institute of Building Construction
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• v.23 no.4
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• pp.369-380
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• 2023

The incorporation of innovative technology systems into domestic construction practices has catalyzed an organic evolution of the industry, significantly enhancing the level of domestic construction technology and intensifying competitiveness. In particular, the on-site implementation of these groundbreaking construction technologies has proven effective in diminishing construction costs and accelerating project timelines. Nevertheless, despite a period of 33 years since the inception of this new construction technology system, both the volume of designated construction technologies and their practical application on construction sites remain static. As a consequence, this study introduces a strategic plan to dissect and overcome the barriers faced in the adoption of new construction technology across a multitude of sectors. The chief outcomes encompass the inception of a new construction technology utilization surveillance system, an assessment of distinct technologies, refinement of the post-evaluation system, and the creation of a new technology market system. This systematic enhancement is anticipated to foster the practical application of new construction technologies within the industry.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.2
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• pp.185-190
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• 2006

This study carried out an evaluation of an oil tank that was defective in structure. This paper is divided into two sections which are analysis for the working process and suggestion for improving on the structure of the oil tank. As stated above, it has three major factors as to an improvement, such as the life cycle of structure (especially physical life cycle), and the many factors related to the duration years of the oil tank and analysis result. Based on this study, the improvement of oil tank was established. For example, the ground investigation needs before design and construction of oil tank, and constructing the oil tank by retaining wall type tank is good for maintenance. Also, it is important that the system for drainage is related to maintenance.

• Korean Journal of Construction Engineering and Management
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• v.12 no.1
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• pp.62-72
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• 2011

Currently, The failure of construction project is increasing to be caused by a changing construction environment. According to this circumstances, Researches of project success factors affecting performance have been presented to develop strategies for efficient construction project management in the construction industry. However, Conducting efficient construction project management is difficult because project manager could not know which project success factors can be improved or not. Especially, although the project characteristics were derived the level of difficulty for performance, research of the project characteristics which could not be improved as influence factor to performance is lacking. Therefore, This paper has developed the Performance Predicting System(PPS) with Fuzzy set theory to establish. PPS has been developed to establish efficient project management strategies and to save time and effort. As Contractor inputs the project characteristics, PPS can predict the level of difficulty of performance.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.2183-2185
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• 2011

전기 철도시스템에는 많느 궤환 전류가 흐르고 이로 인하여 제어시스템의 오동작과 인명 손상의 위험이 따른다. 본 연구에서는 대용량의 노이즈 및 서지 전류로부터 인명과 설비를 보호를 위한 대책으로 역사간의 접지 매설 지선을 할용하여 안전성을 개선하기 위한 방안을 연구하였다. 본 논문에서는 역사내 전체의 통합접지를 구성하여 등 전위를 확보하고, 역사간 매설지선과 일정 간격 접지봉으로 시공함으로서 전기철도 선로에서 지락사고 및 낙뢰등에 대한 위험전압을 감소시킬 수 있는 방안을 시뮬레이션하여 확인하였다.

• Cement
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• s.59
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• pp.26-38
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• 1975

본고는 일본 소야전Cement Co.의 중앙연구소주임연구원으로 있는 Hiroshi Uckikawa 박사가 일본의 Ceramics-Japan지(''74.10)에 기고한 것을 번역한 것으로서 그 내용에 의한 목차는 다음과 같다. 즉 근년에 개발된 새로운 cement로서는 1. 속경성 cement 2) 초속경 cement(jet cement, regulated set cement) 2) Alumina cement 3) 초조강 cement 4) 급경 cement 2. 고강도 cement 3. 내구성 cement 1) 내유산균 cement 2) 내화 cement (1) alumina cement 계 (2) barium, strontium 계 cement (3) 인산 aluminium 계 cement 3) 방사선차폐용 cement 4. 팽창 cement 1) alumine 산, 유산 calcium 수화물의 생성에 의한 것 2) 수산화 calcium의 생성에 의한 것 3) 기타 5. 시공성을 개선한 cement (예: 유정용 cement, 도장용 cement) 등이 있다. 머지 않아 우리나라에서도 cement 품종의 다양화가 필연적인 문제로 대두될 것을 생각하여 본번역문이 다소나마 도움이 되기를 바란다.

• Proceedings of the KIEE Conference
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• 2015.07a
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• pp.1473-1474
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• 2015

0.6/1kV CV 전선은 저압 지중선용 또는 가공저압배전선로 및 복잡한 인입선 정비를 위한 가공인입 간선용으로 사용한다. CV 전선은 내열성이 높고 내약품성 및 내유성이 우수하며 시공에 따른 미관성이 우수하여 가공인입용으로 적용이 증가하는 추세이다.[10] 가공인입용 CV 전선내 전압선과 중성선 단면적은 동일하게 제작, 현장에 적용되고 있다. 본 논문에서는 3상4선식 0.6/1kV CV 전선을 가공인입선에 적용시 중성선의 단면적을 전압선 단면적보다 평균 47%를 축소 개발, 현장에 적용하여 최적으로 중성선을 운영하는 방안을 제시하였다.

• 월간 기계설비
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• no.3 s.200
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• pp.46-62
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• 2007

월간「설비건설」은 지령 200호를 맞아 설비건설산업의 제2 도약을 위한 발전방안 모색과 월간「설비건설」발전을 위해 산·학·연·관에서 설비건설산업 제도개선 및 설비건설산업 발전에 일익을 담당하고 있는 인사를 모시고‘설비건설산업 제2 도약을 위한 발전방안 ’이라는 주제 하에 지난 2월 13일 라마다 르네상스 인 서울 호텔에서 좌담회를 개최했다. 이날 좌담회에서는 건설업계의 관심사인 건설생산체계 개편과 관련하여‘일반·전문 겸업제한 폐지시 설비공사 분리발주가 이루어져야 균형적인 법개정이 될 것’이라는 의견과 함께‘설비분야는 독립성이 있음에도 불구하고 인정받지 못하는 현실을 극복하기 위해 설계, 시공, 감리, 유지관리를 일관성 있게 지원 가능한 설비건설업법 제정이 필요하다’는데 의견을 모았다. 또한 월간「설비건설」의 발전방향에 대해‘창의적인 기획기사 발굴과 독자의 참여도를 더욱 높여야 할 것’이라고 지적했다. 본지는 이날 좌담회에서 논의된 내용을 정리하여 게재한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.29 no.1A
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• pp.45-52
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• 2009

In conventional structural design, deterministic optimization which satisfies codified constraints is performed to ensure safety and maximize economical efficiency. However, uncertainties are inevitable due to the stochastic nature of structural materials and applied loads. Thus, deterministic optimization without considering these uncertainties could lead to unreliable design. Recently, there has been much research in reliability-based design optimization (RBDO) taking into consideration both the reliability and optimization. RBDO involves the evaluation of probabilistic constraint that can be estimated using the RIA (Reliability Index Approach) and the PMA(Performance Measure Approach). It is generally known that PMA is more stable and efficient than RIA. Despite the significant advancement in PMA, RBDO still requires large computation time for large-scale applications. In this paper, A new reliability-based design optimization (RBDO) method is presented to achieve the more stable and efficient algorithm. The idea of the new method is to integrate a response surface method (RSM) with PMA. For the approximation of a limit state equation, the moving least squares (MLS) method is used. Through a mathematical example and ten-bar truss problem, the proposed method shows better convergence and efficiency than other approaches.