• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.111-117
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• 2019

Shear experiments were carried out to evaluate shear performance of SFRC deep beams with end-anchorage of SD600 high strength headed reinforcing tensile bars. The experimental variables include the end-anchorage methods of tensile bars (headed bar, straight bar), the end-anchorage lengths, and the presence of shear reinforcement. Specimens with a shear span ratio of 1 showed a pattern of the shear compression failure with the slope cracks progressed after the initial bending crack occurred. Specimens with end-anchorage of headed bars (H-specimens) showed a larger shear strengths of 5.6% to 22.4% compared to straight bars (NH-specimens). For H-specimens, bearing stress reached 0.9 to 17.2% of the total stress of tensile bars up to 75% of the maximum load, and reached 22.4% to 46%. This shows that the anchorage strength due to the bearing stress of headed bars has a significant effect on shear strength. The experimental shear strength was 2.68 to 4.65 times the theoretical shear strength by the practical method, and the practical method was evaluated as the safety side.

• Journal of Korean Society of Archives and Records Management
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• v.19 no.2
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• pp.25-50
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• 2019

Different environmental changes involving records management increased the need to improve the curriculum of archives and records management in terms of practice. Given this, the study aims to propose improvement plans for the curriculum by analyzing its operation in domestic graduate schools and determining how the courses are necessary and useful in practice. To achieve this goal, a survey was conducted to records managers in fields, who were asked about the subjects they took, the prerequisites, whether subjects are necessary to be reformed or not, and so on. The results showed the importance of courses related to electronic management for records and practice of records management. Hence, the following insights and methods to improve the curriculum were proposed: (1) the operation of the extension of courses related to electronic management for records and practice of records management; (2) the standardization of courses and the designation of compulsory subjects; (3) the reinforcement of courses; and (4) the offering of diverse courses. This study is significant in gathering the perceptions of field records managers regarding the proposals of the improved curriculum and can serve as preliminary data to develop specific courses for records management.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.454-464
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• 2021

Purpose: There is a need to construct an evacuation passageway for the 2-Arch tunnel, which has been constructed and is in operation. Therefore, it aims to analyze tunnel and center wall behaviour and stability due to excavation of the center wall. Method: We describe the theoretical background of 2-Arch tunnel and evacuation passageway, and focused on analyzing the behaviour of tunnel and wall using 3-dimensional finite element analysis. Parametric analysis according to rock rating was performed with various ground conditions, and the displacement and stress of the center wall were intensively analyzed. Result: With the center wall excavation, the largest amount of settlement was shown in the center of the opening, and the stress was greatest during the first excavation. In addition, it was shown that stress concentration occurred at the top of both openings, and stability reviews considering the concept of allowable stress showed that it exceeded the allowable stress. Conclusion: Although the displacement of the tunnel has secured stability within the allowable standard, the generated stress is found to exceed the allowable standard, so it is necessary to prevent sudden stress release by applying appropriate reinforcement methods during construction.

• Korean Journal of Heritage: History & Science
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• v.54 no.3
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• pp.106-125
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• 2021

This paper presents several reasons for the necessity of archaeological hands-on training and strategies for its implementation. First, it is necessary to produce a specialized manual for local cultural heritage education that can enhance the specialization and educational effectiveness of archaeological experience education. In addition, in order to secure professionalism in hands-on education and conduct it systematically, the ability of instructors to conduct education is important, so instructor competence reinforcement education needs to be conducted regularly. In addition, hands-on education needs a strategy of planning and content development of archaeological education programs, with consideration given to the subjects of learning, and the establishment of a cooperative network. It is time to cooperate with various experts to establish an education system necessary for cultural heritage education in the region and develop customized content for local archaeological heritage supplementary textbooks. Finally, due to Covid-19, we agonized over effective education plans for online archaeological heritage education, which requires active interaction class design and a strategy to promote interaction between professors and learners. In addition, such archaeological heritage education should be compatible with the goal of providing customized lifelong education.

• Industry Promotion Research
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• v.6 no.1
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• pp.55-62
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• 2021

This study regards the need for jobs to overcome the poverty of the elderly in an aged society, and as well as researches ways to participate in active economic activities in old age. The results of the study are as follows. First, the legal system needs to be improved. In addition to institutional support for the expansion of jobs for the elderly, improvement of awareness of the elderly and reinforcement of infrastructure such as a delivery system are required, and a legal basis for this is needed. To this end, occupations targeting the elderly must be selected first, and legal procedures must be prepared by the government. Second, there must be social consideration and support for the elderly. Extension of the retirement age plays an important role in enhancing employment for the elderly. Along with the improvement of the legal system, social consideration is required. Therefore, since the elderly policy without social consensus is bound to fail, various support methods that can lead to social support must be devised. Third, the elderly must have a sense of poverty and willingness to rehabilitate themselves. Elderly people should not only ask for their children and social support. The elderly must be able to find a way to become the economic agent themselves. To do this, a basic awareness of the elderly poverty consciousness is needed, and a change of awareness to escape the poverty of the elderly is necessary. Therefore, the elderly need to be self-reliant, and they must choose jobs according to their own abilities. In conclusion, the elderly job program is a part of income increase that solves the poverty of the elderly in the aged society, and the elderly are required to actively participate in economic activities.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.22 no.1
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• pp.672-680
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• 2021

The purpose of this study is to understand the effects of adolescent wellbeing of school maladjusted teens on the career decision self-efficacy and the mediating effect of community capital. The subjects were 116 school maladjusted teens in Ulsan metropolitan area. As analysis methods, frequency analysis, descriptive statistics analysis, correlation analysis, three-step mediation effect analysis, and a Sobel test were performed based on factor analysis, reliability analysis, and regression analysis, using the R program. As a result, adolescent wellbeing was found to have a significant positive (+) effect on career decision self-efficacy. The effect of adolescent's wellbeing on career decision self-efficacy was confirmed. This means that the self-efficacy of career decisions will improve as the adolescent's wellbeing of school maladjusted teens increases and there is more positive community capital. Overall, it will be necessary to develop and utilize educational programs that can improve the sense of youth wellbeing and implement systematic intervention of specialized counseling services helpful in career search and decision-making in light of the psychological characteristics of youth. Therefore, to improve the career decision self-efficacy of school-maladjusted teens, reinforcement of teenage wellbeing and various strategies utilizing community capital will be necessary.

• Korean Journal of Heritage: History & Science
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• v.55 no.2
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• pp.186-197
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• 2022

The Daejanggakgibi Stele of Silleuksa Temple in Yeoju is a stone stele from the Goryeo Dynasty that is inscribed with various stories about the construction of Daejanggak, a place where Buddhist scriptures were kept. This stele has been maintained for a long time in a state in which discoloration of the body has occurred, and the inscription has been partially damaged due to dozens of cracks. Using non-destructive analysis methods for stone artifacts, material investigation, portable X-ray fluorescence analysis, and ultrasonic velocity analysis for the stele were performed. It was confirmed that the stele body was composed of light gray crystalline limestone, and the base stone, support stone, and cover stone were medium-grained biotite granite. Portable X-ray fluorescence analysis confirmed that iron(Fe) was an original coloring element of the stele surface. From the distribution pattern of the coloration, it can be inferred that iron-containing materials flew down from between the stele body and the cover stone. Thereafter, living organisms or organic contaminants attached to it so that yellow and black contaminants were formed. Ultrasonic diagnosis revealed that the physical property of both the front and back surfaces ranged from fresh rocks(FR) to completely weathered rocks(CW), and the average weathering index was grade 3(intermediate). However, the point where cracks developed intensively was judged to be the completely weathered stage(CW), and some cracks located in the upper and lower parts of the stele bear potentially very high risk. It is necessary to monitor the movement of these cracks and establish reinforcement measures for conservation in the future.

• Journal of Korean Tunnelling and Underground Space Association
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• v.23 no.6
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• pp.559-575
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• 2021

Due to the increase in ground excavation work, the possibility of ground subsidence accidents is increasing. And it is very difficult to prevent these risk fundamentally through institutional reinforcement such as the special law for underground safety management. As for the various cases of urban ground excavation practice, the ground subsidence behavior characteristics which is predicted using various information before excavation showed a considerable difference that could not be ignored compared to the results real construction data. Changes in site conditions such as seasonal differences in design and construction period, changes in construction methods depending on the site conditions and long-term construction suspension due to various reasons could be considered as the main causes. As the countermeasures, the safety management system through various construction information is introduced, but there is still no suitable system which can predict the effect of excavation and risk assessment. In this study, a web-based system was developed in order to predict the degree of impact on the ground subsidence and surrounding structures in advance before ground excavation and evaluate the risk in the design and construction of urban ground excavation projects. A system was built using time series analysis technique that can predict the current and future behavior characteristics such as ground water level and settlement based on past field construction records with field monitoring data. It was presented as a geotechnical data visualization (GDV) technology for risk reduction and disaster management based on web-based system, Using this newly developed web-based assessment system, it is possible to predict ground excavation impact prediction and risk assessment.

• Journal of the Korean GEO-environmental Society
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• v.22 no.6
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• pp.5-15
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• 2021

One of the construction methods applied as a pier foundation type is a single type cast-in-place pile. In applying a pile bent system as a foundation type, the main concern in designing can be said to secure the lateral bearing capacity of pile structure in system. In addition, to increase the rigidity of the pile structure, a method of increasing the lateral bearing capacity by reinforcing the pile structure with a casing has been used. However, although the reinforcing effect and appropriate reinforcing length of casing may vary depending on the soil conditions, there is insufficient studies on this, and for this reason, the entire pile structure in a pile bent system is reinforced with a casing, in the field. In addition, if the length of the entire pile is reinforced with a casing, it may lead to delays in construction and increase in construction costs. That is, in order to more effectively reinforce the pile structure with a casing, it is necessary to study the lateral bearing characteristics of the reinforced pile structure in system. And it should be determined the appropriate reinforcing length of the casing from the evaluated bearing characteristics. Therefore, in this study, the lateral bearing characteristics of piles applied with the reinforcing length of casing for each condition were evaluated through a numerical analysis. And, based on the analysis results, the appropriate reinforcing length of casing was proposed. As a result of the study, it was found that in order to effectively increase the lateral bearing capacity of pile structure, the reinforcing length of casing should be applied twice the influence range of the bending behavior of the pile, 1/β.

• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.506-513
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• 2021

The durability and safety of reinforced concrete structures significantly depend on the reinforcement conditions, concrete cover thickness, cracks, and concrete strength. There are two ways to accurately determine the information on reinforcing bars embedded in concrete - the local destructive method and the non-destructive rebar detection test. In general, the non-destructive rebar detection tests, such as the electromagnetic wave radar method, electromagnetic induction method, and radiation method, are adopted to avoid damage to the structural elements. The moisture content and temperature of concrete affect the dielectric constant, which is the electrical property of concrete, and cause interference in the non-destructive rebar detection test results. Therefore, in this study, the effects of the electromagnetic wave radar method and electromagnetic induction method have been analyzed according to the temperature and surface moisture content of concrete. Due to the technological advancement and development of equipment, the average error rate was less than 5% in the specimens at 24℃, irrespective of their operating principles. Among the tested methods, the electromagnetic induction method showed very high accuracy. The electromagnetic wave radar method indicated a relatively small error rate in the dry state than in the wet state, and exhibited a relatively high error rate at high temperatures. It was confirmed that the error could be reduced by applying the electromagnetic wave radar method when the temperature of the probe was low and in a dry state, and by using the electromagnetic induction method when the probe was in a wet state or at a high temperature.