Comparison of pile load test methods

1989 ◽  
Vol 26 (4) ◽  
pp. 742-744 ◽  
Author(s):  
R. C. Joshi ◽  
H. D. Sharma ◽  
D. G. Sparrow
Keyword(s):  
Axial Force ◽  
Applied Load ◽  
Ultimate Load ◽  
Axial Loading ◽  
Test Methods ◽  
Point Load ◽  
Load Test ◽  
Force Distribution ◽  
Loading Test ◽  
Shaft Resistance

Instrumented model piles were loaded to failure using slow-maintained-load, quick-maintained-load, and constant-rate-of-penetration methods of loading. The piles were driven in a prepared dry-sand bed. The applied load, point load, and shaft resistance were measured using load cells and strain gauges, and axial force distribution was determined. Test data indicate that all the three methods give similar ultimate load at failure. Nonetheless, out of the three methods, the slow-maintained-load method of testing piles, which seems to simulate field conditions, gives the largest settlement for the same applied load. The axial force distribution and shaft resistance along the pile were observed to be identical for all the three pile test methods. Key words: model piles, laboratory study, axial loading, test methods, sands, point load, shaft resistance, ultimate load.

Influence of loading rate on the capacity of a model pile in clay

1995 ◽  
Vol 32 (2) ◽  
pp. 364-368 ◽  
Author(s):  
Robert G. Horvath
Keyword(s):  
Loading Rate ◽  
Axial Loading ◽  
Displacement Transducer ◽  
Test Methods ◽  
Point Load ◽  
Test Results ◽  
Loading Test ◽  
Normal Loading ◽  
Model Pile ◽  
Rate Of Loading

Loading tests were carried out on a model pile embedded in clay to examine the influence of rate of loading on the capacity of the pile. The pile was loaded to failure using constant rate of penetration (CRP), quick maintained loading (QML), and quick continuous loading (QCL) methods of loading. The QCL test models the Statnamic loading test, which has been recently developed in Canada. The CRP tests were used as a reference, and the results were normalized using the CRP test results. The durations of the QML and QCL tests varied from approximately 0.1 s to 17 min, which are significantly faster than normal loading rates. Applied loads and point load were measured using load cells, and top displacement was measured using a displacement transducer. The test results showed an increase in pile capacity with increased rate of loading. Damping was found to be significant for the QCL tests (duration = 0.1 s) and negligible for the QML tests (duration ≥ 10 s). Correcting the results of the QCL tests for damping, using the equilibrium point method developed for Statnamic testing, greatly improved the correlation of the QCL and QML test results. Key words : model piles, axial loading, loading rate, clay, laboratory study, test methods.

Multiple loading method for field testing drilled piers

1985 ◽  
Vol 22 (4) ◽  
pp. 592-599
Author(s):  
R. G. Horvath
Keyword(s):  
Test Procedure ◽  
Load Cell ◽  
Load Test ◽  
Test Method ◽  
Single Test ◽  
Loading Test ◽  
Shaft Resistance ◽  
Loading Method ◽  
Multiple Loading ◽  
Base Load

A multiple loading testing method is suggested, which permits testing a single drilled pier foundation under three different conditions of load support. The pier may be tested under conditions of combined shaft and end-bearing resistance, end-bearing resistance only, and shaft resistance only. The advantages of this multiple loading test method include observation of the load-transfer and displacement behaviours of the pier under these three different support conditions and verification of the values obtained for the components of load support, i.e., shaft and end-bearing resistance, all from a single test pier.A special base load cell capable of performing a different function during each cycle of loading is required. A suitable load cell, consisting of a series of Freyssi flatjacks, and the method of operation are described.A multiple loading test procedure was used successfully as part of a field investigation program on full-scale pier sockets in weak shale. Data on the load-displacement behaviour of the pier tested using the multiple loading method are reported. Information concerning piers tested using conventional single loading methods are provided for comparison.The multiple loading test results were in good agreement with results obtained from conventional testing methods. Thus the multiple loading test method provides an economical means of obtaining a large amount of design information for drilled pier foundation systems, using a single test pier. Key words: field load test, multiple loading, drilled piers and caissons, shaft resistance, end-bearing resistance, combined shaft and end-bearing resistances, base load cell, shale.

Ultimate Load Test and Analysis of a Retrofitted Model Steel Dome

1998 ◽  
Vol 13 (2) ◽  
pp. 53-63
Author(s):  
Hewen Li ◽  
Lewis C. Schmidt
Keyword(s):  
Finite Element ◽  
Ultimate Load ◽  
Load Capacity ◽  
Load Test ◽  
Finite Element Analyses ◽  
Loading Test ◽  
Ultimate Load Capacity ◽  
Geometrical Imperfections ◽  
Hexagonal Grids ◽  
Post Tensioned

This paper concerns the test and analysis of a retrofitted post-tensioned and shaped steel dome that failed in an original loading test. The post-tensioned and shaped steel dome was formed by a post-tensioning operation from a planar layout constituted of hexagonal grids. After its first loading to failure, the dome was retrofitted in situ. The retrofitting method and the results of a subsequent ultimate load test and nonlinear finite element analyses of the retrofitted dome are presented. It is found that the retrofitted dome has a much greater ultimate load capacity than the original dome. The results of finite element analyses show that the prestress member forces caused during shape formation can cause a reduction of ultimate load capacity, and that the post-tensioned and shaped steel dome investigated here is sensitive to geometrical imperfections. It is also noted that the retrofitting process can be used to erect a domic structure from a near flat layout. The proposed method of considering prestress forces can be useful in nonlinear analysis of structures involving prestress forces.

Field Axial Loading Tests of Screw Micropiles in Sand

2021 ◽  
Author(s):  
Mujtaba Khidri ◽  
Lijun Deng
Keyword(s):  
Axial Strain ◽  
Earth Pressure ◽  
Axial Loading ◽  
Resistance Factor ◽  
Load Test ◽  
Shaft Resistance ◽  
Cone Penetration Tests ◽  
Tip Resistance ◽  
Pile Type ◽  
Penetration Tests

A screw micropile consists of a smooth shaft at the top, threaded shaft at the middle and tapered shaft at the bottom. Research is required to investigate the axial behavior and capacities of this pile type in sand. A field load test program was performed on six types of full-scale screw micropiles installed at a sandpit site using torque. Selected piles were instrumented with axial strain gauges. A geotechnical investigation, including cone penetration tests (CPT) and standard penetration tests, was undertaken. In total, 41 piles, including 8 instrumented piles, were tested. The ultimate capacities and the unit shaft resistance distributions were determined. The shaft resistance was then compared with the tip resistance of CPT. The coefficient of lateral earth pressure and combined shaft resistance factor was determined for each pile segment, and then an effective stress method based on the combined shaft resistance factor was used to estimate the capacity of test piles. A theoretical torque model was developed using CPT sleeve friction; the model was verified by comparing the estimated torque to the measured torque of test piles. In the end, empirical torque factors were developed.

The Test Analysis of the Bearing Capacity of Foundation

2014 ◽  
Vol 962-965 ◽  
pp. 357-360
Author(s):  
Ya Jun Yin ◽  
Xue Wen Xie ◽  
Yong Mei Qian
Keyword(s):  
Bearing Capacity ◽  
Standard Penetration Test ◽  
Test Methods ◽  
Test Point ◽  
Load Test ◽  
Test Method ◽  
Penetration Test ◽  
Loading Test ◽  
Test Analysis ◽  
Foundation Soil

The test method of shallow plate load was used in the bearing capacity of foundation of Yushu City , doing two groups of loading test in different depths and doing survey and comparative test between test point nearby and sites in the same horizon.It gets the law of foundation soil bearing capacity value got by different test methods and provides the basis for Jilin Province to establish the local standards through the comparison of load test and geotechnical test , static cone penetration test and standard penetration test.

Research on Load Transfer Behavior of Cement-Soil Mixing Piles by Load Test

2012 ◽  
Vol 174-177 ◽  
pp. 228-231
Author(s):  
Dong Xiao Zhang ◽  
Peng Li He
Keyword(s):  
Axial Force ◽  
Load Transfer ◽  
Load Test ◽  
Loading Test ◽  
Soil Mixing ◽  
Before And After ◽  
Static Loading Test ◽  
Transfer Behavior ◽  
Cement Soil ◽  
Side Friction

The pile axial strains were measured according to the results of static loading test. The axial force and side friction of pile were calculated, and load transfer behaviors were researched. Analysis of the data shows that cement-soil mixing pile has the characteristics of friction piles. The rapid reducing of the upper pile axial force and friction show that load passed within a certain range. Horizontal crack occurred at the upper of the pile. Before and after the destructing of the pile load transfer mechanism is different.

scholarly journals Strengthening of RCC Beams in Shear by Using SBR Polymer-Modified Ferrocement Jacketing Technique

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Rajinder Ghai ◽  
Prem Pal Bansal ◽  
Maneek Kumar
Keyword(s):  
Carrying Capacity ◽  
Shear Failure ◽  
Ultimate Load ◽  
Load Test ◽  
Wire Mesh ◽  
Styrene Butadiene Rubber ◽  
Shear Load ◽  
Butadiene Rubber ◽  
Load Carrying Capacity ◽  
Load Carrying

There is a common phenomenon of shear failure in RCC beams, especially in old buildings and bridges. Any possible strengthening of such beams is needed to be explored that could strengthen and make them fit for serviceable conditions. The present research has been made to determine the performance of predamaged beams strengthened with three-layered wire mesh polymer-modified ferrocement (PMF) with 15% styrene-butadiene-rubber latex (SBR) polymer. Forty-eight shear-designed and shear-deficient real-size beams were used in this experimental work. Ultimate shear load-carrying capacity of control beams was found at two different shear-span (a/d) ratios 1 and 3. The sets of remaining beams were loaded with different predetermined damage levels of 45%, 75%, and 95% of the ultimate load values and then strengthened with 20 mm thick PMF. The strengthened beams were then again tested for ultimate load-carrying capacity by conducting the shear load test at a/d = 1 and 3. As a result, the PMF-strengthened beams showed restoration and enhancement of ultimate shear load-carrying capacity by 5.90% to 12.03%. The ductility of strengthened beams was improved, and hence, the corresponding deflections were prolonged. On the other hand, the cracking pattern of PMF-strengthened beams was also improved remarkably.

scholarly journals Point Load Test of Half-Cylinder Core Using the Numerical Model and Laboratory Tests: Size Suggestion and Correlation with Cylinder Core

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Fengyu Ren ◽  
Huan Liu ◽  
Rongxing He ◽  
Guanghui Li ◽  
Yang Liu
Keyword(s):  
Numerical Model ◽  
Laboratory Tests ◽  
Failure Load ◽  
Field Tests ◽  
Point Load ◽  
Diameter Ratio ◽  
Load Test ◽  
Index Test ◽  
Point Load Test ◽  
Calculation Procedures

The point load test (PLT) is intended as an index test for rock strength classification or estimations of other strength parameters because it is economical and simple to conduct in the laboratory and in field tests. In the literature, calculation procedures for cylinder cores, blocks, or irregular lumps can be found, but no study has researched such procedures for half-cylinder cores. This paper presents the numerical model and laboratory tests for half-cylinder and cylinder specimens. The results for half-cylinder and cylinder specimens are then presented, analysed, and discussed. A correlation of failure load between half-cylinder and cylinder specimens is established with a suitable size suggestion and correction factor. It is found that the failure load becomes stable when half-cylinder specimens have a length/diameter ratio higher than 0.9. In addition, the results show that the point load strength index (PLSI) of half-cylinder cores can be calculated using the calculation procedures for diametral testing on cylinder cores, and it is necessary to satisfy the conditions that the length/diameter ratio be higher than 0.9 and the failure load be multiplied by 0.8.

Sign in / Sign up

Export Citation Format

Share Document