• Journal of Korean Society of Steel Construction
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• v.18 no.1
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• pp.53-58
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• 2006

The aim of this paper is to verify the dynamics stability of the continuous PSC Box bridges on the high-speed Kyoung-bu railway when a high-sped train runs through it. An experimental study was carried out to investigate the dynamic behaviors of the PSC Box railway bridge, which had ben designed based on dynamic design criteria. As a result, it was determined that PSC Box railway bridges possess enough dynamics stability for use by high-speed trains. According to the result of a field test (dynamics measuring analysis) that was conducted, an application of the natural frequency of train speed and the adjustment of the bridge's span length will allow one to come up with a more economical and suitable bridge design. Furthermore, it was found that the continuous control of the bridge's dynamic behavior and the bridge's maintena nce require the recording of data. The results of this study are very important in evaluating the structural stability of high-speed line bridges.

• Journal of the Korean Geotechnical Society
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• v.20 no.7
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• pp.119-126
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• 2004

A small-scale reinforced earth wall was constructed in a laboratory to investigate the effect of wall rigidity and of construction sequence on the wall. A full continuous wall facing and a discrete wall facing were designed and constructed for tests. These two different facing systems should adapt different construction procedures due to their different facing shapes. The model wall was built with geo-grid reinforcement, sand, and facings on rigid surface. The model wall was instrumented with earth pressure gages, LVDTs, and strain gages. The experimental results have shown differences in wall behavior related to construction sequence and types of wall facing. It is found in this study that the reinforced earth wall built with full continuous facing is safer than the reinforced earth wall built with the discrete wall facing.

• Journal of the Korean Institute of Gas
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• v.16 no.5
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• pp.35-40
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• 2012

To analyze the macroscopic fracture behavior as functions of the gas pipeline grade and the working environment, following analyses have been accomplished. Computer analysis of changes in fracture behaviors according to the working conditions of pipelines and Analysis of dynamic ductile fracture behaviors using the Battelle Two Curve Method. Recently, an economic and reliable pipe materials with improved performance has been needed for the severe pipeline working condition and new transporting materials. As the grade of pipe materials became higher, the possibility of dynamic ductile fracture could be increased. Therefore, the understanding of the technology to control and arrest the dynamic ductile fracture is important.

• Proceedings of the Korean Society for Rock Mechanics Conference
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• 2000.09a
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• pp.105-115
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• 2000

As large underground projects such as radioactive waste disposal, hot water and heat storage, and geothermal energy become influential, the study, which consider all aspects of thermics, hydraulics and mechanics would be needed. Thermo Hydro-Mechanical coupling analysis is one of the most complex numerical technique because it should be implemented with the combined three governing equations to analyze the behavior of rock mass. In this study, finite element code, which is based on Biot's consolidation theory, was developed to analyze the thermo-hydro-mechanical coupling in continuum rock mass. To verify the implemented program, one-dimensional consolidation model under the isothermal and non-isothermal conditions was analyzed and was compared with the analytic solution. The parametric study on two-dimensional consolidation was also performed and the effects of several factors such as poisson's ratio and hydraulic anisotropy on rock mass behavior were investigated. In the future, this program would be revised to be used for analysis of general discontinuous media with incorporating discrete joint model.

• Tunnel and Underground Space
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• v.10 no.3
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• pp.355-365
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• 2000

As large underground projects such as radioactive waste disposal, hot water and heat storage, and geothermal energy become influential, the study, which consider all aspects of thermics, hydraulics and mechanics would be needed. Thermo-Hydro-Mechanical coupling analysis is one of the most complex numerical technique because it should be implemented with the combined three governing equations to analyze the behavior of rock mass. In this study, finite element code, which is based on Biot's consolidation theory, was developed to analyze the thermo-hydro-mechanical coupling in continuum rock mass. To verify the implemented program, one-dimensional consolidation model under the isothermal and non-isothermal conditions was analyzed and was compared with the analytic solution. The parametric study on two-dimensional consolidation was also performed and the effects of several factors such as poisson's ratio and hydraulic anisotropy on rock mass behavior were investigated. In the future, this program would be revised to be used for analysis of general discontinuous media with incorporating discrete joint model.

• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.13-19
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• 2014

Dynamic ductile fracture (DDF) has been studied in the transportation pipeline for the carbon dioxide capture and storage(CCS) system. DDF behavior of CCS transportation pipeline has been analyzed using Battelle Two Curve Method (BTCM) and compared with the DDF behavior of natural gas pipeline. The operating safety criteria against the DDF has been investigated based on the sensitivity analyses of the pipe thickness and the operating temperature for the $CO_2$ pipeline. The DDF criteria can be applied to confirm the operating safety of the $CO_2$ pipeline. If the commercial natural gas pipeline were used at room temperature as a $CO_2$ pipeline, the thickness of pipe should be at least 7mm and the pressure should be less than 54bar for the $CO_2$ pipeline system.

• Journal of the Korea Concrete Institute
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• v.22 no.2
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• pp.247-254
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• 2010

The purpose of study is to investigate the load resistance mechanism of MRS continuous joint designed with different details. Six full-scale specimens, which could simulate the negative moment region of the 8 m long MRS system, were prepared to evaluate the structural performance of the continuous joint. According to the experimental results, all specimens which include the specimen with dapped ends designed by loads at the construction stage were failed in a flexural manner and showed the load carrying capacity over the nominal flexural strength. Therefore it is recommended that the dapped ends for MRS continuous joints be designed for the loads of the construction stage. And the shear key, which was installed on the top of rib for MRS slab, helps the enhancement of strength and especially deformation capacity.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.30 no.4C
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• pp.175-183
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• 2010

The load distribution and deflection of large diameter piles are investigated by lateral load transfer method (p-y curve). The emphasis is on the effect of the soil continuity in a laterally loaded pile using 3D finite element analysis. A framework for determining a p-y curve is calculated based on the surrounding soil stress. The parametric studies that take into account the soil continuity are also presented in this paper. Through comparisons with results of field load tests, it is found that the prediction by the present approach is in good agreement with the general trend observed by in situ measurements and thus, represents a significant improvement in the prediction of a laterally loaded pile behavior. Therefore, a present study considering the soil continuity would be more economical pile design.

• Journal of Navigation and Port Research
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• v.42 no.1
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• pp.1-8
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• 2018

This study covers the selection of systems measuring the behaviour of the slender structure in the underwater environment and its performance assessment. From a comparison of an instrumentation system that can measure the continuous behaviour along the entire length of the slender structure, the underwater camera system is finally selected as the most appropriate semi-permanent measurement system for Deep-sea Ocean Engineering Basin of KRISO. An experiment on the rigid pipes for a basic performance evaluation of the underwater camera is conducted in this study. The motion of a top excited rigid pipe is measured with the utilization of the underwater camera system. The performance of the underwater camera is evaluated by comparing the movement of a pipe measured by the underwater camera with the measured input signals. Through the top excitation experiment for the slender structure, the real-time three-dimensional measurement of the underwater camera system is qualitatively evaluated in this case. The developed underwater camera system can apply to the system to measure dynamic behaviour of a slender structure and mooring line in Deep Ocean Engineering Basin.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.4
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• pp.293-308
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• 2012

The shear behavior at the particle/surface interface such as rock joint can determine the mechanical behavior of whole structure. Therefore, a fundamental understanding of the mechanisms governing its behavior and accurately estimation of the interface strength is essential. In this paper, PFC, a numerical analysis program of discrete element method was used to investigate the effects of the surface roughness on interface strength. The surface roughness was characterized by smooth, intermediate, and rough surface, respectively. In order to investigate the effects of particle shape and crushing on particle/surface interface behavior, one ball, clump, and cluster models were created and their results were compared. The shape of particle was characterized by circle, triangle, square, and rectangle, respectively. The results showed that as the surface roughness increases, interface strength and friction angle increase and the void ratio increases. The one ball model with smooth surface shows lower interface strength and friction angle than the clump model with irregular surface. In addition, a cluster model has less interface strength and friction angle than the clump model. The failure envelope of the cluster model shows non-linear characteristic. From these findings, it is verified that the surface roughness and particle shape effect on the particle/surface interface shear behavior.