• Proceedings of the Korea Concrete Institute Conference
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• 2004.05a
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• pp.846-849
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• 2004

It is important to decide the precise chloride diffusion coefficient in order to predict the durability plan of concrete structure chloride and prediction of remaining lifetime. However, the inland references are limited to the rapid test in laboratory. The purpose of this study is to examine and analyze the established data, which are restricted by chloride diffusion coefficient, and to examine the prediction of the concrete structure durability by an FEM interpretation and the chloride diffusion coefficient as a variable.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.3
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• pp.33-44
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• 1999

An energy balance procedure is developed to incorporate the effects of earthquake duration which involves the effect of cyclic loading and the corresponding cumulative plastic deformation. Particular emphasis is given to the flexural failure of non-seismically designed columns of reinforced concrete frames. For this, conceptual strength deterioration models for columns, governed by concrete, anchorage failure and longitudinal steel fracture due to low-cycle fatigue, are proposed. It is evident that the energy-based method has good agreement with the experimental data and is able to predict the failure mode.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.291-296
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• 2000

In this paper a relatively simple and reliable wall models are investigated, which are suitable to be efficiently incorporated in a practical nonlinear seismic analysis of reinforced concrete shear wall structural systems. Four types of analogous frames have been selected for the elastic stress analysis. Three types of macro-elements model which include wide-column model, truss model and Kabeyasawa model, are chosen for the use in nonlinear analysis. A numerical analysis is carried out for six stories plane coupled wall structure. Analysis results indicate that macro-elements wall model is effective and suitable for simulating stress in elastic analysis. In inelastic analysis, the yielding strength have little effect on different wall model, and the effect on post-yielding stiffness in story shear-drift relationship depend on force-deformation properties of macro-elements.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.10a
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• pp.87-92
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• 2000

The real situation of an underground reinforced concrete(RC) structure with the surrounding soil medium subjected to seismic load is quite difficult to be simulated through an expensive work and, even if it is possible to arrange such an experiment, it will be too expensive. So development of analytical method can be applied usefully to seismic design and seismic retrofit through an analysis of seismic behavior and seismic performance evaluation. A path-dependent constitutive model for soil that can estimate the response of soil layer is indispensible for dealing with kinematic interaction of RC/soil entire system under seismic loads. And interface model which deals with the dynamic interaction of RC/soil entire system is also necessary. In this study, finite element analysis program that can consider path-dependent behavior of RC and soil, and interfacial behavior between RC and soil is developed for rational seismic analysis of RC/soil entire system. Using this program, nonlinear behavior of interface between RC and soil is analyzed, and the effect of interfacial behavior to entire system is investigated.

• Proceedings of the KIEE Conference
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• 2009.04a
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• pp.15-17
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• 2009

송전선로 철탑은 비교적 작용하는 하중이 크고 바람과 피빙의 영향을 많이 받는 구조물로써 이를 안정적으로 지탱하기 위해서는 튼튼한 기초를 필요로 한다. 그러나 무근콘크리트 기초는 재료의 특성상 휨인장력에 대하여는 지지력이 없어 철탑기초로는 부적절한 구조물이다. 본 고에서는 무근콘크리트 기초에 대한 철근 콘크리트 보강공법 시공기술에 대하여 고찰하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 1993.10a
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• pp.71-78
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• 1993

The R/C structures is very popular because of its low construction cost and its semi-permanent life. But in Korea, unfortunately there are few exprets in this field, and the repair methods and selection of material for R/C structures are determined by their subjective personal opinions. Therefore systematic study of this field is ulgently required. For attainning this purpose, in this study the related documents and knowledge or experience from human experts were collected. Based on the collected information cracks are classified into 25 patterns and repair related-knowledge base, which will be formulated and encoded into the domain knowledge, is built. And then an expert system, that can suggest the repair methods in the same way the human experts would, is developed. The results using the developed expert system are compared to the real field practices and they are satisfactory.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.366-371
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• 1995

it is extremely difficult to perform the dynamic experiments with full-scale specimens. For this reason, small-scale structural models offer an attractive means to peform dynamic loading experiments. The purpose of this reserch is to estabilish the reliance for modeling techniques of small-scale specimens subjected to dynamic cyclic loading. This research focused on the similitude requirements for reinforced concrete frame structures subjected to dynamic cyclic loading. Length scale ratio of specimens were 1:2:4, and six specimens were tested at the frequencies of 0.0025Hz~2.0Hz. It was confirmed that modeling techniques based on the similitude requirements were useful method to evaluate the behavior of full-size R/C structures subjected to earthquake type loading.

• Proceedings of the Korea Concrete Institute Conference
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• 1995.10a
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• pp.193-197
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• 1995

Computer-based methods have often been used in the structural analysis. But, regardless of the progress in the technique of structural analysis, there are inevitable limitations in consideration of the material and eometric nonlinearity and prediction of failure loads. Model analysis of concrete structure can supplement this kind of limitations to reasonably predict behavior of the structure. Similitude requirement in the reinforced concrete structure is often hard to be secured because of peculiar uncertainty of concrete. In this study, small scale model of subway box structure was constructed using strength model and results of model of subway box structure was constructed using strength model and results of model test and computer-based analysis were compared.

• Proceedings of the Korea Concrete Institute Conference
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• 2010.05a
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• pp.145-146
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• 2010

A moment redistribution method was developed for earthquake design of reinforced concrete moment-resisting frames. For a frame designed with strong column-weak beam, the moment redistribution mechanism was investigated. Based on the result, the relationship between redistributed moment and plastic rotation in plastic hinges was established. By using the relationship, we developed a method for the evaluation of plastic rotations during the moment redistribution, addressing the effects of various design parameters including member stiffness, load condition, and plastic mechanism of structure.

• Proceedings of the Korea Concrete Institute Conference
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• 2000.04a
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• pp.781-786
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• 2000

This paper presents the behavior and strenghening effect of reinforced concrete rectangular beams strengthened sing CFRP sheets with different strengthening level. In general, normally strengthened beams are failed by interfacial shear failure (delamination) within concrete, instead of by tensile failure of the CFRP sheets. The delamination occurred suddenly and the concrete cover cracked vertically by flexure was spalled off due to the release energy. The ultimate load considerably increased with an increase of strengthening level, while the ultimate deflection significantly decreased. The tensile force of CFRP sheets and average shear stress of concrete at delamination failure were curvilinearly proportional to the strengthening level. Therefore, the increment of ultimate load obtained by strengthening was curvilinearly proportional to th strengthening level.