• Title/Summary/Keyword: Pile load tests

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The Behavior of Axial Load Transfer for S.L. Coated Pile And Uncoated Pile (S.L. 도포 및 미도포 말뚝의 축하중전이거동)

  • 배기열;김정환;이민희;최용규
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.03a
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    • pp.373-380
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    • 2002
  • In this study, In order to compare the behavior of axail load transfer for S.L. coated piles and uncoated piles installed at a field test site. During static pile load tests, axial load transfer for S.L. coated piles and uncoated piles were measured.

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Characteristics of Load-Settlement Behaviour for Embeded Piles Using Load-Transfer Mechanism (하중전이기법을 이용한 매입말뚝의 하중-침하 거동특성)

  • Oh, Se Wook
    • Journal of the Korean GEO-environmental Society
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    • v.2 no.4
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    • pp.51-61
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    • 2001
  • A series of model tests and analyses by load transfer function were performed to study load-settlement behaviour with relative compaction ratio of soil and embeded depth of pile. In the model tests, embeded depth ratio(L/D) of pile were installed 15, 20, 25 and relative compaction of soil(RC) is 85%, 95% and then cement were injected at around perimeter of pile. For analysis of embedded pile, the paper were compared results of model tests with analysis results by Vijayvergiya model and Castelli model, Gwizdala model of elastic plasticity-perfect plastic model and then the fitness load transfer mechanism was proposed to predict load-settlement behaviour of embeded pile. The analysis results of predicted bearing capacity by load transfer function, ultimate bearing capacity of embeded pile were approached to measured value and behaviour of initial load-settlement curve were estimated that load transfer function by Castelli were similar to measured value. The result of axial load analysis of bored pile shows that skin friction estimated by load transfer mechanism is investigated more a little than that of measured values.

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Influence of Pile Cap On The Behaviors of End Bearing Pile Groups (말뚝캡이 선단지지 무리말뚝의 지지거동에 미치는 영향)

  • 최영석;이수형;정충기;김명모
    • Proceedings of the Korean Geotechical Society Conference
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    • 2000.11a
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    • pp.245-252
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    • 2000
  • Model tests on free standing pile groups and piled footings with varying a pile spacing in two layered soils are carried out. The influence of pile cap on the behaviors of end bearing pile groups is analyzed by comparing the bearing behavior in piled footings with those in a single pile, a shallow footing(cap alone) and free standing pile groups. From the test results, it is found that the bearing characteristics of cap-soil-pile system are related with load levels and pile spacings. Before yield, the bearing resistance by cap is not fully mobilized, however, as the applied load increases, the bearing resistance of cap approaches to that of cap alone and settlement hardening occurs after yield due to the compaction caused by the contact pressure between cap and soil. By the cap-soil-pile interaction, shaft friction and point resistance of piles considerably increase with dependency of pile spacings. In two layered soil, the increasing effect of dilatancy in dense sandy soil adjacent to pile tips, increases the point resistance of pile.

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Reliability Updates of Driven Piles Using Proof Pile Load Test Results (검증용 정재하시험 자료를 이용한 항타강관말뚝의 신뢰성 평가)

  • Park, Jae-Hyun;Kim, Dong-Wook;Kwak, Ki-Seok;Chung, Moon-Kyung;Kim, Jun-Young;Chung, Choong-Ki
    • Proceedings of the Korean Geotechical Society Conference
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    • 2010.03a
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    • pp.324-337
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    • 2010
  • For the development of load and resistance factor design, reliability analysis is required to calibrate resistance factors in the framework of reliability theory. The distribution of measured-to-predicted pile resistance ratio was constructed based on only the results of load tests conducted to failure for the assessment of uncertainty regarding pile resistance and used in the conventional reliability analysis. In other words, successful pile load test (piles resisted twice their design loads without failure) results were discarded, and therefore, were not reflected in the reliability analysis. In this paper, a new systematic method based on Bayesian theory is used to update reliability index of driven steel pile piles by adding more pile load test results, even not conducted to failure, into the prior distribution of pile resistance ratio. Fifty seven static pile load tests performed to failure in Korea were compiled for the construction of prior distribution of pile resistance ratio. Reliability analyses were performed using the updated distribution of pile resistance ratio and the total load distribution using First-order Reliability Method (FORM). The challenge of this study is that the distribution updates of pile resistance ratio are possible using the load test results even not conducted to failure, and that Bayesian update are most effective when limited data are available for reliability analysis or resistance factors calibration.

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Evaluation of Bearing Capacity of Piles in Sand Using Pile Driving Analyzer (동재하시험을 이용한 모래지반의 말뚝지지력 산정)

  • 이우진;석종수
    • Geotechnical Engineering
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    • v.13 no.5
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    • pp.145-154
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    • 1997
  • Though the static pile load tests gives the mosts accurate estimation on the load carrying capacity of tested pile, it appears time-consuming and not economical. Many test methods using equipments, such as Pile Driving Analyzer(PDA), STATNAMIC, and Osterberg cell, have been introduced in Korea, and pile best using PDA has been gaining popularity because of iris fast and simple operation. Static and dynamic tests results on the piles installed in the granular coils were analyzed to investigate the effect of geometrical damping on the estimated load carrying capacity. It was found that the CAPWAP analysis without considering geometrical damping effect underestimates the pile capacity by 30~60% under certain conditions. It was observed that the underestimation of pile capacity by CAPWAP occurs on the piles installed in the water-borne granular boils by SIP methods. When Smith skin damping value(SSkn) greater than 1.0 sec/m is obtained in CAPWAP analysis, it may reflect the large possibility of underestimation of pile capacity. The introduction of the geometircal damping option in CAPWAP analysis gives reasonable pile capacity, compared with the static pile load test results, and reduces the SSb value under 0.7 sec/m.

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Development of an integrated Web-based system with a pile load test database and pre-analyzed data

  • Chen, Yit-Jin;Liao, Ming-Ru;Lin, Shiu-Shin;Huang, Jen-Kai;Marcos, Maria Cecilia M.
    • Geomechanics and Engineering
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    • v.7 no.1
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    • pp.37-53
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    • 2014
  • A Web-based pile load test (WBPLT) system was developed and implemented in this study. Object-oriented and concept-based software design techniques were adopted to integrate the pile load test database into the system. A total of 673 case histories of pile load test were included in the database. The data consisted of drilled shaft and driven precast concrete pile axial load tests in drained, undrained, and gravel loading conditions as well as pre-analyzed data and back-calculated design parameters. Unified modeling language, a standard software design tool, was utilized to design the WBPLT system architecture with five major concept-based components. These components provide the static structure and dynamic behavior of system message flows in a visualized manner. The open-source Apache Web server is the building block of the WBPLT system, and PHP Web programming language implements the operation of the WBPLT components, particularly the automatic translation of user query into structured query language. A simple search and inexpensive query can be implemented through the Internet browser. The pile load test database is helpful, and data can be easily retrieved and utilized worldwide for research and advanced applications.

말뚝기초의 연적 방향 극한하중

  • 김명모
    • Proceedings of the Korean Geotechical Society Conference
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    • 2002.11a
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    • pp.209-236
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    • 2002
  • Ultimate pile capacity - Point resistance - Frictional resistance - Determination of point and frictional resistances from field tests - Summary of recommendations from design Group effects Settlement analysis.

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Evaluation of Field Applicability of Helical Pile Using Hexagon Joints (육각형 이음부를 이용한 회전관입말뚝의 현장적용성 평가)

  • Jeong, Sangguk
    • The Journal of Engineering Geology
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    • v.30 no.4
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    • pp.635-648
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    • 2020
  • Performance improvement of helical piles in static load tests using hexagon joints that do not require welding or bolting was investigated. Two sites were selected for pile field tests to evaluate their bearing capacity. Static and pull-out load tests were undertaken to assess the method for estimating bearing capacity. The field tests indicated that the bearing capacity of the gravity grout pile was ≥600 kN in the static load test, consistent with the AC 358 Code. The non-grout pile had a bearing capacity of ≤600 kN, suggesting that gravity grouting is required. Field pile load-test results were used to establish the bearing capacity equation, based on a small number of helical pile.

Estimation of Vertical Load Capacity of PCFT Hybrid Composite Piles Using Dynamic Load Tests (동재하시험을 통한 긴장력이 도입된 콘크리트 충전 강관말뚝을 사용한 복합말뚝의 연직지지력 평가)

  • Park, Nowon;Paik, Kyuho
    • Journal of the Korean GEO-environmental Society
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    • v.20 no.3
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    • pp.31-38
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    • 2019
  • To determine the optimum dynamic load test analysis for PCFT (Prestressed Concrete Filled steel Tube) hybrid composite piles that PCFT piles are connected to the top of PHC piles, the dynamic load tests and CAPWAP analyses were performed on two hybrid composite piles with steel pipe and PCFT piles as upper piles. The results of the dynamic load tests and CAPWAP analyses showed that the particle velocity measured in PCFT hybrid composite piles was equal to the wave speed of PHC piles when the strain gauges and accelerometers are attached to the surface of inner composite PHC pile after removing the steel pipe in the upper PCFT pile. In addition, when assuming that the material of that upper PCFT pile was the same as that of the lower PHC pile and the cross-sectional area of the steel pipe in upper PCFT pile was converted to that for concrete through the pile model (PM) in CAPWAP analysis, the accuracy of the CAPWAP analysis result for PCFT hybrid composite piles was very high.

Estimation of Bearing Capacity of Non-Displacement Piles in Sand Considering Pile Shape (모래지반에서 말뚝형태를 고려한 비배토말뚝의 지지력 산정)

  • Paik, Kyu-Ho;Lee, Jun-Hwan;Kim, Dae-Hong
    • Journal of the Korean Geotechnical Society
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    • v.23 no.5
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    • pp.101-110
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    • 2007
  • In order to investigate the effect of the pile shape on the bearing capacity of non-displacement piles, a series of model pile load tests were performed using a calibration chamber and three model piles with different shape. Results of the model tests showed that the bearing capacity of tapered piles was affected by its taper angle as well as the stress states and relative density of soil. Based on the results of model pile load tests, a new design equation for estimation of the bearing capacity of non-displacement piles was proposed, and it takes into account the effect of the taper angles on the bearing capacity of non-displacement piles.