• Tunnel and Underground Space
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• v.21 no.4
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• pp.251-263
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• 2011

The geomechanical characteristics of rock and the structural geological feature of the fault should be studied and examined for the successful construction of large-span tunnel. In this case study, that is a important case for the tunnel collapse and reinforcement during the construction for the waterway tunnel at large thrust fault zone in schist, we carried out geological and geotechnical survey for make the cause and mechanism of tunnel collapse. Also, we have designed the reinforcement and re-excavation for the safe construction for collapse zone and have carried out successfully the re-excavation and finished the final concrete lining.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.1
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• pp.243-250
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• 2005

In elevated irrigation aquaducts, one can observe a common damage pattern. That is, cracks, and crushing of concrete are usually repeated at a certain interval even if no faults are found in the design and construction of the structures. To investigate the causes of this damage, longitudinal deformations of several aquaducts have been measured. The analysis of the measured data suggests that the damages are mainly caused by cumulative repetition of extension and contraction due to temperature changes.

• Journal of the Korea institute for structural maintenance and inspection
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• v.11 no.5
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• pp.123-134
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• 2007

A method to determine the initial force of external tendon is proposed to improve the load carrying capacity in existing steel-concrete composite bridges. This method is applied to tensioning external tendons prior to and after concrete replacement for strengthening composite girders. A procedure to determine the number of tendon and initial tendon force is described with the proposed rating factor, which considers the increment of tendon force due to live loads. The method is applied to the improvement of rating factor in an existing composite bridge and its validity is confirmed.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.7
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• pp.5021-5028
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• 2015

Previous studies have considered the permeability and construction method of paving materials, thus focusing on more practical issues rather than basic research of their properties. The present study investigated the possibility of using an elastic paving material having lesser thickness in the resurfacing of existing concrete or asphalt paved areas while satisfying the necessary conditions of resilience and water permeability. An alternative to complete reconstruction would reduce the amount of resource wastage and environmental pollution, as well as the cost of projects. This study investigated five variants of thickness (10, 13, 15, 20, 25mm) and three mixing ratios of binder to rubber chips (20, 22.5, 25%) to ascertain the ideal basic properties of each. The obtained test data revealed that a minimum thickness(10~25mm) of the elastic paving materials can be determined from a qualitative point of view, and alternatives should be provided to improve the durability of the paving material on account of the temperature sensitivity.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.99-105
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• 2008

For large-scale projects, supply chain management of construction materials is a key to a successful construction project. Inefficient management would cause significant loss in project cost, quality problems (and possible re-work), delayed delivery, claims, etc. On the other hand, efficient supply chain management system can reduce risks even the given project suffers from tricky details and frequent changes thanks to reduced material loss, shortened delivery time, and the quality outcome; this is a win-win situation for both clients and contractors. This paper presents a next-generation intelligent supply chain management system, which is intended to support large-scale construction projects such as urban high-rise buildings, as a strategic vision of the future construction logistics.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.24 no.3
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• pp.251-259
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• 2006

For the electrification of the existing railways, the security of the restriction boundary of building with mechanistic stability research on the antiquated tunnel must be accomplished essentially. If the tunnel don't secure its restriction boundary of building, the reconstruction based on improvement of tunnel alignment are generated and its surveying data are required. The precise surveying was conducted with the same coordinate system for three tunnels of Youngdong tramline, and the restriction boundary of building of the straight and curve section were analyzed effectively by acquiring the data of profile and cross section, profile rail-height, rail-grade, cross tunnel height, and restriction boundary of building. This study is presented for valuation data of the stability of the electrification design to construct and analyze restriction boundary of building, which compared with the drawing and its existing design using profile and cross section. After this, it is interoperable to increase the development of real-time monitoring system on the tunnel structures.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.141-141
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• 2016

방식 코팅 기술은 조선해양산업은 물론 에너지, 철강 및 비철 소재, 건설 산업 등 산업 전반에서 폭넓게 적용되고 있다. 또한 산업 고도화에 따라 점차 가혹해지는 소재의 적용 환경을 고려해보면 향후 지속적으로 산업 수요가 증대될 것으로 예상할 수 있는 기술이다. 특히 아크 열용사법을 이용한 방식 코팅 기술은 미국이나 일본과 같은 선진국에서는 해양플랜트, 석유 시추시설 등 대형 해양 구조물은 물론 다리, 항만시설과 같은 철재 또는 시멘트 구조물의 방식 기술로 널리 적용되어 일반화된 기술이다. 그러나 국내에서는 아직까지도 초기 비용 상승 및 미약한 관련 기술 등의 이유로 대부분 방식도료를 사용하고 있는 실정이다. 그리하여 단기 수명에 따른 재시공 시 많은 환경오염을 유발하는 방식도료를 대체할 수 있는 아크 열용사법을 이용한 방식코팅 기술에 대한 관심과 수요가 점차 증가되고 있다. 그 일환으로 본 연구에서는 해양 구조물 강재의 방식을 위해 니켈계 용사재료를 이용하여 아크 열용사 코팅을 실시한 후 다양한 전기화학적 실험을 통해 내식성을 평가하고자 하였다. 아크 열용사 코팅은 구조용 강재 SS400강에 대하여 니켈합금 선재(1.6 Ø)를 사용하여 실시하였다. 용사 시 용사거리는 200 mm, 공기압력은 약 $7kg/cm^2$ 정도로 유지하면서 용사코팅을 실시하여 약 $200-250{\mu}m$ 두께로 코팅 층을 형성시켰다. 그리고 전기화학적 실험은 천연해수 속에서 자체 제작한 홀더(holder)를 이용하여 $3.14cm^2$의 용사코팅 층만을 노출시켜 실시하였다. 그리고 기준전극은 은/염화은 전극을, 대극은 백금전극을 사용하였다. 전기화학적 실험을 통해 부동태 특성 및 용사코팅 층 표면의 양극 용해반응 특성을 분석하기 위한 양극분극 실험은 OCP로부터 +3.0 V까지 실시하였다. 또한 부식전위 및 부식전류밀도 분석을 위한 타펠분석은 OCP를 기준으로 -0.25에서 +0.25 V까지 분극시켜 실시하였다. 그리고 주사전자현미경과 3D 분석을 통해 부식손상 표면을 관찰하였다. 그 결과 니켈합금으로 용사코팅된 강재의 내식성이 상당히 향상되었다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.242-245
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• 2003

Most engineering tasks require collaboration between many users in major hospital Construction Projects that have many risks. Loss of cost and change orders occurred in factors such as information exchange, misunderstandings, advanced Technology in hospital projects. Moreover, changes in context, costs, requirements, deadlines, etc. require negotiation of issues that may modify important project characteristics. Each part of the major hospital construction projects have been rapidly changed technology of equipments. Therefore it is a major challenge to make a high level of communication and to have mutual understanding. The objective of this paper is to reduce risks for the design process and construction process of hospital projects.

• Tunnel and Underground Space
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• v.9 no.2
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• pp.114-130
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• 1999

It is very important to study on the structural behaviors of structurally damaged tunnel linings. A series of centrifuge model tests were performed in order to investigate different behaviors of tunnel linings. A 1/100-scaled aluminum horseshoe tunnel linings with a radius 5 cm, height 8 cm were buried in a depth with dry Joomunjin standard sand, the relative density of which was 86%. Such sectional forces as bending moments and thrusts along the tunnel circumference were measured by twelve strain gages. Earth pressures in soil mass and on the outside of lining model were estimated by pressure transducers, ground surface settlements at a center and edges by using LVDTs.

• Korean Journal of Construction Engineering and Management
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• v.11 no.2
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• pp.74-82
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• 2010

A government agency has been announced to increase 23,663 hundred million wons by cost of design change which occurred in the pre-construction and construction phase. As design change is a phenomenon to occur by means of a characteristic of the building design that standardization is difficult, even if it is said that a perfect design is done in design phase, design change is prevented, and it is going to decrease, and there is a limit. Because there are some causes in all of the construction project, it is change order of client, relative system, unfit design and field condition, etc. In this study, we are suggested logic and basic model of the decision making support process model that it should selecting the optimal alternative through complex and quantitative analyzed: that is cost, performance and constructability as respect Owner or CMr is executing project under the CM delivery system construction project which it occurred design change.