• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.3
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• pp.41-50
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• 2012

Improvement of steel material quality made fatigue problems more critical than failure of the material itself. In many cases, cracks on the welded parts of steel deck bridges are reported against the failure of steel materials. And the cracks are caused by alternate stress on the welded parts due to live loads on the bridge. The range of alternate stress on the welded part is related to property of the sections which compose othortropic steel deck. Othortropic steel deck is mainly composed of deck plate, ribs and floor beams, wearing surface, etc. In this paper, a methology to estimate the alternate stress for pthortropic steel deck using Pelikan-Esslinger method and signed Von-Mises equivalent stress is proposed first. Parametric study served references for fatigue stresses when designing or repairing othortropic steel deck bridges, by analyzing relationship between alternate stress range and properties of steel deck members.

• Journal of the Korea institute for structural maintenance and inspection
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• v.9 no.4
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• pp.209-216
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• 2005

The objective of this paper is to investigate the H & Channel type lining board's capacity by using the fatigue test. The accumulated test result will be used to analyze the relation between the cause of crack occurrence and the behavior of structure. H type lining boards was comfortable behaved in over one million recycled. loading test. In case of channel type lining board specimens occurred the fatigue fracture in about one hundred thousand recycled loading test, and then could not secured endurance life that used servicing load.

• Journal of the Korea institute for structural maintenance and inspection
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• v.8 no.4
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• pp.135-143
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• 2004

In this paper, 6 span SCP continuous girder bridge's structural behavior were studied by analytic and experimental method To study structural behavior of SCP girder, we used PSC theory and steel girder theory. To examine slab concrete crack, concrete stress, and fatigue stress of steel, we achieved a static load and fatigue test. In the result, 6 span SCP girder bridge connected at the interior support about actuality bridge have enough structural capacity under service loads.

• Journal of Hospice and Palliative Care
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• v.11 no.4
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• pp.175-180
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• 2008

진행된 암환자에서 피로는 70% 이상이 경험하게 되는 흔한 증상이며 삶의 질을 저하시키는 주된 요인이다. 피로에 대한 선별검사는 "피곤하거나 지친감이 있나요?"라는 단순한 질문으로 가능하며 이미 개발된 평가도구를 사용하여 평가할 수 있다. 동반 질환이나 피로의 원인을 알기 위한 병력청취와 검사실 검사가 필요할 수 있으며 결과에 따라 가역적 인자를 치료하는 과정이 우선되어야 한다. 적절한 약물치료를 시행하여 증상을 호전시킬 수 있으며 이중 methylphenidate는 암 연관 피로를 호전시키고 마약성 진통제에 의한 진정에 효과가 입증되었다. 환자의 여명에 따라 부신 피질 호르몬제도 사용할 수 있고, 운동 및 환자의 교육과 영양관리 또한 중요하다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2012.06a
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• pp.463-465
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• 2012

선박근무자의 피로는 해양사고의 잠재적 요인으로 혹은 인적과실에 기여하는 한 요인 정도로만으로 여겨졌으나, 최근 이와 관련한 연구에 의하면 선박근무자의 피로가 임무수행에 밀접하게 영향을 미치며, 인적과실을 유발하는 주요한 원인 중 하나라는 사실이 밝혀지게 되면서 선박 인간공학분야에서의 인간공학적 요소들의 고려 여부가 관심의 대상이 되고 있다. 선박근무자의 피로 발생원인은 명확히 밝혀져 있지 않으며, 선상작업에서 오는 스트레스, 감정 및 작업 등에 의해 영향을 받는 것으로 보이나, 통상 피로는 주로 한 가지 원인보다 복합적인 원인에 의하여 발생되는 것으로 알려져 있다. 본 연구에서는 이러한 선박근무자의 자각피로도와 직무스트레스의 효율적 관리를 위하여 선상에서 간편하게 자각피로도를 측정할 수 있는 방법을 제안하고자 한다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.4
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• pp.433-439
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• 2016

The purpose of this study was to investigate the current status of job-stress factors associated with fatigue among emergency rescue workers. A self-reported questionnaire was completed by 264 rescue workers in J province from January 5 to March 14, 2015. The questionnaire consisted of general characteristics about the subjects, health-related characteristics, a job stress instrument, and a subjective fatigue instrument. The results were analyzed using a t-test, ANOVA, Pearson correlation, and multiple regression analysis to determine the factors related to fatigue. Fatigue was influenced by the personal characteristics of the rescue workers and job stress. To reduce fatigue, effort to manage and relieve stress is required after a job is done in the field. In addition, it is expected that fatigue can be reduced by providing methods that can improve the healthcare capacity of the rescue workers.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.179-188
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• 2011

Steel structures have been allowed to have fatigue damage tolerance in fact. If it would be assessed whether fatigue crack is growing or not and How fast fatigue crack is propagating, we should make a rational decision on methods and a period of reinforcement in the maintenance. In this study, fatigue crack growth tests on two kinds of through-thickness cracked steel plates and a out-of-plane gusset welded joint were conducted to evaluate fatigue crack growth rate using the COD(Crack Opening Displacement), and COD measurement using strain gauges was examined to offer a practical method. As a result, we proposed a reasonable assessing method for fatigue crack growth rate using the COD and it was experimentally proved practical to estimate the COD through measuring strains.

• Journal of the Korea institute for structural maintenance and inspection
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• v.18 no.5
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• pp.68-77
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• 2014

In this study, polysulfide epoxy polymer concrete was chosen as an ultra thin bridge deck overlay, and the effect of polymer concrete pavement on the fatigue stress range of the orthotropic steel deck was analyzed through the comparative analysis with epoxy asphalt pavement and SFRC pavement. Abaqus was used to estimate the fatigue stress range, and signed von-mises stress was used to estimate fatigue stress range according to pavement materials and thickness, considering there were multi axis stresses which have longitudinal and lateral direction on the welded parts of the steel deck.

• Journal of the Korea institute for structural maintenance and inspection
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• v.10 no.6
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• pp.205-212
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• 2006

In recent investigations, reinforced concrete beams strengthened with Carbon Fiber Sheets (CFS) subjected to fatigue loading were reported to be failed at the ends of CFS by its debonding. U-shaped CFS were attached to both ends of the CFS when fatigue tests on strengthened beams were conducted to delay and/or prevent fatigue failures of adhesive interface. The experimental parameters of this study were the usage of anchorage at the ends of CFS, the number of CFS layers, and the applied load levels of 60%~90% of the static ultimate load obtained from the static tests. The failure modes and the load cycle-deflection relations were observed and discussed from the experimental results. Those results also showed that the U-shaped anchoring system changes the fatigue failure modes and influences greatly on the fatigue capacity of the strengthened beams.

• 건강소식
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• v.24 no.2 s.255
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• pp.38-39
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• 2000