• Journal of the KSME
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• v.28 no.4
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• pp.322-327
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• 1988

용접구조물의 파괴는 단순 역학적인 차원을 넘어서 재료공학적 검토와 시공상의 각종 변수를 고려해야만 정확하게 이해할 수가 있으며 방지할 수 있다. 용접도중에 발생되는 미소파괴(균열) 는 적절한 재료의 선정과 적당한 시공법으로 해결할 수 있으며, 사용도중 발생되는 거시적 파 괴는 사용조건에 유의하고 발생된 용접결함을 제거할 수 있다면 방지할 수 있다. 결론적으로 용접구조물의 파괴는 용접도중에 결함을 발생시키지 않는 방법으로 방지하는 것이 가장 효과적 이기 때문에 시공법의 선정 및 실시는 충분한 검토와 주의가 필요하다. 용접품의 파괴현상을 해석하는 데는 현재까지 잘 연구되어진 각종 파괴역학적 및 피로역학적 해석이 적용될 수 있 으나 용접부의 불균일한 조직형성에 따른 기계적 성질의 불균일성과 잔류응력 등을 추가로 고 려해야 하는 것이 약간 다를 뿐이다. 현재 용접부의 취성 및 피로파괴에 대한 다방면의 연구가 활발하게 이루어지고 있는 형편이며 향후에는 용접구조물의 수명예측을 포함한 가족 파괴해석 기술이 확립될 것으로 생각된다.

• Journal of Welding and Joining
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• v.1 no.1
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• pp.13-20
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• 1983

본 연구는 후판 SEG아아크 용접 조건의 변수가 충격 강도에 미치는 영향을 검토함으로써 최적 용접 시공조건을 선정하는데 주목적을 두었다. 본연구를 통하여 얻은 바로는 32mm 후판을 SE G아아크 용접법을 적용하여 용접할 때 최적 용접 시공 조건은 다음과 같다. 1) 뒷면 받침재는 가볍고 취급하기 편리한 것이어야 한다. 2) 바람직한 저입열 용접은 입열량 160KJ/cm, 흠 각도 03$^{\circ}$, 루우트 간격 8mm, 와이어 돌출 길이 45mm, 전류 320~350AmP, 전압 36V, oscillation 폭 13mm의 용접 시공 조건하에서 적절히 이루어질 수 있다. 이상에서 선정된 용접 시공 조건을 사용하면 32mm 후판 SEG 아아크 용접에서는 용접 결함이 없고, ABS선급규정의 2A, 2YA 요구사항을 만족시킬 만한 성능의 용접부를 얻을 수 있다.

• Journal of the Korea Concrete Institute
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• v.15 no.3
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• pp.425-432
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• 2003

The joint treatment of concrete is one of the technical problems in concrete constructions. Joints created with concrete constructions result in serious weakness in the aspects of both structural and water-barrier function. The radar and the infrared thermography method have been used for the non-destructive inspection of several construction joints of concrete structures in this study. The advantages and limitations of these methods are investigated for non-destructive inspection on construction joints of concrete columns. It can be shown that the detecting precision of construction joints using these methods is improved if radar analysis is carried out with a simulation analysis. In case of the infrared thermography method, the shape of construction joints can be also detected when heating is performed before testing. As the result, it has been verified that the construction joints, difficult to be detected by visual inspection, could be inspected effectively in broad areas at short period of time when these two methods are applied.

• 월간 기계설비
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• s.307
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• pp.69-69
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• 2016

지방계약법 시행령 개정을 통해 공사 분야의 최저가낙찰제가 과도한 가격경쟁을 유발함에 따라 300억원 이상인 공사입찰의 경우 국제표준에 맞게 시공실적, 기술능력, 시공품질 등을 종합적으로 고려하여 낙찰자를 선정하는 종합평가낙찰제로 전환하고, 지방재정 조기집행 활성화를 위하여 계약이행 대가의 지급기간을 단축했다. 또한 지방계약예규 개정을 통해 주계약자공동도급 시 주계약자가 선금 수령일로부터 5일 이내에 부계약자에게 지급토록 하였다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2006.11a
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• pp.448-452
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• 2006

Remodeling is deemedto be very important from the perspective of the recycling of resources, instead of scrapping the existing structure, and the creation of 'value added' which is equivalent to the 'value added' from the new construction. In addition, the selection of the appropriate construction method assures the saving of construction cost, the shortening of construction period, and the improvement of quality. Moreover, the selection of the construction method for the remodeling construction is far more important than the current new construction work, considering that the characteristicsof construction site and the structure have a great effect on the construction in case of the remodelingconstruction. Current selection of the construction method, however, does not reflect the construction information, but just adheres to the construction method which was commonly applied previously. Therefore, this study proposes the measure to embody the tool that assists the decision making in selecting the construction method.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.223-224
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• 2023

Optimal fleet management in the planning stage is one of the most critical activities that guarantee successful construction projects. In South Korea, the construction standard production rate database (CSPRD) is normally employed. However, when it comes to a trade-off problem that involves decision-making on optimal sets of equipment to perform a certain task, the method will require the planners' in-depth knowledge and experience regarding the target process and a time consuming estimation of the performance of every possible scenario must be conducted for the deduction of the optimal fleet management. On this account, this research paper proposes a lightweight method of using mixed integer nonlinear programming (MINLP) in multi-objective problems based on CSPRD-based mathematical equations to assist planners in the preplanning stage of choosing the optimal sets of types and size machinery to efficiently arrange the construction scheduling and budgeting.

• Journal of Korean Tunnelling and Underground Space Association
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• v.8 no.3
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• pp.197-204
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• 2006

A large sectional tunnelling method using Shield TBM is expected to be popular as domestic demand of long tunnel gets growing. Although a shield tunnelling method has been recognized as prominent method in consideration of stability and applicability in shallow and poor ground, the cases of accident and constructional trouble have been often happened due to unexpected poor ground condition, or selection and use of improper shield machine. Especially, troubling cases at tunnel face are frequently occurred, so supporting pressure control of tunnel face would be the main issue for securing safer and more efficient tunnel excavation using Shield TBM. In this point, we carried out the numerical feed-back analysis to compare the ground deformation pattern with theoretical result at tunnel face.

• Journal of the Korea Institute of Building Construction
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• v.19 no.6
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• pp.557-566
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• 2019

The construction industry has the most safety accidents of any of the domestic industries. Special care must be taken because disasters in the construction industry lead to social problems caused by huge property losses and casualties. As a result, there is a growing awareness of disasters occurring in the construction industry, and government departments are tightening their regulations on safety management. In particular, the OSHA (Occupational Safety and Health Agency) focuses on the expansion of protection targets and the clarification of responsibility in the full amendment OSHA. As a result, a study that focuses on the client's responsibility for safety management is needed. In this study, the project performance capability assessment of construction project management contractors, which is being carried out with uniform assessment criteria without considering the characteristics of the construction project, is considered and all the amendments to the OSHA are considered, and the factors were derived for improvement measures.

• International Journal of Highway Engineering
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• v.9 no.2 s.32
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• pp.27-37
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• 2007

This research was conducted to determine the optimum lifting positions on precast concrete slabs for precast concrete pavement construction, based on the analysis of concrete stress distribution under various lifting conditions. To analyze stresses in concrete slabs, the finite element method was implemented and a numerical model of the precast slab that was going to be used in the experimental construction was developed. Changes in the stress distribution due to the lifting angle were investigated because slab lifting is not always performed in the perpendicular direction to the slab surface. In addition, the effect of the lifting level, the distance between the neutral axis of the slab and the lifting point, on the stress distribution was investigated since the lifting point is not always at the neutral axis of the slab. To consider the actual steel design of the precast slab, the effect of the reinforcement near the lifting point was also investigated. From this study, the optimum lifting positions of the precast slabs were determined according to the lifting angle and level, and the results were compared with the lifting positions used in the PCI standards.

• Korean Journal of Construction Engineering and Management
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• v.13 no.2
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• pp.58-69
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• 2012

In modern society, rooftops and underground spaces are utilized for overcoming a confined space limitation of metropolitan areas. Therefore, floor covering construction is also increasing steadily. From the user's viewpoint, skid resistance performance of floor covering methods is a very important performance criterion for safety and amenity, but an appropriate design and assessment criteria for skid resistance performance are not available. This study presents the skid resistance performance assessment method of floor covering methods considering the sidewalk skid resistance standard of Seoul city and the guideline of the Ministry of Land, Transport and Maritime Affairs(MLTM) of Korea for road safety facilities'installation and maintenance. For this research, three alternatives among urethane floor covering methods are selected and their skid resistance performance is analyzed through an experimental study. The analyzed performance is also evaluated by the skid resistance performance assessment method. Finally, the comprehensive performance assessment including the results of skid resistance performance assessment is conducted by Value Analysis(VA) in order to encourage the construction methods of floor covering which have a high skid resistance performance. As a result of VA, the particle method which the skid resistance performance is improved up to four times more than other alternatives shows the highest performance index of 83.86.