Dynamic pile testing in the Baltic Countries

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.

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.

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.

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.

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.

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.

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.

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.

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.

Field inspectors often observe a dramatic increase in penetration resistance between initial driving and restrikes of driven piles, a result of additional static "setup" capacity. Designers often ignore setup when specifying pile lengths and blow count acceptance criteria, and pile capacity design methods, calibrated against static load tests, already incorporate some setup that occurs during the test preparation delay. Research indicates that setup results mostly from an increase in side shear and occurs in all soil types as a result of combined pore pressure dissipation, consolidation, and mechanical aging effects. Repeated static tests provide a reliable measurement of setup, but also delay construction. Penetration resistance (set per blow) does not reliably measure setup during isolated restrikes as it varies per blow due to inconsistent driving system performance and changing pile capacity. Instrumented dynamic tests, using strain gages and accelerometers, provide an "easy button" to verify hammer energy and pile capacity during all phases of installation. This paper reviews pile setup, its causes, and related properties. It presents a simple method, with examples, to measure and analyze setup from dynamic test results. An engineer may use these results to reduce the length, size, or number of production piles, and adjust the required set per blow. Caveats include staged testing effects and consideration of the setup contribution from different soil strata.

The noble crayfish, Astacus astacus, is the only native species in the Baltic and Nordic countries. Crayfish plague struck the native stocks in the various countries under consideration during the period 1890–1971 and reduced crayfish abundance and distribution. Later, man made pollution and habitat changes have also reduced both crayfish production and the potential for crayfish production. Many of the remaining stocks of noble crayfish in Norway, Sweden, and Finland result from stocking into new areas during this century. To substitute the loss of the noble crayfish, the crayfish plague resistant, North American, signal crayfish, Pacifastacus leniusculus, was introduced into Sweden in 1960. Later the signal crayfish was introduced into Finland, Latvia, Lithuania, and Denmark. The narrow-clawed crayfish, Astacus leptodactylus, has expanded, due to a combination of stocking and further natural dispersion, from its former area of distribution in southeastern Europe, and is now found in Lithuania, Latvia, Finland, and Denmark. The North American, introduced, spiny-cheek crayfish, Orconectes limosus, has expanded widely from the first introduction in the Oder River in Germany and it has recently invaded Lithuanian rivers and lakes. At present, Norway and Estonia are the only countries without introduced crayfish. The interest for conservation of the noble crayfish has increased in all Nordic and Baltic countries and measures are planned and partly implemented to improve protection of remaining stocks and restore former crayfish localities. The expansion of the introduced North American crayfish species do, however, represent a threat since they both out-compete the noble crayfish and are carriers of the crayfish plague fungus. Also the expansion of the more competitive European narrow-clawed crayfish represent a threat to the native crayfish. Present catch of noble crayfish from the wild, in the Baltic and Nordic countries, is less than 200 tons, compared to historic records of more than 2000 tons.

In this paper, a static load test and a multiparameter statistical analysis method are used to study the value of pile side friction in different soil layers in a loess region. Currently, static load testing is the most commonly used method to determine the bearing capacity of pile foundation. During the test, a vertical load is applied at the top of the pile, the data under each load level are recorded, and a Q‐S curve is drawn to obtain the ultimate bearing capacity of a single pile. Reinforcement stress gauges are installed at different sections of the pile body, and then the axial force and the pile side friction of each section are calculated. Few studies have investigated the calculation of pile side friction in different soil layers using the multiparameter statistical analysis method. Obtaining accurate results using this method will provide an important supplement to the calculation of pile side friction and will also be conducive to the development of theoretical calculation of pile side friction. Therefore, taking Wuding Expressway project in loess region as an example, the lateral friction resistance of six test piles is studied through static load testing and multiparameter statistical analysis. The multiparameter statistical analysis method is compared with the static load test results, and the error is controlled within 20%. The results show that the calculation results of multiparameter statistical analysis essentially fulfill engineering requirements.

Field tests were conducted to study set-up effects in long driven piles founded in completely decomposed granite (CDG). Two steel H-piles 56 m and 58 m in embedment depth were fully instrumented with vibrating-wire strain gauges and installed. Several restrike dynamic tests were carried out on each test pile from 1 day and up to 95 days after the end of initial driving. Static load testing was later carried out to substantiate the dynamic tests. The test programme is described in detail. Changes with time in pile capacity and in the shaft and toe resistances were studied based on the results of the pile tests. The development of the shaft resistance set-up with depth and time was studied in particular. It was found that setup took place in the shaft resistance and relaxation in the toe resistance. The overall set-up was found to be at the lower bound of the values found with concrete piles. More significant set-up in shaft resistance was observed in the shallower fill and alluvium layers. The dimensionless set-up factor A for shaft resistance in CDG ranged from 0·53 to 1·06, and the set-up factor decreased with depth and with increasing blow count in the standard penetration test.

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.

Six cases are presented showing the benefit of dynamic testing and analysis of driven piles, comprising (1) a comparison between two types of piles and a correlation between CAPWAP determined capacity and load-movement response to that determined in a static loading test, (2) the benefit of time-dependent increase of pile capacity, (3) a study how a soil plug can be shown to replace a pile shoe, (4 & 5) the effect on pile capacity from removing soil inside the pile, (6) set-up and effect of excavation. Together the cases show that the dynamic testing can be used to investigate problems in design and construction of piles much beyond a simple capacity determination.