• Journal of the Korean Geotechnical Society
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• v.18 no.4
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• pp.285-294
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• 2002

Embankment Piles, which is subjected to damage due to lateral movement of soft ground, can be classified into pile slab, cap beam pile, and isolated cap pile according to the installation pattern of pile cap. In the cap beam pile and the isolated cap pile method, the soil arch is developed by the different stiffness between pile and soil, and most embankment loads are transferred into embankment piles through soil arch. In these two methods, the difference of soil arch is that the soil arch of the cap beam pile method develops like the arch from of tunnel between cap beams and the soil arch of the isolated cap pile method develops like dome between isolated caps. Therefore, theoretical analysis methods on soil arching effect of the cap beam pile and the isolated cap pile method were respectively proposed according to their own arch form considering the limiting equilibrium of stresses in a crown of soil arch. And a series of model tests were performed both to investigate the load transfer by soil arching in fills above embankment piles and to verify the reliability of the theoretical analysis.

• Journal of the Korean GEO-environmental Society
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• v.20 no.8
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• pp.5-12
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• 2019

A pile group, that consists of several piles connected by a pile cap, is used as the superstructure. The pile supports vertical and horizontal load to design the pile group, but the effect of bearing capacity of the pile cap has not considered. Various researches have been conducted to reflect the effect of bearing capacity of the pile cap in order to reduce the amount of piles in the range of the stability under the vertical load of the superstructure. However, the effect of bearing capacity under the horizontal seismic load has not been studied adequately. Therefore, a shaking table test was carried out with different-sized pile caps that support the superstructure in this study. This test was to verify the influence of the size of the pile cap in the group pile under the horizontal load. The result shows that the size of the pile cap affects to the dynamic behavior of the superstructure and the pile group. Also, the bigger size of the pile group makes the larger constraint effect of ground, and it results that both the ground and the pile moves as a whole.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.05a
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• pp.630-633
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• 2006

In this study, we concerned the steel cap and head part arrangement of PHC pile structure to complement existing construction process which have the defects such as highly hazardous circumstance for safety concerns and retard a term of works. The steel cap developed for supplement the stiffness between extend foundation and contact section of PHC pile that is based on structural theory. The experiments have been performed to evaluate the characteristics of behavior between head part of PHC pile using steel cap and extend foundation.

• Proceedings of the Korea Concrete Institute Conference
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• 2006.11a
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• pp.221-224
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• 2006

For structural engineers, design of pile cap causes difficulties since design of this member is not specifically addressed by codes. In general, pile cap is considered as deep beam and designed for shear and moment at specified critical section. This is called as traditional section method. However, many international design codes suggest the application of strut tie method for better design of this member. In this paper, a brief application of strut tie method to the design check of pile cap structure designed by section method is presented. Unlike well known pile cap with single column, the example pile cap has two columns. In order to find out proper load path under various load condition, three dimensional finite element method was carried out. The result indicates that provided reinforcement by traditional section method has sufficient capacity to meet the design requirements.

• Journal of the Korean GEO-environmental Society
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• v.20 no.10
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• pp.39-46
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• 2019

The interaction between the ground and structures should be considered for seismic design of group piles supporting the superstructure. The p-y curve has been used widely for the analysis of nonlinear relationship between the ground and structures, and various researches have conducted to apply the dynamic p-y curve for seismic design of group piles. This curve considers the interaction between the ground and structures under the dynamic load such as an earthquake. However the supported effect by the pile cap and the interaction by inertia behavior of superstructures. Therefore, the shaking table test was conducted to verify the effect of the change of the pile cap in group piles supporting superstructures embedded in sandy soil. The test condition is that the arrangement and distance between centers of piles are fixed and the length of the pile cap is changed for various distances between the pile cap side and the pile center. The result shows that the distance between the pile cap side and the pile center have an effect on the dynamic p-y curve and the effect of group piles.

• Journal of the Korea institute for structural maintenance and inspection
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• v.20 no.3
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• pp.25-32
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• 2016

The pile-cap connection part which transfers foundation loads through pile body is critical element regarding flexural and shear force because the change of area, stress, and stiffness occurs in the this region suddenly. The purpose of this study is to investigate the structural behavior of pile-cap connection dependent on fabrication methods using conventional PHC pile and composite PHC pile. A series of test under cyclic lateral load was performed and the connection behavior was discussed. From the test results, it was found that the initial rotational stiffness of pile-cap connection was affected by the length of pile-head inserted in footing and the location of longitudinal reinforcing bars. The types of pile and location of longitudinal reinforcing bars governed the behavior of pile-cap connection regarding load-carrying capacity, ductility, and energy dissipation.

• Journal of the Korean Geotechnical Society
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• v.24 no.7
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• pp.61-73
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• 2008

Piles of a bridge pier are connected with the column through the pile cap (footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. Connection methods between pile heads and the pile cap are divided into two groups : rigid connections and hinge connections. Domestic design code has been specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However, some specifications prescribe that conservative results through investigations of both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which has high-quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) is unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the large diameter drilled shaft and the pile cap for Incheon Bridge which will be the longest bridge of Korea were investigated through the full modeling for rigid connection conditions.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.843-851
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• 2008

The conventional pile cap reinforcement systems regulated in the design specifications have some restrictions in design and construction such as requirement of shear key, disposition of reinforcing bars and insurance of anchoring length of reinforcements. This study suggests a new type of steel pipe pile cap system with perforated flat bar shear connector as an alternative to the conventional pile cap system for the improvement in structural performance and simplification of construction. And, experimental results of push-out and bending behavior are scribed for the evaluation of structural performance of the new pile cap system and it was compared to the structural behavior of conventional pile cap system.

• Journal of the Korean Geotechnical Society
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• v.17 no.6
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• pp.37-46
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• 2001

Pile load tests were carried out to investigate the contribution of the pile cap to the carrying capacity of a pile group and load transfer characteristics of piles in the group. A group of 24 piles$(4 \times6 array)$ of 92.5mm diameter steel pipe were installed to the depth of 3m fron the ground surface, the top of weathered rock. A maximum load of 320ton was applied to the pile cap, $1.5\times2.3m$, in contact with the ground surface. At the maximum load of 320ton, the pile cap has carried 22% of the total load. Average ultimate capacity of pile in the pile group was estimated to be 16.4ton, substantially higher than that of single pile, installed at the corner and tested before pile cap construction. For the same magnitude of settlement, the pile in the center carried less load than the pile at the perimeter due to strain superposition effect. Piles in the group showed almost constant contribution(approx. 60%) of side friction to the total capacity for all of the loading stages, while that of single pile decreased from 82% to 65%.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.445-448
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• 2001

Noise radiated from pile driving operation is one of major sources of community noise pollution and thus its operation method is strictly restricted by regulations. Although the drilling method is now used been commonly used in urban areas because of its activity, the benefit of low noise decreases due to high working cost. In the present work, noise characteristics of pile driving operation are carried out. Based on the study result, a low-noise pile cap for driven piles is developed in order to satisfy both the noise level restriction and the economical efficiency. Effects of pile cap are investigated by a scale model experiment, which is focused on the variation of impact force and sound pressure level. The results show a good possibility of noise reduction by an appropriately designed pile cap.