Analytical and Practical Comparison of Various Test on Pile

The Port Mann Bridge on Highway 1 in Metro Vancouver links the cities of Surrey and Coquitlam in British Columbia, Canada. A new 10-lane 2.02 km long cable-stayed bridge is being constructed over the Fraser River to replace the existing 5-lane bridge. Twelve of the twenty-five bridge piers will be supported on driven steel pipe piles. As part of the foundation design approach, a full-scale instrumented static pile load test was performed along with dynamic pile testing. The test and reaction piles consist of 75 m long, 1,830 mm diameter by 25 mm thick, open-ended steel pipe piles driven into glacially overridden soil using an APE D-180-42 diesel hammer. A custom-built static load frame and hydraulic jacking system provided incremental compressive loads up to 53 MN on the test pile. Following the compression test, an uplift test to 29 MN was performed. The pile was restruck with a Menck MHU 500T hydraulic hammer 9 days after the uplift test. Evaluation of the pile resistance distribution included impacts of residual load and pile plugging. Pile performance during the static load test indicated that approximately 36 MN was carried in side resistance and approximately 17 MN was provided in base resistance. The static pile load test and dynamic testing of selected production piles enabled the use of increased resistance factors for final design, thereby reducing the number of piles to 255, a reduction of approximately 30 percent.

This paper employs a simplified analytical method to investigate the influence of reaction piles on the load–displacement behaviour of a test pile in static load testing. A parametric study is conducted to examine the effects of factors such as pile spacing ratio, pile slenderness ratio, and pile soil stiffness ratio. Several soil profiles are considered in the study. The parametric study also includes the cases of static load testing in the lateral direction. The correction factors for the initial pile head stiffness obtained from static pile load tests with the use of reaction piles are given in charts. Furthermore, analyses of centrifuge modelling of axially loaded piles are carried out using the simplified analytical method. Good agreements between the test results and the analysis results are demonstrated, and the applicability of the correction factors is verified.Key words: reaction piles, interaction, initial pile head stiffness, static vertical load testing, static lateral load testing, simplified analytical method.

Pilesr are both statically and dynami cally tried to acquire the limit and to check outline. The two sorts will give comes about that may differ in light of the technique utilized as a part of leading the test. It is thusly, important to think about the aftereffects of a static load test with dynamic load test. Numerous comparison studies are directed around the world, yet the vast majority of them are for displacement driven pile. In this way, the consequences of the test are looked at for substitution-exhausted piles. The piles are tested statically before dynamic test. The test results show that a not too bad comprehension was expert between both the tests with in addition to less 7mm at design load regarding settlement. Moderately, the settlement foreseen in powerful load test is littler diverged from static load test. Regarding absolute bearing limit, Davisson's technique gives the insignificant outrageous load regard diverged from various strategies. The Davisson's strategy is utilized to analyze the outcomes since it is more moderate. The examination shows that the piles are inside 15% in regard as far as possible traversed Davisson's strategy. Since the static test was coordinated before unique test, the limit got from dynamic test is higher because of the pile experienced flexible pressure amid static load test and furthermore because of soil setup.

Estimation of bearing capacity and settlement plays an essential role in designing pile foundations of buildings. This paper presents the results of pile static and dynamic loading tests taken place in the construction sites of Caspian Sea Port Prorva and Tengiz. The static loading tests (SLT) and static compression loading tests (SCLT) were carried out according to the Kazakhstan GOST and ASTM standards correspondingly. The dynamic loading tests (DLT) were performed by GOST, as well as by pile dynamic analyzer (PDA) in accordance with ASTM standards. According to the results of DLT of driven joint piles (with a cross-section of 40×40 cm, lengths of 25 m and 27 m) performed by PDA, the bearing capacity of the piles was 2143 kN. In the construction site of Prorva, the bearing capacities of driven joint piles according to the results of SCLT were2067 kN and 2042 kN. In the construction site of Tengiz, the bearing capacities of driven piles tested by SLT were 1000 kN and 1605kN. These investigations are important for the understanding of soil-structure interaction, especially of driven piles with a cross-section of 40x40 cm and lengths of 12 and 16m in construction site Tengiz.

The Chin's plot method is the most widely used method in Singapore to assess the ultimate skin friction and ending bearing separately based on static pile load test results. In this study, a large number of pile load tests for driven piles were back analyzed using the Chin's plot method. The obtained data were examined in order to evaluate the appropriate design ranges for skin friction coefficient, Ks and end bearing coefficient Kb, which are the two key parameters for pile capacity estimation in design. It was revealed that, generally, the currently adopted design ranges were over-conservative for displacement piles. New design ranges and limits for Ks, Kb and unit end bearing, qb, were suggested, and their typical values for conventional designs were recommended. Further, the importance of pile load test in the design of piling foundation was emphasized. Whenever practicable the ultimate pile bearing capacity should be obtained from pile load tests, and all indirect estimations of pile capacity should be evaluated against the static load test 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.

This research compares theoretical methods with static pile load test results to identify the most effective approaches for determining pile capacity across various soil and pile types, while also proposing modifications to the Bangladesh National Building Code (BNBC) 2020 guidelines. The study involved broad data collection from pile load test reports and subsoil investigations across six projects, focusing precast and cast-in-situ piles. Theoretical analyses were performed using i) bearing capacity equations as per BNBC 2020 (α-method and β-method), ii) Standard Penetration Test (SPT)-based BNBC 2020 method, and iii) SPT-based other methods from literature including Meyerhof, and Shioi Fukui equations. Following ASTM D1143 guidelines, eight evaluation methods were used to interpret load-settlement data from static load test. Statistical analyses involving Mean Absolute Percentage Error (MAPE), Bias Factor (λ), and Coefficient of Variation (COV) were conducted to evaluate predictive accuracy. Findings indicate that for clay soil, the SPT-based equations of Shioi & Fukui for skin friction and Meyerhof for end bearing can be considered as suitable alternatives for future BNBC revisions, showing lower variation with actual capacity. For sandy, silty, and layered soil devoid of clay, the SPT-based equations from BNBC 2020 are deemed appropriate.

This paper deals with the prediction of shaft resistance of single driven pile based on Meyerhoff formulation and empirical method based on SPT test. The accuracy of these predictions was evaluated by comparing the results with static load test (SLT) and dynamic loading test analyzed by Pile Driving Analyzer (PDA) and Case Pile Wave Analysis Program (CAPWAP) programs. The data for this study was collected from University Riau Hospital Project in Pekanbaru. The result of static and dynamic pile load test shows that only a small capacity of end resistance was mobilized due to insufficient pile deformation.

An instrumented test pile was installed at the Bayou Zourie bridge reconstruction site as part of a Louisiana Department of Transportation and Development (LADOTD) research initiative to study the setup phenomenon of piles driven in Louisiana soils. Pile instrumentation included pressure cells to measure the total pressure at the pile face, piezometers to monitor the excess pore water pressure at the pile face, and “sister bar” strain gauges to measure the strain distribution along the pile. Additional instrumentation consisted of multilevel piezometers installed within soils at different locations/depths from the pile and accelerometers attached to the piles during dynamic load testing. A total of two static load tests and four dynamic load tests were conducted on the test pile. During the static load tests, the strains within the pile were measured by the strain gauges, which were used to calculate the distribution of load transfer along the pile. Both static and dynamic load tests demonstrated the increase in pile resistance with time (setup). Results of dynamic load tests confirmed that pile setup occurs at a logarithmic rate after the end of driving (EOD) and is mainly attributed to the increase in side resistance. Good correlation was observed in this study between the pile setup and the percentage of dissipated excess pore water pressure with time. The measured excess pore water pressure suggested that the surrounding soil, along the pile (within distance 2B), is significantly influenced during pile driving. Results indicated that the changes in side resistance are directly related to the changes in the horizontal effective stress acting on the pile face.

People have used pile foundations throughout history to support structures by transferring loads to deeper and stronger soil layers. One of the most important questions during the design of the pile foundation is the bearing capacity of the pile. The most reliable method for determining the bearing capacity is to use results from pile load tests. Traditionally, the static pile load tests have been used and more recent the dynamic tests. The rapid load test, at intermediate loading rates, was invented to overcome the disadvantages of the static tests (expensive and time-consuming) and the dynamic tests (the stress wave effects) and is conducted more and more in practice.

Static and dynamic tests were conducted at the time of driving on each of two instrumented piles driven into cohesive soils to embedded depths of 64 and 74 feet. The tests were repeated 11 days later in order to investigate the response of the reconsolidated soil. The purpose of this study was to investigate the time dependent force displacement response of cohesive soils induced by dynamic pile loads and to compare dynamic response with static response. All past attempts to achieve such comparisons were based either upon an assumed dynamic soil model and/or a simulated applied dynamic force estimated from the weight and speed of the driving hammer. In order to eliminate such assumptions in this study, the induced dynamic force was measured at five strategic locations along each instrumented pile. An accelerometer was used to record the motion at the head of the pile. This motion, together with the induced forces, were utilized in a multi degree spring-mass, system to directly compute the displacements of the masses representing various pile segments. The result of this analysis showed that when the applied loads were maximum, each pile experienced What may be described as rigid body motion. Consequently, a rigid pile model was utilized in a single-degree of freedom system to compute the dynamic soil resistance. Since both the dynamic soil resistance and the pile motions were known, a rigorous, or closed form solution of the equation of motion leads to a direct computation of the static component of soil resistance. This static component was found to approximate the static ultimate bearing capacity when the pile had experienced significant relative motion with respect to the soil. Introduction The bearing capacity of piles supporting Offshore structures is often determined by the so called static method. It is noteworthy that this method relies on correlations between soil shear strength, as determined from laboratory or in situ tests, to skin friction along the pile shaft and to end bearing below the pile point. Such relations have been reported by Terzaghi and Peck (15). Skempton (13), Tomlinson (16), Peck (9). Woodard et al. (18). and by Coyle and Reese (2). All of these studies undoubtedly advanced the state of the art. but uncertainties still remain. The overriding cause for uncertainty in the static method is that pile driving changes the shear strength of the clay, and it is difficult to estimate the strength of the clay after driving. In contrast to land piles, it is difficult to verify the design of offshore piles by static load tests, due to prohibitive costs and to high design loads that are difficult to attain. An alternate approach to the static field load test would consist of utilizing the resistance of the pile during driving as a dynamic field test to compute the static ultimate bearing capacity. The dynamic test may be conducted at any time after driving, and may therefore include some of the effects of soil reconsolidation and setup. However, dynamic test methods are not problem free for several reasons. First, the forcing function induced between hammer and pile is difficult to evaluate theoretically. Second, the relation between static and dynamic resistance is usually empirically defined by use of a damping coefficient which is held constant throughout the duration of impact. Even though this is an accepted procedure in the analysis of 1ineari1y elastic solids, it may not be sufficient for ultimate bearing capacity determinations in clay, because the material properties are vastly different.

A full-scale static compression pile load test was conducted in connection with construction of a new road bridge in Silkeborg, Denmark. The new road bridge crosses a river between two existing bridges, one for pedestrians and one for an existing rail way. An existing pedestrian bridge was moved five meters to the north to give space for the new road bridge. The western part of the existing bridge was therefore to be founded partly on the existing footing of the pedestrian bridge and partly on a new pile-based footing. Bored cast-in-place piles were chosen to minimize vibrations during construction. The pile load test was necessary to document the bearing capacity of the bored piles because the Danish National Annex to the Eurocode 7, part 1 (2015), Annex L (DS/EN 1997-1 DK:NA) obligates the designer only to regard 30 % of the shaft resistance determined by geostatic calculation for the corresponding driven pile. Furthermore, it is a common design practise to disregard the toe resistance, as mobilization only occurs after deformations larger than normally acceptable for the superstructure. To overcome the latter, the test pile was constructed with a flat-jack device to allow post installation prestressing by grouting underneath the pile toe. Hence, it was possible to include toe resistance with only minimal displacements of the pile toe, as the grouting was conducted successfully, and post installation pre-stressing was obtained. The results of the pile load test show a bearing capacity up to 50% larger than estimated by geostatic calculation, even when including toe resistance and disregarding the 70 % shaft reduction in the geostatic calculation for the corresponding driven pile. An estimate of the displacement of the new pile-based footing was made based on load-displacement curves for the test pile, and the subsequent production piles were installed using the same principles due to the flat-jack device’s effective post installation pre-stressing.

The statnamic load test (STN) has gained popularity as an alternative pile load testing method in Southeast Asia compared with the conventional static load test (SLT). Owing to the local geological conditions and regulation requirements, drilled shafts in Malaysia and Singapore are basically designed to pass through a layer of soft soil at the upper part of the pile and then socketed into the stiff residual soil/old alluvium/weathered rock. Thus, these piles mobilize relatively higher skin friction near the bottom of the pile with a strong end-bearing component. The rate effect of friction piles under rapid loading that is usually exhibited in stiff clay is found to be insignificant, which allows the unloading point method to work reasonably well to derive the static-equivalent capacity of the pile. Furthermore, the test load usually is still much lower than the real ultimate capacity. Thus, the load-settlement response obtained from the STN is basically identical to the SLT response without any further correlation. To date, there are limited case references on correlation work for these kind of piles. Therefore, we performed a comparison study to evaluate the SLT and STN on two instrumented piles that were installed within a similar soil profile but different in working load, diameter, and length. In this comparison study, the load-settlement behavior and load-transfer curve were evaluated. The correlation between the two tests was found to be excellent in terms of specific settlement values at a specific load, normalized load-settlement response, and normalized load-transfer curve. The normalized load-settlement and normalized load-transfer curve were found to be consistent between the SLT and STN. Hence, it could be concluded that the STN provided a good alternative for a conventional SLT, at least for this category of drilled shafts.

The purpose of this paper is to present the results of a study which involves the prediction of the static bearing capacity of a pile from a wave equation analysis of piling behavior. Recently developed soil parameters including point damping, friction damping and quake are used in the computer solutions of the wave equation analysis. Also, the wave equation program is modified so that velocity may be raised to a power less than 1 in order to insure constant damping effects. Curves of total static soil resistance at the time of driving vs pile penetration resistance in blows per foot are developed. Different curves are generated for different distributions of total soil resistance between the side of the pile and the tip and for varied soil parameters. These curves are compared with similar curves developed using E. A. L. Smith's recommended soil parameters. Using the computed curves and the knowledge of pile penetration resistance during the last foot of driving, the static bearing capacity of the pile is predicted. These values of pile capacity are compared to actual values determined full-scale static load tests made in the field. INTRODUCTION In 1960, Smith7 presented a mathematical model to simulate pile-soil interaction. At the same time he proposed a numerical method for analysis of piling behavior based upon the one-dimensional wave equation. Smith' s model idealized the pile as a series of masses and springs as shown in Fig. 1. The load deformation characteristics of the soil as shown in Fig. 2 are described the parameters Ru, Q, J, J1 and V, where (available in full paper) The total soil resistance mobilized during dynamic loading was given by Smith as: (available in full paper) Research personnel at Texas A&M later modified Smith's original equation so that the velocity term is raised to a power [N]. 3,4,6 Eq. 1 is rewritten as: (available in full paper) When Smith's paper was presented in 1960, factual information concerning the magnitudes of the damping constants and J1 were virtually unavailable smith recommended parameters of 0.15 and 0.05 for J and J1, respectively. He also recommended a value of 0.10 for the parameter Q. Smith based his recommendations mainly on the strength of his own field experience with the piling behavior problem. Recent research conducted at Texas A&M has resulted in What is believed to be more representative values for the parameters Q, J1 and J.3,4,6 The values obtained are presented in Table 1. There values are based mainly on the work of Korb,4 which involved small-scale dynamic and static pile loading tests in a variety of soils. Parameter Study Using Field Test Data The computer program for solving the one-dimensional wave equation is used to generate a curve relating total static soil resistance at the time of driving to the driving resistance expressed in blows per foot.

Before year 2000 the dynamic testing in Baltic Countries was very unusual. The most common way to determine pile capacity was by means of static load test. Static load tests are still very common but also dynamic tests have become general. This differs a bit from the Nordic Countries, for example in Finland the static load tests are very uncommon and the pile capacity with is almost always determined with dynamic test. The main reason for this is the differences in soil conditions.The use of friction piles in the Baltic Countries is more common because the hard soil layer is quite deep and it has been a common practice to test these friction piles with static load test.