• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2021년도 가을 학술논문 발표대회
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• pp.194-195
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• 2021

Due to urban regeneration projects or changes in the living environment, there is an increasing need to demolish old buildings that have lost their functions. Demolition of above ground and underground structures is an important construction project that greatly affects the construction period and safety of the entire process. However, it is difficult for the safety officer to manage the demolition work due to the lack of specific and diverse data applicable to the site of the demolition plan. Therefore, in this study, items that need to be improved in structural safety when the above-ground and underground structures are demolished are reviewed and organized. For the main contents of structural safety management in demolition work, 1) structural review reflecting the order of demolition work, 2) installation and dismantling of steel pipe scaffolding and dust nets, 3) installation and dismantling of system scaffolding, 4) installation and dismantling of fall prevention nets, 5) jack support Installation and dismantling, 6) movement of equipment, movement and planning between floors, 7) equipment for demolition of structures, height of remnants, 8) site cleanup, and 9) equipment operators were categorized and arranged.

• 대한안전경영과학회지
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• 제22권3호
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• pp.1-8
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• 2020

The desulfurizers facility is cylindrical shape. To operate properly it needs nozzles cleaned, get rid of lime adhesion and sludge, repair the wear and corrosion of facility regularly. For this purpose, workers shall access the ceiling or vertical wall at high place. Ordinary scaffoldings such as steel pipe scaffolding or system scaffolding have been using so that workers can access them. With these ordinary scaffoldings, openings around cylindrical wall are inevitable which make workers can expose always to the risk of falling. The purpose of this study is to develop customized scaffolding to minimize the openings to prevent workers form falling during maintenance it. It consists of a hexagonal central tower and six trapezoidal outer towers. And the bracing among the towers have connected each other for self-standing and for maintaining the structure of towers. Span decks, the circumference footstools, steps, etc. are laid on each floor. The safety is reviewed by structural analysis and performance test. With this study, openings each floor of this scaffold are removed. The gap between the cylindrical wall and the edge of the work stage is approximately 100 mm. Therefore, we expect that workers can work safely and efficiently.

• 한국산학기술학회논문지
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• 제22권3호
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• pp.94-100
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• 2021

멤브레인(membrane) LNG 운반선 화물창(cargo containment) 공사의 생산성 향상을 위해서는 공사 작업대인 비계 시스템(scaffolding system)의 설치 기간 및 공정 단축이 요구된다. 이를 위한 효과적인 방안으로 모듈의 탑재 단위를 기존의 2단에서 8단으로 대형화하자는 의견이 수렴되고 있다. 하지만, 모듈의 대형화로 인해 탑재 하중이 증가하면 메인 수직 파이프를 연결해주는 핀(pin)과 홀(hole) 주위에 국부 응력이 증가하여 재료의 항복응력을 초과하게 되는 문제점이 발생한다. 본 연구의 목적은 이러한 문제점을 해결하기 위해 트리즈(TRIZ)를 도입하여 새로운 대형 모듈의 탑재 방안을 수립하는 것이다. 본 연구에서는 트리즈의 여러가지 문제해결 도구 중 하나인 40가지 발명원리를 활용하는 방안을 채택하였다. 먼저 기술적 모순을 도출하고, 공학변수를 선정하였으며, 모순행렬을 활용하여 기술적 모순을 극복하기 위한 효율적인 발명원리를 선정하였다. 선정된 발명원리를 통해 일반해결안 및 특정해결안을 도출하였고, 구조해석을 통해 구조물에 발생하는 응력이 낮은 수준임을 확인하였다. 수립된 탑재 방안을 적용한 대형 모듈의 실제 탑재에 성공함으로써 트리즈의 유용성을 확인하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 춘계 학술논문 발표대회
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• pp.162-163
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• 2013

A temporary work are lifting equipment that tower crane or lift, and temporary architectures that office building and storage in construction site. And it is main construction work that built and used temporarily like to a scaffolding, a walk plate, and a formwork. This study is to adjust breakdown structure of temporary work to introduce technical tendency. With a site manager, it is collected a detailed statement and compared. As a result to break down a tendency that temporary equipment, additional function, and direct work of temporary technique, first, existing detail technical indexes that group I, group J, group K, and group L are classified. Second, due to set up and manage to main agents in case of existing detail technical indexes that B1, B2, it is not wrong to classify. But, it is somewhat different, and therefore adjust it to same level. Finally, as a technical tendency that temporary equipment, additional function, and direct work of temporary technique, it is adjusted the others.

• 한국게임학회 논문지
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• 제12권5호
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• pp.5-12
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• 2012

그래픽으로 표현된 정보는 컴퓨터게임에 익숙한 게임세대들에게 정보를 인지하는데 텍스트보다 선호하는 스타일이다. 또한 수학교육에 있어서도, 그래픽으로 표현된 수학문제를 통해 해를 찾는 학습은 학습자들에게 문제해결 능력을 향상시키는 데 뚜렷한 효과가 있다고 한다. 본 논문에서는 게임세대인 학습자들의 효과적인 학습을 위해, 수학문장을 그래픽적으로 표현하는 방법을 제안하였다. 제안하는 방법은 가시성이 우수한 그래픽 요소들을 사용하여 단위정보를 논리적인 구조로 배치하고 단위 정보들 사이의 논리적인 연관성을 기호, 선분, 또는 화살표로 표현하여 게임세대들이 문장의 내용을 인지하지 쉽고 논리적으로 정확하게 이해할 수 있다. 기존의 수학문장의 그래픽표현방법과 달리 제안하는 방법은 문장의 시제와 태까지도 정확하게 표현할 수 있다. 제안하는 방법은 게임세대인 학습자들에게 효과적인 수학학습이 이루어질 수 있도록 학습도구로 사용될 수 있고 또 수학교육용 컴퓨터게임의 학습 스캐폴딩 기능을 위해 사용되는 수학정보의 그래픽표현을 위해 널리 활용될 수 있다.

• 한국안전학회지
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• 제33권1호
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• pp.73-80
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• 2018

According to the statistics publication of KOSHA, more than half of serious accidents at the construction sites were related to the temporary works and/or the temporary structures such as scaffoldings, shores, earth retaining walls, etc. The structural failures are occurred because of the overload acting on the structures or lack of performance of the one or more members of the structures. For the prevention of the collapse accidents relating to the temporary structures at the construction sites, we have to control construction processes not to occur the overload and also to control the performance and quality of each member of the temporary structures. MOLIT has amended the "Construction Technology Promotion Act" on Jan. 7th, 2015 to ensure the structural safety of the temporary structures. According to the Act, the designers of the construction design projects should check the structural integrity of the structures including the temporary structures and the construction companies have to let 'the Relative Professionals' confirm the structural integrity of temporary structures, the shores(${\geq}5m$ high) and the scaffolds(${\geq}31m$ high), before construction. Also, MOLIT has amended the "Regulation for Construction Technology Promotion Act" on Jul. 4th, 2016 for quality management and testing of temporary equipments. According th this regulation, the construction companies and supervisors should manage and test the temporary equipments before using them. In this paper, the standard drawings of the shores(< 5 m high) and the scaffolds(< 31 m high) and the amended "Business Guideline for Quality Management of Construction Work" are presented. As the result of this study, MOLIT noticed the amended "Business Guideline for Quality Management of Construction Work" on Jul. 1st, 2017.

• 한국산업안전학회:학술대회논문집
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• 한국안전학회 1997년도 추계 학술논문발표회 논문집
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• pp.157-164
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• 1997

Construction accident happens all of the process in work and contains materials types of causes. Especially, temporary work material in the great problem in industrial accident. Because temporary work In essential to build the main structure. The most frequent type of accident by the temporary work is the falling and so on. Its causes were the failure of scaffolding, imperfection of temporary material etc. These accident properties the Primitive and repetitive accident. The prevention counterplan of construction accident by temporary material work in need to protect worker and make more safer construction site. Therefore in this paper analyzed of the serious accident of construction by the temporary work material and present reasonable solution method to reduce the construction accident by the temporary work material.

• 한국건축시공학회지
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• 제14권2호
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• pp.177-186
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• 2014

The gang-form widely used in apartment construction sites has advantages compared to scaffolding in preventing falling accidents. One problem, however, is that safety accidents associated with gang-form works repeatedly occur due to worker carelessness. In this study, hierarchical checking tables are provided to support safety management activities for the gang-form works at the sites. Through a survey of experts and analyses of case studies of construction accidents, 137 safety check items are classified by participant type based on a hierarchical safety check scheme. The applicability and effectiveness of the hierarchical checking tables was evaluated through interviews with experts. It was found that the hierarchical checking tables enabled each gang-form related participant to check his own safety management items, and provided a level-wise structure to site safety management systems.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.3950-3956
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• 2012

In order to improve the bioactivity and mechanical properties of hydroxyapatite (HAp), chitosan (Chi) was in situ combined into HAp to fabricate a composite scaffold by a sublimation-assisted compression method. A highly porous film with sufficient mechanical strength was prepared and the bioactivity was investigated by examining the apatite formed on the scaffolds incubated in simulated body fluid. In addition, the cytotoxicity of the HAp/Chi composite was studied by evaluating the viability of murine fibroblasts (L-929 cells) exposed to diluted extracts of the composite films. The apatite layer was assessed using scanning electronic microscopy, inductively coupled plasma-optical emission spectrometry and weight measurement. Composite analysis showed that a layer of micro-sized, needle-like crystals was formed on the surface of the composite film. Additionally, the WST-8 assay after L-929 cells were exposed to diluted extracts of the composite indicated that the HAp/Chi scaffold has good in vitro cytocompatibility. The results indicated that HAp/Chi composites with porous structure are promising scaffolding materials for bone-patch engineering because their porous morphology can provide an environment conductive to attachment and growth of osteoblasts and osteogenic cells.

• Advances in concrete construction
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• 제9권3호
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• pp.235-248
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• 2020

Progressive collapse in a structure occurs when load bearing members are failed and the adjoining structural elements cannot resist the redistributed forces and fails subsequently, that leads to complete collapse of structure. Recently, construction using precast concrete technology is adopted increasingly because it offers many advantages like faster construction, less requirement of skilled labours at site, reduced formwork and scaffolding, massive production with reduced amount of construction waste, better quality and better surface finishing as compared to conventional reinforced concrete construction. Connections are the critical elements for any precast structure, because in past, major collapse of precast structure took place because of connection failure. In this study, behavior of four different precast wet connections with U shaped reinforcement bars provided at different locations is evaluated. Reduced 1/3^rd scale precast beam column assemblies having two span beam and three columns with removed middle column are constructed and examined by performing experiments. The response of precast connections is compared with monolithic connection, under column removal scenario. The connection region of test specimens are filled by cast-in-place micro concrete with and without polypropylene fibers. Performance of specimen is evaluated on the basis of ultimate load carrying capacity, maximum deflection at the location of removed middle column, crack formation and failure propagation. Further, Finite element (FE) analysis is carried out for validation of experimental studies and understanding the performance of structural components. Monolithic and precast beam column assemblies are modeled using non-linear Finite Element (FE) analysis based software ABAQUS. Actual experimental conditions are simulated using appropriate boundary and loading conditions. Finite Element simulation results in terms of load versus deflection are compared with that of experimental study. The nonlinear FE analysis results shows good agreement with experimental results.