• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.59-67
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• 2014

In tension lap splices of straight deformed bars, KCI Code (KCI2012) and ACI Code (ACI318-11) requires that the lap lengths for class B splice are 1.3 times as development length. KCI2012 contains development length provisions for the use of headed deformed bars in tension and does not allow their tension lap splices. The purpose of this experimental study is to evaluate that KCI2012 equation for the development length, $l_{dt}$, of headed bars can be used to calculate the lap length, $l_s$, of headed deformed bars in grade SD400 and SD500, having specified yield strength of 400 and 500 MPa. Test results showed that specimens with $l_s$ equal to $1.3l_{dt}$ had maximum flexural strengths as 1.16~1.31 times as the nominal flexural strengths, flexural failure mode, and ductility. These observations indicate that $1.3l_{dt}$ is suitable to the tensile lap length of headed deformed bars in grade SD400 and SD500.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.4
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• pp.396-402
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• 2021

A cross section in RC flexural members must be designed to satisfy flexural strength and ductility requirements simultaneously. In design provisions, ductile behavior is ensured by a sufficient reinforcement ratio or depth of the neutral axis. If the reinforcement ratio is less than the balanced reinforcement ratio, ductile behavior is secured, and this value is theoretically the maximum reinforcement ratio. But for a cross section with less steel, brittle failure can occur regardless of ductile behavior because of unqualifying a cracking moment. Recently, designs with a minimum steel ratio have been increasing along with the use of high-strength material, so in design provisions, a minimum amount of reinforcement is suggested. In the KCI(2012) standard, a minimum amount of reinforcement was suggested in terms of strength of steel and concrete. But in the revised KCI(2017) standard, a minimum amount of reinforcement was suggested by a relationship between the design flexural strength and cracking moment indirectly. This code can reflect the effect of cover thickness, but a material model must be defined. Therefore, the minimum amount of reinforcement in KCI(2012) and KCI(2017) was examined, and a rational review method was studied by parametric analysis.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.211-218
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• 2014

In the design of reinforced rectangular concrete beam structure, the minimum amount of flexural reinforcement is required to avoid brittle failure. KCI code is based on concept of ultimate strength and usually used as a model code. But bridge design code enacted by Ministry of land, transportation and maritime affairs in 2012 is based on concept of limit state and similar to Euro code EN 1992-2. This means that the minimum reinforcement presented in both design codes has different origination and safety margin. When rectangular concrete beams with minimum reinforcement are designed according to EN and KCI codes, the amount of minimum reinforcement specified in EN code is only 76% of that in KCI code. This makes the design engineers to be confused. In this study, flexural tests were conducted on nine beams with the two different minimum reinforcement specified in KCI and EN design codes. In results, the measured ratios of nominal strength to crack strength from the test were about 25% greater than those evaluated from the equations presented in KCI and EN codes. The EN beams having only 76% of the minimum reinforcement for the KCI beams were fractured by rupture of steel reinforcement but in ductile manner. It is confirmed that the minimum reinforcement concrete beams designed according to both codes have enough safety margin in flexural capacity and moreover in ductility.

• Journal of the korean academy of Pediatric Dentistry
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• v.39 no.3
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• pp.325-331
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• 2012

Korean medical databases are various from managing institutions. Korean major medical databases are KoreaMed, KoMCI, Synapse of Korean Association of Medical Journal Editors (KAMJE) made by medical researchers and doctors, and KMbase of Medical Research Information Center (MedRIC), RISS of Korea Education & Research Information Service (KERIS), NDSL of Korea Institute of Science and Technology Information (KISTI), KCI of National Research Foundation of Korea (NRF) made by government. Private companies made KISS (Koreanstudies Information Service System) and DBpia are providing medical information on charge. Internet portal site, Google and Naver, also provide enormous materials.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.10a
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• pp.109-110
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• 2012

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.4
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• pp.144-152
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• 2016

This paper focuses on the experimental study for investigating the performance for lap splice of hooked or headed reinforcement in beam with different depths. In the experiment, seven specimens, with its variables as the lap length of headed or hooked bar, the existence of stirrups, etc., was manufactured. Bending test was conducted. Lap strengths by test were compared with the theoretical model based on KCI2012. The result showed that the cracks at failure mode occurred along the axial direction to a headed bar. The initial stiffness and the stiffness after initial crack were similar for all specimens. For HS series specimens without stirrups, a 25% increase in lap length was increased 11.8~18.1% maximum strengths. For HH series specimens without stirrups, a increase in lap length did not affect the maximum strengths because of the pryout failure of headed bar. For HS series specimens, the theoretical lap strengths based on KCI2012 considering the B grade lap and the reduction factor for stirrup were evaluated. They are smaller than the test strengths and can ensure the safety in terms of strength capacity. For HH series specimens, the stirrups in the lap zone are needed to prevent the pryout behaviour of headed bar.

• Journal of the Korean Society for Library and Information Science
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• v.46 no.2
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• pp.245-260
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• 2012

This study aims to analyze the change in the correlation between the index values and qualitative quantitative evaluation elements by applying 'the decile of total number of articles' instead of the average annual number of articles in Kor-Factor2, and to evaluate the distinction ability between registered journals and register nominee journals of the KCI. The correlation between the index values and qualitative quantitative evaluation elements was analyzed by calculating the correlation coefficient between the index values and the evaluation elements, and then the correlation was compared with that of Kor-Factor2. To evaluate the distinction ability, we carried out independent samples t-test on the mean difference between index values of register nominee journal group and registered journal group and compared the mean difference with that of Kor-Factor2, IF and journal h-index. As a result, we found that the modified index applying the decile of total number of articles was effective in improving the balance among the correlation between the index values and qualitative quantitative evaluation elements compared to Kor-Factor2, and the new index appeared to be superior to other indexes on distinction ability of the journal's registration condition in the KCI.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.173-174
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• 2012

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.189-190
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• 2012

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2012.05a
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• pp.213-214
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• 2012