• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.143-153
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• 2006

In design of bridges, estimation of actions and loadings is very important for the safety and maintenance of bridges. In general, effect of traffic loading on the bridge can be modeled as live load (including impact load) and fatigue load. For estimation of traffic loading, it is important to get reliable and comprehensive truck statistical data such as the traffic and weight information. To get statistical data, Bridge Weigh-In-Motion (BWIM), which measures the truck weights without stopping the traffic, is need to be developed. In this study, BWIM system with various functions is developed first. Then this system is used to get comprehensive truck data. Traffic loadings including fatigue and live loading are formulated from the truck data acquired from the bridges. Objectives of this study are to develop the BWIM system, to apply the system in test bridge in Highway, and to formulate the live and fatigue loading for bridge design.

• Journal of Korean Society of Steel Construction
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• v.11 no.4 s.41
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• pp.329-338
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• 1999

A systematic procedure to evaluate fatigue damages and to predict remaining fatigue lives is introduced for a steel railway bridge. Fatigue damages are evaluated by using the currently available fatigue damage theory. Fatigue lives with the condition of fatigue crack initiation are estimated by the probabilistic approach based on the reliability theory as well as the simplified procedure. A equivalent deterministic procedure is also suggested to assess the remaining fatigue life under various traffic conditions. Numerical simulations are used to assess dynamic stress histories with correction factors. Loading models are obtained from the passenger volume data. Train coincidences are also considered. Based on the results, the fatigue life is found to be underestimated by without considering the coincidence of trains on the bridge. The simplified method proposed in this study are found to yield approximately the same results as the systematic procedure.

• Journal of the Korea Convergence Society
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• v.8 no.7
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• pp.75-84
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• 2017

The purpose of this study is to find the relation between the detailed categories of the self-efficacy of workers in the field of railroad signaling and the detailed categories of their fatigue in the use of analysis of moment structure(AMOS) model. A self-administered questionnaire survey of workers in the field of railroad signaling had been conducted and a total of 341 copies were analyzed. This study had the assumption that their general self-efficacy and social self-efficacy would negatively influence their physical fatigue and mental fatigue. As a result, their general self-efficacy negatively influenced their physical fatigue and mental fatigue, whereas their social self-efficacy didn't influence their physical fatigue and mental fatigue. Therefore, it is possible to reduce the fatigue of the study subjects by enhancing corporate support to increase their general self-efficacy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.7
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• pp.688-698
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• 2017

This study was conducted to identify the conceptual definitions and attributes of fatigue in hemodialysis patients based on the Hybrid Model of concept development. The Hybrid Model was used to investigate the main attributes and indicators of the concept by applying three stages. After a literature review, data were collected through observation and interviews including qualitative research in the field work stage. The participants included 10 patients in hemodialysis center of two hospitals in Gwang-ju, Korea. The attributes of fatigue concept in the hemodialysis patients were divided into four dimensions, physical activity, affective mood, social role, and cognitive reflection. The definition of fatigue by hemodialysis patients was defined as 'subjective feeling usually experienced in four dimensions during the process to recognize and adjust energy deficiency and limited functions caused by uremia and repeated hemodialysis for chronic renal failure'. Considering the dimensions and attributes derived from this study, it may be possible to develop an effective intervention program for fatigue in hemodialysis patients.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.8 no.2
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• pp.167-175
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• 1988

The principle objective of this study is to evaluate the fatigue behavior of structural steel components of highway bridges subjected to service stresses. The main aspects of this investigation are; 1) a measurement and statistical analysis of service stress cycles observed in highway bridge. 2) fatigue tests under equivalent constant-amplitude(CA) loading and simulated variable-amplitude(VA) loading 3) a evaluation of the fatigue behavior under VA-loading by eqivalent root mean cube (RMC) stress range. Theoretically, the RMC model is adequate in evaluation of fatigue behavior under VA-loading, because the regression coefficient (m) of crack growth rate is 3 approximately. The result of fatigue test shows that the RMC model is fitter than the current RMS model in fatigue evaluation under VA-loading. The interaction effects and sequence effects under VA-loading affect little fatigue life of structural components. As the transition rate of stress ranges is higher, the crack growth rate is higher.

• The Journal of the Korea Contents Association
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• v.22 no.7
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• pp.432-442
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• 2022

This study aimed to investigate depression, fatigue, and role-overload in nurses caring for COVID-19 patients and identify factors affecting depression. Data were collected from 142 nurses caring for COVID-19 patients at four designated COVID-19 hospitals using self-report questionnaires, from September 8, 2020, to September 17, 2020. The subjects' scores for depression, fatigue, and role-overload were 14.51±9.54, 3.19±0.64, and 3.30±0.64 points, respectively. Depression was positively correlated with fatigue (r=.40, p<.001) and role-overload (r=.30, p<.001), and fatigue was positively correlated with role-overload (r=.54, p<.001). Factors affecting depression included fatigue (β=.23, p=.014), health status (moderate: β=.28, p=.001; unhealthy: β=.26, p=.002), and hospital type (university hospital: β=.18, p=.024). The explanatory power (R²) of the model was 28.1%. In order to manage the nurse's depression level, a strategy for lowering the fatigue level and a strategy for improving the nurse's health statue are needed.

• Journal of the Society of Naval Architects of Korea
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• v.38 no.3
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• pp.74-83
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• 2001

After the concept of fracture mechanics was applied to fatigue crack propagation by Paris. Paris' law is widely used to predict fatigue crack growth behavior. Since Elber proposed the effective stress intensity factor(SIF) and showed a good agreement with experimental results using the proposed SIF, emphasis in crack propagation studies has been placed on measuring the effective stress range ratio. This paper proposes a numerical model to simulate the crack closure and propagation behaviour under various loading spectrum. The validity of the proposed model is checked by comparing with the Toyosada numerical solutions on the crack propagation behaviour. Important insights developed are summarized.

• 한국도로학회:학술대회논문집
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• 2004.10a
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• pp.95-100
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• 2004

• 한국도로학회:학술대회논문집
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• 2011.03a
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• pp.277-284
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• 2011

• 한국도로학회:학술대회논문집
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• 2006.03a
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• pp.119-126
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• 2006