Comparison Between Model and Full Scale Pile Capacity Gain in the Boston Area

Helical Pile Capacity-to-Torque Correlation: A More Reliable Capacity-to-Torque Factor Based on Full Scale Load Tests

DFI Journal The Journal of the Deep Foundations Institute ◽

10.37308/dfijnl.20190716.208 ◽

2020 ◽

Vol 14 (2) ◽

Author(s):

Moncef Souissi

Keyword(s):

Axial Load ◽

Static Load ◽

Full Scale ◽

Load Direction ◽

Pile Capacity ◽

Helical Piles ◽

Load Tests ◽

High Torque ◽

Low Torque ◽

The One

The capacity-to-torque ratio, Kt, has been used in the design of helical piles and anchors for over half a century. Numerous research efforts have been conducted to accurately predict this capaci-ty-to-torque ratio. However, almost of all these Kt factors are based on shaft geometry alone. The ca-pacity-to-torque ratio described herein was found to depend on the shaft diameter, shaft geometry, helix configuration, axial load direction, and installation torque. In this study, 799 full scale static load tests in compression and tension were conducted on helical piles of varying shaft diameters, shaft geometry, and helix configurations in different soil types (sand, clay, and weathered bedrock). The collected data were used to study the effect of these variables on the capacity-to-torque ratio and resulted in developing a more reliable capacity-to-torque ratio, Km, that considers the effect of the variables mentioned above. The study shows that the published Kt values in AC358 (ICC-ES Acceptance Criteria for Helical Piles Systems and Devices) underestimate the pile capacity at low torque and overestimate it at high torque. In addition, and based on probability analysis, the predicted capacity using the modified Km results in a higher degree of accuracy than the one based on the published Kt values in AC358.

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Design and Construction of Three Instrumented Test Piles to Examine Time Dependent Pile Capacity Gain

Geotechnical Testing Journal ◽

10.1520/gtj12191 ◽

2004 ◽

Vol 27 (6) ◽

pp. 12191

Author(s):

L David Suits ◽

TC Sheahan ◽

SG Paikowsky ◽

EL Hajduk

Keyword(s):

Time Dependent ◽

Pile Capacity ◽

Capacity Gain ◽

Design And Construction

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The effects of plugging on pile performance and design

Canadian Geotechnical Journal ◽

10.1139/t90-059 ◽

1990 ◽

Vol 27 (4) ◽

pp. 429-440 ◽

Cited By ~ 61

Author(s):

Samuel G. Paikowsky ◽

Robert V. Whitman

Keyword(s):

Dynamic Analysis ◽

Key Words ◽

Dynamic Behavior ◽

Time Dependent ◽

Limited Attention ◽

Pile Driving ◽

Pile Capacity ◽

Static Capacity ◽

Capacity Gain ◽

Open Pipe

During installation of open-pipe piles, soil enters the pile until the inner-soil cylinder develops sufficient resistance to prevent further soil intrusion and the pile becomes "plugged." In spite of its frequent occurrence, only limited attention has thus far been given to this phenomenon and its consequences. The effects of plugging on pile performance and design are examined in reference to the following aspects: ultimate static capacity, time-dependent pile capacity, and dynamic behavior. Pile plugging is shown to have the following effects: marked contribution to the capacity of piles driven in sand; delay in capacity gain with time for piles driven in clay; and change in behavior of piles during installation, causing it to differ from that described by the models commonly used to predict and analyze pile driving. Key words: pipe piles, pile plugging, open-ended piles, static capacity, time-dependent capacity, dynamic analysis, pile driving, pile performance.

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Comparison of Full and Partial Drilled Displacement Pile Capacity from Full-Scale Load Testing

IFCEE 2021 ◽

10.1061/9780784483404.014 ◽

2021 ◽

Author(s):

Scott Jacobs ◽

Jorge Malave

Keyword(s):

Full Scale ◽

Load Testing ◽

Pile Capacity

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Screen versus cyclone for improved capacity and robustness for sidestream and mainstream deammonification

Environmental Science Water Research & Technology ◽

10.1039/c9ew00384c ◽

2019 ◽

Vol 5 (10) ◽

pp. 1769-1781

Author(s):

Tim Van Winckel ◽

Siegfried E. Vlaeminck ◽

Ahmed Al-Omari ◽

Benjamin Bachmann ◽

Belinda Sturm ◽

...

Keyword(s):

Full Scale ◽

Operational Conditions ◽

Capacity Gain

Combining physical and metabolic selection allowed for determination of ideal operational conditions and capacity gain in full-scale deammonification systems.

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Relation of Statistically Significant, Abnormal, and Typical WAIS-R VIQ-PIQ Discrepancies to Full Scale IQs

European Journal of Psychological Assessment ◽

10.1027//1015-5759.16.2.107 ◽

2000 ◽

Vol 16 (2) ◽

pp. 107-114 ◽

Cited By ~ 3

Author(s):

Louis M. Hsu ◽

Judy Hayman ◽

Judith Koch ◽

Debbie Mandell

Keyword(s):

Graphical Method ◽

The United States ◽

Full Scale ◽

True Score ◽

Absolute Value ◽

Normative Population ◽

The Us ◽

The Mean ◽

And Performance ◽

Quadratic Models

Summary: In the United States' normative population for the WAIS-R, differences (Ds) between persons' verbal and performance IQs (VIQs and PIQs) tend to increase with an increase in full scale IQs (FSIQs). This suggests that norm-referenced interpretations of Ds should take FSIQs into account. Two new graphs are presented to facilitate this type of interpretation. One of these graphs estimates the mean of absolute values of D (called typical D) at each FSIQ level of the US normative population. The other graph estimates the absolute value of D that is exceeded only 5% of the time (called abnormal D) at each FSIQ level of this population. A graph for the identification of conventional “statistically significant Ds” (also called “reliable Ds”) is also presented. A reliable D is defined in the context of classical true score theory as an absolute D that is unlikely (p < .05) to be exceeded by a person whose true VIQ and PIQ are equal. As conventionally defined reliable Ds do not depend on the FSIQ. The graphs of typical and abnormal Ds are based on quadratic models of the relation of sizes of Ds to FSIQs. These models are generalizations of models described in Hsu (1996) . The new graphical method of identifying Abnormal Ds is compared to the conventional Payne-Jones method of identifying these Ds. Implications of the three juxtaposed graphs for the interpretation of VIQ-PIQ differences are discussed.

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A Modification of the Payne-Jones Method of Identifying Abnormal Differences in WISC-R Performance and Verbal IQ's

European Journal of Psychological Assessment ◽

10.1027/1015-5759.12.1.27 ◽

1996 ◽

Vol 12 (1) ◽

pp. 27-32 ◽

Cited By ~ 1

Author(s):

Louis M. Hsu

Keyword(s):

Full Scale ◽

True Score ◽

Verbal Iq ◽

Score Difference ◽

The Difference ◽

And Performance

The difference (D) between a person's Verbal IQ (VIQ) and Performance IQ (PIQ) has for some time been considered clinically meaningful ( Kaufman, 1976 , 1979 ; Matarazzo, 1990 , 1991 ; Matarazzo & Herman, 1985 ; Sattler, 1982 ; Wechsler, 1984 ). Particularly useful is information about the degree to which a difference (D) between scores is “abnormal” (i.e., deviant in a standardization group) as opposed to simply “reliable” (i.e., indicative of a true score difference) ( Mittenberg, Thompson, & Schwartz, 1991 ; Silverstein, 1981 ; Payne & Jones, 1957 ). Payne and Jones (1957) proposed a formula to identify “abnormal” differences, which has been used extensively in the literature, and which has generally yielded good approximations to empirically determined “abnormal” differences ( Silverstein, 1985 ; Matarazzo & Herman, 1985 ). However applications of this formula have not taken into account the dependence (demonstrated by Kaufman, 1976 , 1979 , and Matarazzo & Herman, 1985 ) of Ds on Full Scale IQs (FSIQs). This has led to overestimation of “abnormality” of Ds of high FSIQ children, and underestimation of “abnormality” of Ds of low FSIQ children. This article presents a formula for identification of abnormal WISC-R Ds, which overcomes these problems, by explicitly taking into account the dependence of Ds on FSIQs.

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