• 한국방재학회:학술대회논문집
• /
• 2009.02b
• /
• pp.79.2-79.2
• /
• 2009

• Journal of the Korean Geotechnical Society
• /
• v.35 no.3
• /
• pp.5-16
• /
• 2019

With the recent concentration of urban populations, the constructions of large structures are increasing, along with the development of foundations for large structures. PHC Piles have been used in many structures ever since Japanese introduced the technology at the end of the 20th century. Recently, many studies on the use of the PHC Pile have been carried out as earth retaining using the merits of PHC piles. In this study, static axial compression tests were conducted on the PHC-W piles constructed as column-type in building underground additional wall using the PHC-W earth retaining wall. The end bearing capacity of pile was calculated using the axial load transfer measurement that was obtained from the static axial compression test result. Since end bearing capacity of the PHC-W pile embedded in weathered rock showed a different behaviour from the conventional PHC pile, the calculation method of end bearing capacity for column-type PHC-W piles would be proposed. The unit ultimate end bearing equation proposed for single and group PHC-W pile embedded in weathered rock is $q_b=13.3N_b$ and $q_b=6.8N_b$.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.3
• /
• pp.25-32
• /
• 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 Korea institute for structural maintenance and inspection
• /
• v.10 no.6
• /
• pp.213-223
• /
• 2006

In this study, artificial neural network is applied to the evaluation of bearing capacity of the PHC auger-drilled piles at sites of domestic decomposed granite soils. For the verification of applicability of error back propagation neural network, a total of 168 data of in-situ test results for PHC auger-drilled plies are used. The results show that the estimation of error back propagation neural network provide a good matching with pile test results by training and these results show the confidence of utilizing the neural networks for evaluation of the bearing capacity of piles.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.20 no.5
• /
• pp.109-115
• /
• 2016

A demand of high bearing capacity of piles to resist heavy static loads has been increased. For this reason, the utilization of large diameter PHC piles including a range from 700 mm to 1,200 mm have been increased and applied to the construction sites in Korea recently. In this study, in order to increase the flexural strength capacity of the PHC pile, the large diameter composite PHC pile reinforced by in-filled concrete and reinforcement was developed and manufactured. All the specimens were tested under four-point bending setup and displacement control. From the strain behavior of transverse bar, it was found that the presence of transverse bar was effective against crack propagation and controlling crack width as well as prevented the web shear cracks. The flexural strength and mid-span deflection of LICPT specimens were increased by a maximum of 1.08 times and 1.19 times compared to the LICP specimens. This results indicated that the installed transverse bar is in an advantageous ductility performance of the PHC piles. A conventional layered sectional analysis for the pile specimens was performed to investigate the flexural strength according to the each used material. The calculated bending moment of conventional PHC pile and composite PHC pile, which was determined by P-M interaction curve, showed a safety factor 1.13 and 1.16 compared to the test results.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.21 no.6
• /
• pp.67-73
• /
• 2017

Recently, the demand for large diameter piles has been rapidly increased in order to secure the allowable bearing capacity of pile foundation due to the increase of large structures such as high rise buildings. In this study, to improve the shear capacity of a conventional PHC pile, a large diameter composite PHC pile strengthened by in-filled concrete and shear reinforcement was manufactured. All the piles were tested according to the shear strength test method of Korean Standard. As a result of the shear test, the F-type piles which are produced without shear reinforcement occurred abrupt horizontal cracks after flexural and inclined shear cracks occurred. On the contrary, the FT-type piles which are produced with shear reinforcement exhibited stable flexural and inclined shear cracks uniformly over the entire pile without abrupt horizontal cracks. Furthermore, the maximum load of the large diameter composite PHC pile improved to 2.9 times in the F series, and more than 3.3 times in the FT series compared to the conventional PHC pile. This result indicated that FT-type piles had excellent composite behavior due to the shear reinforcement and effectively prevented the unstable growth of inclined shear cracks.

• Land and Housing Review
• /
• v.1 no.1
• /
• pp.67-73
• /
• 2010

Method of protruding steel bar embedded in PHC pile for connecting with foundation plate is an intermediate form of fixed and hinged connection and has often been used in architectural structures such as apartment complex. However, mechanical properties of this method have not been proved and its construction process is not simple. In this study, therefore, by analyzing previous research and by considering ratio of steel bar and concrete in PHC pile, which is minimum reinforcement of rebar, the newly optimized method of reinforcing joint of PHC pile and foundation plate is suggested with respect to PHC pile type (PHC 450, PHC 500, and PHC 600). To assess mechanical properties (ultimate tensile and shear strength) of joint of PHC pile and foundation plate, full scale experimental tests are performed. As a result, all cases are satisfied with required design criteria and can be practically applied. Our results indicate that reduction of rebar reinforcement compared to previous method would lead cost saving in PHC pile construction.

• Journal of the Korea Concrete Institute
• /
• v.29 no.3
• /
• pp.249-257
• /
• 2017

The purpose of this study was to contribute to the field application cost effectively and reasonably by developing the functional piles that make up for the defects of PHC piles. CFP (Concrete Filled Pretensioned Spun High Strength Concrete Pile with Ring type Composite shear connectors) piles developed in this study increases the compressive stress through enlarged cross section by rearranging composite shear connectors and filling the hollow part of PHC pile with concrete. And it improved shear and bending performance placing the rebar (H13-8ea) within the PHC pile and the hollow part of PHC pile of rebar (H19-8ea). In addition, the composite shear connectors were placed for the composite behavior between PHC pile and filled concrete. Placing Rebars (H13-8ea) of PHC pile into composite shear connector holes are sleeve-type mechanical coupling method that filling the concrete to the gap of the two members. Nonlinear finite element analyzes were performed to verify the performance of shear and bending moments and it deduced the spacing of the composite shear connectors. Through a various interpretation of CFP piles, it's proved that the CFP pile can increase the shear and bending stiffness of the PHC pile effectively. Therefore, this can be utilized usefully on the construction sites.

• Proceedings of the Korean Institute Of Construction Engineering and Management
• /
• autumn
• /
• pp.244-247
• /
• 2002

The pile foundations have been chosen more frequently as the comprehensive development of the country progressed, especially where the ground conditions are not suitable for the construction and the dimension and the length of the piles utilized becomes larger and longer. The purpose of this study suggests the improvement method of construction management for PHC pile in an apartment house. To do This, We analyzed about current process and provided improved Process with IDEF method. And, The objectives of this research is to propose the means to solve the current problems and management factors from the results of the investigation.

• Journal of the Korean GEO-environmental Society
• /
• v.20 no.3
• /
• pp.21-30
• /
• 2019

Composite pile, which is composed of the steel pipe pile in which the large horizontal force acts and the PHC pile in which the small horizontal force acts by a special connecting devices, is being commercialized as a base material for civil engineering structures. The core of such a composite pile can be said to be a design criterion for estimating the joint position and stability of the connection device between steel pipe pile and PHC pile. In Korea, there is no precise specification for the location of composite pile joints. In the LH Design Department (Korea Land & Housing Corporation, 2009), "Application of composite pile design and review of design book marking" was made with reference to Road Design Practice Volume 3 (Korea Expressway Corporation, 2001). this is used as a basis of the design of the composite pile. It can not be regarded as a section change of the composite pile, so it has a limitation in application. Therefore, In this study, we propose a design criterion for the location of the section of the composite pile (joint of steel pipe pile and PHC pile) and evaluate the stability and economical efficiency of it by using experimental method and analytical method. Analysis of composite pile design data installed in 79 domestic bridges abutment showed that the stresses, bending moments, and displacements acting on the pile body and connection of the pile were analyzed. Through the redesign process, it was confirmed that the stresses generated in the connecting device occur within the allowable stress values of the connecting device and the PHC pile. In conclusion, the design proposal of composite pile joint location through empirical case study in this study is an improved design method considering both stability and economical efficiency in designing composite pile.