Static Pile Load Test: International Practice Review and Discussion About the European and Japanese Standards (original) (raw)
Related papers
Congresso Brasileiro de Mecânica dos Solos e Engenharia Geotécnica, 2020
The static load test (SLT) in piles may provide the axial force applied at the top of the pile and its corresponding displacement. According to the ABNT NBR 12131, the measured load may be done through a calibrated manometer or a load cell installed in series with the hydraulic jack. However, according to the ASTM D1143, if the maximum test load will exceed 900 kN, place a properly constructed load cell or equivalent device in series with each hydraulic jack. The same load test can be represented by three different load vs. displacement curves (Load cell, manometer, theoretical SLT). The analysis of the results will be different depending on the corresponding curve that is used on the analysis, for example, the use of extrapolation methods to predict the ultimate load. The results revealed that static load tests performed in different project sites might present different over predicted manometer error rates when the hydraulic jack is loading and different under predicted manometer error rates when the hydraulic jack is unloading. The manometer error depends on numerous factors: eccentric and inclined load, the inclination of the reaction beams and the pile cap, manometer accuracy, possible influence of the residual force at the pile toe.
A proposal for static load tests on piles: the Equilibrium Method
Soils and Rocks, 2021
This note presents an alternative method for static load tests on piles (and caissons). Called Equilibrium Method by its first proponents, the method was applied in some load tests in Brazil, in addition to being the object of theoretical studies conducted at the Federal University of Rio de Janeiro. The method consists, in each step, to keep the load constant for a period of time and then let it relax (not pumping the jack) until the displacement and the load reach mutual equilibrium. The stabilized displacement and the relaxed load (the so-called load and displacement in equilibrium) are considered for the load-displacement curve. The method has the advantage of producing the load-displacement curve close to that of a slow, stabilized test (incremental slow maintained load test), but with a shorter total execution time. The paper includes a short theoretical background and a review of the Brazilian experience.
sgem-2017-0026 STATIC LOAD TEST ON INSTRUMENTED PILE – FIELD DATA AND NUMERICAL SIMULATIONS
2017
Static load tests on foundation piles are generally carried out in order to determine load – the displacement characteristic of the pile head. For standard (basic) engineering practices this type of test usually provides enough information. However, the knowledge of force distribution along the pile core and its division into the friction along the shaft and the resistance under the base can be very useful. Such information can be obtained by strain gage pile instrumentation [1]. Significant investigations have been completed on this technology, proving its utility and correctness [8], [10], [12]. The results of static tests on instrumented piles are not easy to interpret. There are many factors and processes affecting the final outcome. In order to understand better the whole testing process and soil-structure behavior some investigations and numerical analyses were done. In the paper, real data from a field load test on instrumented piles is discussed and compared with numerical s...
Comparison Between Dynamic and Static Pile Load Testing
Based on experience and extrapolation, it is found that the best way to predict pile behavior is to perform a pile loading test. In this study a comparison between the static and dynamic load tests results was made to evaluate the ability of the High Strain Dynamic Pile Testing (HSDPT) using SIMBAT method to estimate the static capacity of bored concrete piles. Four case studies conducted in Red Sea state were taken. The two test results are consistent to a good extent. The dynamic load pile test, which is a simple quality control test offering a considerable savings of time and cost and requires less space, can be used for predicting pile capacity and pile integrity under proper care and it should be calibrated by at least one static test. The (settlement/pile diameter) ratios, which are less than 1% for all piles, reflected conservative pile design. The pile design for projects should be optimized by determining the actual ultimate pile capacity, which may need to conduct pile test to failure or near to failure.
Experimental investigations and analysis on different pile load testing procedures
Acta Geotechnica, 2012
The paper presents experimental results of two Osterberg's cell load tests (OLTs) and three conventional load tests (COLTs) in the same subsoil conditions on Continuous Flight Auger (CFA) piles carefully monitored during construction stages. The instrumentation along the pile shaft in all the tests allows interesting comparisons of both global behaviour and local load transfer. Significant differences in the stiffness of the soil-pile system with the different test procedures is outlined. The main differences between the two test procedures occur at the two opposite ends of the pile, as could have been expected, while the observed behaviour in the middle part of the tested piles is close for the two models. A relatively simple FEM model has been calibrated on the basis of the OLTs results. The same model is capable of accurately matching the experimental results of the COLTs, proving that the observed differences are not due to random factors. Furthermore, the same model has been used to simulate ideal load tests. Such a reliable simulation shows that both the experimental procedures are actually responsible for significant differences in the behaviour of the soil-pile system even in the simple case of a concentrated axial load. Large differences arise in terms of the stiffness of the system with the OLTs providing by far the stiffest response. Despite being intermediate between the OLT and the ILT, the COLTs provide a response of the pile-soil system, which is on the average about two times stiffer than the Ideal test, where the force applied on top of the pile does not depend on a tangible reaction system. Care should be thus taken when considering the results of such tests in the prediction of the settlement of a piled foundation. Correction factors should be applied to the experimentally observed behaviour.
Common Mistakes in Static Loading-test Procedures and Result Analyses
2019
Static loading tests on piles are arranged in many different ways ranging from quick tests to slow test, from constant-rate-ofpenetration to maintained load, from straight loading to cyclic loading, to mention just a few basic differences. Frequently, the testing schedule includes variations of the size of the load increments and duration of load-holding, and occasional unloading-reloading events. Unfortunately, instrumenting test piles and performing the test while still using unequal size of load increments, duration of load-holding, and adding unloading-reloading events will adversely affect the means for determine reliable results from the instrumentation records. A couple of case histories are presented to show issues arising from improper procedures involving unequal load increments, different load-holding durations, and unloading and reloading events—indeed, to demonstrate how not to do. The review has shown that an instrumented static loading test, be it a head-down test or ...
First results of pipe pile static load test in small laboratory scale
MATEC Web of Conferences, 2018
Presented laboratory testing program of tubular steel piles is a part of a bigger research program which contained static load tests in full scale and numerical simulations of conducted research. The main goal of the research is to compare static load tests with different working conditions of a shaft. The presented small scale model tests are the last part of the research. The paper contains the testing methodology description and first results of model pile axial loading. The static load tests in a small laboratory scale were conducted in a container filled with uniformly compacted medium sand (MSa). The first results of the investigation are presented in this paper, with the comparison of two pile capacities obtained for different roughness of the pile shaft (skin friction). The results are presented as load-displacement curves obtained by means of the Brinch-Hansen 80% method.
Interpretation of static pile loading test results and application for design of pile groups
2015
Recent major bridge projects in the Greater Vancouver Area showcase the experience of local geotechnical engineers. Large static pile loading tests have been carried out on a number of these projects including the Pitt River Bridge, Golden Ears Bridge and Port Mann Bridge projects. This paper briefly discusses different analytical approaches to load test interpretation and reviews the approach as applied to some classic and recent local case histories. Where applicable, the paper considers the influence of reaction piles on the initial stiffness of the test pile and explores the application of different methods of interpretation to published test data including some local projects. The paper summarizes the results of the analyses and provides recommendations for design.
A New Method for the Evaluation of the Ultimate Load of Piles by Tests not Carried to Failure
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