• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.11
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• pp.137-146
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• 2019

Recently, the Near-Surface-Mounting method using Fiber reinforced polymer (FRP) has been developed and applied to the reinforcement of many concrete structural members. However, as a part of the fire resistance design, there is a lack of research related to fire insulation for the areas reinforced with FRP. In case of NSM reinforcement, there is a difference in the transferred temperature from the external surface to the groove corresponding to the location of the groove where the FRP is embedded, and the effect of this should be reflected in the fireproof insulation design. Therefore, in this study, after forming grooves for surface embedding in concrete blocks, fireproof insulation reinforcement was performed using Calcium Silicate (CS) fireproof board and an experiment to evaluate the temperature transfer was performed. By observing the temperature at these groove positions, the reduction of temperature transfer according to fireproof insulation detail was studied. As a result, when the NSM-FRP is properly fire-insulated using the CS-based fireproof board, the epoxy inside the groove does not reach its glass transition temperature until the external temperature reaches $800^{\circ}C$.

• Journal of the Korea Concrete Institute
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• v.26 no.2
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• pp.159-169
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• 2014

This study generalizes the lateral load-displacement relationship of reinforced concrete shear walls from the section analysis for moment-curvature response to straightforwardly evaluate the flexural capacity and ductility of such members. Moment and curvature at different selected points including the first flexural crack, yielding of tensile reinforcing bar, maximum strength, 80% of the maximum strength at descending branch, and fracture of tensile reinforcing bar are calculated based on the strain compatibility and equilibrium of internal forces. The strain at extreme compressive fiber to determine the curvature at the descending branch is formulated as a function of reduction factor of maximum stress of concrete and volumetric index of lateral reinforcement using the stress-strain model of confined concrete proposed by Razvi and Saatcioglu. The moment prediction models are simply formulated as a function of tensile reinforcement index, vertical reinforcement index, and axial load index from an extensive parametric study. Lateral displacement is calculated by using the moment area method of idealized curvature distribution along the wall height. The generalized lateral load-displacement relationship is in good agreement with test result, even at the descending branch after ultimate strength of shear walls.

• Journal of the Korean Wood Science and Technology
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• v.45 no.1
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• pp.53-61
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• 2017

In this study, specimens were produced with a column member and a wooden gusset only by inserting an wooden gusset which is a substitute for steel plate into the center of a slit-processed column member. The moment resistance performance of the specimens was compared with that of control specimens that used a steel plate. The measured maximum moments of the specimens produced with GFRP-reinforced wooden laminated gussets and pins were lower by 24% on average compared to the steel plate-inserted specimens, but they showed good toughness. The fracture shape suggests that it was fractured along the annual rings between the pin and the end of the column member. The rigid specimen that integrated a laminated wood and a wooden laminated gusset with adhesive showed 2.8 times greater initial rigidity and 40% greater maximum moment on average compared to the control specimen. The rigid specimens mainly fractured on a glulam around glue line.

• Magazine of the Korea Concrete Institute
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• v.6 no.5
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• pp.171-182
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• 1994

Recently, several prestressed concrete box girder bridges have experienced severe cracking along the tendon path when prestress force has been transferred to the anchorage zone. The purpose of the present study is therefore to explore characteristics of the local stress distribution, to study the effects of section geometry of anchorage zones, i.e., tendon inclination, tendon eccentricity and concrett. cover thickness anti to develop recornrncnd;itions for specific design criteria for post~tensioned a:lchorage zones. 7'0 accomplish these objectives, a cc~mprehen sive nonlinar finite element study has been conducted. From this study, realistic forrnulas for crackinq and ultimate load capacities are proposed. 'These equations reasonably well predict the crackinq and ultimate loads of prestressed concrete anchorage zones.

• Journal of Korean Society of Steel Construction
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• v.25 no.6
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• pp.659-669
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• 2013

The purpose of this study is to investigate the ultimate strength and curling influence using finite element analysis based on the previous test results of ferritic stainless steel bolted connections. Results obtained from finite element analysis (FEA) were compared with those of test results and the validity of numerical modeling was verified. The conditions of curing occurrence for edge/end distance were investigated and ultimate strength reduction ratio caused by curling was estimated quantitatively. Moreover, the ultimate behaviors such as fracture mode and ultimate strength by FEA were compared with those predicted by current design specifications such as AISC, KBC2009, AIJ and AISI.

• Journal of Korean Society of Steel Construction
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• v.29 no.2
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• pp.169-180
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• 2017

Cyclic loading tests for beam-to-column weak-axis connections were performed to investigate the seismic performance. In this study, the connections were developed to improve the constructability on the basis of investigation for existing small-size steel structures. The primary test parameter is the number of high-tension bolts which are used to connect steel beam and column using exterior and interior flange plates. Test results showed that the number of bolts had a significant effect on the cyclic behavior of beam-column weak-axis connections. From the analysis of test results, it is concluded that more than four bolts in the connections can satisfy the requirements of semi-rigid connection presented in current design codes. All of specimens showed the bearing failure around bolt holes and fracture at the beam flange. However, when the web height and the flange width is relatively small, the number of the bolts used in the connections might be limited. Thus, the additional research in this area is needed.

• Journal of Conservation Science
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• v.32 no.2
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• pp.215-221
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• 2016

This study conducted analysis of paint samples from defense industries equipments of Korean Conflict in The War Memorial of Korea to identify the characteristics of the modern paint. The samples were analyzed by microscopic observation, infrared spectroscopy and SEM-EDS. Cross-section of paint samples are made up of several layers of about 9 to 20 times, and thickness of the layer is not uniform in the $10{\sim}100{\mu}m$. The putty was used for the surface treatment before painting. Inorganic analysis showed that one type of the putty consist of minium and kaolin, talc, titanium dioxide. According to the results of infrared spectroscopy, paint samples were identified as alkyd resin. Some bands such as C-H bending, C-O and C-C stretching, C-H rocking were found in spectra.

• Journal of Conservation Science
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• v.35 no.5
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• pp.403-415
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• 2019

According to oral tradition, the King Sejo's palanquin is indeed the palanquin of King Sejo, the 7^th monarch of the Joseon dynasty who reigned from 1455 to 1468, which was left behind after visiting the Magoksa temple. The palanquin is painted in five colors, mainly black, white, yellow, red and green. The chromaticity measurement of the yellow pigment showed that orpiment and gold are a noticeable distinction between the lightness and b^⁎ values. In the case of the red pigment, a^⁎ values of areas painted with cinnabar tend to measure at high values. As a result of the optical microscopy, scanning electron microscopy and energy dispersive spectroscopy analyses, it was determined that Chinese ink was used for the black pigment, lead white and white clay were used for the white, and orpiment and gold for the yellow. The red pigment was found to be the result of minium, cinnabar and red ocher, atacamite was used as green pigment. Though the analysis results of the cross sections on very small exfoliation fragments of pigments, it was confirmed that white clay and lead white were used for the preparation layer. In addition, several coloration techniques were considered based on these analyses.

• Journal of Conservation Science
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• v.35 no.6
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• pp.689-700
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• 2019

This study aimed to analyze the nature and characteristics of the preserved state, materials, and colored pigments of a Buddhist painting of Eunhaesa temple(gwaebultaeng), which is Treasure No. 1270 of Korea, through scientific investigation and analysis. Based on the historical background of the subject, the study investigated the aspects of conservation and analyzed the material characteristics of each pigment in the painting. Results indicate that various colors were created using inorganic pigments such as white lead, minium, cinnabar, orpiment, gold, atacamite, malachite, and smalt and using organic pigments such as black and indigo. The Eunhaesa painting used "cho" as a material for wallpaper, which was unusual during the Joseon period. In addition, a white layer was formed using various white pigments, which was also rare during this period.

• Journal of Korean Library and Information Science Society
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• v.38 no.2
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• pp.31-50
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• 2007

This paper presents a scientometric analysis of the growth of literature output in the field of Hepatitis covered in three bibliographic databases namely MEDLINE, CINAHL and IPA. The literature covered in three databases for the period 1984-2003 was considered. MEDLINE covered the maximum of 75750 records during the study period 1984 to 2003. This is followed by CINAHL and IPA databases. It is found that the annual growth rate of literature in a particular field of knowledge will not be uniform and in order to measure the rate of growth from year after year, the application of RGR is quite appropriate. The RGR has shown a decreasing trend, with a slight fluctuation of growth rate for the years 1985 and 1997. The output by colleges, universities, corporate sector and research institutions with reference to RGR and Dt has shown mixed results such as increasing trend, decreasing trend and fluctuation trend. Hepatitis research indicates a different picture when the RGR and Dt were calculated by year-wise both in terms of number of papers and number of pages.