A Comparison Between Static and Dynamic Load Tests on Bored Piles

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.

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.

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.

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.

For over 30 years, cast-in-place concrete piles have been dynamically load tested in Germany. In the first 10 years (up to about 1995) this test method was only applied for special cases, and the involved parties were well aware of the differences between dynamic and static load tests. Since then, this method was more and more frequently executed as a low-cost static test, often merely to support the business of piling contractors—i.e., selling piles. Many tests were carried out with low-impact energy because the available drop weights had only up to 12 tons. Thus, the geotechnical and engineering aspects of the test method were more and more neglected. Some clients accepted what was delivered despite the fact that EC 7 defines a clear safety concept for dynamic pile load tests. Given this situation, one main public authority wanted to examine the proficiency of the German pile testers and prepared a series of controlled tests. As a consequence, recommendations of the German Geotechnical Society were revised, and an addendum was published. It is the intent of this paper to show that dynamic pile load tests are a reliable and valuable tool for axial bearing-capacity assessment for cast-in-place piles and will provide useful results if the tests are conducted by experienced engineers in accordance with the revised recommendations.

At present, subway platform doors have become the standard configuration of Chinese subways due to the advantages of energy saving, environmental protection, passenger safety, and improvement of the waiting environment. In order to solve the problem of insulation failure of traditional platform door thresholds, threshold manufacturers use composite materials with their own insulating properties to manufacture composite thresholds. Instead of the aluminium alloy and stainless steel structures commonly used in the industry, the composite threshold uses polymer composite as the basic carrier, and then covers the aluminium alloy panel on the surface of the basic carrier. The non-metallic material of the composite threshold has a unique advantage in insulation, but its mechanical properties still need to be verified by experiments. In view of the lack of test method for the compound threshold of subway platform doors, this paper formulates the method for the composite threshold of platform door based on the test method of escalator steps. PWS-20 electro-hydraulic servo cascade fatigue testing machine was used as the test equipment. The static load test and dynamic load test were carried out on the composite threshold samples respectively. When a force of 1000N is applied for the static load test, the maximum deflection value is 0.919mm. After 1 million cycles of dynamic load test with a non-interfering resonance force wave with a frequency of 5 Hz and a pulsating load between 50N and 1000N, no cracks were observed in the sample. For the composite threshold made of other materials, this test method can also be used to carry out static load test and dynamic load test.

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.

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.

Many studies have been conducted on energy dissipation walls for small houses to improve the earthquake resistance of structures in Japan. Oil dampers, a main damper, is installed in studs to increase their strength. However, this method tends to deform each member and joint—“support members”—owing to tensile force, and therefore, the energy absorption performance of the damper tends to decrease. In this study, we propose an energy-dissipation wall that increases the overall stiffness by prestressing the support members to prevent tensile deformation. From 2020 to 2021, two types of specimens using laminated veneer lumber (LVL) as supporting members—Type 1 and Type 2—were tested to understand the mechanical behavior of the wall. Both types were subjected to static loading tests. Additionally, dynamic loading tests were applied to Type 2. Moreover, the dynamic behavior of the one-story wooden structure installed on the Type 1 wall was investigated by subjecting it to artificial earthquake waves. In state R which the damper part of the energy dissipation wall is restrained the load-deformation relationships obtained from the static loading tests for the two types of specimens using LVL as support members showed almost linear behavior up to the assumed damper load level for both specimens. In the dynamic loading test on Type 2, a stable load-deformation history with almost no slip was obtained. In shaking table test on Type 1, it was found that the energy dissipation wall incorporated into the wooden structure absorbed the energy of the artificial earthquake shaking and prevented the deterioration of its bearing capacity.

High Strain Dynamic Pile Test (HSDT) is increasingly being used for pile load testing. HSDT offers a considerable savings of time, cost and requires very little space compared to the conventional static test. However, it is yet mandatory to compare HSDT tests with static load tests (SLT) to confirm the validity of HSDT as the results are generally site specific. This study presents comparison of static pile load test (SLT) vs HSDT and attempt is made to close the gap between theoretical and practical justification for replacing SLT with HSDT by identifying the problems while conducting and comparing both the tests. Also, a resourceful methodology is produced to conduct efficient comparison of SLT and HSDT which can be used at any site.

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.

The article presents the development of a SHM (Structural Health Monitoring) strategy intended to confirm the improvement of the load-bearing capacity of a bridge over the Ružín Dam using static and dynamic load tests, as well as numerical simulations. The paper comprises measurements of the global response of the bridge to prepare a verified and validated FEM (Finite Element Method) model. A complex measuring system used for the tests consisted of two main parts: an interferometric IBIS-S (Image by Interferometric Survey-Structures) radar and a multichannel vibration and strain data logger. Next, structure–vehicle interactions were modelled, and non-linear numerical dynamic analyses were performed. As a result, the time histories of displacements of the structure from traffic effects were obtained. Their comparison with IBIS-S radar records proves that this method can be effectively used for assessing bridges subjected to common traffic loads. The results (measured accelerations) obtained by local tests in external pre-stressed cables are presented and a convenient method for acquiring the axial force in the cables is proposed.

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.

The Swift Anchor, designed and built by SCHOTTEL Marine Technologies (SMT), was created for challenging geotechnical and metocean environments to anchor floating marine energy systems. The system was originally designed for tidal energy sites, where rock seabeds are common due to scour from high speed flows. Additionally, high yield tidal energy sites have small slack water windows and so rapid installation is imperative to minimise time on site. By relying on a mechanical interlock between the anchor and the surrounding rock, the groutless self-drilling Swift Anchor utilises the load bearing capacity of rock. Thus, the technology represents a cost-efficient anchoring solution not only for tidal energy devices, but also for further floating marine energy systems in the field of wave and floating wind energy. In order to verify the Swift Anchor design, including installation efficiency and load bearing capacity, the anchors have undergone rigorous testing: onshore testing in quarry trials, and offshore in device applications. Most recently SMT have conducted a series of land trials in Dörth, Germany, to test the load holding limits, determined through numerical analyses. The anchor was designed to withstand the loads from a specific tidal energy device at a highly energetic tidal site, and so this defined the anchor sizing and minimum break load (MBL). Due to the variable water depth, flow speed, and load applied to the mooring lines (due to drag, thrust and wave loading) the anchor must operate within a wide range of load angles and limits. As the anchor is expanded into other markets, such as offshore wind and aquaculture, these regimes are further expanded. SMT have developed a novel test methodology including: static load testing, to prove the anchor’s specified load holding capacity; dynamic (or cyclic) load testing, to demonstrate fatigue loading; and test-to-failure to find the principal failure mechanism at the given site conditions. A unique test rig was designed and built which allows a test anchor to be installed in conjunction with another reaction anchor (so that loads are resisted between each anchor to reduce additional test equipment), and any load angle from 0 to 90° can be achieved for vertical, lateral, and inclined testing. The load holding envelope of the anchor can then be tested, as defined by given site conditions. This paper presents the details of the Swift Anchor, the test methodology, the test rig, and the geotechnical conditions of the test site. The initial load testing results will be presented to demonstrate that the novel test methodology and test rig represent a rigorous and efficient setup to de-risk critical infrastructure of floating marine energy systems