• 한국지열·수열에너지학회논문집
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• 제18권2호
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• pp.1-9
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• 2022

A novel steel-pipe energy pile is introduced, in which the deformed rebars for main reinforcing are replaced with steel pipes in a large diameter cast-in-place energy pile. Here, the steel pipes act as not only reinforcements but also heat exchangers by circulating the working fluid through the hollow hole in the steel pipes. Under this concept, the steel-pipe energy pile can serve a role of supporting main structures and exchanging heat with surrounding mediums without installing additional heat exchange pipes. In this study, the steel-pipe energy pile was constructed in a test bed considering the material properties of steel pipes and the subsoil investigation. Then, the thermal performance test (TPT) in cooling condition was conducted in the constructed energy pile to investigate thermal performance. In addition, the thermal performance of the steel-pipe energy pile was compared with that of the conventional large diameter cast-in-place energy pile to evaluate its applicability. As a result, the steel-pipe energy pile showed 11% higher thermal performance than the conventional energy pile along with much simpler construction processes.

• 한국안전학회지
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• 제16권3호
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• pp.99-105
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• 2001

This paper presents results km a series of model tests oil vertically loaded single piles to compare the behaviors of H and pipe piles under the same ground condition. The aims of this paper were to compare the bearing capacity of H-pile md pipe piles under in the same ground condition and to estimate the effect of gravity acceleration and relative soil density. Relative density of soil were made to be 40%, 80% and embedded length of pile on sand was increased by 10, 12, 14, 16 times of the diameter of pile, respectively. As a results of test series, allowable load of H-pile is from 6.4% to 18.2% larger than allowable load of pipe pile in relative density 80% and from 9.1% to 39.4% larger than allowable load of pipe pile in relative density 40%. As a results of numerical analysis, we were predicted behaviour of stress-displacement of pile with model test. In the case of relative density 80% and 40%, bearing capacity of H pile represent from 17.74% to 18.6% larger than allowable load of pipe pile.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1999년도 봄 학술발표회 논문집
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• pp.447-454
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• 1999

The compressive capacity and the soil plugging resistance of single open-ended pipe pile were completely decreased in the previous study on the behavior of shorter single pile during simulated seaquake induced by the vertical component of earthquake. But the capacity of single open-ended pipe pile with greater penetration and the capacity of piles group with shorter penetration were expected to be stable after seaquake motion. In this study, first, 2-piles or 4-piles are driven into the calibration chamber included in saturated fine medium sand with several simulated penetrations, and the compressive load test for each piles group was performed. Then, about 95 % compressive load of the ultimate capacity was applied on the pile head during the simulated seaquake motion. Finally, In confirm the reduction of pile capacity during the simulated seaquake motion, the compressive load test for each single pile or piles group after seaquake motion was performed. During the simulated seaquake, the compressive capacity of open-ended pipe piles with greater penetration ( 〉about 27 m) was not degraded even in deep sea deeper than 220 m and soil plug within open-ended pipe pile installed in deep sea was stable after seaquake motion. Also, in the case of 2-piles or 4-pile groups, the compressive capacity after seaquake motion was not degraded at all regardless of pile penetration depth beneath seabed, sea water depth and seaquake frequency.

• 대한토목학회논문집
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• 제31권6C호
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• pp.251-258
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• 2011

강관말뚝은 오랫동안 다양한 깊은 기초에 적용되어 왔으나 최근 강재가격의 상승으로 균질한 품질, 큰 강성, 용이한 시공 등의 장점에도 불구하고 기술자들이 자유롭게 적용 못하고 있다. 그러므로 강관말뚝으로 시공할 경우에는 초기 항타후 계획고 이상에서 절단된 강관을 재활용할 수 있다면 공사비를 절감하는데에 기여할 수 있다. 이러한 사유로 인하여 시공자들은 항타후 절단된 강관말뚝을 새롭게 시공할 말뚝과 함께 시공하고자 하나 명확한 정량적인 항타후 강관말뚝의 거동특성의 부재 및 재활용을 위한 적절한 대응방법과 기준의 부재로 인하여 말뚝의 건전도 문제, 문제 발생시의 대응방법 부재 등이 실제 현장에서 종종 발생하고 있다. 본 연구에서는 신규 강관말뚝과 사용자 하중 또는 극한 하중을 받은 강관말뚝에 대하여 현장에서 수행한 말뚝 동재하시험과 실내에서의 피로시험, 인장시험, 샤르피 충격시험을 실시하여 그 결과를 비교분석하였다. 시험결과로부터 허용응력 수준의 항타응력이 발생한 사용 하중조건에서는 항복강도의 변화가 2% 이하이며 최대 허용항타응력($0.9{\sigma}_y$)을 항타횟수가 3000회까지 받은 극한 하중조건에서는 항복강도의 변화가 5% 이하인 것을 확인할 수 있다. 또한 각 변수의 민감도를 확인하기 위하여 통계분석을 실시하였다. 모든 실험결과로부터 강관말뚝의 재활용 가능여부에 대한 판단 기준은 항복강도의 변화 보다는 오히려 샤르피충격에너지, 용접부에서의 강도변화 및 품질관리, 강관의 단면 변화, 항타후 강관의 국부좌굴에 기인하는 것을 확인할 수 있었다.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2001년도 봄 학술발표회 논문집
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• pp.283-290
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• 2001

In this study, static Pile load tests and PDA for open-ended steel pipe pile($\phi$ = 609.6 mm, t = 14 mm) penetrated into the gravel layer(GP - GM) was accomplished and axial load distribution was measured. Based on the tests results, the ultimate bearing capacity and axial load bearing mode were examined. Also, the ultimate pile capacity was calculated by APIL $E^{PLUS}$./.

• Geomechanics and Engineering
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• 제24권4호
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• pp.337-348
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• 2021

Brillouin Optical Frequency Domain Analysis (BOFDA) is a distributed fiber optic sensing (DFOS) technique that has unique advantages for performance monitoring of piles. However, the complicated production process and harsh operating environment of offshore PHC pipe piles make it difficult to apply this method to pile load testing. In this study, sensing cables were successfully pre-installed into an offshore PHC pipe pile directly for the first time and the BOFDA technique was used for in-situ monitoring of the pile under axial load. High-resolution strain and internal force distributions along the pile were obtained by the BOFDA sensing system. A finite element analysis incorporating the Degradation and Hardening Hyperbolic Model (DHHM) was carried out to evaluate and predict the performance of the pile, which provides an improved insight into the offshore pile-soil interaction mechanism.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 1997년도 가을 학술발표회 논문집
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• pp.357-364
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• 1997

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2000년도 말뚝기초 학술발표회
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• pp.107-141
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• 2000

Large diameter piles can be defined as piles with diameter of at least 0.76 m (2.5 ft). In bridge foundation, large diameter piles have been used as pier foundations and their use has been increased greatly. In this study, static pile load tests for large diameter piles peformed in Kwangan Grande Bridge construction site were introduced. Also, various sensor installation methods for several types of piles (that is, open-ended steel pipe pile, drilled shafts and socketed pipe piles), pipe axial load measuring method, load transfer analysis method and pile load test results (pile-head load - settlement curve, and pile axial load distribution curve along the pile depth) were introduced.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2005년도 춘계 학술발표회 논문집
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• pp.1-8
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• 2005

In this study, static pile load tests for instrumented drilled shaft pile and instrumented driven steel pipe pile were performed. Based on the results of pile load test, skin friction of each stratum was compared. Skin friction of drilled shaft were more than those of driven pile at the same settlement. This was based on the difference of surface roughness of piles and pile construction methods.

• 한국산업융합학회 논문집
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• 제9권3호
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• pp.183-190
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• 2006

Generally, application of steel pile as deep foundation member needs specials requirement for the connection method between steel pipe and concrete footing. To investigate real compressive behavior of connection member between steel pipe pile and concrete footing, three specimens were tested with carefully designed experimental system. Main test variable is the connection method between steel pipe pile and concrete footing. The bolted bonding method and hook bonding method was considered as the connection method in this study. From the test results gained from experiment, it was conformed that two types of connection method have the almost same compressive resistance capacity. Therefore, we can conclude that these two connection methods can be used as the strengthening method to verify the compressive composite action of concrete and steel pipe pile.