Investigation into the factors affecting the shaft resistance of driven piles in sands

2013 ◽  
pp. 252-257
Author(s):  
D Igoe ◽  
K Gavin ◽  
L Kirwan
Keyword(s):  
Driven Piles ◽  
Factors Affecting ◽  
Shaft Resistance

scholarly journals Empirical Shaft Resistance of Driven Piles Penetrating Weak Rock

2020 ◽  
Vol 53 (12) ◽  
pp. 5531-5543
Author(s):  
John W. Barrett ◽  
Luke J. Prendergast
Keyword(s):  
Empirical Relationship ◽  
Empirical Relation ◽  
Driven Piles ◽  
Case Histories ◽  
Pile Capacity ◽  
Shaft Resistance ◽  
Fatigue Model ◽  
Load Tests ◽  
Pile Load Tests ◽  
Engineering Projects

AbstractIn this paper, an empirical relationship between the Unconfined Compressive Strength (UCS) of intact rock and the unit shaft resistance of piles penetrating rock is investigated. A growing number of civil engineering projects are utilizing steel piles driven into rock where a significant portion of the pile capacity is derived from the shaft resistance. Despite the growing number of projects utilizing the technology, little to no guidance is offered in the literature as to how the shaft resistance is to be calculated for such piles. A database has been created for driven piles that penetrate bedrock. The database consists of 42 pile load tests of which a majority are steel H-piles. The friction fatigue model is applied to seven of the pile load tests for which sufficient UCS data exists in order to develop an empirical relation. The focus of this paper is on case histories that include driven pipe piles with at least 2 m penetration into rock.

The shaft capacity of pipe piles in sand

2003 ◽  
Vol 40 (1) ◽  
pp. 36-45 ◽  
Author(s):  
Kenneth G Gavin ◽  
Barry M Lehane
Keyword(s):  
Design Method ◽  
Test Chamber ◽  
In Situ Stress ◽  
Simple Expression ◽  
Cone Penetration ◽  
Factors Affecting ◽  
Shaft Resistance ◽  
Pile Installation ◽  
Shaft Capacity

This paper describes results from an experimental programme that investigated factors affecting the shaft capacity of open-ended (pipe) piles in sand. A number of jacked pile installations in a test chamber filled with loose sand were performed using both open- and closed-ended, 114 mm diameter piles. The test series was designed to investigate the effects of in situ stress level, pile end condition, and degree of plugging on the development of pile shaft resistance. The results indicate that the maximum local shaft resistance that can develop at a given location on a pipe pile may be expressed as a function of the incremental filling ratio of the soil plug during installation, the cone penetration test (CPT) qc value, and the relative position of the pile toe. The experimental results allowed a simple expression to be developed for the plug resistance during pile installation, and this is used in conjunction with a popular design method for closed-ended piles to provide a means of estimating the shaft capacity of open-ended piles. The new approach is shown to provide good estimates of overall shaft capacity and skin friction distribution.Key words: shaft capacity, pipe piles, sand.

Analysis of Distribution Characteristics and Reliability for Bearing Capacity of Piles

2014 ◽  
Vol 638-640 ◽  
pp. 365-369
Author(s):  
Shu Jun Zhang ◽  
Zhi Jun Xu ◽  
Kai Wang ◽  
Bo Zhang
Keyword(s):  
Bearing Capacity ◽  
Ultimate Bearing Capacity ◽  
Distribution Characteristics ◽  
Driven Piles ◽  
Performance Function ◽  
Shaft Resistance ◽  
Bored Pile ◽  
Tip Resistance ◽  
Bored Piles ◽  
The Impact

This paper aims to study the distribution characteristics of the ratio of measured value and calculated value for ultimate bearing capacity, shaft resistance and tip resistance, and discuss the impact of shaft resistance and tip resistance on ultimate bearing capacity. A new performance function is proposed in terms of the three types of bearing capacity mentioned ahead. Take bored piles and driven piles for example, and the results from analysis indicate that the ratio of the measured value to calculated value of bored piles ranges from 0.75 to 1.45, and mostly is greater than 1.0; The ratio of the measured to predicted bearing capacity of driven piles lies between 0.8 and 1.5, and is larger than the corresponding ratio of bored piles. In addition, the reliability of tip resistance is lager than that of shaft resistance for bored pile, while the reliability of tip resistance is less than that of shaft resistance for driven piles. Meanwhile, the method presented in this paper can offer references to designers for revising and improving the technical code for pile foundations.

Axial compressive capacity of driven piles in sand: a method including post-driving residual stresses

2001 ◽  
Vol 38 (2) ◽  
pp. 364-377
Author(s):  
Ahmed Shlash Alawneh ◽  
Osama Nusier ◽  
Abdullah I Husein Malkawi ◽  
Mustafa Al-Kateeb
Keyword(s):  
Residual Stresses ◽  
Bearing Capacity ◽  
Relative Density ◽  
Friction Angle ◽  
Accurate Estimate ◽  
Driven Piles ◽  
Pile Capacity ◽  
Shaft Resistance ◽  
Load Tests ◽  
Pile Load Tests

In this paper, empirical formulae were developed between the well-known pile bearing capacity factors (Nq and β) and parameters which include friction angle of sand, relative density, average effective vertical stress, and deformability of the soil below the pile toe. The developed empirical formulae were totally based on a database comprised of 28 well-documented compressive pile load tests collected exclusively from geotechnical literature. The actual measurements of shaft and end-bearing resistances of each pile in the database were adjusted to account for post-driving residual loads. Calculation of pile bearing capacity factors (Nq and β) was based on the adjusted shaft and end-bearing resistances rather than the actual unadjusted measured resistances for residual loads. Comparison of predicted and measured compressive capacity of an independent database comprised of 18 pile load tests showed that the developed formulae yield a reasonably accurate estimate of compressive pile capacity in cohesionless soils.Key words: driven piles, residual load, toe resistance, shaft resistance.

Progress In The Practical Application Of Automated Image Analysis To Tem Negatives

1977 ◽  
Vol 35 ◽  
pp. 214-217
Author(s):  
F. A. Heckman ◽  
E. Redman ◽  
J.E. Connolly
Keyword(s):  
Image Analysis ◽  
Image Quality ◽  
Exposure Time ◽  
Image Contrast ◽  
Automated Image Analysis ◽  
Practical Application ◽  
Factors Affecting ◽  
High Image Quality ◽  
Qualitative Evidence ◽  
Comprehensive Study

In our initial publication on this subject1) we reported results demonstrating that contrast is the most important factor in producing the high image quality required for reliable image analysis. We also listed the factors which enhance contrast in order of the experimentally determined magnitude of their effect. The two most powerful factors affecting image contrast attainable with sheet film are beam intensity and KV. At that time we had only qualitative evidence for the ranking of enhancing factors. Later we carried out the densitometric measurements which led to the results outlined below.Meaningful evaluations of the cause-effect relationships among the considerable number of variables in preparing EM negatives depend on doing things in a systematic way, varying only one parameter at a time. Unless otherwise noted, we adhered to the following procedure evolved during our comprehensive study:Philips EM-300; 30μ objective aperature; magnification 7000- 12000X, exposure time 1 second, anti-contamination device operating.

Factors affecting microstructural scale in liquid crystalline polymers

1990 ◽  
Vol 48 (4) ◽  
pp. 220-221
Author(s):  
Christine M. Dannels ◽  
Christopher Viney
Keyword(s):  
Liquid Crystalline ◽  
Liquid Crystalline Polymers ◽  
Factors Affecting ◽  
Crystalline Polymers ◽  
Thermal Expansion Coefficients ◽  
Low Thermal Expansion ◽  
Lower Viscosity ◽  
Fine Microstructure ◽  
Planar Orientation ◽  
Strength And Stiffness

Processing polymers from the liquid crystalline state offers several advantages compared to processing from conventional fluids. These include: better axial strength and stiffness in fibers, better planar orientation in films, lower viscosity during processing, low solidification shrinkage of injection moldings (thermotropic processing), and low thermal expansion coefficients. However, the compressive strength of the solid is disappointing. Previous efforts to improve this property have focussed on synthesizing stiffer molecules. The effect of microstructural scale has been overlooked, even though its relevance to the mechanical and physical properties of more traditional materials is well established. By analogy with the behavior of metals and ceramics, one would expect a fine microstructure (i..e. a high density of orientational defects) to be desirable.Also, because much microstructural detail in liquid crystalline polymers occurs on a scale close to the wavelength of light, light is scattered on passing through these materials.

Factors affecting dentist participation in a state Medicaid program

1990 ◽  
Vol 54 (11) ◽  
pp. 638-643 ◽  
Author(s):  
PC Damiano ◽  
ER Brown ◽  
JD Johnson ◽  
JP Scheetz
Keyword(s):  
Medicaid Program ◽  
Factors Affecting

Speech Therapy Services in a Large School System: A Six-Year Overview

1976 ◽  
Vol 7 (4) ◽  
pp. 207-219 ◽  
Author(s):  
Constance P. DesRoches
Keyword(s):  
School System ◽  
Speech Therapy ◽  
Factors Affecting ◽  
Case Load ◽  
Number Of Children ◽  
School Population ◽  
System A ◽  
Therapy Services ◽  
And Shifts ◽  
Selection Factors

A statistical review provides analysis of four years of speech therapy services of a suburban school system which can be used for comparison with other school system programs. Included are data on the percentages of the school population enrolled in therapy, the categories of disabilities and the number of children in each category, the sex and grade-level distribution of those in therapy, and shifts in case-load selection. Factors affecting changes in case-load profiles are identified and discussed.

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