• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.2
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• pp.7-21
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• 2008

Foundation failure due to bridge scour during floods is the leading cause of bridge failure. Performed were the evaluation of bridge scour vulnerability and prioritization on real bridges registered in the National Highway Bridge Inventory of the capital region. The case studies for 30 national highway bridges consist of site investigation including boring test, bridge scour analysis fur the design flood, bearing capacity evaluation of the bridge foundation before and after scour, comprehensive evaluation of bridge scour vulnerability, and prioritization. Nine of 26 spread (feting bridges showed the potential future vulnerability to scour with significant decrease in the bearing capacity of foundations due to scour and the remaining 17 spread footing bridges were expected to maintain their stability to resist the effects of scour. Three of 4 pile foundation bridges exhibited considerable decrease in the bearing capacity of foundation after scour.

• Proceedings of the Korean Geotechical Society Conference
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• 1994.09a
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• pp.94-110
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• 1994

Types of foundation of high rise buildings are primarily determined by loads transmitted from super structure, soil bearing capacity and available construction technology. The usd of deep foundation cannot be justified due to the fact that rock of enough bearing capacity is not found down until 90 ~ 100m. When a concentration of high soil pressure must be distributed over the entire building area, when small soft soil areas must be bridged, and when compressible strata are located at a shallow depth, mat foundation may be useful in order to have settlement and differential settlement of variable soils be minimized. The concept of mat foundation will also demonstrate some difficulities of applications if the load bearing demand directly carried down to the load -bearing strata exceeds the load -bearing capacity. This paper introduces both the analysis and design of mat type foundation for high rise buildings as well as the methodology of modelling of the soil foundation, especially, engineered to redistribute the stress exceeding the soil bearing capadity. This process will result in the wid spread of stresses over the entire building foundation.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.331-335
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• 2004

This study is focused to analyze the movement of thermal effluent dischargeed from nuclear power plant by season, ebb and flow, and before and after foundation of tide embankment using thermal infrared band image of 28 scenes observed from Landsat from 1987 to 2004, which is the early stage of operation of young-kwang nuclear power plant. In diffusion of thermal effluent discharge by seasons, spring and summer is spreading further than autumn and winter. It is considered to distribute widely mixed with thermal effluent discharge and hot water, which is distributed naturally along the seaside. It is known the fact that tidal currents control the direction of diffusion of thermal effluent discharge by the change of ebb and flow. Namely, it is distributed widely on the Southwest direction along the seaside by tidal currents when ebb and, it is moved widely on the Northeast direction along the seaside by tidal current when flood. However, in the early stage of flood current, the mainstream of thermal effluent discharge is spread on Southwest direction and, the direction is changed on North­east way when the latter period of flood current. Similarly, in the early stage of ebb current, the mainstream of thermal effluent discharge is spread on Northeast direction and, the direction is changed on Southwest direction when the latter period of ebb current. As the result of comparing to the diffusion pattern of thermal effluent discharge before and after the foundation of seawall, discharged thermal effluent from the drain of plant by the foundation of dike is shown as curved circle pattern on Northeast to West direction from the ending portion of the seawall.

• Proceedings of the Korea Institute of Convergence Signal Processing
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• 2003.06a
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• pp.300-303
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• 2003

In this paper, a baseband module of the spread spectrum system with FPGA is designed. A spread spectrum system spreads the signal bandwidth necessary for information transmission. We focused on the design of FEC decoder, especially the convolutional code fo constraint length K=3, rate R=l/2, is designed. For the VHDL design the Xilinx Foundation 3.1 is used. As results, a spread spectrum modem with convolutional coding is designed and we have plan to apply this modem to short distances wireless communication.

• Journal of the Korean Geosynthetics Society
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• v.3 no.4
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• pp.41-48
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• 2004

Recently a method for increasing the bearing capacity by laying the reinforcing materials with three or four layers as a method reinforcing the ground was studied recently. The purpose of this study is to examine the method for increasing shear-strength factor of the ground by reinforcing the ground under the foundation. According a method of wrapping ground with bakk-shape or semicircle-shape by geotextile was developed in this study and it looks likes anaspect that spreading footing exits under spread footing. A simulation loading-test using Aluminum sticks was carried out in order to examine the mechanism about bearing capacity of spread footing reinforced by geotextile. Increase of ultimate bearing capacity was verified in this simulation loading-test when charging loads to spread footing, which is propose from this study, reinforced by geotextile. And moving directions of points of the ground were also checked by grid-type indication method, and the areas where plastic failure appeared were checked by B-shutter photographing.

• The Journal of Engineering Geology
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• v.15 no.4 s.42
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• pp.423-433
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• 2005

For the design of spread foundation and the stability evaluation, we compared and analyzed it for theoretical, empirical bearing capacity formulas, and various settlement computation formulas, by conducting the plate bearing test at the site of A and B, which consisted of gneiss weathered soil. In addition, we considered the effective method of stability evaluation by carrying out the plate bearing test carried out on the ground consisted of weathering soil of gneiss. Consequently, it was found out that the allowablebearing capacity by the theoretical formula of Terzaghi was too excessive in comparison with the result of the plate bearing test and the Terzaghi-Peck method, which was used widely domestically in designing the spread foundation. It was more effective for a stable design. As a result of the plate bearing test carried out, on the ground consisted of weathering soil. It was found that reviewing the stability by the bearing capacity calculated with load-settlement curve. It is evaluated in a safer side than the point of view of the settlement.

• Proceedings of the Korean Geotechical Society Conference
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• 2002.10a
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• pp.659-664
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• 2002

New design method about the spread footing was developed using only soil and geosynthetics. This footing will be able to replace the concrete footing at constructing the foundation of small structures. As shown in Fig-3(b), after excavating the ground in semicircular shape, geosynthetics is layed on the semicircular shape of ground and let the soil filled. Geosynthetics of upper side are fixed tightly each other It can be thought to be a kind of great bag with semicircular shape. We performed two kinds of experiments to investigate the deformation and the failure shape of spread footing reinforced by geosynthetics. First, after making model ground with aluminium rods, the lattice point of 1cm ${\times}$ 1cm size of the side of aluminium rods have been painted with various kinds of colors. We have observed the movement of painted rods during loading. Second, we have taken pictures about failure process using B-shutter method. Analysing the behavior of model ground reinforced in a semicircular shape, we could know the reinforced one has much greater and wider plastic area than unreinforced one at failure. Based on the experimental results, new design method was proposed, which has a possibility to apply at the field works.

• Geotechnical Engineering
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• v.11 no.2
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• pp.51-70
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• 1995

Types of foundation of high rise buildings are primarily determined by loads transmitted from super structure, soil bearing capacity and available construction technology, The use of deep foundation of the buildings considered in this study due to the fact that rock of enough bearing capacity is not found down until 90~l00m. When a concentration of high soil pressure must be distributed over the entire building area, when small soft soil areas must be bridged, and when compressible strata are located at a shallow depth, mat foundation may be useful in order to have settlement and differential settlement of variable soils be minimized. The concept of mat foundation will also demonstrate some difficulties of applications if the load bearing demand directly carried down to the load -bearing strata exceeds the load -bearing capacity. This paper introduces both the analysis and design of mat type foundation for high rise buildings as well as the method-ology of modelling of the soil foundation, especially, engineered to redistribute the stress exceeding the soil bearing capacity. This process will result in the wide spread of stresses over the entire building foundation.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.1108-1117
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• 2005

RAP(rammed aggregate pier) method which is intermediate foundation of deep and shallow foundation is used to improve the ground with high compaction energy. This method is widely spread around the world, but there are few examples and systemic researches for failure mechanism and bearing capacity of this method are not organized yet. In this paper, soil laboratory tests were carried out to evaluate the applicability of RAP method as the foundation of a structure. And the bearing capacity and the failure mechanism of RAP method were studied with respect to various relative densities(35%, 65%, 90%), diameters(45mm, 60mm) and lengths(20cm, 30cm, 40cm). As results, stress concentration ratio decreased as diameter of RAP was increasing or length of RAP was decreased or relative density was decreased. however these results were not always constant. because systematic interaction between relative density and diameter and length of RAP can affect stress concentration ratio, more studies on stress concentration ratio are needed throughout laboratory and field tests.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.168-175
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• 1999

The previous study was an expert system development that help engineers select proper foundation types and construction methods for structures under various subsoil condition. The system includes geographical and geological data in certain areas of Ulsan and a knowledge base for the selection of foundation types. However, the system, a kind of application program, has a weakness that it can be used only when it is installed at each user's own computer. Therefore, the purpose of the research is to more the system operated on Internet and spread over to more users. So, Server Installation, ActiveX, ADO(Active Data Objects) and ASP(Active Server Pages), which are the requirements to operate the system on Internet, are to be investigated through the research.