Cast-in-place bored piles on soft rock under artesian pressures

1984 ◽  
Vol 21 (4) ◽  
pp. 684-698 ◽  
Author(s):  
Hari D. Sharma ◽  
S. Sengupta ◽  
Glen Harron
Keyword(s):  
Soft Rock ◽  
Load Test ◽  
Rock Surface ◽  
Weathered Rock ◽  
Concrete Piles ◽  
Geotechnical Investigations ◽  
Load Tests ◽  
Undrained Strength ◽  
Pile Load Tests ◽  
A Site

This paper outlines the geotechnical investigations and axial compression, pullout, and lateral pile load tests that were carried out at a site where cast-in-place bored concrete piles were installed. These piles were designed to bear on top of soft weathered rock surface that was under artesian pressures. Pile load test results have been compared with theoretically calculated pile capacities. It has been found that in areas of high artesian pressures in bedrock axial compressive pile load capacities theoretically estimated by conventional methods were significantly higher than the values obtained from load tests. Recommendations have been made that representative exposed bedrock samples be tested to determine their undrained strength, and these values be used for estimating theoretical pile capacities. Construction problems encountered during pile installation, such as locating the top of weathered bedrock without penetrating through water-bearing layers that were under artesian pressures, are presented briefly and a solution provided to install belled piles on top of bedrock is discussed. Key words: bored concrete piles, construction problems, load tests, soft weathered rock under artesian pressures, ultimate pile load capacities.

Pile load tests for the Calgary Air Terminal building

1983 ◽  
Vol 20 (2) ◽  
pp. 353-361
Author(s):  
J. Bertok ◽  
M. Berezowski
Keyword(s):  
Technical Note ◽  
Load Test ◽  
Load Testing ◽  
Test Results ◽  
Concrete Piles ◽  
Building Foundation ◽  
History Of ◽  
Load Tests ◽  
Pile Load Tests ◽  
Pile Type

This technical note describes a case history of pile load tests for the Calgary Air Terminal building. One drilled, cast-in-place, concrete caisson, socketed into bedrock, and compacted expanded-base concrete piles were tested and evaluated to select a pile type that would support column loads up to 6700 kN. This note describes the pile test program, interprets the load test results, and summarizes the pile specifications and installation. Keywords: building foundation, piles, load testing, interpretation, installation.

Predicting the Ultimate Bearing Capacity of Single Piles Based on CPTU

2011 ◽  
Vol 243-249 ◽  
pp. 4402-4407
Author(s):  
Yong Hong Miao ◽  
Guo Jun Cai ◽  
Song Yu Liu
Keyword(s):  
Load Test ◽  
Load Testing ◽  
Pile Capacity ◽  
Piezocone Penetration Test ◽  
Load Carrying ◽  
Load Tests ◽  
Pile Load Test ◽  
Single Piles ◽  
Pile Load Tests ◽  
Best Fit

Six methods to determine axial pile capacity directly based on piezocone penetration test (CPTU) data are presented and evaluated. Analyses and evaluation were conducted on three types piles that were failed during pile load testing. The CPT methods, as well as the CPTU methods, were used to estimate the load carrying capacities of the investigated piles (Qp ). Pile load test were used to determine the measured load carrying capacities (Qm). The pile capacities determined using the different methods were compared with the measured pile capacities obtained from the pile load tests. Two criteria were selected as bases of evaluation: the best fit line for Qp versus Qm and the arithmetic mean and standard deviation for the ratio Qp /Qm. Results of the analyses showed that the best methods for determining pile capacity are the CPTU methods.

A note on pile load test interpretation

1970 ◽  
Vol 7 (4) ◽  
pp. 479-481
Author(s):  
K. Peaker
Keyword(s):  
Soil Type ◽  
Test Procedure ◽  
Load Test ◽  
Building Code ◽  
Test Interpretation ◽  
Load Tests ◽  
Pile Load Test ◽  
Pile Load Tests ◽  
Pile Type

Pile load tests are normally carried out in accordance with A.S.T.M. or other building code specifications without regard to the actual pile type or soil type. The example quoted indicates that the test procedure may lead to incorrect interpretation of failure and conservative design.

Load tests on bedrock

1970 ◽  
Vol 7 (4) ◽  
pp. 464-470 ◽  
Author(s):  
J. L. Seychuk
Keyword(s):  
Elastic Material ◽  
Steel Plate ◽  
Applied Pressure ◽  
Load Test ◽  
Vertical Load ◽  
Subgrade Reaction ◽  
Concrete Piles ◽  
Limestone Bedrock ◽  
Load Tests ◽  
Pile Load Test

Load tests involving the use of a steel plate, a concrete socket, and full scale concrete piles were carried out at two separate sites in Ontario to determine the load bearing characteristics of shale and limestone bedrock. It was found that the essentially sound bedrock behaved as an elastic material under the maximum applied pressure of 260 tons/sq. ft (254 × 104 kg/m2). In addition to the vertical load tests on the rock, a lateral pile load test was carried out to evaluate the modulus of horizontal subgrade reaction of the fissured clay overburden at one of the sites.

scholarly journals Large-diameter helical pile capacity – torque correlations

2017 ◽  
Vol 54 (7) ◽  
pp. 968-986 ◽  
Author(s):  
Jared Harnish ◽  
M. Hesham El Naggar
Keyword(s):  
Large Diameter ◽  
Failure Criteria ◽  
Load Test ◽  
Ultimate Capacity ◽  
Pile Capacity ◽  
Shearing Resistance ◽  
Helical Piles ◽  
Torque Capacity ◽  
Load Tests ◽  
Pile Load Tests

Large-diameter helical piles are utilized increasingly to support heavy structures. Both the magnitude of the required installation torque and the pile capacity can be directly attributed to the soil shearing resistance developed over the embedded area of the pile including the shaft and helical plates. Hence, the pile capacity can be correlated to installation torque. Such correlations are widely used in the helical pile industry as a means for quality control and quality assurance. In the current study, a total of 10 test piles were installed while monitoring the installation torque continuously with depth. The recorded installation torque profiles were demonstrated to be accurate and repeatable. Field pile load tests were conducted and their results were analyzed to determine the interpreted ultimate capacity of the test piles. The results demonstrate that the ultimate capacity of large-diameter helical piles can be interpreted from pile load test data employing the failure criteria proposed by Elkasabgy and El Naggar in 2015 and Fuller and Hoy in 1970. The measured installation torque and corresponding ultimate capacity values were employed to define torque–capacity correlation (Kt) based on embedded pile area. It was demonstrated that the proposed Kt is suitable for large-diameter helical piles.

scholarly journals Within-site variability and reliability of foundation designs based on load tests

2019 ◽  
Author(s):  
◽  
Andrew Z. Boeckmann
Keyword(s):  
Load Test ◽  
Test Results ◽  
Considerable Variability ◽  
Specific Load ◽  
Primary Input ◽  
Bayesian Techniques ◽  
Test Information ◽  
Load Tests ◽  
A Site ◽  
Site Variability

Probabilistic evaluations of the reliability of foundation designs based on site-specific load test information are somewhat limited in number. Published evaluations have generally relied on Bayesian techniques. A primary input for Bayesian analysis is within-site variability, which describes the variability of foundation resistance across a site. Within-site variability is attributed to geologic variation across a site and to differences in construction outcomes among foundation elements. Published evaluations have generally used a deterministic value of within-site variability wherein within-site variability is treated as a known parameter and is not subject to updating based on load test results. In contrast, probabilistic within-site variability treats within-site variability as an uncertain parameter with its own probability distribution that is updated based on load test results. Probabilistic within-site variability has not been applied commonly. This research examines differences in reliability outcomes between deterministic and probabilistic within-site variability. Analysis of micropile load test results from five different sites was used to develop a distribution of within-site variability. The resulting distribution is relatively variable (i.e. the value of within-site variability is, itself, variable), which demonstrates that there is, in fact, considerable variability and uncertainty in the value of within-site variability.

Evaluation of pile load tests in the Edmonton area

1981 ◽  
Vol 18 (2) ◽  
pp. 313-316 ◽  
Author(s):  
S. Thomson
Keyword(s):  
Test Data ◽  
Carrying Capacity ◽  
Vertical Movement ◽  
Load Carrying Capacity ◽  
Design Procedures ◽  
Concrete Piles ◽  
Load Carrying ◽  
Load Tests ◽  
Pile Load Tests

The design of cast-in-place concrete piles is essentially empirical; hence, an examination of commercial pile load tests is of value. The test data of four pile load tests consisted of the vertical movement of the top of the pile and the load on top of the pile. It was therefore necessary to calculate the shaft and base loads assuming that the till was homogeneous with regard to strength over the length of the pile.The results of the back analyses suggest that the design procedures are valid within practical limits for the prediction of load carrying capacity and for immediate settlement.

Performance of helical piles in oil sand

2009 ◽  
Vol 46 (9) ◽  
pp. 1046-1061 ◽  
Author(s):  
Mohammed Sakr
Keyword(s):  
Full Scale ◽  
Load Test ◽  
Test Results ◽  
Lateral Loads ◽  
Oil Sand ◽  
Deep Foundation ◽  
Helical Piles ◽  
Load Tests ◽  
Pile Load Test ◽  
Pile Load Tests

The results of a comprehensive pile load-test program and observations from field monitoring of helical piles with either a single helix or double helixes installed in oil sand are presented in this paper. Eleven full-scale pile load tests were carried out including axial compression, uplift, and lateral load tests. The results of the full-scale load tests are used to develop a theoretical design model for helical piles installed in oil sand. Test results confirm that the helical pile is a viable deep foundation option for support of heavily loaded structures. The test results also demonstrated that circular-shaft helical piles can resist considerable lateral loads.

A new socket roughness factor for prediction of rock socket shaft resistance

2001 ◽  
Vol 38 (1) ◽  
pp. 138-153 ◽  
Author(s):  
J P Seidel ◽  
B Collingwood
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Resistance Coefficient ◽  
Complex Problem ◽  
Load Test ◽  
Technical Literature ◽  
Analysis And Design ◽  
Shaft Resistance ◽  
Load Tests ◽  
Pile Load Tests

Prediction of rock socket shaft resistance is a complex problem. Conventional methods for predicting the peak shaft resistance are typically empirically related to unconfined compressive strength through the results of pile load tests. It is shown by reference to international pile socket databases that the degree of confidence which can be applied to these empirical methods is relatively low. Research at Monash University has been directed at understanding and then modelling the complex mechanisms of shear transfer at the interface between the socketed piles and the surrounding rock. Important factors that affect the strength of pile sockets have been identified in laboratory and numerical studies. With a knowledge of the effect of these factors, the reasons for the large scatter around traditional empirical correlations can be deduced. A computer program called ROCKET has been developed which encompasses all aspects of the Monash University rock socket research. This program has been used to develop design charts for rock-socketed piles based on unconfined compressive strength and a nondimensional factor which has been designated the shaft resistance coefficient (SRC). Implementation of the SRC method in design requires an estimate of the likely socket roughness to be made. Very few researchers or practitioners have measured socket roughness, so there is little available guidance in selection of appropriate values. Although many socket load tests are described in the technical literature, the physical parameter which is regularly missing is the socket roughness. With a knowledge of the shaft resistance, and an estimate of all other relevant parameters, the authors have been able to back-calculate the apparent socket roughness using the SRC method. Based on the back-calculated roughness data, socket roughness guidelines for use in analysis and design of rock sockets have been proposed. Using these roughness guidelines, it is shown that the SRC method is able to predict the scatter observed in previously published international load test databases.Key words: rock socket, drilled shaft, shaft resistance, roughness, shaft resistance coefficient.

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