• Journal of the Korean Geotechnical Society
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• v.16 no.3
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• pp.57-65
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• 2000

다층의 지오그리드로 보강된 사질토 지반에 축조된 줄기초의 극한 지지력을 결정하기 위하여 실내모형실험을 실시하였다. 한가지 종류의 사진토와 지오그리드를 사용하였으며, 시험은 기초의 근입깊이(Df)가 없을 때와 근입깊이(Df)가 있을 때로 분류하여 시행되었다. 기초의 근입깊이(Df)는 기초의 폭(B)보다 작도록 제한되었다. 시험결과, 주어진 보강깊이의 두께에 대하여 지지력비(BCR)는 기초의 근입깊이(Df)가 0보다 클 때 증가하였다.

• Structural Engineering and Mechanics
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• v.10 no.1
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• pp.27-36
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• 2000

The Oktalok nodal connection system is an aesthetic and efficient system. It has been widely used throughout Australia. The paper will briefly introduce the concept and application of the Oktalok nodal system. The existing design method is based on the assumption that the joints are pin-ended, i.e., the rotational stiffness of the joints is zero. However the ultimate capacity of the frame may increase significantly depending on the rotational stiffness of the joints. Stiffness tests and finite element simulations were carried out to determine the rotational stiffness of the Oktalok joints. Column buckling tests and non-linear finite element analyses were performed to determine the member capacity of columns with semi-rigid end conditions. A simple formulae for the effective length factor of column buckling is derived based on the above experimental and theoretical investigations.

• Journal of Information Technology Services
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• v.17 no.1
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• pp.1-16
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• 2018

In this research, we tried to suggest the guidelines to stakeholder of ICT startup for picking up the excellent startups and nurturing them. We designed the research model focused on the good startup team's knowledge based interaction mechanism. A research model and hypotheses were developed from literature review and empirically validated. The research model consisted relationship among the knowledge sharing (knowledge donation and knowledge collection), absorptive capacity (member's ability and member's motivation), team creativity, and innovation capability. Data were collected from ICT Service Startups, and a partial least squares (PLS) analysis was made on 175 data points. The analysis results showed that absorptive capacity has significant effect on team creativity and innovation capability directly. And also it has indirect effect on the dependent variable through team creativity. On the contrary, knowledge sharing does not have statistically significant effect on team creativity and innovation capability; only have an effect on absorptive capacity. Based on the results, we proposed several team management skills for ICT startup leaders and members, and the guidelines to stakeholder such as government and private investors. Also there are some ideas for startup nurturing polices for government officers. Theoretical contributions are discussed at the end with limitations and further studies.

• 한국공간정보시스템학회:학술대회논문집
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• 2004.05a
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• pp.83-88
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• 2004

First author proposed a proportioning method for member sections of a single layer reticulated dome subjected to uniform and non-uniform load without any geometrical initial imperfection, and discussed the validity and effectiveness of the method which was based on linear buckling stress and a knock down factor. However, buckling of a single layer reticulated dome is strongly affected by initial imperfection. It is well known that geometrical initial imperfections reduce the nonlinear buckling capacity of a single layer raticulated dome. Thus, structural engineers may be recommended to reflect the effects of geometrical initial imperfections in proportioning member sections. In this paper, firstly, the presented proportioning method by first author is applied to dome without consideration of any imperfections and the thickness and diameter of each member are determined. Secondly, the load bearing capacities of the proportioned domes are checked with the imperfection, by the inelastic buckling analysis.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.11a
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• pp.891-896
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• 2001

As composite materials, the addition of steel fiber in concrete significantly improves the engineering properties of structural members, notably shear strength and ductility, In this study, shear capacity evaluation method according to steel fiber contents was proposed from the literature surveys and member tests. For this, previously proposed five shear strength equation were examined and evaluated by maximum shear strength and shear capacity ratio. From the parametric study and regression analysis, following conclusion can be made; the maximum shear strength of steel fiber reinforced column will be estimated by relative shear capacity ratio.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.2
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• pp.10-17
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• 2016

Steel corrosion is a very significant problem both to durability and structural safety since reinforcement has to support loads in tensile region in RC(Reinforced Concrete) member. In the paper, newly invented FRP Hybrid Bar and normal steel are embedded in RC beam member, and ICM (Impressed Current Method) is adopted for corrosion acceleration. Utilizing the previous theory of Faraday's Law, corrosion amount is calculated and flexural tests are performed for RC beam with FRP Hybrid Bar and steel, respectively. Corrosion amount level of 4.9~7.8% is measured in normal RC member and the related reduction of flexural capacity is measured to be -25.4~-50.8%, however there are no significant reduction of flexural capacity and corrosion initiation in RC samples with FRP Hybrid Bar due to high resistance of epoxy-coated steel to corrosion initiation. In the accelerated corrosion test, excellent performance of anti-corrosion and bonding with concrete are evaluated but durability evaluation through long-term submerged test is required for actual utilization.

• Structural Engineering and Mechanics
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• v.45 no.1
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• pp.129-144
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• 2013

Load-carrying capacity of combined members consisted of inner and sleeved tubes subjected to axial compression was investigated in this paper. Considering the initial bending of the inner tube and perfect elasto-plasticity material model, structural behavior of the sleeved member was analyzed by theoretic deduction, which could be divided into three states: the elastic inner tube contacts the outer sleeved tube, only the inner tube becomes plastic and both the inner and outer sleeved tubes become plastic. Curves between axial compressive loads and lateral displacements of the middle sections of the inner tubes were obtained. Then four sleeved members were analyzed through FEM, and the numerical results were consistent with the theoretic formulas. Finally, experiments of full-scale sleeved members were performed. The results obtained from the theoretical analysis were verified against experimental results. The compressive load-lateral displacement curves from the theoretical analysis and the tests are similar and well indicate the point when the inner tube contacts the sleeved tube. Load-carrying capacity of the inner tube can be improved due to the sleeved tube. This paper provides theoretical basis for application of the sleeved members in reinforcement engineering.

• Journal of the Korean Institute of Educational Facilities
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• v.19 no.3
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• pp.33-40
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• 2012

At present, the problem to secure seismic resistance capacity is one of the most important issue in school buildings. However, the range of facilities to consider retrofit or the proper direction of seismic retrofit haven't provided in details. Therefore in this study, a series of school buildings were chosen as established time, and the structure composition and the seismic performance of the school buildings were investigated to get the comprehensive features of seismic resistance capacity in school buildings. At result, it was presented that the member capacities were less than criteria and structure system was showed the brittle behavior at the collapse prevention level at the school buildings before 1990 year. At the school buildings after 1990 year, though it is hard to get general features for various compositions, it was presented that they have problems for seismic performance evaluation in some buildings at life safety level, specially in the direction of X axis. So, considering the introduction process of seismic criteria in Korea, the school buildings before 2005 year should be examined for seismic resistance capacity and the seismic performance should be examined as well as member capacity to resist seismic.

• Steel and Composite Structures
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• v.45 no.3
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• pp.369-388
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• 2022

Composite effect between steel and recycled aggregate concrete (RAC) in steel reinforced-RAC (SRRAC) structures can effectively improve RAC's adverse mechanical properties due to the natural defects of recycled coarse aggregate (RCA). However, the performance of SRRAC after thermal exposure will have a great impact on the safety of the structure. In this paper, firstly, the mechanical properties of SRRAC structures after high temperatures exposure were tested, including 24 SRRAC columns and 32 SRRAC beams. Then, the change rules of beams and columns performance with the maximum temperature and replacement percentage were compared. Finally, the formulas to evaluate the residual bearing capacity of SRRAC beams and columns after exposure to high temperatures were established. The experimental results show that the maximum exposure temperature can be judged by the apparent phenomenon and mass loss ratio of RAC. After high temperatures exposure, the mechanical properties of SRRAC beams and columns change significantly, where the degradation of bearing capacity and stiffness is the most obvious. Moreover, it is found that the degradation degree of compression member is more serious than that of flexural member. The formulas of residual bearing capacity established by introducing influence coefficient of material strength agree well with the experimental results.

• Journal of the Korea Concrete Institute
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• v.22 no.4
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• pp.535-546
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• 2010

Recently, the probability of collision accident between vehicles or vessels and infrastructures are increasing at alarming rate. Particularly, collision impact load can be detrimental to sub-structures such as piers and columns. The damaged pier from an impact load of a vehicle or a vessel can lead to member damages, which make the member more vulnerable to impact load due to other accidents which. In extreme case, may cause structural collapse. Therefore, in this study, the vehicle impact load on concrete compression member was considered to assess the quantitative design resistance capacity to improve, the existing design method and to setup the new damage assessment method. The case study was carried out using the LS-DYNA, an explicit finite element analysis program. The parameters for the case study were cross-section variation of pier, impact load angle, permanent axial load and axial load ratio, concrete strength, longitudinal and lateral rebar ratios, and slenderness ratio. Using the analysis results, the performance based resistance capacity evaluation method for impact load using satisfaction curve was developed using Bayesian probabilistic method, which can be applied to reinforced concrete column design for impact loads.