• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1695-1704
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• 2008

The problems associated with constructing high-speed concrete track embankments over soft compressible soil has lead to the development and/or extensive use of many of the ground improvement techniques used today. Drains, surcharge loading, and geosynthetic reinforcement, have all been used to solve the settlement and embankment stability issues associated with construction on soft soils. However, when time constraints are critical to the success of the project, owners have resorted to another innovative approach. Especially, the design criteria of residual settlement is limited as 30mm for concrete track embankment, it is very difficult to satisfy this standard using the former construction method. Pile net method consist of vertical columns that are designed to transfer the load of the embankment through the soft compressible soil layer to a firm foundation and one or more layers of geosynthetic reinforcement placed between the top of the columns and the bottom of the embankment. This paper will present the guidelines for the design of pile net method to supported embankments. These guidelines were developed based on a review of current design methodologies and a parametric study of design variables using numerical modeling.

• Journal of the Society of Naval Architects of Korea
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• v.46 no.3
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• pp.325-334
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• 2009

Generally, functional design of FPSO has been done by the engineering firm designated by ship owner. Main equipment such as topside facility is imported from abroad. But sometimes, OFE (Owner Furnished Equipment) does not satisfy the PND (Product Need Date) of each production stage because the delivery date of OFE is not scheduled to satisfy the PND. And sometimes many loose items and equipment are complex from engineering which does not consider pre-outfitting. Main objective of this study is process improvements by maximizing pre-outfitting rate in the stage of equipping STP (Submerged Turret Production), one of main equipment on FPSO. In this study, we analyzed the factors which obstructed pre-equipping STP using the past records of FPSO projects.

• Journal of Korean Institute of Industrial Engineers
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• v.42 no.4
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• pp.270-279
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• 2016

A glass product manufacturing company transports a large number of flat glass products from a manufacturing firm to a building construction site. The products are transported using specially designed racks, which assure fewer glass breakages during the deliveries. This study determines the sizes of the racks which minimize the total logistics cost including costs for rack purchasing, handling, transportation, and inventory costs. The determination of the rack size should consider tradeoff relationships between the amount of glasses piled in a rack and the number of racks loaded on a truck, and affects the required number of racks and the truck operational cost. A truck loading algorithm is proposed to maximize a high truck utilization, and an enumeration method is proposed to determine the optimal combination of rack sizes considering the total logistics cost. The numerical example is solved by using a real data.

• Steel and Composite Structures
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• v.50 no.4
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• pp.419-428
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• 2024

Prefabricated partially-encased composite (PEC) structural component is widely used in construction industry due to its superior structural performance and easy assembly characteristic. However, the solid web in traditional PEC components tends to split concrete into two halves, thus potentially reduces structural integrity and requires double concrete pouring. To overcome the above disadvantages, a new PEC beam with open-web π-shaped steel is proposed in this paper. Four open-web PEC beams with varying sectional height, flange thickness and web void rate were constructed and tested under flexural loads. During experimental tests, all beams exhibited typical flexural failure modes with strong moment capacities and excellent ductility. Owing to the unique construction form of web opening, steel-concrete bonding properties were enhanced and very small relative steel-concrete slips were observed. Experimental results also showed that the flexural capacity of such PEC beams increased with the increase of the sectional height and flange thickness, while was not affected by the web void rate. At last, a flexural capacity formula of the open-web PEC beam was proposed based on the whole section plastic rule. The formula results agreed well with experimental results.

• Korean Journal of Construction Engineering and Management
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• v.14 no.5
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• pp.122-130
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• 2013

As the level of competition has increased in the construction management market, it becomes a critical issue for CM firms to secure competitive edges. The objective of the study is to investigate elements of competitive strategy as perceived by CM firms and to discuss key features and implications. Michael Porter's Competitive Strategy Model was used as a framework to analyse the elements under three strategy categories. A major finding includes that Differentiation Strategy is generally perceived most important strategy category but, depending on the group to which a CM firm belongs, there exist a gap in the perception. However, regardless of the group, Cost Leadership is commonly considered least important strategy category. In particular, lowest-bidding strategy element showed the least importance. Understanding CM firms' perceptions on elements of competitive strategy provides an insight into CM firms' current strategy directions and can be useful for future tuning in a firms' own strategy.

• Korean Journal of Construction Engineering and Management
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• v.19 no.1
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• pp.74-79
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• 2018

The establishment of an effective bidding system is critical to ensure both the high quality of civil infrastructure and proper earning of contractors. However, the continuous changes of a bidding system in South Korea reveal that problems such as a dumping or high price winning have not been fully resolved yet. This study thus aims at understanding the bidding behavior and strategies of contractors by analyzing a tender ratio in historical data. Multiple regression analysis is conducted to understand the effect of internal and external factors (e.g., estimated cost, combined value of construction performance evaluation) on a tender ratio. The results statistically show that such factors affect the tender ratio an individual bidder determines and have the varying effect on the tender ratio by contractors' firm size.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.247-252
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• 2009

The LMC method of construction which have application to the road bridge is being considered the least relative importance about the watertight performance, because it focused on the durability of concrete. However, The LMC which is being expanded scope of application to the method of construction has grown importance about the watertight performance on the usability and maintenance side as well as durability. In this study, The latex concrete of two types which are different from mingled-ratio of the latex made a comparison to the compressive strength, watertight performance, dynamic wheel load resistance performance and confirmed what it has resistibility about chemical action through the chemical resistance test. The initial strength and watertight performance showed that were tendency the downward at 14 days. However, The long-term strength after 28 days showed that it has firm performance. In consequence, The initial curing of latex concrete is required to scrupulous care and attention at the site application. As a chemical resistance test result, The specimen that is steeped in sulphuric acid solution of 2% discovered the delamination phenomenon. However, it was confirmed that delamination phenomenon don't have an effect on the compressive strength. Moreover, As a dynamic wheel load resistance test result, The latex concrete was concluded to confirming the durability and running stability, because it had hardly any thickness reduction of latex concrete surface about dynamic wheel load and rarely found crack and delamination.

• Journal of the Korean Society of Safety
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• v.20 no.3 s.71
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• pp.120-125
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• 2005

Formwork is a temporary structure that supports its weight and that of freshly placed concrete as well as construction live loads. Among the accidents and failures that occur during concrete construction, many are formwork failures which usually happen at the time concrete is being placed. In constructions site, pipe supports are usually used as shores which are consisted of the slab formwork. The strength of a pipe support is decreasing as it is frequently being used at the construction site. The objective of this study is to find out the strength change of used pipe support and unused pipe supports according to aging. In this study, 2857 pipe supports were prepared. Among these pipe supports, 2337 pipe supports were lent to the construction companies fire of charge. 520 pipe supports were kept on the outside. Compressive strength was measured by knife edge test and plate test at each 3 month. Test results show that the strength of unused pipe supports as well as used pipe supports was decreasing according to age, use frequency and load carrier, and the strength of used pipe supports was lower than the strength of unused pipe supports at the same age. So, the strength of used pipe supports from 191 days to present day was not satisfied the specification of KS F 8001. According to these results, it shows that attention has to be paid to formwork design using used pipe supports. Therefore, the present study results will be able to provide a firm base to prevent formwork collapses.

• Proceedings of the Technology Innovation Conference
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• 1996.12a
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• pp.99-117
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• 1996

본 논문은 기업내의 수직적 기술이전 문제를 다룬 사례연구로서 한 건설업체의 연구소에서 이루어진 기술개발 결과가 사업부문의 현장에 이전 활용되는 과정에서 기술이전 정도가 어떤 요인에 의해 영향을 받는지 분석하였다. 사례분석 결과 D건설의 경우 기술이전팀 및 프로젝트 추진자(Project Champion)의 존재여부가 기술이전의 성패에 가장 큰 영향을 미치는 것으로 나타났으며 최고경영자의 적극적인 지원도 성공적인 기술이전에 강한 긍정적인 요인이 되는 것으로 분석되었다. 또한 당초 사례분석의 틀에서 고려하지 않았던 기술인지도나 기술수용자의 시장평가가 기술수용 노력에 영향을 미치는 것으로 분석되었다. 사내기술이전시 이러한 요인들을 고려한다면 보다 효과적인 기술이전이 될 것으로 기대된다.

• Proceedings of the KSR Conference
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• 2003.10b
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• pp.277-284
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• 2003

To meet demand for large-scale new personnel caused by active railway investment projects such as high-speed line construction, electrification and double-tracking of the existing lines, we KNR need to establish a subsidiary firm for each field instead of personnel augmentation. The establishment of subsidiaries is expected to solve the problem of the current outsourcing services, reduce costs and in the long term, improve the efficiency of railway business. In addition, we also suggest, as a pilot project, setting up Korean Freight Inspection Company in charge of conducting light and heavy maintenance for freight cars.