• Journal of the Korea Concrete Institute
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• v.27 no.2
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• pp.157-167
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• 2015

Cement composites subjected to high-velocity projectile shows local failure and it can be suppressed by improvement of flexural toughness with reinforcement of fiber. Therefore, researches on impact resistance performance of cement composites are in progress and a number of types of fiber reinforcement are being developed. Since bonding properties of fiber with matrix, specific surface area and numbers of fiber are different by fiber reinforcement type, mechanical properties of fiber reinforced cement composites and improvement of impact resistance performance need to be considered. In this study, improvement of flexural toughness and failure reduction effect by impact of high-velocity projectile have been evaluated according to fiber type by mixing steel fiber, polyamide, nylon and polyethylene which are have different shape and mechanical properties. As results, flexural toughness was improved by redistribution of stress and crack prevention with bridge effect of reinforced fibers, and scabbing by high-velocity impact was suppressed. Since it is possible to decrease scabbing limit thickness from impact energy, thickness can be thinner when it is applied to protection. Scabbing of steel fiber reinforced cement composites was occurred and it was observed that desquamation of partial fragment was suppressed by adhesion between fiber and matrix. Scabbing by high-velocity impact of synthetic fiber reinforced cement composites was decreased by microcrack, impact wave neutralization and energy dispersion with a large number of fibers.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2A
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• pp.115-120
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• 2011

The strength of reinforced concrete members has uncertainty from material properties of, concrete and reinforcements, section dimensions, and construction errors and so on. The accurate evaluation of these uncertainties is necessary to assure the reasonable safety. The uncertainties should be taken into account in design using structural reliability theory which requires probabilistic models for such uncertainties. In current Korean design code, most reliability evaluations were performed based on foreign data because of lack of local data. In this paper, the probabilistic models for yield strength of reinforcements were developed based on local data. The effects of various factors, nominal yield strength, diameter of reinforcements, and companies, on the models are also examined. According to data analysed, the effects of those factors are not significant. The probability model for yield strength of reinforcements in Korea can be expressed with Beta distribution based on collected data.

• Journal of The Korea Institute of Healthcare Architecture
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• v.11 no.2
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• pp.73-81
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• 2005

The disabled has remarkable difficulties to participate social activities and those, that block them up from access to public facilities and the comfortable habitation so they should get help from others, are mainly made by architectural facts. Buildings without impediment which consider the disabled would be the things responding to the needs of the times. If the disabled would be convenient to use facilities, there should be no difficulties to normal people. A first began to examine into the role of the architecture. And to establish radical standards for the disabled to use cultural and assembly facilities through scrutinizing facilities to get access for the disabled and movement circulations in the cultural facilities should be the conclusion. This study which is a kind of fundamental study to construct cultural facilities without obstacles for the disabled began from consideration for the problem flow line of the disabled in cultural facilities and analyzed flow lines for them to use, access, and evacuate from those which are main facilities in the region. Though, evacuation rules in cultural and assembly facilities are recommendatory in existing laws for convenience of the disabled, the congestion of the crowd coming out after performances impedes safe flows of both the disabled and crowds. Further, in case of evacuation, there would be more serious problems. Therefore, consideration of reinforcement for existing laws for convenience of the disabled is needed.

• Journal of the Korea Concrete Institute
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• v.22 no.6
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• pp.805-816
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• 2010

For earthquake simulation test it is essential to make sure the similitude in behaviors between the full scale prototype and the reduced scale model. This paper presents the test results obtained through the cyclic lateral-force test, on two-story RC wall subassemblages. A lower 2-story portion of the prototype structure was selected as subassemblages. The global behavior such as the strength and ductility, and the local behavior such as flexural, shear and uplift deformation were measured. The test results of the 3 : 5 scale specimens representing the prototype were compared with those of 1 : 7 scale models. Two types of subassemblages were used: One with lintel beams and one without lintel beams. The comparison shows that 1 : 7 scale model simulated in general successfully the global and local behaviors of the prototype.

• International Area Studies Review
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• v.14 no.3
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• pp.131-154
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• 2010

This study tries to analyze what the most significant factors are in Brazil, where the Korean investing firms have to overcome and adapt to various difficulties, especially in terms of political environment. This main purpose of this research is to test empirically some relations of between the managing strategy of Korean firms and the environment factors of politics in Brazil while this is conducted in two stages. First, the research model is designed by reviewing relevant theories, previous studies, and the current investment conditions in local Brazil. Second, the survey of Korean firms engaged in investment activities in there is done by collecting questionnaires from them. with this survey, the strategic method of multiple regression is used to testing some hypotheses. At the result of Analysis, It is proved there haven been negative affecting political factors of law/regulation system and administrative operation service, and Korean firms have implementing the responding management strategies with reasonable adaptation to risks and human network reinforcement.

• Journal of Society of Preventive Korean Medicine
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• v.24 no.3
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• pp.57-67
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• 2020

Background : The Life cycle Health Promotion Programs using Traditional Korean Medicine (the Life cycle HaPPs-TKM) are the on-going 3rd stage projects that have centered on the development and dissemination of the standard life cycle HaPPs-TKM in the local community. The purpose of the study was to introduce the development background of the standard life cycle HaPPs-TKM and to suggest its activation plan. Methods : Academic and government research reports on the life cycle HaPPs-TKM were analyzed to introduce the development process, development backgrounds and the details of KM-HPP for each life cycle, such as infants and toddlers, adolescents, pregnant women, adults and the elderly. Results : We reviewed the development process of the standard life cycle HaPP-TKM consisted of a series of diagnosis on community members' health problems, establishment of project purpose, research on the involvement of KM intervention in a project, and final development of the project model. And we rediscovered that in the development backgrounds of KM-HPP, there were beneficial goals to manage and promote public health conditions for each life cycle. Conclusion : To activate life cycle HaPPs-TKM, we would recommend that activation plan should include six factors through systematic analysis of research reports. These factors consist of diversified goals for each life-cycle, competency reinforcement of local project manager, diversified Korean Medicinal modalities to enhance Sasang Constitution and Qigong, development of standard Outcome Index, periodical holding of performance contest, and improved guidance of government and associated entities through whole process of HaPP-TKM.

• Steel and Composite Structures
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• v.38 no.5
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• pp.563-582
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• 2021

The present study experimentally and analytically investigated the push-out behaviour of H-shaped steel section embedded in ultrahigh-performance fibre-reinforced concrete (UHPFRC). The effect of significant parameters such as the concrete types, fibre content, embedded steel length, transverse reinforcement ratio and concrete cover on the bond stress, development of bond stress along the embedded length and failure mechanism has been reported. The test results show that the bond slip behaviour of steel-UHPFRC is different from the bond slip behaviour of steel-normal concrete and steel-high strength concrete. The bond-slip curves of steel-normal concrete and steel-high strength concrete exhibit brittle behaviour, and the bond strength decreases rapidly after reaching the peak load, with a residual bond strength of approximately one-half of the peak bond strength. The bond-slip curves of steel-UHPFRC show an obvious ductility, which exhibits a unique displacement pseudoplastic effect. The residual bond strength can still reach from 80% to 90% of the peak bond strength. Compared to steel-normal concrete, the transverse confinement of stirrups has a limited effect on the bond strength in the steel-UHPFRC substrate, but a higher stirrup ratio can improve cracking resistance. The experimental campaign quantifies the local bond stress development and finds that the strain distribution in steel follows an exponential rule along the steel embedded length. Based on the theory of mean bond and local bond stress, the present study proposes empirical approaches to predict the ultimate and residual bond resistance with satisfactory precision. The research findings serve to explain the interface bond mechanism between UHPFRC and steel, which is significant for the design of steel-UHPFRC composite structures and verify the feasibility of eliminating longitudinal rebars and stirrups by using UHPFRC in composite columns.

• Geomechanics and Engineering
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• v.25 no.3
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• pp.195-205
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• 2021

Time effect on the deformation and strength characteristics of geogrid reinforced sand retaining wall has become an important issue in geotechnical and transportation engineering. Three physical model tests on geogrid reinforced sand retaining walls performed under various loading conditions were simulated to study their rate-dependent behaviors, using the presented nonlinear finite element method (FEM) analysis procedure. This FEM was based on the dynamic relaxation method and return mapping scheme, in which the combined effects of the rate-dependent behaviors of both the backfill soil and the geosynthetic reinforcement have been included. The rate-dependent behaviors of sands and geogrids should be attributed to the viscous property of materials, which can be described by the unified three-component elasto-viscoplastic constitutive model. By comparing the FEM simulations and the test results, it can be found that the present FEM was able to be successfully extended to the boundary value problems of geosynthetic reinforced soil retaining walls. The deformation and strength characteristics of the geogrid reinforced sand retaining walls can be well reproduced. Loading rate effect, the trends of jump in footing pressure upon the step-changes in the loading rate, occurred not only on sands and geogrids but also on geogrid reinforced sands retaining walls. The lateral earth pressure distributions against the back of retaining wall, the local tensile force in the geogrid arranged in the retaining wall and the local stresses beneath the footing under various loading conditions can also be predicted well in the FEM simulations.

• Korean Journal of Heritage: History & Science
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• v.54 no.3
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• pp.106-125
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• 2021

This paper presents several reasons for the necessity of archaeological hands-on training and strategies for its implementation. First, it is necessary to produce a specialized manual for local cultural heritage education that can enhance the specialization and educational effectiveness of archaeological experience education. In addition, in order to secure professionalism in hands-on education and conduct it systematically, the ability of instructors to conduct education is important, so instructor competence reinforcement education needs to be conducted regularly. In addition, hands-on education needs a strategy of planning and content development of archaeological education programs, with consideration given to the subjects of learning, and the establishment of a cooperative network. It is time to cooperate with various experts to establish an education system necessary for cultural heritage education in the region and develop customized content for local archaeological heritage supplementary textbooks. Finally, due to Covid-19, we agonized over effective education plans for online archaeological heritage education, which requires active interaction class design and a strategy to promote interaction between professors and learners. In addition, such archaeological heritage education should be compatible with the goal of providing customized lifelong education.

• Korean Journal of Heritage: History & Science
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• v.43 no.1
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• pp.56-85
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• 2010

UNESCO World Heritage Programme was introduced following the adoption of Convention Concerning the Protection of the World Cultural and Natural Heritage by the General Conference of UNESCO in 1972 in order to protect cultural and natural heritage with superb value for all mankind. Despite its short history of less than 40 years, it has been evaluated as one of the most successful of the cultural area projects of UNESCO with 890 world heritage registered worldwide. For systematic protection management of World Heritage, UNESCO, through systemization of registration, emphasis on the importance of preservation management plan, institutionalization of monitoring, and operation of World Heritage Fund, has utilized World Heritage Programme not just as a means of listing excellent cultural properties, but as a preservation planning tool, and accordingly, such policies have had a significant influence on the cultural heritage protection legislations of numerous nations. Korea has ratified World Heritage Convention in 1988, and with the registration of the Royal Tombs of the Joseon Dynasty in 2009, it has 9 World Heritage Sites. Twenty years have passed since Korea joined the World Heritage Programme. While World Heritage registration contributed to publicity of the uniqueness and excellence of Korean cultural properties and improvement of Korea's national culture status, it is now time to devise various legislative/systematic improvement means to reconsider the World Heritage registration strategy and establish a systematic preservation management system. While up until now, the Cultural Properties Protection Law has been amended to arrange for basic rules regarding registration and protection of World Heritage Sites, and some local governments have founded bodies exclusive for World Heritage Site management, a more fundamental and macroscopic plan for World Heritage policy improvement must be sought. Projects and programs in each area for reinforcement of World Heritage policy capacity such as: 1) Enactment of a special law for World Heritage Site preservation management; 2) enactment of ordinances for protection of World Heritage Sites per each local government; 3) reinforcement of policies and management functionality of Cultural Heritage Administration and local governments; 4) dramatic increase in the finances of World Heritage Site protection; 5) requirement to establish plan for World Heritage Site preservation protection; 6) increased support for utilization of World Heritage Sites; 7) substantiation and diversification of World Heritage registration; 8) sharing of information and experiences of World Heritage Sites management among local governments; 9) installation of World Heritage Sites integral archive; 10) revitalization of citizen cooperation and resident participation; 11) training specialized resources for World Heritage Sites protection; 12) revitalization of sustainable World Heritage Sites tourism, must be selected and promoted systematically. Regarding how World Heritage Programme should be domestically accepted and developed, the methods for systemization, scientific approach, and specialization of World Heritage policies were suggested per type. In the future, in-depth and specialized researches and studies should follow.