• Korean Journal of Construction Engineering and Management
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• v.4 no.4 s.16
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• pp.173-181
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• 2003

During the last few years, the use of Pre-tensioned spun high strength concrete piles(PHC pile) has been gradually increased in many construction sites. Cutting work of the concrete pile is an important task to crush a part of pile head which is compressed with more than 800$\cal{kg}f/cm^2$. It is usually performed by a crusher and three to four skilled workers. Recent analysis results of the pile cutting work reveal that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is labor-intensive work. The primary objective of this study is to propose conceptual designs for developing an automated pile cutting machine. It is anticipated that the development of the automated pile cutting machine would be able to bring improvements in safety, productivity, quality as well as cost saving.

• Journal of the Korea Institute of Building Construction
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• v.18 no.5
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• pp.439-446
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• 2018

The PHC pile has been increasingly used due to its implementation of the top-base method, which is advantageous in high penetration rate and bearing capacity reinforcement. Typically, when a PHC pile is manufactured, high-strength mixed materials are mainly used to enhance the compressive strength. However, recent studies have been conducted to utilize ground granulated blast-furnace slag (GGBS) in terms of economic efficiency. For this reason, this study manufactured PHC pile considering the replacement ratio and curing conditions of GGBS instead of high-strength mixed materials, and further investigated the engineering properties of the PHC pile. According to the experimental results, the compressive strength of GGBS-replaced PHC pile increased by steam curing, and particularly, PHC pile with 20% replacement of GGBS under $80^{\circ}C$ steam curing condition showed a compressive strength of approximately 84MPa. Furthermore, the experimental results confirmed that more hydration products were generated under the $80^{\circ}C$ steam curing condition than that under the $20^{\circ}C$ steam curing condition, which would affect the higher density of the PHC pile as well as the increase in the compressive strength.

• Korean Journal of Construction Engineering and Management
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• v.21 no.2
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• pp.98-106
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• 2020

Conventional method of PHC pile head cutting work has several challenges with regard to safety, convenience, productivity, and quality. To address such problems, a prototype of the all-in-one attachment-based PHC pile cutting robot is developed(Yeom, 2018). The Primary objective of this study are to develop a final prototype of all-in-one attachment-based PHC pile cutting robot and to analyze technical feasibility and field applicability of final prototype. According to the technical feasibility and field applicability analysis result, at least 74.2% of the respondents are selected positive answer about technical feasibility of the final prototype, at least 66.6% of the respondents are selected positive answer about field applicability of the final prototype. It is expected that when deployed onsite, the final prototype can not only increase the practical use but also improvement the work safety and productivity of work at the PHC pile head cutting job site.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• 2004.11a
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• pp.531-534
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• 2004

Cutting work of the concrete pile is an important task to chsh a part of pile head which is compressed with more than $800kgf/cm^{2}$. It is usually performed by a crusher and three to four skilled workers. llecent analysis results of the pile cutting work reveal that it frequently makes a lot of cracks which significantly reduce the strength of the pile and is labor-intensive work. The primary objective of this study is to propose the end-effector which can effectively break PHC Pile without any longitudinal cracks before developing an automated pile cutting machine having unified grinder and crusher parts. It is anticipated that the development of the automated pile cutting machine would be able to bring improvements in safety, productivity, quality as well as cost saving.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.04a
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• pp.152-153
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• 2022

In this study, the mechanical properties of PHC Pile were investigated using α-calcium sulfate hemihydrate, an industrial by-product with excellent expansion performance. As a result, the compressive strength of PHC pile showed a tendency to be higher than that of general Portland cement (OPC).

• Journal of the Korea Concrete Institute
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• v.13 no.1
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• pp.16-22
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• 2001

Pretensioned spun high strength concrete (PHC) pile has to be quality-controlled and provided an adequate concrete cover to assure high load carrying capacity, impact resistance, economy, and durability. During spun pre-casting, the pile section is divided into several segregated layers such as laitance, paste, mortar, and concrete layers. Greater the thickness of segregated layers, more difficult it is to guarantee the capacity and the durability of PHC pile. The experimental study was performed to investigate the effects of centrifugal condition on the segregated layers of materials and the compressive strength of concrete for PHC pile. The considering factors in the test were centrifugal time and magnitude of centrifugal force. These factors have been found to have greater influence on the segregation than the concrete strength. The moderate centrifugal condition has to be considered to maintain quality assurance in the production of PHC pile, especially to provide the adequate concrete cover over its tendons.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.273-274
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• 2018

When IGCC Slag(CGS) aggregate was used as PHC-Pile, the moldability was lowered as the mixing ratio increased. concrete mix design. Also the mix characteristics increased the use of AD depending on the usage rate, however, require detailed consideration.

• Journal of the Korean Recycled Construction Resources Institute
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• v.2 no.2
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• pp.137-144
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• 2014

The PHC pile utilizing the air-cooled blast-furnace slag as coarse aggregate was studied. This research was progressed with the range from the indoor mixing design evaluation into the actual goods production. The physical properties of the PHC pile are determined to satisfy through the appropriate mixing design adjustments. However, it should eliminate the aggregates including CaO and MgO in SG when it utilize in an AC (autoclave) type manufacturing process. It satisfied the bending moment, shear strength, and compressive strength of KS F 4306 except the surface states of the pile.

• Journal of Digital Convergence
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• v.18 no.10
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• pp.219-224
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• 2020

The purpose of this study is to develop a device to replace the pre-boring method, which is generally constructed, to prevent pile damage caused by tension cracks that reason from tension waves generated during PHC pile construction on soft ground. Tension cracks are caused by tension waves from the hammer striking during the PHC pile hitting on the soft ground, which in turn leads to faulty construction. In order to prevent the occurrence of tension waves generated during driving, apply separate driving force increasing device to prevent the generation of tension waves, and pile damage as well. Also, it is an eco-friendly construction method that reduces smoke and noise by improving construction speed, reducing construction costs, and able to small equipment when developing equipment. This development equipment is a piece of effective equipment that can pioneer the Saemangeum reclamation area, the South-east Asian construction market, where the Deep soft ground is distributed.

• Journal of Korean Society of Steel Construction
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• v.30 no.2
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• pp.97-104
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• 2018

The safety evaluation of horizontal and vertical bolted connection between PHC piles is presented. The numerical analysis model is constructed using the commercial finite element program, ABAQUS, in which 3D solid element is used to model all the connection devices. The actual bolted connection is idealized by the contact and tie condition given in ABAQUS. Through the finite element analysis, the compression, tensile, bending and shear behaviors of PHC pile connection were analyzed. The safety factor based on Von-Mises and yield stress was calculated for the safety evaluation of each connection devices.