• Journal of Korean Society of Steel Construction
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• v.17 no.6 s.79
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• pp.673-679
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• 2005

According to continuous welded rails on a bridge, temperature changes bring about the expansion of the bridge deck,adding axial forces on the track. Moreover, the ballast on the bridge deck expansion joint is moved due to the bridge deck. The longer the bridge deck is, the greater the influence will be, loosening the ballast, causing track irregularities, and deteriorating passenger comfort. Considering the structure of the bridge itself and tolerance for track irregularities caused by the loosened ballast on the bridge, the maximum length of the deck should be less than 80 m, which is the same as the standard of French railways. In this study, the interaction between the expansion related to the bridge length and the irregularity in the longitudinal level, referring to measurements and maintenance work performed in high-speed railways, was analyzed. This research shows that the installation of a sliding plate or a vertical ballast stopper is not a good option, since it is difficult. On the other hand, the installation of a ZLR fastener or gluing is easy, but its influence is insignificant. In conclusion, switch tie tamping or manual tamping is more effective than other methods of what?

• Journal of the Korea Institute of Building Construction
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• v.11 no.4
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• pp.345-352
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• 2011

The purpose of this study was to investigate the expansion of alkali-activated mortar based on ground granulated blast furnace slag containing reactive aggregate due to alkali-silica reaction. In addition, this study was particularly concerned with the behavior of these alkaline materials in the presence of reactive aggregates. The experimental program included expansion measurement of the mortar bar specimens, as well as the determination of the morphology and composition of the alkali-silica reaction products by using scanning electron microscopy(SEM), and energy dispersive x-ray(EDX). The experiment showed that while alkali-activated ground granulated blast furnace slag mortars showed expansion due to the alkali-silica reaction, the expansion was 0.1% at Curing Day 14, showing that it is safe. After the accelerated test, SEM and BEM analysis showed the presence of alkali-silica gel and rim around the aggregate and cement paste. According to the EDX, the reaction products decreased markedly as alkali-activated ground granulated blast furnace slag was used. In addition, for the substitutive materials of mineral admixture, a further study on improving the quality of alkali-activated ground granulated blast furnace slag is needed to assure of the durability properties of concrete.

• Journal of the Korean GEO-environmental Society
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• v.20 no.2
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• pp.19-28
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• 2019

Grounds of the western coast of the Korean Peninsular are mostly composed of soft and cohesive soils, and it is necessary to carry out soil improvement before construction. The CGS (Compaction Grouting System) method has been commonly applied for the purpose of not only improving soft ground but also serving as the pile foundation of a bridge. In this paper, the CGS method was applied to the Incheon International Airport facility site, which consists of reclaimed landfill and soft clay soil, so as to evaluate the applicability of this soil improvement method to soft clay ground formations. Futhermore, results of construction were intensively studied along with a series of field experiments and theoretical consideration. The cone penetration tests were performed to assess the ground improvement effect of the CGS method. Consequently, the application of CGS method led to an increase in soil strength enough to be used as the pile foundation to support the bridge at the site. In addition, the size of the upper grout-bulb was estimated by adopting the cavity expansion theory and compared with that of actual grout bulb exhumed in the field. Therefore, it is proved that the cavity expansion theory can be utilized to predict and evaluate the improvement of soft ground.

• Journal of the Korean Geotechnical Society
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• v.25 no.7
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• pp.35-46
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• 2009

Pressure grouting is a common technique in geotechnical engineering to increase the stiffness and strength of the ground mass and to fill boreholes or void space in a tunnel lining and so on. Recently, the pressure grouting has been applied to a soil-nailing system which is widely used to improve slope stability. The soil-nailing design has been empirically performed in most geotechnical applications because the interaction between pressurized grouting paste and the adjacent ground mass is complicated and difficult to analyze. The purpose of this study is to analyze the increase of pullout resistance induced by pressurized grouting with the aid of performing laboratory model tests and field tests. In this paper, two main causes of pullout resistance increases induced by pressurized grouting were verified: the increase of mean normal stress and the increase of coefficient of pullout friction. From laboratory tests, it was found that dilatancy angle could be estimated by modified cavity expansion theory using the measured wall displacements. The radial displacement increases with dilatancy angle decrease and the dilatancy angle increases with injection pressure increase. The measured pullout resistance obtained from field tests is in good agreement with the estimated one from the modified cavity expansion theory.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.59
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• pp.27-57
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• 2013

Traditionally construction has been an industry that favoured ADR over formal litigation due to the complexity of technical issues. However, over the past decade construction arbitration has come under increasing attack for its rising costs and growing delays, and expansion of arbitration processes to the point that those processes are approaching the more complex and formal processes followed to resolve disputes litigation. As a result, parties are looking for new methods of resolving their disputes in a more efficient and economical manner, such as ODR. A review of the history of ODR and the practical applications of ODR in use today lead to the conclusion that the concept of ODR for construction dispute resolution appears to be possible and realistic. The advantages seem to outweigh the disadvantages, especially given the solutions suggested to overcome many of the disadvantages. While ODR may not be a realistic venue for large complex construction cases, it may be just the ideal venue for smaller and simple construction disputes. In conclusion, given the advantages that ODR arbitration does offer, the most realistic use of ODR in the short term would involve disputes consisting of a simple, one-dimensional dispute within which the parties can stipulate to the facts in the case. In such simple disputes ODR may be not only an appropriate vehicle within which the dispute can be resolved; it might be more easily accepted by the parties as the preferred platform for resolution. Hopefully, international institutions of arbitration will be successful in their development of a international standards and platform fir disputes that can be adapted for use in construction and will serve as the first step in developing ways to handle small construction claims, thereby allowing parties to resolve their disputes in a faster and more economical manner.

• Korean Journal of Construction Engineering and Management
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• v.16 no.3
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• pp.78-90
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• 2015

Due to a significant decrease in the number of construction projects in the domestic market of Korea, overseas expansion of the Korean construction companies has been accelerated in recent years. However, the practice of bidding at a low price and lacking information about foreign new markets caused many companies to fail in their entries to these markets. As a measure to prevent such failures, this study has developed a framework which first defines the key research items that must be identified beforehand and then classifies them into a structured way so that the construction companies can actually use this framework to be better prepared for their forays into the new markets. The framework was actually applied for a construction project in Morocco, and its usefulness was proven by the user's successful participation into the project, nevertheless the application and result was limited. Although perhaps this framework should be applied to many more construction projects for its validity to be verified and for its structure to be better standardized, the framework still has its value due to the following two reasons: first, it has systemized the research items that had been only conceptually defined but had never been organized, and second it can be utilized as a investigation tool at the marketing stage.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.382-387
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• 2008

Current global construction market has grown at a dramatic expansion rate every year in connection with more market accessibility by foreign contractors. The market openness is largely due to globalization of world construction markets, rapid development of world-wide telecommunication technologies, the formation of collaborative acquisitions and joint ventures among contractors, development of regional Free Trade Blocks, and just name a few. This paper focuses on the formation of collaborative networks when expanding into new foreign markets. The social network analysis (SNA) is introduced to investigate a variety of the collaboration patterns and also their impacts on the performance. To this end, the collaboration cases of 600 international construction projects performed by Korean contractors since 1990 were collected and classified into firm's size, project types, collaboration modes, and performance levels using social network analysis. The results showed a direction in establishing business strategy associated with experienced or inexperienced contractors in international construction projects.

• Journal of the Korea Institute of Construction Safety
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• v.3 no.1
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• pp.25-31
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• 2020

While the disaster rate in all industries has been on a steady decline over the past decade, the accident rate in the construction industry has been on the rise, and it is urgent to improve it. The purpose of this study is to compare and analyze domestic design safety review system with overseas cases to derive problems of domestic design for safety review system and find ways to improve it. Like U.K and Singapore, it should be reviewed from the beginning of the working design, and Safety reviews should be conducted not only in large-scale construction but also in small-scale construction to reduce construction industry disasters. In particular, it is necessary to prepare a system for the lack of related systems, and the Design for safety system is meaningful in that it is an expansion of the spectrum from operator-centered safety management system and requires sufficient improvement and research in the future.

• Journal of the Korean GEO-environmental Society
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• v.24 no.5
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• pp.5-12
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• 2023

Recently, due to urban development and expansion, construction plans have been increasing adjacent to existing tunnel structures such as subways, roads, and large pipelines. Structural plans adjacent to existing tunnels have different effects on tunnel stability depending on the construction method, degree of proximity, and location of new structures. In particular, the pressure water tunnel shows a very large difference from other road tunnels and railway tunnels in geotechnical characteristics and operation characteristics. Therefore, it is necessary to review the safety zone due to adjacent construction in consideration of the geotechnical characteristics of the water tunnel and the new sturure construction method. In this study, the existing tunnel safety zone standards were investigated. A stability evaluation performed numerical analysis considering the deterioration of concrete lining in operation and the characteristics of water tunnel. In addition, the impact of vibration caused by pile construction and blasting excavation of new structures was reviewed. Based on this, a pressure water tunnel safety zone was proposed in consideration of adjacent construction.

• Journal of the Korean Professional Engineers Association
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• v.27 no.4
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• pp.46-55
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• 1994

Demand Side Management(DSM) is a system to reduce the investment cost for new power plant construction and expansion of supply facilities, power through the investment for the energy conservation and load management. In this study, the trend of the energy environment, the necessity and feasibility of DSM shall be investigated and analysed, so that this study will give a help to select and develope a proper DSM technologies for actual use.