• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.43-50
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• 2018

In this study, to investigate the shear connection material for the composite of steel plate and bottom plate, design standards and research cases for shear connectors in various countries around the world were analyzed and shear tests were performed on the Push-out specimens with a shear connection, which transmits the horizontal shear force developed on the contact surface between the steel plate and the concrete slab due to various vertical loads acting on the bridge deck. Through Push-out tests of shear studs, of which FRP bar instead reinforcement is placed, the shear stud evaluation formula of the steel strap bottom plate was suggested. The suggested equation suggested in this study has the safety factor of approximately three times compared to allowable strength of highway bridge design criteria. In addition, compared to existing DIN standards and Viest assessment equation, the results showed similar values(approximately, 5% error).

• Journal of the Korea institute for structural maintenance and inspection
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• v.26 no.5
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• pp.151-160
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• 2022

Owing to the recent increase in the frequency of explosion accidents, blast resistive design has garnered attention to reduce the damage of important structural elements. However, domestic research on the blast resistive structures is still insufficient, and domestic design guideline against blast loads are not documented yet. In this study, a numerical study on the RC blast resistive walls, where the test variable was the presence of FRP sheet, was performed using LS-DYNA program. Based on the numerical results, displacement-time hysteretic curve, pressure-impulse diagram, and fragility curve of the test specimens were derived. It was shown that the FRP sheet strengthening method is efficient to improve the blast resistive performance of the RC wall. Also, the strengthening effect of FRP sheet on the RC wall was stronger when the magnitude of the blast load was greater.

• Composites Research
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• v.21 no.5
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• pp.1-8
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• 2008

In recent years, the reversed L-shaped perforated shear connector has been developed to mitigate the problem associated with headed stud and Perforbond shear connector and to simulate the simultaneous failure of concrete and shear connector. And FRP perforated shear connector has been applied to composite concrete and FRP module in the FRP-concrete composite bridge deck. The design criterion of the reversed L-shaped and FRP perforated shear connector has not been established yet since the lack of experimental and analytical study results. In this paper, the existing design equations for the Perforated were briefly discussed and the equation fur the prediction of shear resisting capacity of the reversed L-shaped and FRP perforated shear connector was suggested based on the experimental test, FEM analysis. and the existing equation for the Perfobond. The predict results obtained by the suggested equation arc compared with the experimental results, the applicability and effectiveness of suggested equation was verified.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3A
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• pp.357-366
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• 2008

This study addresses the analysis of the behavioral characteristics of bridge expansion joints under wheel loading through wheel load test and the proposal of relevant wheel load specifications for expansion joints. To that goal, specimens of rail and finger expansion joints that are widely used in Korea were fabricated and subjected to static wheel load test using a real tire wheel. The wheel load distribution factor in the rail and finger expansion joints in contact with the wheel load was evaluated. The evaluation revealed that the portion of load sustained by the central rail of rail expansion joint was decreasing with larger wheel load, and that the portion of load sustained by the finger expansion joint was practically insensitive to the increase of the contact area and remained nearly constant. Since the wheel load characteristics showed large difference compared to former design specifications, it appears necessary to prepare rational specifications relative to the distribution of the wheel load contact pressure for the design of expansion joints.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.111-121
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• 2001

Rockfall protection fences are used for diminishing rockfall damage in roads side slopes. In order to install the fences in effective way, the conditions of rock slopes and total predicted impact energy of fa11ing rock should be considered. However, the fences have been constructed without any consideration for lithology, height and slope angle of rock slope in Korea. In addition, the information about the performance of the protection fences, which should be evaluated by in-situ test or laboratory test in order to check out the practical use in the field, is not available. Therefore, in design manual for the rockfall protection fence, the specific details for the installation of this type of fence are not provided yet. The full sized rockfall in situ test was carried out for the calculation of falling energy of rock and the evaluation of the maximum energy absorbing capacity of fence. For this test, the rock slopes whose heights are about 20 m and dip angle of 65 degree, have been chosen. This is because those geometries are mean height and slope angle of most road cut slopes along Korean national highway. Based on the preliminary simulation procedure, four different sizes of concrete ball (0.7, 1.3, 2.3 and 4.3 ton) were prepared and flour different types of protection fence were constructed. The results of this test provide information about the maximum energy absorbing capacity of the fence, kinetic energy of rockfall and restitution coefficient, and these results can be utilized in the establishment of rockfall fence design and construction manual.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.38 no.6
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• pp.655-662
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• 2014

This study conducted tensile tests on an Alloy 690TT tube at room temperature (RT) and at $343^{\circ}C$ using tube- and ring-type specimens to investigate the stress-strain behavior and tensile properties of a steam generator (SG) tube in the axial and circumferential directions at RT and at the design temperature of a nuclear power plant (NPP). The results of the axial tensile test showed that yield point phenomena appeared at both RT and $343^{\circ}C$, and serrated flow in the stress-strain curve appeared at $343^{\circ}C$. Yield and tensile strengths for both directions were clearly lower at $343^{\circ}C$ compared to RT; however, the elongations were approximately the same at both test temperatures. Regardless of the test temperature, the strengths in the circumferential direction were lower by approximately 5~10 % than those in the axial direction. In addition, the test data revealed that the reduction in the yield and tensile strengths of the Alloy 690TT SG tube with the test temperature was more significant than that estimated by the temperature correction factor of ASME Sec.II.

• Journal of the Korean Recycled Construction Resources Institute
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• v.3 no.2
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• pp.109-114
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• 2015

Recently, numerous studies were dedicated on the HVFA concrete using high volume CCPs. In initial studies, main topics are dependent on material properties of HVFA concrete, but several studies were dedicated on the structural behavior of HVFA concrete such as elasticity modulus, stress-strain relationship and structural behavior nowadays. Therefore, in this paper, on the basis of recent studies on the structural behavior, 2 large-scale test members were manufactured with 7.5m span length and fly ash replacement ratio 50%, concrete compressive strength 50MPa in order to apply to the practical structure and evaluate possibility of application. From the test results, although there were small differences between test results and existing research results on the stress-strain relationship, the application to practical structure is not hard. In flexural test, as the produced pattern of displacement and strain were similar to those of general concrete without fly ash, the difference between 50% fly ash concrete and general concrete is very small. And the concrete shear strength obtained by test was similar to that of design code, so existing design code will be also able to apply.

• Journal of the Korea Convergence Society
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• v.12 no.11
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• pp.185-191
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• 2021

The purpose of this study is to develop middle school English classes using Problem-Based Learning(PBL) based on flipped learning and to examine its effects. Recently, various attempts to combine flipped learning and PBL have been made; however, many studies have not been applied to middle and high school curriculums yet. The attempt of this study is expected to have theoretical and practical significance. The instructional model was derived from the review of previous studies, and the development of instructional program followed the general design procedure(analysis-design-development-implement-evaluation), and its validity was secured with the advice of related experts. To verify the effectiveness of the program, the English academic achievement test and the English key competency test were conducted before and after the program. Changes in English academic achievement were analyzed by the paired-sample t-test, and the effect of key competency and the level of achievement test performance (high vs, low) on the pre-post score change was analyzed by the mixed effects repeated measures ANOVA. As a result of the analysis, both academic achievement and key competencies increased, and the low-level students in the pre-academic achievement test showed more improvements. In conclusion, the PBL class based on flipped learning is effective in improving the English academic achievement and key competencies of middle school students, and in particular, it is shown to be an effective teaching method for students with low academic achievement.

• Journal of Distribution Science
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• v.16 no.11
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• pp.57-64
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• 2018

Purpose - As the importance of salesperson attitudes and behaviors enhancing customer perception and loyalty have increased, many retail companies put emphasis on internal marketing activities. The issue also has captured the interest of academics, but most of the previous research tends to be limited to investigating antecedents of salesperson job satisfaction and commitment. Based on the consumer-brand relationship concepts, this study aims to examine the effects of the salesperson-brand relationships on customers' service evaluation and store loyalty. Research design, data, and methodology - In a structural equation model, it is hypothesized that salesperson brand identification influences salespersons' brand trust and affect, which are the two dimensions of consumer-brand relationships. Salespersons' brand trust and affect are expected to increase salespersons' customer orientation, which in turn influences customers' service evaluations and store loyalty. To test this hypotheses a set of data collected from department stores in Seoul is utilized. Results - First, it was found that salesperson brand identification is a significant antecedent to salespersons' brand trust and affects, the two dimensions of salesperson brand relationships. Second, salespersons' brand trust and affect were found to enhance salespersons' customer-oriented behaviors. Third, salespersons' customer orientation showed a significant effect on customers' service evaluation. When a salesperson makes more effort to provide useful information for fulfilling customer needs, customers evaluate the salesperson's service more positively. Finally, customers' service evaluation had a positive impact on customers' store loyalty. Conclusions - This study provides significant academic and practical implications. First, based on the theory of consumer-brand relationships, the concept of salesperson-brand relationships was introduced and found to be an effective motivator of salespersons' customer oriented attitudes and behaviors. Therefore, the two dimensions of brand relationships, brand trust and affect, should be considered as the critical factors both in developing theoretical research and improving long-term company performance. Also, internal marketing activities should focus on maximizing employees' brand identification. That is, retail companies need to put emphasis on sharing their brand values and personality with internal customers to strengthen the brand relationships with salespersons and to enhance customer responses.

• The Journal of Korean Academic Society of Nursing Education
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• v.2
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• pp.7-19
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• 1996

The purpose of this study was to analysis the effect of service education that would improve the image of nursing as a qualified nurse. This study was designed one group pretest-posttest design. The sample was consisted of 274 nurses who was all of the nurses participated in the education of service. The education was provided during eight hours a day each group. The program of the education was devided eight sections and each section had it's own individual teacher. The member of each group was consisted of about twenty-five nurses. The questionnaire was developed by researchers and was applied two times just at the preeducation and two weeks after the education. The criteria of the developed questionnaire was consisted of two aspects, one was recognizant aspect of service and the other was behavioral aspect of service. The reliability of the questionnaire was Chronbach's $\alpha$=0.778. The questionnaire was exammed collected in the morning when the education of the service was started and two weeks after the education. The data were analyzed by descriptive statistics, paired T-test, Pearson's correlations. The result of the study are as follows : 1. There was a significant difference in the aspect of recognition of service between pre and post self-evaluation. 2. There was no significant difference in the aspect of behavior service between pre and post self-evaluation. 3. There was a significant difference in the aspect of total sense, score between pre & post self-evaluation. 4. There was a significant correlation between clinical experience and aspect of recognition of service. The positive correlation was shown in the longer clinical experience between nurse's role and service. But there was not a statistically significant correlation between clinical experience and aspect of behavior of service. Through the result it can be concluded that the education of service was needed to improve image of nursing as a practical and basic factor for the nurses, even though the education was not directly related to the nures's professional knowledge and skills.