• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.273-276
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• 2008

Thermoplastic resin takes place stress relaxation and creep according to temperature and time. In room temperature, time dependent deformation (TDD) of polymer was carried out at previous study. In this study, it evaluates time dependent deformation to relate temperature. Nanoscale indents can be used as cells for molecular electronics and drug delivery, slots for integration into nanodevices, and defects for tailoring the structure and properties. Therefore, it is important to control pattern depth for change of indent depth by creep when using Nanoindenter. For evaluating TDD at high temperature, it is occurred thermal-nanoindentation test by changing hold time at maximum load. Temperature is putted at $90^{\circ}C$, hold time at maximum loads are putted at 1, 10, 50, 100, 200, 300 and 500s.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.709-712
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• 2008

RC super tall buildings are planned and constructed recently in domestic area. Concrete is characterized by time dependant material such as creep and shrinkage. For this properties of concrete, differential shortening is one of the main issues on super tall buildings construction. This study includes material research, which is performing as a pre design stage to solve differential shortening on Lotte Super Tower Jamsil core structure(50, 60, & 70 MPa). The major part of this study is composed with comparison and analysis between experimental data and predicted data on total shrinkage and total compliance which were used on design stage. Four models, ACI209R Model, Ba${\check{z}}$ant-Baweja B3 Model, CEB MC99 Model, & GL2000 Model, were employed to predict them. It also tries to seek a proper model for high strength and high performance concrete in the case of no concrete test.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.331-340
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• 2002

In this paper, finite element analysis is applied for simulation of cracks due to restraining autogenous and drying shrinkage at early-age concrete. A micro-level heat hydration model and a shrinkage prediction model along with a moisture diffusion model are adopted for the finite element analysis. Then, an axial restraint test is carried out for concrete specimens containing different amounts of chloride ions to evaluate stress development and cracking due to the restraining shrinkages at early ages. Test results show that the increase of contents of chloride ions increases restrained stress, but does not increase strength. By this increase of shrinkage strain at early-age, time to occur the crack is accelerated. Finally, stress development and cracking of concrete specimens containing different amount of chloride ions we simulated using the finite element analysis. Results of the analysis using the Proposed model are verified by comparison with test results.

• Magazine of the Korea Concrete Institute
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• v.10 no.6
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• pp.149-159
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• 1998

The reasonable prediction of time-dependent deformation of prestressed concrete(PSC) box girder bridges is very important for accurate construction as well as good serviceability. The long-term behavior is mostly influenced by the probabilistic characteristic of creep and shrinkage. This paper presents a method of statistical analysis and sensitivity analysis of creep and shrinkage effects in PSC box been taken into account - model uncertainty, parameter variation and environmental condition. The statistical and sensitivity analyses are performed by using the numerical simulation of Latin Hypercube sampling. For each sample, the time-dependent structural analysis is performed to produce response data, which are then statistically analyzed. The probabilistic prediction of the confidence limits on long-term effects of creep and shrinkage is then expressed. Three measure are examined to quantify the sensitivity of the outputs of each of the input variables. These are rank correlation coefficient(RCC), partical rank correlation coefficient(PRCC) and standardiozed rank regression coefficient(SRRC) computed on the ranks of the observations. Three creep and shrinkage models - i. e., ACI model. CEB-FIP model and the model in Korea Highway Bridge Specification - are studied. The creep model uncertainy factor and the relative humidity appear to be the most dominant factors with regard to the model output uncertainty.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.51-64
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• 2000

This paper presents a procedure of calculating a safety factor of the unsaturated slope suffering from the rainfall infiltration. The process of infiltration into a slope due to rainfall and its effect on the behavior of the soil slope are examined by using a two dimensional finite element flow-deformation coupled analysis. A factor of safety is calculated at various elapsed times after the commencement of rainfall as in the following procedure. First, stresses are estimated at each Gaussian point from the coupled finite element analysis. Then, the global stress smoothing method is applied to get a continuous stress field. Based on this stress field, a factor of safety is calculated for a specified slip surface by a stress integration scheme. Then, a search strategy is used to find out a critical slip surface which is associated with the minimum factor of safety. Some numerical examples are analyzed in order to study the effect of hydraulic conductivity on the slope stability during rain-induced infiltration. According to the results, local failure zone can be formed near the slope surface due to inhomogeneous distribution of hydraulic conductivity If the failure zone is once formed, then the region extends until a large amount of slide activates. Therefore the local failure can be neglected no longer in the stability analysis.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.6
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• pp.113-123
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• 2012

The technology developed for the decrease of applying loads and self-weight of a structure is to improve conventional Foam Cement Banking Method (FCB) by applying mixed slurry of bottom ash, cement and foams. Since the foam-mixed concrete, which is a major material of the Bottom ash-mixed Light weight concrete Banking method (BLB) developed, contains mineral admixture such as cement, the behavior shows time-dependent deformation and deterioration of durability due to environmental exposure. Thus, this study is subject to figure out the characteristics of long-termed behavior and durability of the developed method by carrying out experiments for schemed parameters, which are considered to be factors affecting mainly on concrete's characteristics from mechanical analysis. As results of tests, it was found that the developed concrete offers higher resistance than conventional foamed concrete in terms of long-termed behaviors associated with drying shrinkage and creep, and durability problems of freeze-thaw and carbonation processes, especially with addition of bottom ash.

• Journal of the Korea Concrete Institute
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• v.20 no.6
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• pp.765-772
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• 2008

For RC structures, long-term deformation occurs due to the inherent characteristics, which are creep and shrinkage. In terms of serviceability, it is important to limit deflection caused by the deformation to the allowable deflection. In the recent years, various repair and strengthening methods have been used to improve performance of the existing RC structures. One of the typical methods is FRP externally bonded method (EBR). Fiber reinforced polymer (FRP) has been used worldwide as repair and strengthening materials due to its superior properties. Besides, it has to offer improved strengthening performance not only under instantaneous load but sustained load. Therefore, accurate prediction method of deflection for the RC members externally bonded with FRP under sustained load is required. In this paper, three beams were fabricated. Two beams were externally strengthened with one of CFRP plate and GFRP plate respectively. Total three beams were superimposed under sustained load of 25 kN. During 470 days, deflections at midspan were obtained. Moreover, creep coefficients and shrinkage strains were calculated by using ACI-209 code and CEB-FIP code. In order to predict the deflection of the beams, EMM, AEMM, Branson's method and Mayer's method were used. Through the experiment, it was found that the specimen with CFRP plate has the most flexural capacity and Mayer's method is the most precise method to predict total long-term deflections.

• Journal of the Korea Concrete Institute
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• v.18 no.1 s.91
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• pp.29-36
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• 2006

Steel reinforced concrete(SRC) columns, which have been widely employed in high-rise buildings, exhibit a time-dependent behavior because of creep and shrinkage of concrete. This long-term behavior may cause a serious serviceability problem in structural systems, so it is very important to predict the deformation due to creep and shrinkage of concrete. However, it was found from the previous experimental studies that the long-term deformation of SRC columns was quite dissimilar from that of RC columns. A new method is required to quantitatively predict the long-term deformation of SRC columns. In this study, the causes of the discrepancy between the behaviors of RC and SRC columns are investigated and discussed. SRC columns exhibit a time-dependent relative humidity distribution in a cross section differently from that of reinforced concrete(RC) columns owing to the presence of a inner steel plate, which interferes with the moisture diffusion of concrete. This relative humidity distribution may reduce the drying shrinkage and the drying creep in comparison with RC columns. Therefore it is suggested that the differential moisture distribution should be taken into account in order to reasonably predict column shortening of SRC columns.

• Journal of the Korea Concrete Institute
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• v.14 no.3
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• pp.291-298
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• 2002

Recently, construction of reinforced concrete tall buildings is widely increased according to the improvement of material quality and design technology. Therefore, differential shortenings of columns due to elastic, creep, and shrinkage have been an important issue. But it has been neglected to predict the Inelastic behavior of RC structures even though those deformations make a serious problem on the partition wall, external cladding, duct, etc. In this paper, analysis system for prediction and compensation of the differential column shortenings considering time-dependent deformations and construction sequence is developed using the objected-oriented technique. Developed analysis system considers the construction sequence, especially time-dependent deformation in early days, and is composed of input module, database module, database store module, analysis module, and analysis result generation module. Graphic user interface(GUI) is supported for user's convenience. After performing the analysis, the output results like deflections and member forces according to the time can be observed in the generation module using the graphic diagram, table, and chart supported by the integrated environment.

• Journal of Korean Philosophical Society
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• no.120
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• pp.217-250
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• 2018

Subjekt oder $Selbstbewu{\ss}tsein$ ist ein grundlegendes Prinzip neuzeitlicher Philosophie. Das $Selbstbewu{\ss}tsein$ ist bei Kant $Selbstbewu{\ss}tsein$(analytische Einheit der Apperzeption als klare Selbstbeziehung) in Objekts $bewu{\ss}tsein$(synthetischer Einheit der Apperzeptuion). Dabei zeigt er ein Reflexionsmodell des $Selbstbewu{\ss}tseins$. Aber er $erkl{\ddot{a}}rt$ nicht systematisch ein $Verh{\ddot{a}}ltnis$ zwischen synthetischer Einheit und analytischer Einheit der Apperzeption, und auch $l{\ddot{o}}st$ er nicht theorienimmanente und formale Schwierigkeiten von Zirkelargument bzw. unendlicher Iteration in der Reflxionsstruktur des $Selbstbewu{\ss}tseins$. Aufgrund der Voraussetzungen seiner eigenen Fundamentalontologie kritisiert der $fr{\ddot{u}}he$ Heidegger, $da{\ss}$ Kants $traditionsabh{\ddot{a}}ngige$ $Subjektivit{\ddot{a}}tstheorie$ Symptome der Seins vergessenheit zeigt, transformiert Kants $Selbstbewu{\ss}tseinstheorie$, interpretiert Kants transformierte Theorie als $subjektivit{\ddot{a}}tstheoretische$ $Begr{\ddot{u}}ndung$ der traditionellen Ontologie von Vorhandenheit, und versteht sie als ersten Schritt und erstes phlosophisches Modell seiner Fundamentalontologie. Durch kritische Interpretation von Kants Lehre von Selbstaffektion und $Selbstbewu{\ss}tsein$ deutet er ein Modell des $Selbstbewu{\ss}tseins$ als des $ph{\ddot{a}}nomenologischen$ $Horizontsbewu{\ss}tseins$ an. In diesem Modell der vorreflexiven und unmittelbaren Selbstbeziehung entstehen Schwierigkeiten von Zirkelargument bzw. unendlicher Iteration nicht. Apel kritisiert Kants $selbstbewu{\ss}te$ Apperzeptionstheorie in dem Sinne, $da{\ss}$ sie solipsistisch sei, und in seiner Transzendentalpragmatik $vervollst{\ddot{a}}ndigt$ er Kants transzendentalphilosophische $G{\ddot{u}}ltigkeit$ in der Dimension von $Intersubjektivit{\ddot{a}}t$ diskurierender Menschen. Hierbei ersetzt die Kommunikationsgemeinschaft Kants Apperzeption oder $Bewu{\ss}tsein$ ${\ddot{u}}berhaupt$. In der transzendentalpragmatischen Sicht, die auf den sprachlichen Bezug des Denkens und Erkennens und die Kommunikationsgemeinschaft geht, beruht das $Selbstbewu{\ss}tsein$ oder die Reflexion des Subjekts wesentlich auf seinem sprachlich vermittelten sozialen Bezug. Also geht es nicht um Zirkelargument und unendliche Iteration in denkender Selbstbeziehung des Subjekts. Ebeling hebt Heideggers Daseinsanalytik auf das Niveau von Apels Transzendentalpragmatik an und entwickelt Fundamatalpragmatik ${\ddot{u}}ber$ $Widerstandsbewu{\ss}tsein$ gegen allgemeinen Tod. Dieser $Widerstandsbewu{\ss}tsein$ ist fundamentalpragmatische Transformation von Kants $Selbstbewu{\ss}tsein$. Der $Widerstandsbewu{\ss}tsein$ der Vernunft bleibt in der solipsistischen Dimension nicht und ist ein $Bewu{\ss}tsein$, das in der Widerstandsgemeinschaft durch Argumentation universalisiert werden kann. Hierbei geht es nicht um Zirkelargument und unendliche Iteration.