• Proceedings of the Korean Institute of Building Construction Conference
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• 2007.11a
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• pp.71-74
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• 2007

With the changes of times the building materials tend to extend the demand for application under the special environment. Since high-ductile mortar is developed, the building materials show excellent performance like toughness, compression, tensile, and bending, etc. in the general concrete from the existing brittle point. And, recently they are widely used as repairing and reinforcing materials both at home and abroad because they are recognized as excellence like durability and fire-resistance. However, it is in a situation of creating problems in durability because it frequently happened deterioration of buildings that have already repaired and reinforced at a time when it requires reconstruction of recently deteriorated construction structure recently. Therefore, in this study improved with a more repair Material development and reinforcement of the second high-ductile mortar products for a variety of basic materials were presented want, research plans used include traditional repair materials and the newly developed PCM (polymer cement mortar) structural reinforcement type indicated that comparison. PCM analysis in order to present a rate depending on the types fiber 0, 1.2 and 2.0(%) at three levels and mixture water according to ratios of weight to Plain in the 2.0 and 1.85(kg) at two levels is set, the results were as follows. 1) This study has shown that PCM had excellent strain hardening behavior at the same time that the bending stress increased according to the fiber contents. 2) This study has shown that it had the durability performance due to the high substance transmission according to the fiber contents.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.18 no.3
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• pp.303-309
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• 2005

Numerical analysis is carried out to identify the appropriateness of the design codes that is available for the tensile design of fastening system at Nuclear Power Plant (NPP) in this study. This study is intended for the cast-in-place anchor that is widely used for the fastening of equipment in Korean NPPs. The microplane model and the elastic-perfectly plastic model are employed for the quasi-brittle material like concrete and for the ductile material like anchor bolt as constitutive model for numerical analysis and smeared crack model is employed to simulate the clack and damage phenomena. The developed numerical model is verified on a basis of the various test data of cast-in-place anchor. The appropriateness of both ACI 349 Code and CEB-FIP Code is evaluated for the tensile design of cast-in-place anchor and it is proved that both design codes give a conservative results for real tensile capacity of cast-in-place anchor.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.2
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• pp.121-128
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• 2014

In this study, The purpose of this study is to experimentally investigate the shear behavior of reinforced flat plate embedded with GFRP(glass fiber reinforced polymer) plate with openings. The GFRP shear reinforcement is manufactured into a plate shape with several openings to ensure perfect integration with concrete. The test was performed on 7 specimens. the parameters include the type of reinforcement and amount of the shear reinforcement., From the test, we analysed the crack, failure mode, Strain, load-displacement graph. a calculation of the shear strength of reinforced flat plate with GFRP plate based on the ACI 318-11 was compared with the test results. The results of the experiment indicate that GFRP plate is successfully applied as a shear reinforcement in the flat plate under punching shear.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.23 no.4
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• pp.285-291
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• 2011

In this study the mechanical performance of the new wave dissipating block is evaluated through experiment and numerical analysis. Also, by selecting adequate reinforcement, the improvement of the structural performance is examined. The reinforcement is designed by predicting the amount of tensile force and the location where the tensile stress develops in the new wave dissipating block through numerical analysis. The new wave dissipating block is reinforced with the ordinary steel bars and the fiber reinforced plastic(FRP) bars which have advantages in ocean environment in terms of corrosion and fatigue. The test result shows that the fracture resistance of the un-reinforced concrete block is 350 kN which is about 6.2 times that of the weight of the block. All the test blocks which are reinforced by either steel of FRP bars show strength capacity of over 900 kN which is the maximum load of the test equipment. Although the single reinforcement with larger-diameter bars has advantage in terms of construction convenience, it is recommended to use multiple number of smaller-diameter bars in order to reduce the crack width.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.11
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• pp.7244-7249
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• 2015

In this study, in order to asses the structural performance of trapezoidal PSC girder using a socket joint system and it is possible to calculate the optimized cross-section of the web element tests were carried out for each specimens. we conducted a socket joint performance test, web bending and shear performance tests and all tests were performed at 4 point loading method. The initial crack load of socket joint specimen was significantly lower than the reference specimen but post peak behavior was no significant differences. And the length of the loop joint of the reinforcing bars had no significant effect on the maximum load. As a web shear tests, to obtain a maximum load of the specimen has a prestressing rod reinforced at tension side. As a web flexural tests, to obtain higher diagonal cracking load in specimen of reinforced using prestressing rod than reference specimen.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.13 no.5
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• pp.38-50
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• 2010

Expressways are often upgraded by widening the lanes and/or by reshaping the roads to be more linear for faster travel time. However, during the process of improving the route of the expressways, the areas where the old expressways used to be are often unused and abandoned. When these neglected sites are left alone, they often become dump sites causing pollution and impacting the surrounding environment. Therefore, it is important to restore the abandoned expressway sites to its full natural beauty. In this study, the abandoned expressway at the Soksa interchange in Pyungchang county, located in Kangwon province was studied for establishing the model of ecological restoration project. Considering the characteristics of the site, the target flora species was chosen to be Quercus species and the target fauna species as amphibians. After the target species were carefully chosen, each species' habitat requirements were studied in order to figure out the appropriate methods toward habitat restoration specifically for these species. In addition, to determine the most efficient method toward restoration of abandoned expressways, the study utilized the planting hole techniques, the crack techniques, and the colonization techniques. In terms of the spatial organization, public education program is incorporated at the main entrance area and the programs for experimenting, and developing vegetation and habitat restoration techniques are placed in the vicinity. In the master plan-to provide natural ecosystem at the site-ASCON (asphalt concrete) was removed first, then plans for restoration including species' habitat restoration were established. Furthermore, the project included plans for improving water quality polluted through non-point source considering the surrounding nearby road and farm lands. Finally, the study established a planning process that will experimentally apply to the abandoned expressway restoration method. In the future, there will be a continuous monitoring of the methods applied to verify if the restoration methods are effective. Also, new restoration techniques should be available according to a variety of abandoned expressways' characteristics.

• International Journal of Highway Engineering
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• v.2 no.2
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• pp.129-138
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• 2000

This study presents the mechanical characteristics, such as the permanent deformation and the crack, of the large stone asphalt mixtures. The large stone mixture was studied by Kandhal at NCAT(National Center for Asphalt Technology) in 1989. Japan and Arabian countries adopted the large stone mixture for the pavement construction. The experience and the study results showed that the interlocking of the aggregate system of the large stone mixtures is stable and less dependent on the binder characteristics in high temperature. These properties are known as the rutting resistant parameters. However, the mechanical test results should be supported to prove the benefits of the large stone mixtures. The creep test, resilient modulus tests on three different temperature, wheel tracking test and ravelling tests were conducted to evaluate the performance of the large stone mixtures in this study. The test results were compared with the conventional mixtures and modified asphalt concrete mixtures. The large stone mixtures showed better rutting resistance performance.

• Journal of the Korean Recycled Construction Resources Institute
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• v.7 no.3
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• pp.210-215
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• 2019

Concrete members with wide surface area are vulnerable to cracking due to material behavior such as hydration heat and drying shrinkage. Recently many researches have been performed on improvement of strength and cracking resistance through fiber reinforcement, which are mainly focused on enhancement of tensile strength against cracking due to material behavior. In this paper, CFs(Cellulous Fibers) are manufactured for slurry type, and the engineering properties in cement mortar incorporated with CFs are evaluated for flow-ability, compressive, and flexural strength. Through SEM analysis, a pull-off characteristics of CF in matrix are analyzed. With CF addition of $0.5kg/m^3{\sim}1.0kg/m^3$, flexural strength is much improved and enough toughness of pull-off is also observed unlike plastic fiber containing smooth surface.

• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.105-112
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• 2019

Fine aggregate made of ferronickel slag(FNS) is similar to natural fine aggregates and is used in concrete structures both domestically and abroad, but its applications and research areas are limited. In this research, in order to expand the availability of FNS and improve the performance of cement mortar products, the applicability of FNS on dry mortar for floor was examined. Experimental results show that FNS improves flow of cement mortar because it has low absorption rate, spherical shape, and glassy surface. Also, the high stiffness of the FNS aggregate itself is considered to contribute to the improvement of cement mortar quality such as crack reduction by improving the compressive strength and shrinkage reducing. In addition, when FNS fine aggregate is applied, it was possible to secure the impact sound insulation performance equal to or higher than that of mortar using natural fine aggregate.

• Advances in Computational Design
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• v.7 no.3
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• pp.229-251
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• 2022

In 2017, an intraplate earthquake of Mw 7.1 occurred 120 km from Mexico City (CDMX). Most collapsed structural buildings stroked by the earthquake were flat slab systems joined to reinforced concrete (RC) columns, unreinforced masonry, confined masonry, and dual systems. This article presents the simulated response of an actual six-story RC frame building with masonry infill walls that did not collapse during the 2017 earthquake. It has a structural system similar to that of many of the collapsed buildings and is located in a high seismic amplification zone. Five 3D numerical models were used in the study to model the seismic response of the building. The building dynamic properties were identified using an ambient vibration test (AVT), enabling validation of the building's finite element models. Several assumptions were made to calibrate the numerical model to the properties identified from the AVT, such as the presence of adjacent buildings, variations in masonry properties, soil-foundation-structure interaction, and the contribution of non-structural elements. The results showed that the infill masonry wall would act as a compression strut and crack along the transverse direction because the shear stresses in the original model (0.85 MPa) exceeded the shear strength (0.38 MPa). In compression, the strut presents lower stresses (3.42 MPa) well below its capacity (6.8 MPa). Although the non-structural elements were not considered to be part of the lateral resistant system, the results showed that these elements could contribute by resisting part of the base shear force, reaching a force of 82 kN.