• 한국안전학회지
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• 제19권1호
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• pp.108-116
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• 2004

After the IMF financial crisis, a lot of risks in construction industry have been increased gradually with the expansion of construction industry widely, higher stories of building, and the expansion of the underground space and excavation work. These risks are bringing out construction accidents such as the death, the injury of worker and so on, not so much as it would be effected the corporation's image. In spite of these situations, many construction industries still maintain the wrong methods and not try to decrease construction accidents. Recently, we should focus on the fact that management system of the larger construction also is being good, on the other hand, the condition of the work in the case of smaller construction industries is very poor, construction company have a particular safety management system but it has a difference according to the construction magnitude, construction companies have a particular safety management system but it has a difference depending on the construction according to the construction magnitude. Therefore, this study will suggest the developed way of construction safety management by the comparison and analysis from the difference between the higher and the smaller construction industries.

• 한국건설관리학회논문집
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• 제7권6호
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• pp.202-211
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• 2006

Rework in the construction industry can adversely affect project cost and schedule performance. Based on direct rework costs recorded on 359 construction projects, this paper presents an assessment of the magnitude of rework by various types of projects and sources of rework. The results from this paper establish that on average 4.5% and 2.5% of actual construction costs were spent on rework for owner and contractor projects, respectively. Furthermore, this paper determines that the direct rework costs differ by project types and sources of rework. Finally, it permits the development of rework reduction initiatives. By quantifying and recognizing the different magnitude of rework, the industry can be aware of the waste from rework and develop effective plans for managing rework, ultimately improving project cost performance.

• The Korean Journal of Ecology
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• 제21권3호
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• pp.251-255
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• 1998

To elucidate the effects of a hydroelectric dam construction on annual ring growth of Pinus densiflora, the annual ring widths of 68 trees collected from 7 sites were closely examined. The result was analyzed to ask three special questions first, whether there are real effects of dam construction on the radial growth second, would the magnitude of the effect be different due to two periods of under-construction and post-construction the last, would it be different among age classes. Annual ring growth has been significantly enhanced by the dam construction. Specially, its effect was marked after the construction was finished and the reservoir was filled up with water. There was, however, no remarkable evidence that pine growth would be reduced while the dam was under construction, even though there was a minor decreasing trend. The magnitude of the effect was different among age groups. That is, the changed condition after the construction enhanced relatively the growth of aged trees monre. According to other meterological research since the dam was constructed, the reasons of enhancing pine growth assumed to be the increase of daily temperature, the decreased of daily temperature difference and the increased of rainy days.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 춘계 학술논문 발표대회
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• pp.3-4
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• 2015

Vibration occur at construction sites due to various causes. Starting from the movement of heavy equipments and construction vehicles, the machine crushing of embedded obstacles and rocks creates not only noise but also vibration. Furthermore, the blasting of rocks tops the other causes. In this paper, the measurements of various vibration occurring at the construction site are made and analyzed to determine the magnitude of vibration upon different sources of vibration. The results showed the relative magnitude of vibration for the site studied.

• 국제학술발표논문집
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• The 3th International Conference on Construction Engineering and Project Management
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• pp.1231-1236
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• 2009

Many work-related risk factors can cause construction site hazards. Therefore, safety management begins with measuring the magnitude of risk involved in a project. This study proposes a methodology for risk assessment of major trades at a particular construction site. To assess risk, this methodology integrates hazard severity and frequency, and their magnitude is calculated based on actual work-site hazards. This methodology also considers the influence factors that affect the frequency of work-related hazards. To select the appropriate influence factors, a two step approach is deployed. First, the predominant factors are identified through a literature review. Second, a selective process filters out the influence factors that are difficult to analyze quantitatively, and these extracted factors are weighted using expert surveys. Finally, the factors are combined and a quantitative risk assessment methodology is proposed.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.545-548
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• 2008

In this study, the concept of safety impact assessment to achieve 'Design-for-Safety' in design phase is introduced. For this purpose, safety impact assessment model was devised and a methodology using the risk-based safety impact assessment approach for NATM of tunnel projects is suggested. The suggested methodology includes safety information survey, classification of safety impact factors caused by design and construction, and quantitative estimation of magnitude and frequency of safety impact factors. A real-world case study on the safety impact assessment of a tunnel construction project is also provided in the paper.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.38-45
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• 2011

Studies have shown that infrastructure projects have continued to experience significant delays and cost overrun over an extended period of time and no evidence of learning ever have happened [1] [2]. Various causes contribute to the bias towards overrun [3]. This study contributes to literature by developing and subsequently validating a set of hypothesized relationships between project complexity and project performance. The results show that project complexity is associated with both the magnitude and variance of overrun. Further, the extent and magnitude of the positive bias towards overrun are moderated by project complexity.

• 국제학술발표논문집
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• The 4th International Conference on Construction Engineering and Project Management Organized by the University of New South Wales
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• pp.234-240
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• 2011

Preventing incidents occurred in construction process is important for safe implementation of construction projects. Due to the complexity and magnitude of the project and moreover, poor safe planning and management, construction incidents in Korea have been increasing. Reducing construction incidents effectively, appropriate safety management program in consideration of the incident rate of each facility is to be adapted. This study analyzes incident frequency and severity rate of each facility based on the data of construction sites(about 1,560 thousand cases) recorded by Korea Occupational Safety & Health Agency for 3 years from 2007 to 2009, and the incident related data (about 40 thousand cases) of Korea Workers' Compensation & Welfare Service. The results of this study revealed that construction incident rates of 'cold refrigeration storage facilities' are the highest among building types, followed by traditional building religious building, arcade department store and shopping center. In case of other facilities, the incident rate and the rate of intensity of 'pipelining project' are the highest, followed by 'tunneling project'. These results would be used in providing safety programs beneficial for preventing construction incidents.

• 한국강구조학회 논문집
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• 제12권3호통권46호
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• pp.269-279
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• 2000

차량하중의 증가 및 부식 등에 의해 손상된 강교량 구조물들은 보수 보강이 요구되어진다. 손상부채를 보수 보강하는 방법은 단면결손이 없다는 장점을 가진 용접에 의한 보수방법이 유리하다. 3차원 탄소성해석 결과를 토대로 공용중 보수용접에 의해 생기는 응력과 변형의 거동에 대해 연구하였다. 균열이 있는 부재에 하중만 작용할 경우 과도 응력의 크기는 보수용접균열길이 및 균열깊이가 큰 순으로 크다. $80MPa({\sigma}_y/3)$ 및 $140MPa({\sigma}_a)$의 응력 작용시 보수용접에 의해 발생되는 응력의 크기는 무응력 상태에서 보수용접시 발생되는 응력의 크기와 하중재하에 의해 생긴 응력의 크기의 합과 비슷하다. 응력 작용시 보수용접에 의해 발생되는 용접선방향 인장과도응력 성분은 부재폭에 대한 균열 길이비(1/b)가 커지면 커짐을 알 수 있다. 또한, 응력 작용시 보수용접에 의해 발생되는 용접선 직각방향의 면내수축변위의 크기는 보수용접길이가 긴순으로 크다.

• Geomechanics and Engineering
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• 제17권5호
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• pp.429-438
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• 2019

Microbially induced carbonate precipitation (MICP) is an innovative soil improvement approach utilizing metabolic activity of microbes to hydrolyze urea. In this paper, the shear response and the erodibility of MICP-treated sand under axial compression and submerged impinging jet were evaluated at a low confining stress range. Loose, poorly graded silica sand was used in testing. Specimens were cemented at low confining stresses until target shear wave velocities were achieved. Results indicated that the erodibility parameters of cemented specimens showed an increase in the critical shear stress by up to three orders of magnitude, while the erodibility coefficient decreased by up to four orders of magnitude. Such a trend was observed to be dependent on the level of cementation. The treated sand showed dilative behavior while the untreated sands showed contractive behavior. The shear modulus as a function of strain level, based on monitored shear wave velocity, indicated mineral debonding may commence at 0.05% axial strain. The peak strength was enhanced in terms of emerging cohesion parameter based on utilizing the Mohr-Coulomb failure criteria.