• Journal of the Korean Geotechnical Society
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• v.25 no.9
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• pp.45-55
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• 2009

The quality of railroad trackbed fills has been controlled by field measurements of density and bearing resistance of plate-load tests. The control measures are compatible with the design procedures whose design parameter is $k_{30}$ for both ordinary-speed railways and high-speed railways. However, one of fatal flaws of the design procedures is that there are no simple laboratory measurement procedures for the design parameters ($k_{30}$ or, $E_{v2}$ and $E_{v2}/E_{v1}$) in design stage. To overcome the defect, the compressional wave velocity was adopted as a control measure, in parallel with the advent of the new design procedure, and its measurement technique was proposed in the preliminary investigation. The key concept of the quality control procedure is that the target value for field compaction control is the compressional wave velocity determined at optimum moisture content using modified compaction test, and direct-arrival method is used for the field measurements during construction, which is simple and reliable enough for practice engineers to access. This direct-arrival method is well-suited for such a shallow and homogeneous fill lift in terms of applicability and cost effectiveness. The sensitivity of direct-arrival test results according to the compaction quality was demonstrated at a test site, and it was concluded that compressional wave velocity can be effectively used as quality control measure. The experimental background far the companion study (Park et al., 2009) was established through field and laboratory measurements of the compressional wave velocity.

• 월간 기계설비
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• s.285
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• pp.100-102
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• 2014

대한설비건설협회는 지난해 7월 개정된 도시가스사업법 시행규칙 제20조의2 '특정가스사용시설' 규정과 관련 코드기준(KGS FU551 등) 등 세부기준이 건설업계와 설비시공업계에 규제 강화로 적용됨에 따라 민원이 속출하고 있어, 이를 제외 및 폐지하여 줄 것을 지난 3월 14일 산업자원통상부와 한국가스안전공사에 건의했다. 현재까지 단 한건의 가스누출사고도 없었던 매립(매몰) 배관에 대해 안전성을 강화한다는 명분으로 고가의 다기능가스안전계량기를 설치토록 하고, 추가로 한국가스안전공사의 완성검사 및 기술검토까지 받도록 하는 것은 이중규제로 지적되고 있다. 또한 점검구의 경우 천정높이와 현장여건에 따라 설치 개수도 달라지며, 설치 후 실질적인 수리 보수를 할 수 없는데다 미관상 많은 민원을 초래할 수 있어 무용지물이 될 수 있다고 업계는 지적하고 있다. 이에따라 대한설비건설협회는 ${\triangle}$건축물 내 도시가스 매립(매몰)배관 특정가스사용시설 제외 ${\triangle}$가스용 금속플렉시블배관용호스 은폐(천정) 설치 시 점검구 또는 다기능가스안전계량기 설치 의무화 Code기준의 개선을 촉구했다. 또한 지난 3월 13일 제도 홍보를 위해 개최된 '건축물내 매립배관 제도개선 현황과 과제' 세미나에서도 대한설비건설협회는 이같은 문제점을 지적하고 보완책 마련을 건의했다.

• Korean Journal of Construction Engineering and Management
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• v.15 no.3
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• pp.3-11
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• 2014

Recently, remodeling construction project has been prevalently conducted in major city areas in Korea. However, remodeling construction project has a difficulty in conducting a construction because of non-existing drawing or lack of drawing information. To solve these problems, modeling techniques by using reverse engineering have been widely studied in other industries such as aerospace and automobile industry. But reverse engineering techniques have not been used in remodeling construction projects because those technology haven't supplied less accuracy during required time for surveying. So, this study suggests optimal method of acquiring accurate 3D laser scanner information for reverse engineering at interior remodeling project.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.3
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• pp.20-27
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• 2014

In the construction site, various earth retaining systems are developed and applied to maintain stability of excavated area and structures. Among the methods, the underground continuous wall and the column-type diaphragm wall methods are especially used in construction site nearby buildings or roads. However, these methods have some disadvantages such as the difficulty of quality control and long curing time because these methods need to cast fresh concrete at the construction site. In addition, these methods are usually applied to the site for the temporary purpose. In this paper, we suggest precast hollow prestressed concrete pile for continuous pile wall system. To investigate the structural behavior of suggested pile, which is the main member of the suggested system, tests pertaining to the structural behavior and prestressing force applied in the pile are conducted. From the test results, it was found that the prestressing force measured is sufficient compared with the value obtained by the design equation and the cracking moment measured is 34% higher than the design value. In addition to the above, this precast hollow prestressed concrete pile has an additional safety margin that the maximum moment is 59.2% higher than the cracking moment which is one of the serviceability limits for the design of the system.

• Journal of the Korea Institute of Building Construction
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• v.16 no.5
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• pp.429-436
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• 2016

Because of the shortage of construction workers due to The rising labor costs and an aging labor force, construction time has been extended. As a solution, The construction time of high-rise buildings can be reduced by adopting precast concrete construction methods. Most relevant studies have focused on the development and structural analysis of such methods and not on their construction management. Therefore, this study focused on the construction management of the hollow precast concrete column (HPC) method. The objective of this study was to evaluate the performance of HPC formulations through the analytic hierarchy process and benefit-cost analysis. After a gap analysis of the available literature and expert interviews, the evaluation criteria were selected. A questionnaire survey was administered to professionals with ample experience in precast concrete construction for the pair-wise evaluation of the benefit and costs of the HPC method. The results show that the benefits of the HPC method outweighed its costs. Therefore, the HPC method is a suitable substitute for the half-slab method.

• Journal of the Korea Institute of Building Construction
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• v.13 no.2
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• pp.122-130
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• 2013

One of recent methods to protect wooden cultural assets from fire, there is the flame retardation which is applied directly to wood and it is to prevent fire through securing flame resistance for the material and delaying combustion when failed fire in advance and then to gain time for people in the room to evacuate and it has same goal with the Korean Fire Service Act by protecting life and property. However, in case of spraying flame retardant on the colored surface of the wooden cultural assets, there are continuous problems of decoloration, efflorescence and water absorbtion after sometime and accordingly there increases danger of damages of cultural assets. So when treating with flame retardant on wooden cultural assets, there has to be no problems on dancheong after sometime and securing sustainable methods for flmae retardation should be preceded. Accordingly, this study aims to provide basic sources for selecting proper flame retardation methods by evaluating and analyzing flame retardation capabilities according to types of flame retardants which are frequently used nowadays and spraying them on the dancheong-painted surface and confirming if there is no problem on the dancheong and wood after sometime and if flame retardation effect is sustainable with its quality and capability through precise analysis.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.36 no.4
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• pp.243-250
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• 2023

Both ends of the hoop reinforcement in the reinforced concrete (RC) columns subjected to lateral loading must necessarily be bent by 135° so as to ensure a sufficient level of ductility. However, as this reinforcement is extremely difficult to construct, this requirement is often not satisfied at construction sites. This study entailed an experimental investigation on RC columns subjected to cyclic lateral loading equipped with steel clip-type implements that were developed to replace the complicated 135° hoop reinforcement details. Four RC column specimens were manufactured, and the main test parameters included the use of high-strength concrete and steel clip-type implements. Furthermore, three-dimensional finite element models were employed to evaluate the structural performances of the test specimens via nonlinear analyses. The results of the test and finite element analyses indicate that the RC columns with the steel clip-type implements exhibit structural performances equal to or better than those with the 135° hoop reinforcement details. Further, the finite element analysis results agree well with the test results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.501-509
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• 2019

The construction of foundation piles for buildings and bridges is changing from pile driving to an injected precast pile method. The goal is to minimize environmental damage, noise pollution, and complaints from neighboring residents. However, it is necessary to develop economic piles that are optimized for precasting by a centrifugal method in terms of both the material and structural system. A reinforced joint method is proposed for reinforced concrete piles (RC piles) manufactured by centrifugal casting. A previous study concluded that the structural performance of the current joint system for RC piles could be improved by using a reinforced joint composed of extended circular band plates and studs. In this study, the structural performance of such a joint was validated experimentally by bending and shear strength measurements. The proposed joint reinforcement method showed adequate structural performance in terms of bending and shear strength. The overall load-deflection behavior is close to that of a structure without joints, so it is expected that the behavior and performance of the design can be reliably reflected in site structures.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.5
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• pp.3619-3626
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• 2015

The coal shed at thermal power plant(T.P.P) is the biggest building on size among nuclear, coal and other power plant industry buildings. This the coal shed of indoor type is mass volume, the size of 6 soccer fields and 73 meter in height. Structural and functional elements take priority over aesthetic factors. The shed is built to make mighty space for structural safety and functional store by using the concrete, $75,000m^3$ on the total of central retaining wall and sub buttress, and the steel frame used by 11,744-ton P.E.B. system. The design requirement on its wall and frame, P.E.B. system's feature, and specific data of main process followed by construction are inquired. The aim of this study is to suggest the design requirement and guide for the indoor type of the coal shed.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.1
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• pp.30-39
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• 2022

In this study, laboratory test, program analysis, and test construction in the field were performed to utilize Supplementary Cementitious Material (SCM) developed by recycled resources for slope reinforcement as slope improvement material for aging reservoir, and the results were analyzed. As results of the laboratory test, it was analyzed that the mixing ratio of SCM was appropriate by 9 %, and the coef. of permeability was decreased by about 10,000times, indicating a value close to that of the waterproof material applied in Korea. In addition, as a result of program analysis and test construction, it was analyzed that seepage did not occur in the part of reinforced using SCM and showed a higher safety facto r than domestic criteria. Therefore, since it shows sufficient waterproof and reinforcing effects in aging reservoir, it is judged that the slope improvement using SCM can replace the cement for repair and reinforcement method.