• Coupled systems mechanics
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• 제11권5호
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• pp.439-458
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• 2022

Over-coating is one of the most popular engineering practices to strengthen Reinforced Concrete (RC) structures, due to the relative quickness and ease of construction. It consists of an external coat bonded to the outer surface of the structural RC element, either by the use of chemical adhesives, mechanical anchor bolts or simply mortar injection. In contrast to these constructive advantages, the numerical estimation of the bearing capacity of the strengthened reinforced concrete element is still complicated, not only for the complexity of modelling a flexible membrane or plate attached to a quasi-rigid solid, but also for the difficulties that raise of simulating any potential delamination between both materials. For these reasons, the standard engineering calculations used in the practice remain very approximated and clumsy. In this work, we propose the formulation of a new 2D solid-layer finite element capable to link a solid body with a flexible thin layer, as it were the "skin" of the body, allowing the potential delamination between both materials. In numerical terms, this "skin" element is intended to work as a transitional region between a solid body (modelled with a classical formulation of a standard quadrilateral four-nodes element) and a flexible coat layer (modelled with cubic beam element), dealing with the incompatibility of Degrees-Of-Freedom between them (two DOF for the solid and three DOF for the beam). The aim of the solid-layer element is to simplify the mesh construction of the strengthened RC element being aware of two aspects: a) to prevent the inappropriate use of very small solid elements to simulate the coat; b) to improve the numerical estimation of the real bearing capacity of the strengthened element when the coat is attached or detached from the solid body.

• 한국터널지하공간학회 논문집
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• 제11권4호
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• pp.353-359
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• 2009

서울지하철 5호선을 통과하고 있는 한강 및 중소 7개 하천 7.937 km구간의 터널 내부로 유입되는 지하수 유입량은 평균 $34,444\;m^3/day$로 터널 전구간 31.29 km로 유입되는 지하수량 $62,272\;m^3/day$의 55.3%를 차지하고 있으므로 하천구간에서 지하수 유입을 억제한다면 유지관리 비용을 크게 절감할 수 있을 것으로 기대된다. 또한, 하천구간으로 유입되는 지하수의 양을 설계기준과 비교한 결과 유입량이 $3.01\;m^3/min/km$로서 터널 설계기준 $3.0\;m^3/min/km$과 비슷한 수준으로 유입되고 있었으나, 터널평균 유입량 $1.38\;m^3/min/km$와 비교했을 때 하천구간에서는 2.18배의 지하수가 더 유입되고 있는 것으로 나타났다.

• Coupled systems mechanics
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• 제12권6호
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• pp.481-501
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• 2023

Over-coating is one of the most popular engineering practices to strengthen Reinforced Concrete (RC) structures, due to the relative quickness and ease of construction. It consists of an external coat bonded to the outer surface of the structural RC element, either by the use of chemical adhesives, mechanical anchor bolts or simply mortar injection. In contrast to these constructive advantages, the numerical estimation of the bearing capacity of the strengthened reinforced concrete element is still complicated, not only for the complexity of modelling a flexible membrane or plate attached to a quasi-rigid solid, but also for the difficulties that raise of simulating any potential delamination between both materials. For these reasons, the standard engineering calculations used in the practice remain very approximated and clumsy. In this work, we propose the formulation of a new 2D solid-layer finite element capable to link a solid body with a flexible thin layer, as it were the "skin" of the body, allowing the potential delamination between both materials. In numerical terms, this "skin" element is intended to work as a transitional region between a solid body (modelled with a classical formulation of a standard quadrilateral four-nodes element) and a flexible coat layer (modelled with cubic beam element), dealing with the incompatibility of Degrees-OfFreedom between them (two DOF for the solid and three DOF for the beam). The aim of the solid-layer element is to simplify the mesh construction of the strengthened RC element being aware of two aspects: a) to prevent the inappropriate use of very small solid elements to simulate the coat; b) to improve the numerical estimation of the real bearing capacity of the strengthened element when the coat is attached or detached from the solid body.

• Journal of Astronomy and Space Sciences
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• 제34권2호
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• pp.153-159
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• 2017

The Standard Model of particle physics was established after discovery of the Higgs boson. However, little is known about dark matter, which has mass and constitutes approximately five times the number of standard model particles in space. The cross-section of dark matter is much smaller than that of the existing Standard Model, and the range of the predicted mass is wide, from a few eV to several PeV. Therefore, massive amounts of astronomical, accelerator, and simulation data are required to study dark matter, and efficient processing of these data is vital. Computational science, which can combine experiments, theory, and simulation, is thus necessary for dark matter research. A computational science and deep learning-based dark matter research platform is suggested for enhanced coverage and sharing of data. Such an approach can efficiently add to our existing knowledge on the mystery of dark matter.

• 정보관리연구
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• 제27권2호
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• pp.33-64
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• 1996

본 연구는 데이터베이스 기술분류의 표준시안을 제시하기 위하여 1차년도(1994년) 연구 결과에 대한 관점을 체계화하고 구체화시켜 수정, 보완하는 형식으로 이루어졌다. 분류관점을 정보와 이를 지원하는 시스템 측면으로 크게 나누어, 데이터베이스 일반, 정보유통, 정보검색, 데이터베이스 시스템, 주변 관련주제를 분류기준으로 하는 표준 시안의 모형이 제시되었다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2018년도 춘계 학술논문 발표대회
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• pp.343-344
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• 2018

This study proposes a standard method of diagnosis and repair to prevent and maintain the problem of durability deterioration caused by leakage cracks in apartment basement structures in Korea. Following the announcement of the previous maintenance plan section, this is the second part of the study, focusing on inspection of methods for diagnosing and repairing leakage cracks in apartment basement structures. In this thesis, the matters required for the procedures, types, times and equipment of the inspection plan and the inspection methods, records, and decisions required for the actual inspection are described.

• 한국농공학회:학술대회논문집
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• 한국농공학회 1999년도 Proceedings of the 1999 Annual Conference The Korean Society of Agricutural Engineers
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• pp.465-472
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• 1999

Hydraulic model tests are performed to find economical and hdrqulically stable design of cooling water intake channel of steam power plant. The result of tests show that the standard distributiion of y-components in the chamber of CWP(circulating Water Pump) are recommended below 3.5 to maintain hydraulic stability, so that this value is considered as the design criteria. Common basin is necessary to improve the hydraulic stability of inflow, however the longer basin does not always improve the hydraulic stability , and the optimal length of basin can be found in some range. From the results the flow stability maintained the best condition when the length of basin is 7.2m. Beside the standard tests the auxiliary tests like edge , baffle, trapezoidal section and increase of pump capacity are carried out based on the optimal condition foudn in the standard tests. From the series of tests the economical and hydraulically stable design of intake channel was proposed.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2019년도 춘계 학술논문 발표대회
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• pp.4-5
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• 2019

Smoke and fire spread throughout the building as a result of problems in the fire prevention section of Uijeongbu Apartment Fire in 2015 and Jecheon Sports Center Fire in 2017 in Korea, causing a number of casualties. It is believed that the fire compartment standards need to be reviewed as the fire in recent buildings continues to show problems. In this study, a comparative analysis was conducted on the fire prevention zone standard with Japan to improve the fire compartmente standard in Korea.

• Computers and Concrete
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• 제2권5호
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• pp.367-380
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• 2005

Recent earthquakes have shown that many of existing buildings in Iran sustain heavy damage due to defective seismic details. To assess vulnerability of one common type of buildings, which consists of low rise framed concrete structures, three defective and three standard columns have been tested under reversed cyclic load. The substandard specimens suffered in average 37% loss of strength and 45% loss of energy dissipation capacity relative to standard specimens, and this was mainly due to less lateral and longitudinal reinforcement and insufficient sectional dimensions. A relationship has been developed to introduce variation of plastic length under increasing displacement amplitude. At ultimate state, the length of plastic hinge is almost equal to full depth of section. Using calibrated hysteresis models, the response of different specimens under two earthquakes has been analyzed. The analysis indicated that the ratio between displacement demand and capacity of standard specimens is about unity and that of deficient ones is about 1.7.

• 국제학술발표논문집
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• The 6th International Conference on Construction Engineering and Project Management
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• pp.716-717
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• 2015

A construction temporary work is main process and importance trade section. A technology system of construction temporary has very low availability of field works and needs improvements in Korea as construction site has a quick response about new requirements. This study reviews literature researches and can verify that changes to a comprehensive technology system for construction site. In addition, it suggests a breakdown structure of new standards for temporary construction technology based on views of construction site managers. Meanwhile, temporary construction technology in Korea has changed with a specification of construction temporary work which had been revised in 2014. However, the revision is merely dividing the design and building off of construction temporary technology. It is lacking in many ways to change this in a new standard system for temporary construction technology. Henceforth, it needs to develop a standard system for temporary construction technology and a professional system that is appropriate for different purposes by detail trade sections.