• Proceedings of the Korean Geotechical Society Conference
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• 2009.09a
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• pp.482-491
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• 2009

In this study, the mechanical behavior of very soft ground that is reinforced on the surface has been investigated with the aid of a series of numerical analyses. Key material properties of each dredged soft ground, reinforcement and backfill sand mat have been parametrically estimated in the numerical analysis. Along with the result of the study previously performed, a series of in-situ loading conditions and settlement exerted by surface reinforcing operation by construction vehicles has been numerically simulated. These result have been used to evaluate the limit bearing capacity for the unreinforced and reinforced soft ground. Also, the results of the numerical analysis obtained in this research were compared with Yamanouchi's empirical correlation for the limit bearing capacity. Engineering charts listed in this paper for estimating the limit bearing capacity provide field engineers with preliminary design tool for surface reinforcement of very soft ground.

• Proceedings of the KIEE Conference
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• 2000.07d
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• pp.2535-2537
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• 2000

In order to detect and monitor the broken cords of steel-cord belt from being damaged by impact of large lump of materials and the corrosion of steel cord, we developed a non-contact magnetic coil detection system. This measures the deterioration of reinforcing cables in steel cord conveyor belt which transport the ores in raw material plant. In this research, magnetic coil sensor of broken-cord detection system has exciting part and sensing part. The broken-cord detection system is operated by supplying a transmitter coil with electric power to generate magnetic field, and then the change of induced voltage is detected in each receiver coils due to resultant magnetic flux effected by the broken steel cords at the inside of the conveyor belt. By the informations such as the position and size of the broken steel cords obtained by SCBMS(Steel Cord Belt Monitoring System), it is expected that not only the span of belt life will be lengthened, but also this system can enable operators to plan scheduled maintenance and prevent the enlargement of damaged parts in steel cord belt at an early stage

• Transactions of the Korean Society of Mechanical Engineers A
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• v.31 no.2 s.257
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• pp.205-210
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• 2007

SiC/SiC composites and monolithic SiC materials have been fabricated by the melt infiltration process, through the creation of crystallized SiC phase by the chemical reaction of C and Si. The reinforcing material used in this system was a braided Hi-Nicalon SiC fiber with double interphases of BN and SiC. The microstructures and the mechanical properties of RS-SiC based materials were investigated through means of SEM, TEM, EDS and three point bending test. The matrix morphology of RS-SiS/SiC composites was greatly composed of the SiC phases that the chemical composition of Si and C is different. The TEM analysis showed that the crystallized SiC phases were finely distributed in the matrix region of RS-SiC/SiC composites. RS-SiC/SiC composites also represented a good flexural strength and a high density, accompanying a pseudo failure behavior.

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.8-15
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• 2005

The use of clean gaseous fuels for the purpose of high efficiency and low emission in automotive engines has tendency to increase in order to meet the reinforcing emission regulations and to efficiently utilize limited natural resources. Automotive companies developed and commercialized a LPG liquid injection system, which is mounted on LPLi(Liquid Phase LPG Injection) engines and vehicles based on this research trend. This research examines the biggest problem in LPLi engine, that is, the leakage characteristics of low viscosity LPG fuel according to the injector design variables. This study is also aimed to improve the performance of fuel-leakage in LPLi engine through the addition of a lubrication improver in HFRR(High Frequency Reciprocating Rig) facility. The needle displacement and the spring displacement of an LPLi injector are found to be already optimized. The possibility of a maximum of 70% leakage reduction compared to a conventional case, is verified when 1000ppm of a lubrication improvement material is added and 40% increase of a injector spring constant (K) is applied.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.645-654
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• 2005

This paper presents a nonlinear finite element procedure for the analysis of reinforced and prestressed concrete shells using the four-node quadrilateral flat shell element with drilling rotational stiffness. A layered approach is used to discretize, through the thickness, the behavior of concrete, reinforcing bars and tendons. Using the smeared-crack method, cracked concrete is treated as an orthotropic nonlinear material. The steel reinforcement and tendon are assumed to be in a uni-axial stress state and to be smeared in a layer. The constitutive models, which cover the loading, unloading, and reloading paths, and the developed finite element procedure predicts with reasonable accuracy the behavior of reinforced and prestressed concrete shells subjected to different types of loading. The proposed numerical method fur nonlinear analysis of reinforced and prestressed concrete shells is verified by comparison with reliable experimental results.

• Journal of the Korean Geosynthetics Society
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• v.2 no.3
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• pp.3-9
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• 2003

Geosynthetics as a reinforcing material for earth structures have ever increased due to their excellent economy, fine external appearance, and easy construction. Geogrids are high-strength, orientated-polymer grid structures used to reinforce soil. This paper deals with the construction and sire monitoring for a 5.1m high-reinforcd slope with $75^{\circ}$ steep. The purpose of site monitoring is to evaluate the applicability of reforced slope with geogrid. Full scale field performance during and after construction was monitored by incorporating instrumentation including strain gauges on the geogrid, and horizontal and vertical movements.

• Tunnel and Underground Space
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• v.20 no.5
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• pp.378-389
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• 2010

Submarine tunnels are affected by the surrounding environments more than regular tunnels. Especially, they are often vulnerable to damage by salt in seawater. Seawater is more likely to affect reinforcing rods and steel fibers than concrete. Recently the usage of anti-corrosive fibers increases in the tunnel which is subject to the possibility of damage. By comparing the capability of polypropylene fibers with that of steel fibers, the proper mixture ratio is decided and the supporting capability of polypropylene fibers was tested using round panel and beam specimens. The results of this study can be of great use in selecting the fiber material and designing of fiber reinforced shotcrete of submarine tunnels.

• Journal of the Korean Society of Industry Convergence
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• v.20 no.2
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• pp.149-155
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• 2017

Mechanical properties of carbon coated $SiC_f/SiC$ composites have been investigated, in conjunction with a detailed analysis of microstructure. Especially, the fracture behavior of $SiC_f/SiC$ composites by the induction of carbon coating layers has been examined. The matrix region of $SiC_f/SiC$ composites with ultra-fine SiC powders were consolidated by a liquid phase sintering (LPS) process, using a sintering additive of $Al_2O_3-Y_2O_3$ powder compound. In this composite, plain and satin- woven Tyranno SA fabrics were also utilized as a reinforcing material. A carbon interfacial layer was coated around satin-woven SiC fabrics. The characterization of LPS-$SiC_f/SiC$ composites was investigated by means of SEM and three point bending test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.3 no.2
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• pp.199-204
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• 1999

A recent application of advanced composite materials, primarily fiber-reinforced plastic (FRP) composites, in structures is the reinforcement of conventional structural materials, such as concrete and glued-laminated timber (glulam), to increase their performance. In particular, the construction of large-scale glulam structures usually requires members with large depths and to significantly increase the stiffness and strength of glulam, the members can be reinforced with FRP at top and bottom surfaces. In this paper, glulam beams reinforced with GFRP strip are tested under 2-point bending and results are compared with numerical solution using layer-wise beam theory.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.2
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• pp.63-72
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• 2004

The purpose of this study is to evaluate seismic performance of reinforced concrete bridge piers supported by laminated rubber bearings. A computer program, named RCAHEST(Reinforced Concrete Analysis in Higher Evaluation System Technology), for the analysis of reinforced concrete structures was used. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. Seismic isolator element is developed to predict behaviors of laminated rubber bearings. The proposed numerical method for seismic performance evaluation of reinforced concrete bridge piers supported by laminated rubber bearings is verified by comparison with reliable experimental results.