Field pile load tests in saline permafrost. II. Analysis of results

1993 ◽  
Vol 30 (1) ◽  
pp. 46-59 ◽  
Author(s):  
K. W. Biggar ◽  
D. C. Sego
Keyword(s):  
Load Transfer ◽  
Constant Load ◽  
Frozen Soil ◽  
Load Test ◽  
Time Dependent ◽  
Test Field ◽  
Backfill Material ◽  
Analysis Of Results ◽  
Load Tests ◽  
Pile Load Tests

The results obtained from 14 pile load tests carried out in saline permafrost at Iqaluit, Northwest Territories, are analyzed with respect to (i) the development of load along the length of the piles as determined from strain gauges mounted along the embedded portion of the piles; (ii) the time-dependent displacement of the piles under a constant load; and (iii) the performance of grout as a backfill material. The grout used as a backfill material cured adequately and provided sufficient bond strength between the anchor and the grout to cause either the anchor to yield or failure in the surrounding frozen soil. The development of load along the pile resulted in a nearly uniform stress distribution for smooth-surfaced piles but was highly nonuniform when lugs were added. Time-dependent displacement of the piles without lugs can be described using a power-law relationship. Key words : permafrost, saline, pile, load test, field, in situ capacity, load transfer.

scholarly journals Laboratory Research of Toe Resistance Based on Static Pile Load Tests in Different Schemes

2018 ◽  
Vol 28 (1) ◽  
pp. 172-181 ◽  
Author(s):  
Krzysztof Żarkiewicz
Keyword(s):  
Skin Friction ◽  
Applied Load ◽  
Load Transfer ◽  
Load Test ◽  
Laboratory Research ◽  
Load Tests ◽  
Pile Load Test ◽  
Friction Curve ◽  
Pile Load Tests ◽  
Surrounding Soil

Abstract Transfer of axial force from the head of a pile to the surrounding soil by skin friction and toe resistance is still uncertain. The results of the static pile load test are usually presented as settlement curve. This curve can be divided into two components: skin friction curve and toe resistance curve according to the settlement. Laboratory research of pile load test was carried out in two schemes: with skin friction and without skin friction. The study proved that the toe resistance with and without skin friction is not the same. Skin friction influence on toe resistance due to settlement. This phenomenon is not usually taken into account, but very often has a significant impact on axially applied load transfer. In the paper results of laboratory pile load tests id, different schemes were presented.

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.

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.

Geodetic Measurement of Vertical Displacements (Illustrated with the Slovenian Viaduct)

2015 ◽  
Vol 725-726 ◽  
pp. 913-921 ◽  
Author(s):  
Boštjan Kovačič ◽  
Rok Kamnik ◽  
Nikolay Vatin
Keyword(s):  
Laser Scanning ◽  
Load Test ◽  
Field Observations ◽  
Geodetic Measurement ◽  
Basic Goal ◽  
Vertical Displacements ◽  
Analysis Of Results ◽  
Load Tests ◽  
Geometric Changes ◽  
Displacement Measurements

Today there are a lot of sophisticated methods to measure and analyse a bridge during load tests as a GPS, photogrammetric measurements, laser scanning, etc., The use of an classical techniques as trigonometric hights is still good enough for most demanding field observations. In practice control measurements are performed with the help of geodetic measurements, of which the basic goal is to capture any geometric changes in the measured object, or its displacements and deformations are found. In this article the use of trigonometric hights during a load test on the biggest Slovenian viaduct “Črni Kal” is introduced, displacement measurements on the viaduct and an analysis of results, with particular stress on the accuracy of the calculations.

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.

Parametric analysis of the effects of stress relief on the performance and capacity of piles in nondilative soils

2011 ◽  
Vol 48 (9) ◽  
pp. 1354-1363 ◽  
Author(s):  
Gang Zheng ◽  
Yu Diao ◽  
C.W.W. Ng
Keyword(s):  
Ground Surface ◽  
Stress Relief ◽  
Load Test ◽  
The Other ◽  
Deep Excavation ◽  
Maximum Tension ◽  
Load Tests ◽  
Pile Load Test ◽  
Effects Of Stress ◽  
Pile Load Tests

To provide support to superstructure and substructure, piles are often installed beneath a deep basement prior to its excavation. However, the effects of stress relief on the performance and capacity of piles due to deep excavation are rarely reported in the literature. In this study, two different types of pile load tests were simulated with and without considering excavation effects by conducting parametric axisymmetric finite element analyses. The first test was a pile load test on a sleeved pile from the ground surface prior to deep excavation, and the other is a load test on an unsleeved pile at the final excavated level. It is found that an excavation could reduce the pile capacity by up to 45% and pile stiffness by up to 75%. The effects of stress relief due to an excavation increase with normalized excavation depth (H/L) and excavation radius (R/H). Moreover, the maximum tension induced in a pile by excavation varies with H/L, and it has a peak value when 1 < H/L < 1.25. The value of maximum tension increases with the pile–soil modulus ratio (Ep/Esm). When Ep/Esm = 100, peak tension develops at 0.5H. On the other hand, tension reaches a peak at 0.7H when Ep/Esm = 20.

Field pile load tests in saline permafrost. I. Test procedures and results

1993 ◽  
Vol 30 (1) ◽  
pp. 34-45 ◽  
Author(s):  
K. W. Biggar ◽  
D. C. Sego
Keyword(s):  
Companion Paper ◽  
Load Test ◽  
Load Testing ◽  
Test Procedures ◽  
Testing Procedures ◽  
Uplift Load ◽  
Load Tests ◽  
Pile Load Test ◽  
Pile Load Tests

A pile load test program carried out in Iqaluit, Northwest Territories, to provide design information for the Short Range Radar sites is described. The program consisted of testing 10 steel pipe piles with various surface modifications backfilled with clean sand and 4 Dywidag bars backfilled with Ciment Fondu™ grout. All tests were performed in saline permafrost. This paper describes the site conditions, installation procedures and pile uplift load testing procedures, and results of the pile load tests. The beneficial effect of modifications to the pile surface and backfill material is identified. The analysis and discussions of the results are presented in a companion paper. Key words : permafrost, saline, piles, load tests, field, in situ, capacity.

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