• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2000.04a
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• pp.341-348
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• 2000

The existing solid circular RC pier without seismic detailing is found to have poor ductility due to the premature bond failure of lap spliced longitudinal bars. The steel-jacket was introduced to prevent this unexpected type of failure. The nonlinear behavior and he seismic performance of the retrofitted pier were examined through the scale model test and compared with those of existing one. It is confirmed from the test results that the steel-jacket retrofitting can be used as an measure to improve seismic performance considerably.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.453-458
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• 2001

This paper presents the procedure to find the hysteresis loop of RC member using a modified strut-and-tie model. The forces and displacements at critical points, that are initial yielding point, target displacement point, unloading elastic limit, and reloading point after pinching, are investigated with the strut-and-tie models. Using bond-slip relationship, the elastic behavior of tie element is determined. The plastic flow behavior after flexural yielding is expressed by changing the location of longitudinal strut. Determination of pinching effect completes the initial hysteresis loop, assuming that the behavior of the opposite direction is symmetrical form.

• Magazine of the Korea Concrete Institute
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• v.3 no.2
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• pp.77-86
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• 1991

철근 콘크리트 부재의 부착거동은 철근 콘크리트 구조물을 역학적 거동을 규명하는데 매우 중요한 요소가 된다. 본 논문에서는 이러한 철근 콘크리트의 부착거동을 서술할 수 있는 이론모델을 유도하여 제시하였다. 본 해석모델은 철근 콘크리트부재의 위치에 따라 다랄지는 국부 부착응력과 부착슬립의 관계를 나타내주고 있으며, 이에 대한 실험결과를 잘 설명하고 있음을 보여주고 있다. 본 부착해석모델은 철근콘크리트 구조물의 좀더 정확한 해석과 설계를 가능케 할 것으로 사료된다.

• Computers and Concrete
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• v.9 no.1
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• pp.35-50
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• 2012

The 2D representative volume element (RVE) for softening quasi-brittle materials like concrete is determined. Two alternative methods are presented to determine a size of RVE in concrete subjected to uniaxial tension by taking into account strain localization. Concrete is described as a heterogeneous three-phase material composed of aggregate, cement matrix and bond. The plane strain FE calculations of strain localization at meso-scale are carried out with an isotropic damage model with non-local softening.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05b
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• pp.365-368
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• 2006

In this paper, the post cracking stress-crack width relationship of the composite is studied from a micromechanics points of view. Cook-Gordon debonding effect is studied by more refined method with considering of chemical friction of fiber interface. As a result, fiber with pre-debonding length retards stress development and shows more wide crack width for the same force level. longer pre-debonding length and lower pre-debonding bond strength results in lower full-debonding force, but same crack width.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.199-200
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• 2009

This research developed a long-term crack width prediction model based on bond characteristics that considered steel corrosion, concrete shrinkage and creep in cracking stabilized structural concrete members.

• Journal of Photoscience
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• v.12 no.3
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• pp.185-186
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• 2005

The electronic structure of photoskinsensitizing psoralens has been investigated by the ab initio calculations. The photocycloaddition reaction of 8-methoxypsoralen with thymine is studied as a model for the photosensitizing reaction of psoralen with DNA bases. The photocycloadduct was inferred to be a C4-cycloaddition product with the stereochemistry of Syn, H-H, Syn, H-T formed through [2+2] addition reaction between the 3,4-double bonds of 8-methoxypsoralen and 5,6-double bond of thymine base.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.449-450
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• 2003

Performance of photochemical models and their response to emission controls are heavily dependent on the inputs to the model. Two key inputs to these models are accurate meteorological and emissions data. But they can contain significant errors which contribute to uncertainties in photochemical simulation (Kumar and Russell, 1996; Sistla et al., 1996; Pielke and Uliase, 1998; Barna and Lamb, 2000; Nelson L. Seaman, 2000: Hogrefe et al., 2001; Biswas et al., 2001).(omitted)

• Proceedings of the Korean Statistical Society Conference
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• 2005.05a
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• pp.179-184
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• 2005

Empirical findings on interet rate dynamics imply that short rates show some long memories and non-Markovin. It is well-known that fractional Brownian motion(fBm) is a proper candidate for modelling this empirical phenomena. fBm, however, is not a semimartingale process. For this reason, it is very hard to apply such processes for asset price modelling. With some modifications, this paper investigate the fBm interest rate theory, and obtain a pure discount bond price and Greeks.

• Structural Engineering and Mechanics
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• v.6 no.3
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• pp.291-304
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• 1998

This paper deals with the non-axisymmetric dynamic response of an imperfectly bonded buried orthotropic pipeline subjected to longitudinal wave (P-wave) excitation. An infinite cylindrical shell model, including the rotary inertia and shear deformation effects, has been used for the pipeline. For some cases comparison of axisymmetric and non-axisymmetric responses have also been furnished.