• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.44-57
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• 2010

The purpose of this paper is to introduce case studies on 2 projects for the construction of port facilities in Colombo, Sri lanka. In Queen Elizabeth quay development project in 2000, the damage at the bottom of steel tubular piles were occurred when piles were driven into subsoil for piled wharf structure in Stage 1. In order to prevent same incident in Stage 2 & 3, the pile driveability analysis were executed by dynamic formulas, analysis program, test driving and pile load tests. Through pile driveability analysis, prevention plans were proposed. In Colombo port expansion project in 2008, the mv method was applied to predict a primary consolidation settlement of a subsoil under a breakwater in the calculation stage. The $m_v$ was estimated from results of cone penetration tests and the final settlement by consolidation was calculated with it.

• Proceedings of the Korean Geotechical Society Conference
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• 2006.03a
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• pp.536-545
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• 2006

In this study the behavior of piles with an extended head is invested experimentally using reduced-scale model tests. Special attention is given to verifying the increase of end bearing capacity of piles with spreading head. Model piles and extended head plates made of steel pipe were used in this study. Bearing capacity of piles is regarded as only end bearing capacity. The study analyzed the tendency of single and group pile of bearing capacity compared with the existing PHC pile, and examined optimum effect of extended head.

• Journal of the Korean Society for Advanced Composite Structures
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• v.5 no.4
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• pp.52-57
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• 2014

Due to the advantageous mechanical properties of the fiber reinforced polymeric plastics(FRP), their application in the construction industries is ever increasing trend, as a substitute of structural steel which is highly vulnerable under hazardous environmental conditions (i.e., corrosion, humidity, etc.). In this study, hybrid FRP-concrete composite pile (HCFFT) connection is suggested. The HCFFT is consisted of pultruded FRP unit module, filament wound FRP which is in the outside of mandrel composed of circular shaped assembly of pultruded FRP unit modules, and concrete which is casted inside of the circular tube shaped hybrid FRP pile. Therefore, pultruded FRP can increase the flexural load carrying capacity, filament wound FRP and concrete filled inside can increase axial load carrying capacity. In the study, connection capacity of HCFFT(small and mid size) is investigated throughout experiments and finite element method. From the results of experiments, we suggested the connection methods about HCFFT pile connection.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.1
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• pp.30-39
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• 2011

In this paper, we persent the results of on experimental investigations pertaining to the structural behavior of new type of concrete filled fiber reinforced plastic circular tubes (i.e., hybrid CFFT, HCFFT) which are suggested in order to mitigate the problems associated with the concrete filled steel-concrete composite tube (CFT) and the concrete filled fiber reinforced plastic tube (CFFT). It is found that when the HCFFT is used in the construction of pile foundation the HCFFT pile can transfer axial as well as flexural loads from the superstructure to the underground effectively in comparison with CFT and CFFT piles.

• Proceedings of the Korea Concrete Institute Conference
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• 2005.05a
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• pp.299-302
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• 2005

Generally, steel-concrete composite structures are considered very useful and powerful to resist external axial and flexural load due to its elevated capacity originated from composite action. This usefulness of composite structures can be applied to the drilled shafts of marine bridges that require large-scale such as entire pile-column system. As the basic study of this application, several design codes are analyzed and compared in this research.

• Journal of the Korean Society of Environmental Restoration Technology
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• v.5 no.3
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• pp.23-30
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• 2002

In recently, using of steel reinforcements by reinforcing materials of the reinforced earth, micro-pile and root-pile etc,. is wide-spreading in the stabilizing control of cutting and embankment slopes, but the failure mechanism of reinforced earth as well as the effect of insert angles or types of reinforcement and others are not defined clearly. In this study, therefore heavy-duty direct shear tests were exercised on the reinforced soil and the non-reinforced soil, which was executed for research on the interaction of soil-reinforcement and theirs behavior. The hardness and softness and the standard sands were used for modeling of reinforced soil, the material constants for the computer simulation were estimated from the results of CD-Test. The effects of reinforcing and of friction increasing on the softness, area ratio of reinforcements is equal, were the better than them of the hardness, as well the reinforcing effects of shear strength without regard to the area ratio is much the same at $10^{\circ}$, insert angle of reinforced bar, differ from them of the existing study. Then, the results of numerical analysis showed that the behavior of reinforcements displayed bending resistance and shear resistance at $15^{\circ}$ and $30^{\circ}$, respectively. Also, the state of strain transfer was observed and the behavior of resistance mechanism on reinforcements presented almost the same them of landslides stabilizing pile.

• Journal of the Earthquake Engineering Society of Korea
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• v.23 no.3
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• pp.183-190
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• 2019

Recent changes in the construction method of piles to minimize noise, along with the development of high-strength reinforcement, have provided an economical high performance RC pile development to compensate for the disadvantages of existing PHC piles. In this study, a methodology for the development of cross - section details of high performance RC piles of various performances is presented by freely applying high strength steel and concrete. This study suggested a technique for calculating bending moments for a given axial force corresponding to the allowable crack widths and this can be used for serviceablity check. In calculating the design shear force, the existing design equation applicable to the rectangular or the I section was modified to be applicable to the hollow circular section. In particular, in the limit state design method, the shear force is calculated in proportion to the axial force, and the procedure for calculating PV diagram is established. Last, the section details are determined through PM diagrams that they have the similar flexural and axial-flexural performances of the PHC pile A, B and C types with a diameter of 500 mm. To facilitate the application of the selected standard sections to the practical tasks, the design PM diagram and design shear forces are proposed in accordance with the strength design method and limit state design method.

• Computational Structural Engineering
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• v.12 no.4
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• pp.69-69
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• 1999

Design of Dangsan Steel Railway Bridge(a part of Seoul Subway Line NO. 2), which is supposed to be replaced after its 15years survice, was done, and the reconstruction has begun in Dec. 1997. The design include new superstruc-ture and bridge piers, retrofitting of the foun-dation, rail system, electric and signal, etc. In this paper, design of the structure is mainly summarized. The main span superstructure, across Han river, is composite section which is com-posed of steel box and reinforced concrete deck slab with 9 span continuous. The superstructure for the approaches is bottom througth type 2-cell steel box girder with steel floor system and concrete deck slab with 3 or 4 span continuous. The bridge piers was planned to be reconstructed based upon the result from the various investi-gations, while the foundation(cassion and pile foundation) was planned to be retrofitted. For superstructure erection, the method of combination of barge bent and heavy lifting and the launching truss method was investigated for the main span and approach spans, respectively.

• Journal of the Korean Society for Precision Engineering
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• v.20 no.4
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• pp.204-213
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• 2003

A survey for finding corrosion examples was performed on the underground steel piles buried for 19 years in the area of iron and steel making factory near Young-il bay. A failure probability model, which can be used to check the reliability of the corrosive mechanical element, based on Von-Mises failure criterion and the standard normal probability function is proposed. The effects of varying boundary conditions such as temperature change, soil-friction, internal pressure, earthquake, loading of soil, traffic loads and corrosion on failure probability of the buried steel piles are systematically investigated. To allow for the uncertainties of the design variables, a reliability analysis technique has been adopted; this also allows calculation of the relative contribution of the random variables and the sensitivity of the failure probability.

• Journal of the Korean Geosynthetics Society
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• v.15 no.3
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• pp.57-66
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• 2016

In this study, to prevent possible collapse caused by hydraulic or mechanical instability, liquid nitrogen injection method is developed and implemented at the tip of drilling auger of steel pipe propulsion tunneling. In this study, 1/5-scale model auger and sand chamber were manufactured. The prototype diameter of steel pile (or casing) is assumed about 1,000 mm. For the frictional sandy soils and plastic weathered soils, liquid nitrogen injection methods were tested varying water contents of the soils. For the induced hydraulic instability, the ground near the drilling auger was frozen within approximately 5 minutes preventing mechanical collapse and water infiltration. Securing stability of steel pile propulsion tunneling using liquid nitrogen was much more effective for which the water content of the soil somewhat exceeds the optimum water content.