• Land and Housing Review
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• v.2 no.4
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• pp.553-558
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• 2011

Existing method protruding strands that are embedded in PHC pile to connect pile head and foundation slab shows poor constructibility. As this causes crack and damage in pile head and casualties often occurs in construction site during the work, alternative method called one-cutting method, in which pile above the ground surface and strands embedded in pile are completely cut and pile head is reinforced with rebar for connection with foundation slab, is currently adopted. However, the capacity of details for these methods are not mechanically proved. In this study, in order to suggest proper details of reinforcement for one-cutting method, failures due to lack of shear resistance between infilled concrete and PHC pile are analyzed through experiments and embedded depth with infilled concrete inside PHC pile is suggested. Assuming that slip failure strength is 0.4MPa, which is obtained from experiment conservatively, to have rebar yielded before slip failure, minimum depth of infilled concrete for PHC 450 and PHC 500, need to be 600mm above, and for PHC 600, 1,000mm above.

• Journal of the Korea institute for structural maintenance and inspection
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• v.25 no.3
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• pp.77-84
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• 2021

In this study, flexural tests of prestressed high strength spun concrete (PHC) piles reinforced with infilled concrete and longitudinal rebars were conducted, where the longitudinal rebar ratio and the presence of sludge formed on the inner surface of PHC pile were set as key test variables. A total of six PHC pile specimens were manufactured, and their flexural behaviors including failure mode, crack pattern, longitudinal strain distribution in a section and end slip between external PHC pile and infilled concrete were measured and discussed in detail. The test results revealed that the flexural stiffness and strength increased as the longitudinal rebar ratio became larger, and that the sludge formed on the inner surface of PHC pile did not show any detrimental effect on the flexural performance. In addition to the experimental approach, this study presents a nonlinear flexural analysis model considering compatibility conditions and strain and stress distributions of the PHC piles and infilled concrete. The rationality of the nonlinear flexural analysis model was verified by comparing it with test results, and it appeared that the proposed model well evaluated the flexural behavior of PHC piles reinforced with infilled concrete and longitudinal rebars with a good accuracy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.05a
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• pp.206-208
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• 2018

울산신항의 활발한 개발로 인하여 기존에 설치되어 있던 온산항북방파제는 원래의 목적인 방파제로서의 기능은 사라지고, 울산항 3항로에 간섭된 지장물이 됨에 따라, 기존방파제의 철거를 수행하였으며 철거순서는 상치 콘크리트 깨기, 속채움 제거, 케이슨 절단 및 천공, 인양 및 제거, 케이슨 파쇄의 순서로 진행되었다. 특히, 파쇄한 콘크리트는 크라싱 작업을 통해 재생골재로 생산하였으며, 향후 신설케이슨의 속채움 재료로 재활용하는 것으로 하여 경제적 자원재활용에도 기여하고 있다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.404-408
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• 2006

In this paper, connection strength between facing block and tie-bar was investigated through experimental study with varying in-fill material such as concrete, soil and crushed stone. Also, connection strength between anchor block and tie-bar was investigated with varying in-fill material. According to the experimental results, in case of using in-fill concrete, connection strength between facing block and tie-bar was larger than allowable tension load of tie-bar. Whereas in case of using in-fill soil or crushed stone, connection strength between facing block and tie-bar was less or similiar to allowable tension load of tie-bar. Connection strength between anchor block and tie-bar for which crushed stone was used as in-fill material, was larger than allowable tension load of tie-bar.

• 도로교통
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• s.89
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• pp.22-33
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• 2002

• 도로교통
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• s.93
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• pp.141-157
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• 2003

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

• Journal of the Korea Concrete Institute
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• v.29 no.3
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• pp.259-266
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• 2017

The purpose of this study was to contribute to the field application cost effectively and reasonably by developing the functional piles that reinforces shear force. CFP pile (Concrete Filled Pretensioned Spun High Strength Concrete Pile with Ring type Composite shear connectors) developed in this study increases the shear stress by placing composite shear connector and filling the concrete into hollow part of the pile. By placing the reinforcement (H13-8ea) and the reinforcement (H19-8ea) into hollow section inside of PHC piles, it also improves the shear strength due to increasing steel ratio. It reinforces shear strength effectively by dowel force that is generated by putting reinforcement (H13-8) into the holes of composite shear connectors for the composite behavior of filled concrete and PHC pile. The study was reviewed and compared the calculated result of the shear strength by limit state design method highway bridge design standards (2012) and experiment result of the shear strength by KS F 4306. We can design the shear strength reasonably as the safety ratio of 2.20, 2.15, 2.05 is shown comparing to design shear strength, according to design shear strength on each cross sections and the experiment results of the CFP pile.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.464-468
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• 2005

산업활동으로 인해 발생하는 슬래그 등의 폐기물을 적절히 처리하는 방법으로서는 저비용 처리형태와 자연계에서 슬래그 등의 특성을 고려한 Filter 기능을 수행할 수 있도록 수질이 악화된 하천이나 정체수역에 투입시켜 수질을 개선시킬 수 있는 방법의 도입이 필요하다. 현재 POSCO에서 발생하는 슬래그와 폐콘크리트의 화학적 성분은 주로 $CaO,\;SiO_2,\;Al_2O_3,\;Fe_2O_3$ 등으로 이루어져 있으며, 침전유발물질 및 흡착성물질이 공존하고 있다. 다공질 형태의 비표면적을 가지고 있어서 정화용 필터로 이용하기에 좋은 이점을 가지고 있다. 슬래그나 폐콘크리트를 Mattress/Filter 채움재 및 수질정화용 여재로 활용하면 폐기물처리, 자원 재활용 그리고 수질 환경 개선의 세 가지 효과를 동시에 얻을 수 있는 방법이 된다. 본 연구에서는 슬래그와 폐콘크리트를 활용한 정체수역에서 정화시스템의 정화특성을 조사하기 위하여 유입수와 유출수의 pH, 용존산소, 질소, 인 등을 측정하여 비교하였다. 수질개선을 위한 Mattress/Filter 시스템의 기본개념은 하천의 오염된 물이 Mattress/Filter의 공극사이를 통과하면서 채움재에 형성된 생물막이 수질 개선과정에서 나타나는 접촉작용, 생물 흡착작용, 생물산화의 분해작용 등을 촉진시키도록 하였다. Mattress/Filter를 이용한 수중 수질개선시스템에서 채움재로 제철폐기물인 슬래그와 건설폐기물인 폐콘크리트를 사용함으로써 Mattress/Filter의 다공성 및 넓은 표면적이라는 특성에 따른 물리적$\cdot$화학적$\cdot$생물학적 작용이 촉진되고 있음을 확인할 수 있었으며, 그 결과 정체수역에 설치한 Mattress/Filter는 다공질 속에서 쉽게 생물막을 형성시키고 유기물의 흡착을 촉진시켜 오염물질을 정화하는데 필요한 자정작용의 효과 증대와 수질개선을 촉진시킬 수 있는 자연생태적 하천정화시스템임을 확인할 수 있었다.

• Journal of the Korean Geotechnical Society
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• v.19 no.6
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• pp.15-22
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• 2003

In the conventional load transfer analysis for a steel pipe drilled shaft, it was assumed that the concrete's strain is the same as the measured steel's strain and the elastic modulus of the steel and the concrete calculated by the formular as prescribed by specification is used in the calculation of pile axial load. But, the pile axial load calculation by conventional method differed to some extent from the actual pile load. So, the behavior of a steel pipe drilled shaft could not be analyzed exactly. Thus, the necessity to measure the strain for each pile component was proposed. In this study, a new approach for load transfer measurement of large diameter drilled shafts was suggested ; the strain of each pile component(i. e., steel and concrete) was measured by DRS(Deformable Rod Sensor), the elastic modulus was determined by the uniaxial compression test for concrete specimens made at test site and a value of elastic modulus was evaluated as average tangential modulus corresponding to the stress level of the (0.2-0.6)$f_{ck}$. Field application was confirmed by the results of load transfer measurement tests for 3 drilled shafts. The errors for calculated pile head load were -11 ∼16% and 3.4% separately.