• Earthquakes and Structures
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• v.21 no.6
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• pp.613-625
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• 2021

Non-seismically designed eccentric reinforced concrete beam-column joints were extensively used in existing reinforced concrete frame buildings, which were found to be vulnerable to seismic action in many incidences. To provide a fundamental understanding of the seismic performance and failure mechanism of the joints, three 2/3-scale exterior beam-column joints with non-seismically designed details were cast and tested under reversed cyclic loads simulating earthquake excitation. In this investigation, particular emphasis was given on the effects of the eccentricity between the centerlines of the beam and the column. It is shown that the eccentricity had significant effects on the damage characteristics, shear strength, and displacement ductility of the specimens. In addition, shear deformation and the strain of joint hoops were found to concentrate on the eccentric face of the joint. The results demonstrated that the specimen with an eccentricity of 1/4 column width failed in a brittle manner with premature joint shear failure, while the other specimens with less or no eccentricity failed in a ductile manner with joint shear failure after beam flexural yielding. Test results are compared with those predicted by three seismic design codes and two non-seismic design codes. In general, the codes do not accurately predict the shear strength of the eccentric joints with non-seismic details.

• Structural Engineering and Mechanics
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• v.47 no.2
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• pp.247-263
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• 2013

It is evident that torsional resistance of a reinforced concrete (RC) member is attributed to both concrete and steel reinforcement. However, recent structural design codes neglect the contribution of concrete because of cracking. This paper reports on the results of an experimental and numerical investigation into the torsional capacity of concrete beams reinforced only by longitudinal rebars without transverse reinforcement. The experimental investigation involves six specimens tested under pure torsion. Each specimen was made using a cast-in-place concrete with different amounts of longitudinal reinforcements. To create the torsional moment, an eccentric load was applied at the end of the beam whereas the other end was fixed against twist, vertical, and transverse displacement. The experimental results were also compared with the results obtained from the nonlinear finite element analysis performed in ANSYS. The outcomes showed a good agreement between experimental and numerical investigation, indicating the capability of numerical analysis in predicting the torsional capacity of RC beams. Both experimental and numerical results showed a considerable torsional post-cracking resistance in high twist angle in test specimen. This post-cracking resistance is neglected in torsional design of RC members. This strength could be considered in the design of RC members subjected to torsion forces, leading to a more economical and precise design.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.240-245
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• 2004

It is necessary to analyze the railway accidents and incidents for the purpose of understanding present safety state and enhancing its system. Korea National Railroad has its accident/incident reporting codes, but it is relatively not sufficient for detail classification and investigation of accident and incident compared with foreign countries. This paper suggests how to classify the railway accident/incident, and describes the analysis result for domestic recent railway accidents and incidents according to the new suggested classifying system.

• Journal of Ocean Engineering and Technology
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• v.13 no.1 s.31
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• pp.105-112
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• 1999

This research is an experimental investigation of the region of the Biased Flow. This experiment was carried out in a circulating water channel, and the results are analyzed by using the PIV technique. The results are presented in velocity vector field, velocity contour and vorticity contour. The results were compared with those of Zdravkovich which were carried out in a wind tunnel. These results will be very useful to verify numerical codes.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.332-342
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• 1999

Seismic design codes in japan have been developed from the experience obtained from the past earthquakes. After the Hyogoken-nanbu earthquake occurred in 1995 the seismic design code have adopt the performance-based design methodology. This study introduces the concept and evolution of seismic design in japan. These studies can be utilized as a basic material in establishing new seismic design procedure in Korea

• Journal of Navigation and Port Research
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• v.26 no.5
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• pp.497-504
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• 2002

The investigation of marine accidents in Korea can not handle the international codes and guidelines and is being followed the conventional methods with a big gab to the international criterion and procedure. Also there is no proper investigation manual which is cope with the new era and surrounding circumstances. This study analyzed the investigation manual of other countries, and proposed new investigation manual according to the analysis and international standards and procedure as followings; (1) Develop own investigation manual separating from the field manual which is mixed with judge, (2) Correct and improve the error and hazy words in the existing field manual which is not compatible a current situation, (3) The contents of new manual should be changed to cope with the international rules, criterion and procedures. The list of contents and index is added, an abundant explanation and examples are given, and charts and illustrations are inserted to make the users understand easily. Also the inquiry techniques according to the classification of each accidents are included.

• Wind and Structures
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• v.20 no.6
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• pp.811-827
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• 2015

This study presents experimental and numerical aerodynamic investigation of a prototype vehicle. Aerodynamics forces examined which exerted on a prototype. This experimental study was implemented in a wind tunnel for the Reynolds number between $10^5-3.1{\times}10^5$. Numerical aerodynamic analysis of the vehicle is conducted for different Reynolds number by using FLUENT CFD software, with the k-$\varepsilon$ realizable turbulence model. The studied model aims at verifying the aerodynamic forces between experimental and numerical results. After the Reynolds number of $2.8{\times}10^5$, the drag coefficient obtained experimentally becomes independent of Reynolds number and has a value of 0.25.

• Structural Engineering and Mechanics
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• v.14 no.2
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• pp.237-243
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• 2002

It is well known that torsionally unbalanced buildings are more vulnerable to earthquake hazards than are the regular structural systems. In this paper, a parametric investigation is presented, in order to observe the amplification in the internal forces, when increased eccentricities are used instead of the ones corresponding to the 5% accidental eccentricity. A series of five, ten-story framed and walled structures, with rather high torsional irregularity coefficients, are selected and a numerical test procedure is applied. Numerical results show that the maximum amplification in the internal forces at the most critical beams and columns at the flexible sides of the structures is about 10%. It is concluded that, more serious measures in the codes are needed in the case of this rather dangerous type of irregularity.

• Journal of the Korea Society of Computer and Information
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• v.21 no.11
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• pp.73-78
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• 2016

All citizens will not be infringed communications rub. That can be seen to have the privacy freedom.lot (Internet of things) have released a security system in the era of information privacy appear that public safety and threat. Currently, Information and communication devices can be use criminal investigation, including search and seizure confirmed the fact communication of the communication restriction information storage medium for the common purpose of providing material system, the system provides data and communications. This paper focused on Privacy and open of information data by the Prosecutor and Police in korea. Privacy rights include that transparency information, communication, and protections for the rights of the individuals. It is necessary to be lawfulness of processing, individuals consent while Prosecutors investigations. especially we need explicit condition and National agency need to obtain in order to legitimize their processing of personal information data. The author emphasize are as follows: first, to examine Privacy rights information' necessity and problem, second, to understand Privacy rights and limits, third, to suggest improvements for the purpose of Transparency, codes of conduct and Democracy of information.

• 한국연소학회:학술대회논문집
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• 2013.06a
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• pp.25-28
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• 2013

This study presents both experimental and numerical investigation of ignition characteristics of n-heptane and n-butanol mixture. The $O_2$ concentration was fixed to 9-10% to make high exhaust gas recirculation(EGR) rate condition. Experiments were performed using a rapid compression machine. In addition, a numerical study of the ignition delay time was performed using CHEMKIN codes to validate experimental results and predict chemical species after combustion process. The results showed that the ignition delay time increased with increasing n-butanol ratio and the reactivity decreased by low $O_2$ concentration.