Driven cast-in-situ pile capacity: insights from dynamic and static load testing

2021 ◽  
Author(s):  
Kevin N. Flynn ◽  
Bryan A. McCabe
Keyword(s):  
Dynamic Load ◽  
Shear Stresses ◽  
Load Testing ◽  
Pile Capacity ◽  
Compression Load ◽  
Shaft Resistance ◽  
Pile Installation ◽  
Cast Concrete ◽  
Load Tests

Driven cast-in-situ (DCIS) piles are classified as large displacement piles. However, the use of an oversized driving shoe introduces additional complexities influencing shaft resistance mobilisation, over and above those applicable to preformed displacement piles. Therefore, several design codes restrict the magnitude of shaft resistance in DCIS pile design. In this paper, a series of dynamic load tests was performed on the temporary steel driving tubes during DCIS pile installation at three UK sites. The instrumented piles were subsequently subjected to maintained compression load tests to failure. The mobilised shear stresses inferred from the dynamic tests during driving were two to five times smaller than those on the as-constructed piles during maintained load testing. This was attributed to soil loosening along the tube shaft arising from the oversized base shoe. Nevertheless, the radial stress reductions appear to be reversible by the freshly-cast concrete fluid pressures which provide lower-bound estimates of radial total stress inferred from the measured shear stresses during static loading. This recovery in shaft resistance is not recognised in some European design practices, resulting in conservative design lengths. Whilst the shaft resistance of DCIS piles was underpredicted by the dynamic load tests, reasonable estimates of base resistance were obtained.

Shaft resistance of driven cast-in-situ piles in sand

2016 ◽  
Vol 53 (1) ◽  
pp. 49-59 ◽  
Author(s):  
Kevin N. Flynn ◽  
Bryan A. McCabe
Keyword(s):  
Steel Tube ◽  
Large Displacement ◽  
Shear Stresses ◽  
Load Testing ◽  
Compression Load ◽  
Shaft Resistance ◽  
Cast Concrete ◽  
Local Shear ◽  
Load Tests

Driven cast-in-situ (DCIS) piles are classified as a large displacement pile, despite sharing certain aspects of their construction with replacement pile types. However, there are relatively few case histories of load tests on DCIS piles in the literature to verify the assumption that they behave as large displacement piles. In particular, the shaft resistance of DCIS piles in sand is uncertain due to the complex interaction between the freshly cast concrete and surrounding displaced soil after extraction of the steel installation tube. This paper describes the installation, curing, and maintained compression load testing of three temporary-cased DCIS test piles at a uniform sand site near Coventry, United Kingdom. The piles were instrumented with vibrating wire strain gauges to enable accurate measurement of the local shear stress generated on the pile shaft during maintained compression loading. The tests showed that the peak average and local shear stresses tended to mobilize at greater shaft displacements than traditional preformed displacement piles during loading. A clear reduction in normalized local shear stresses (and hence radial effective stress) at failure with distance from the pile base, i.e., friction fatigue, was evident for all piles, implying that radial stresses generated during driven installation of the steel tube are not erased upon concreting and tube withdrawal. Furthermore, the inferred normalized radial effective stresses at failure were remarkably similar to those reported for traditional preformed displacement piles in the literature.

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.

scholarly journals Bi-Directional Static Load Tests of Pile Models

2020 ◽  
Vol 10 (16) ◽  
pp. 5492
Author(s):  
Michał Baca ◽  
Włodzimierz Brząkała ◽  
Jarosław Rybak
Keyword(s):  
Bearing Capacity ◽  
Static Load ◽  
Load Testing ◽  
Pile Capacity ◽  
Pile Shaft ◽  
Load Tests ◽  
S Curve ◽  
Definition Of ◽  
Standard Tests ◽  
Static Load Testing

This work examined a new method of bi-directional static load testing for piles, referencing the Osterberg test. Measurements were taken, on a laboratory scale, using six models of piles driven into a box filled with sand. This method allowed for separate measurements of pile base and pile shaft bearing capacities. Based on the results, the total pile bearing capacity and equivalent Q–s diagrams were estimated. The results obtained show that the structure of the equivalent curve according to Osterberg is a good approximation of the standard Q–s curve obtained from load tests, except for loads close to the limit of bearing capacity (those estimates are also complicated by the inapplicability and ambiguity of a definition of the notion of limit bearing capacity); the equivalent pile capacity in the Osterberg method represents, on average, about 80% of the capacity from standard tests.

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.

scholarly journals Static and Dynamic Load Tests of Shaft and Base Grouted Concrete Piles

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Jialin Zhou ◽  
Xin Zhang ◽  
Hongsheng Jiang ◽  
Chunhao Lyu ◽  
Erwin Oh
Keyword(s):  
Dynamic Load ◽  
Static Load ◽  
Test Results ◽  
Pile Capacity ◽  
Friction Resistance ◽  
Concrete Piles ◽  
Double Tangent ◽  
Load Tests ◽  
Bored Piles ◽  
Comparison Of The Results

This paper examines shaft and base grouted concrete piles by conducting vertical static load tests (SLTs) and dynamic load tests. Three concrete piles with shaft and base grouting, with base grouting only, and without grouting techniques were selected, and compressive SLTs were conducted. Two piles with grouting were also assessed with dynamic load tests. Another two uplift SLTs were conducted to one shaft and base grouted pile and one pile without grouting. Traditional presentations were provided to check whether the bored piles reached the design requirement. Interpretations of test results were also provided to determine the ultimate pile capacity. Results from these 5 SLT programs indicated that double-tangent and DeBeer's methods are close to each other, and Chin's method overestimates the pile capacity. Comparison of the results from the SLTs and dynamic load tests shows that the results from Chin's method are close to dynamic results, and Mazurkiewicz's method overestimates for friction resistance. The results also demonstrate that base and shaft grouted pile and base grouted pile increase by 9.82% and 2.89% in compressive capacity, respectively, and compared to the uplift SLTs; there is a 15.7% increment in pile capacity after using base and shaft grouting technology.

scholarly journals Empirical Formulas to Predict the Axial Capacity of Driven Piles Using in-Situ Dynamic Load Testing Data

2019 ◽  
Vol 9 (2) ◽  
pp. 129-134
Author(s):  
Anis Shatnawi ◽  
◽  
Wassel AL Bodour ◽  
Mu’tasim Abdel-Jaber ◽  
Bashar Tarawneh
Keyword(s):  
Dynamic Load ◽  
Load Testing ◽  
Driven Piles ◽  
Empirical Formulas ◽  
Axial Capacity ◽  
Testing Data

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.

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.

Plugging effect of open-ended piles in sandy soil

2015 ◽  
Vol 52 (5) ◽  
pp. 535-547 ◽  
Author(s):  
Junyoung Ko ◽  
Sangseom Jeong
Keyword(s):  
Sandy Soil ◽  
Field Tests ◽  
Load Resistance ◽  
Standard Penetration Test ◽  
Compression Load ◽  
Shaft Resistance ◽  
Load Tests ◽  
Highly Correlated ◽  
Full Scale Tests ◽  
Different Diameters

This paper presents an experimental study of the plugging effect on the capacity of open-ended piles installed in sandy soil. Full-scale tests, including dynamic and static axial compression load tests, were carried out on three instrumented piles with different diameters (508.0, 711.2, and 914.4 mm). To measure the outer and inner shaft resistances acting on the piles, a double-walled system was utilized, with instrumented strain gauges on the outside and inside walls of the pile. The results of field tests show that the inner shaft resistance was mostly mobilized at the location between the pile tip and 18%–34% of the total plug length. It was found that the soil plugging in the lower portion has influence on the inner shaft resistance. In addition, it can be also demonstrated that the ratio of inner shaft resistance plus annulus load resistance to total resistance was decreased with increasing pile diameters. The results of these tests show that the relationship between the degree of plugging and pile diameter is clearly established. Direct observations of the soil plugs were made and used to quantify both the plug length ratio (PLR) and the incremental filling ratio (IFR). Based on this result, it was realized that the N value of the standard penetration test (SPT) is highly correlated with the IFR.

Sign in / Sign up

Export Citation Format

Share Document