• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.245-248
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• 2008

Recently, much research has been conducted on FRP composite to replace steel. However, the concept of FRP girder filled with concrete has not been fully attempted. This study focuses on the analytical behavior of FRP girders filled with concrete. FRP girders usually have large deflection due to relatively low elastic modulus compared to steel members. However, in the previous experimental investigation on small sized modular beams, it has been verified that the displacement of FRP-girder filled with concrete is reduced and the strength is increased considerably. In this research, analytical investigations have conducted to verify the analytical method by comparing the results with tests. In addition, analyses on large girders assembled with small modules have been carried out to predict the feasibility before tests. The analytical results showed that the assembled FRP girders can be used as substitutes for steel girders.

• Journal of Korean Society of Steel Construction
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• v.18 no.2
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• pp.261-270
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• 2006

In this paper, the basic data regarding the application of the MSC (Modular Steel Concrete) beam are presented by comparing the experimental value with the theoretical value, focusing on the bending behavior of the Lip-type MSC beam, which is composed of steel and concrete. Considerable manpower is needed to fabricate the traditional MSC beam, particularly for the tasks of cutting, welding, etc. Because much time is needed to fabricate the traditional SC beam, the prefabrication concept is introduced, easily produce the required size of the SC beam by prefabricating the side module and the lower module, which is made up of a steel sheet. The result indicates that the method of uniting the modules, an d the composition method with concrete, should be improved. The proposed MSC beam can be used as a new structural member by increasing its coherent reinforcement with modules and the composition ratio of steel and concrete through a future study.

• The Journal of the Korea Contents Association
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• v.13 no.9
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• pp.410-417
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• 2013

Long-term behavior analysis considering construction sequence should be performed in the design and the actual construction of reinforced tall buildings. Most of the analytical studies on this subject, however, has not been applied directly to the structural design and the construction caused by the simple approach. As the axial force redistribution of shores and columns is time-dependent, the actual construction sequence with the placement of concrete, form removal, reshoring, shore removal, and the additional load application is very important. Object-oriented analysis program considering construction sequence, especially time-dependent deformation in early days, is developed. This system is composed of input module, database module, database store module, analysis module, and result generation module. Linkage interface between the central database and each of the related module is implemented by the visual c# concept. Graphic user interface and the relational database table are supported for user's convenience.

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.2
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• pp.68-75
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• 2022

In this study, in order to directly evaluate the prestress of the PSC structure, a new sensor module based on the measurement of the deformation of concrete was proposed using hetero-core optical fibers and performance tests were performed. In a hetero-core optical fiber, optical loss occurs when a specific part of the transmission path is bent, and the amount of optical loss changes linearly according to the magnitude of the curvature. In order to confirm the measurement performance of the sensor module and the applicability of the optical fiber, the sensor module was deformed and the light passing through the optical fiber was converted into wattage and measured. It can be seen that the light passing through the optical fiber has a linearity of 0.9333 in relation to the deformation while generating the maximum deformation of 0.5 mm at a rate of 0.12 mm/min in a cylindrical concrete specimen with a diameter of 15 cm and a height of 35 cm in which the sensor module is embedded. Based on the results of this experiment, it is judged that it is possible to directly evaluate the prestress of a PSC structure by embedding a sensor module using a hetero-core optical fiber in the structure and measuring the compression deformation in concrete. It is judged that it can be used as useful data for the development of a sheath tube integrated sensor module to be applied to be applied to the girder model experiment.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.2A
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• pp.75-83
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• 2012

In this study, an analytical studies were carried out for the buoyancy preflexion method to improve structural performance of concrete floating structures. The buoyancy preflexion means that the preflexion effects were induced to the floating structure due to the difference in buoyancy between the pontoon modules composing the floating structures. In order to verify the buoyancy preflexion effects, an analytical studies were carried out for the floating structures. The size and dimensions of FE model were determined through the structural design process. The parameter of this analytical study was length ratios of central module part, which induces buoyancy preflexion effects, to the total length. The analysis results were pre-compression on the bottom concrete slab and displacement of freeboard due to buoyancy preflexion effects. These results were processed according to the loading step, buoyancy preflexion loads on the bottom and live loads on the topside. Then, the buoyancy preflexion effects on structural performance was analyzed. As the results of this study, it was found that the buoyancy preflexion significantly influence on structural performance of floating structures. According to the length ratio, the buoyancy preflexion effects have a tendency of parabolic form and maximized at the length ratio of 40~60%. The buoyancy preflexion method is simple in principle and easy in application. Also, it can effectively induce pre-compression on the bottom concrete slab. Therefore, it can be concluded that the buoyancy preflexion method contribute to the improvement of structural performance and decreasing of the cross-sectional depth of floating structures.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2011.11a
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• pp.133-135
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• 2011

플로팅 건축구조용 콘크리트 부유체 구조는 현장 근처의 제작장에서 제작한 후에 제작된 부재를 현장으로 이동하여 가설장비를 이용해 각 부재를 조립해서 부유체 구조를 완성하는 방법인 프리캐스트 부재 방법을 적용하는 것이 유리하다. 따라서, 연결부의 기능과 구조적 성능을 최대한으로 유지시킬 수 있는 적절한 연결기법을 적용해야 한다. 본 연구에서는 콘크리트 부유체 연결부의 강도특성연구를 수행하였다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2008.11a
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• pp.334-339
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• 2008

Construction that over 70% of the structure consists of concrete gets bigger and higher gradually and the demand of that is increasing as well. However, it's not easy to supply young and skilled persons on construction site because of social avoidance phenomena about 3D occupation, so it causes serious problems like aging and shortage of technicians. To solve the problems, executives related to the construction field make a management effort in various ways such as construction period shortening, labor productivity improvement and good quality but recently, they have an increasing interest in the necessity of the modularization of the high-rise building and the automation of the engineering development for the strengthening of international competitive power as more active and long-term alternatives. Therefore, this study is to propose the roadmap in order to make lots of efforts in developing construction technologies of high-rise buildings by performing a foundation study, the strategy for 4-step research development, on modularized construction system of concrete structure of high-rise buildings through domestic and foreign preceding research analyses associated with optimal design modularization technique, module factory automation and assembly automation of modularized objects.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2008.11a
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• pp.334-335
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• 2008

• Journal of Navigation and Port Research
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• v.37 no.2
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• pp.155-163
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• 2013

This study explores the structural behavior of module joints in floating concrete structures subjected to shear. Crack patterns, shear behavior and shear capacity of shear keys in joints of concrete module were investigated. Test parameters included shear key shape, or inclination of shear keys, confining stress levels and compressive strength of concrete. Test results showed that shear strength of joints increased as shear key inclination increased. Test results also showed that shear strength of concrete module joints increased with the increase of confining stress levels. The equation for predicting shear strength of joints was suggested, which was based on the test results. Shear strength prediction by using the equation suggested in this study showed good agreement with test results.

• The Journal of the Korea Contents Association
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• v.16 no.1
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• pp.52-59
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• 2016

For almost of concrete structures by placing in cold weather, it is very important that the selection of curing method at early aged construction stage. The Exothermic curing method with hot wire and rapid hardening cement is used mostly to prevent the initial cracks and the strength decrease. Most of the construction sites, however, have not been applied to the optimal curing method caused by the simple approaches and the empirical judgements. Therefore, this paper has proposed a evaluation algorithm of the exothermic curing method for representing heating temperature, period, position of hot wire by analyzing the transient heat transfer solution. This has been implemented, moreover, using an object oriented programming language to develop structural analysis system taking account risk parameters. This system is composed of input module, database module, database store module, analysis module, and result generation module. Linkage interface between the central database and each of the related module is implemented by the visual c# concept. Graphic user interface and the relational database table are supported for user's convenience.