• KSCE Journal of Civil and Environmental Engineering Research
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• v.32 no.4A
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• pp.245-253
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• 2012

In the longway tunnel and underground traffic road, the structure of transverse ventilation system is constructed by the airpit slab. In this study, the full scale specimens of the PSC airpit slab that attached fire resistance panel are performed the static and dynamic loading tests for evaluation of bending capacity. The first of all, it confirmed the evaluations about the fundamental efficiency of the fire resistance panel and PSC slab by the 3-point bending test and pull-off test. The tests are performed for evaluation of the bending resistance under ultimate static load and the bonded capacity under dynamic fatigue load. A fatigue test is performed for an investigation of the effect on wind pressure that is developed by transit of traffic. The damage or debonding on surface between fire resistance panel and PSC slab was not developed in dynamic fatigue load test, also the behavior of the specimens is very stable and the debonding of the fire resistance panel attached at the bottom surface of PSC slab was not developed in static load test, too. Therefore, the crack or debonding of the fire resistance panel will be not developed by external loads during the construction or completion of the precast fire resistance system.

• International Journal of Highway Engineering
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• v.5 no.3 s.17
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• pp.11-20
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• 2003

Concrete structures such as bridges, pavement, and offshore structures are normally subjected to repeated load. Because highway and airfield pavements are to resist tension in bending, fatigue failure behavior is very important the fatigue life of materials. Therefore, in this paper was carried according to the fatigue test method and experiment variables for pavement concrete. The fatigue tests were applied split tension($150{\times}75$ in size) and flexural($150mm{\times}150mm{\times}550mm$ in size) beam fatigue test method. Major experimental variable in the fatigue tests in order to consideration of fatigue life were conducted loading frequency of 1, 5, 10, 20Hz and loading shape of block, sine, triangle and moisture condition of dry and wet condition and curing age of 28day and 56day. The test results show that the effect of loading frequency increasing the frequency increased fatigue life, decreased significant at frequencies below 200 cycles. The effect of loading wave form on fatigue life show that a block decreased, triangular increased in comparison with sine. The effect of moisture condition decreased in wet condition in comparison with dry condition. The effect of curing age increased in 564ays in comparison with 28day.

• Journal of the Korea institute for structural maintenance and inspection
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• v.27 no.2
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• pp.33-41
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• 2023

The application of seismic separation joints that can improve the deformation capacity of piping is an effective way to improve seismic performance. Seismic separation joints capable of axial expansion and bending deformation are installed where deformation is expected and used for the purpose of safely protecting the piping. Bellows are flexible and have low stiffness, so they can be used as seismic separation joints because they have excellent ability to respond to relatively large deformation. In this study, the seismic performance and limit state for bending deformation of 2-ply and 3-ply bellows specimens were evaluated. Seismic performance was evaluated by applying an increasing cyclic load to consider low-cycle fatigue due to seismic load. In order to confirm the margin for the limit state of the evaluated seismic performance, an experiment was conducted in which a cyclic loading of constant amplitude was applied. As a result of the experiment, it was confirmed that the bellows specimen was made of stainless steel and had a high elongation, so that the 2-ply bellows specimen had the limit performance of resisting within 3 cycles even at the maximum forced displacement of the 3-ply bellows specimen.

• Journal of the Korean Society for Railway
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• v.11 no.3
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• pp.326-333
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• 2008

This study is objected by presenting preliminary data to revise the periodic replacement criteria of continuous welded rail (CWR) in using. In this study, it is investigated information resources for foreign standards, the cause and types of damage in welded rails and the track maintenance history of Seoul metro to analysis the correlation between rail failure and accumulated passing tonnage. Also, it is performed bending test for the laid welded rail reaching the periodic replacement criteria. In result, the correlation between rail failure and accumulated passing tonnage is not obvious and it is a lot of cases for the construction error of welded rail. Also, as a result of bending test of laid welded rail, according to reducing about $17{\sim}18%$ the bending fracture strength of rail, the laid welded rail reaching the periodic replacement criteria is well enough ensured for the load carrying capacity of rail.

• Proceedings of the Korea Concrete Institute Conference
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• 2002.10a
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• pp.401-406
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• 2002

The purpose of this research was to obtain fatigue property of pavement concrete by flexural fatigue test. The size of specimen used in fatigue tests was 10$\times$10$\times$46cm. The specimens of pavement concrete were fabricated using the concrete at job site. The fatigue tests were performed by applying into a constant amplitude loading. The flexural fatigue tests were performed by stress levels of 90%, 80%, 70% and 60%, and stress ratio of 0.1. From this research, the S-N relationship, S-N-P relationship were derived and Weibull probability density functions was plotted using the distribution parameters.

• Journal of the Korean Society for Railway
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• v.20 no.5
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• pp.649-657
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• 2017

In this study, fatigue testing was carried out for long-term use of rail according to track type. From S-N curves for 50%~0.01% failure probability, the fatigue life of the long-term use rail for each track type was derived using the weight probability analysis technique on the experimental data. Because the rails used in the fatigue test have different cumulative tonnages, the number of repetitions was modified by averaging the cumulative tonnage. In addition, the bending stresses of rail bottoms, considering rail surface irregularities, track support stiffnesses and train speeds, were evaluated using the predicted rail bending stresses derived from existing studies. As a result, for rail fatigue life evaluation, the fatigue life of rail on the ballast track was found to be more than 200 million tons higher than the standard value for rail replacement. Also, the fatigue life of rail on concrete track is more than 300 million tons higher than that on ballast track. The Haibach rule is adaptable for the fatigue life evaluation of rail for stress range under fatigue limit.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.2
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• pp.34-42
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• 2018

In order to minimize the deformation of asphalt concrete track(ACT) and ensure the structural safety, a wide type concrete sleeper is necessary to distribute vehicle loading and reduce the exposure of the asphalt roadbed. In this research, the wide prestressed concrete(PSC) sleeper for ACT was developed through the shape design and the structural safety was reviewed using finite element analysis. Furthermore, static test, dynamic test and fatigue test were carried out according to EN13230-2 to verify the design appropriateness of the wide PSC sleepers for ACT. The performance test showed that the developed wide PSC sleeper for ACT meets all the performance requirements by European standard.

• International Journal of Highway Engineering
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• v.7 no.2 s.24
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• pp.13-22
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• 2005

Using recycled aggregate from demolished concrete structures provides a peat opportunity fur conserving natural resources. In many parts of world, virgin aggregate deposits have been depleted, and transporting aggregates over long distances can be much more expensive than using a low-cost recycled aggregate. In Korea, about 7-million tons of concrete occurs annually, out of this, about 2-3 million tons are available for recycling. This study is to present the method of utilizing the recycled aggregate. The recycled aggregate concretes were made for compressive strength test, flexural strength test and fatigue test using w/c of 40, 50 and 60%. The replacing rates of recycled aggregate to virgin aggregate were 0, 25 and 50%. The purpose of this study is to compare the fatigue lift of recycled aggregate concrete with that of virgin aggregate concrete. It was shown that the fatigue life of recycled concrete was function of recycled aggregate replacement ratio and water cement ratio.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.2
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• pp.702-709
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• 2018

A quick-hardened concrete track was developed to improve the aged ballasted track to a concrete track, and applied to earthworks and tunnels of main and urban railways. Rebars for reinforcement are not generally applied to prestressed concrete sleepers. On the other hand, many cracked sleepers have been observed in railroad sites. A wide sleeper, which is one of the main components of quick-hardened concrete track, should be structurally safe and crack-resistant in a ballasted and concrete track to avoid this problem. In particular, a wide sleeper manufactured by a post-tension method must have reinforcing bars applied to the rail-seat section. In this paper, static tests, dynamic tests, and fatigue tests were carried out to compare the flexural strength and crack resistance performance of a wide sleeper with and without reinforcing bars for a quick-hardened concrete track. As a result of the test, if some reinforcing bars are applied appropriately to the rail-seat section of a wide sleeper, it will be possible to prevent the occurrence of cracks, delay the expansion of the crack width, and the flexural fracture.

• International Journal of Highway Engineering
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• v.2 no.4 s.6
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• pp.101-109
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• 2000

This study was performed to estimate fatigue life of polymer-modified and reinforced overlay asphalt mixtures with respect to reflection cracking in asphalt overlay pavement. In order to achieve the goal, the expedited reflection cracking test method was developed and applied to various mixtures and the results were compared one another with respect to the resistant characteristics of reflection cracking. The theoretical prediction equation of fatigue life for each mixture was suggested based on statistical analysis of experimental test results in the flexural failure mode. Since coefficients of correlation between estimated values and measured values were very high ($r^2=0.95$ or higher), the prediction model can be used for relative comparison of various pavement overlay choices to be used in the field.