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Institute Geosynthetic - One of the best experts on this subject based on the ideXlab platform.
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Comparison between model and full scale Pile Capacity gain in the boston area
Geo-Frontiers 2005, 2005Co-Authors: Samuel G Paikowsky, L J Hart, Engineers Geo-institute Of The American Society Of Civil, Int Geosynthetic Mater. Assoc. Of The Industrial Fabri, Edward L. Hajduk, Institute GeosyntheticAbstract:Piles driven into low permeability soils gain Capacity over time. This Capacity gain, often called "set-up" or "freeze", is believed to be controlled by the mechanisms of effective stress increase due to the dissipation of excess pore pressures built up during driving and stress independent phenomena such as strength increase due to thixotropic bonding. Practical efforts have been recently made to quantify time dependent Pile Capacity and develop a methodology of incorporating it into Pile design by utilizing insitu testing. The following paper examines the use of the Multiple Deployment Model Pile (MDMP) and a full-scale instrumented pre-stressed concrete Pile to examine time dependent Pile Capacity gain in Boston Blue Clay. Normalized relationships were used to examine the overall and segmental Pile Capacity gain for both the MDMP and the full scale Pile and correlations are made to normalized excess pore pressure dissipation. The results of the MDMP and full scale instrumented Pile compare favorably with previously comPiled Pile Capacity gain and excess pore pressure measurements.
Samuel G Paikowsky - One of the best experts on this subject based on the ideXlab platform.
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Comparison between model and full scale Pile Capacity gain in the boston area
Geo-Frontiers 2005, 2005Co-Authors: Samuel G Paikowsky, L J Hart, Engineers Geo-institute Of The American Society Of Civil, Int Geosynthetic Mater. Assoc. Of The Industrial Fabri, Edward L. Hajduk, Institute GeosyntheticAbstract:Piles driven into low permeability soils gain Capacity over time. This Capacity gain, often called "set-up" or "freeze", is believed to be controlled by the mechanisms of effective stress increase due to the dissipation of excess pore pressures built up during driving and stress independent phenomena such as strength increase due to thixotropic bonding. Practical efforts have been recently made to quantify time dependent Pile Capacity and develop a methodology of incorporating it into Pile design by utilizing insitu testing. The following paper examines the use of the Multiple Deployment Model Pile (MDMP) and a full-scale instrumented pre-stressed concrete Pile to examine time dependent Pile Capacity gain in Boston Blue Clay. Normalized relationships were used to examine the overall and segmental Pile Capacity gain for both the MDMP and the full scale Pile and correlations are made to normalized excess pore pressure dissipation. The results of the MDMP and full scale instrumented Pile compare favorably with previously comPiled Pile Capacity gain and excess pore pressure measurements.
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Design and Construction of Three Instrumented Test Piles to Examine Time Dependent Pile Capacity Gain
Geotechnical Testing Journal, 2004Co-Authors: Samuel G Paikowsky, Edward L. HajdukAbstract:Three heavily instrumented test Piles were designed, constructed, and installed at a bridge reconstruction site in Newbury, Massachusetts as part of a research initiative into time dependent Pile Capacity gain. Pile instrumentation consisted primarily of an alternating pattern of piezometers and strain gages, allowing for correlation between Pile Capacity gain and excess pore pressure dissipation along discrete Pile segments. Additional instrumentation within the Piles included accelerometers, telltales, and radial pressure cells, allowing monitoring of total pressure at the Pile wall. Standard dynamic gages (strain gages and accelerometers) were also attached to the Piles during dynamic testing. A total of 86 vibrating wire, 17 electrical resistance, 17 telltales, and 4 piezo-resistive gages were installed within the test Piles to record strain, displacement, pressure, and acceleration. This paper describes (i) the initial installation location of the test Piles, (ii) the design and layout of the individual test Piles, (iii) the selection and installation design of the individual instrumentation within the test Piles, and (iv) assembly of the test Piles. Sample measurements of the various instruments and a summary of the instrumentation performance are also presented.
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EXTRAPOLATION OF Pile Capacity FROM NON-FAILED LOAD TESTS
1999Co-Authors: Samuel G Paikowsky, T A ToloskoAbstract:Static Pile load test to failure is the ultimate procedure available to examine the Capacity and integrity of deep foundations. Being expensive and time-consuming, the procedure is often substituted for the application of a load to a certain factor (most often two) times the contemplated design load. In fact, only a proof test is carried out while the ultimate Capacity and actual factor of safety remains unknown. This procedure results in an uneconomic foundation solution, unknown Capacity when modifications are required, and the inability of the engineer to gain insight into the controlling mechanism for improved design. The described state of the practice calls for the ability to reliably estimate the ultimate bearing Pile Capacity for non-failed load tests. A practical analytical method is proposed, capable of extrapolating the measured load-settlement relations beyond the maximum tested load. The proposed procedure, along with two other possible methods, is evaluated. The procedures are examined through a database of 63 driven Piles load-tested to failure. Loading is assumed to be known for only 25%, 33%, 50%, 75%, and 100% of the actual bearing Capacity (typically lower than the maximum applied load), and separately for 25%, 33%, 50%, 75%, and 100% of the entire load-settlement data points. The limited "known" data is then extrapolated using the different methods and the obtained bearing Capacity is compared to the actual measurements. For consistency, only one failure criterion (Davisson) is applied. The obtained results are analyzed statistically to evaluate the accuracy and reliability of the three methods. It is shown that the accuracy of the proposed method is 0.99 +/- 0.21 (1S.D.), 0.96 +/- 0.27, 0.87 +/- 0.30, and 0.78 +/- 0.33 when assuming 75%, 50%, 33%, and 25% of the data points to be known and 0.99 +/- 0.26 (1S.D.), 0.89 +/- 0.41, 0.74 +/- 0.46, and 0.64 +/- 0.44 when assuming 75%, 50%, 33%, and 25% of the bearing Capacity to be known, respectively. The obtained results for the 63 database cases suggest that even when the predicted ultimate Capacity is four times the maximum actual tested load, the associated risk is zero for exceeding the design load, when using the extrapolated value with a factor of safety of 2.0. All the case histories used in this research relate to driven Piles. Even though it is expected to be valid, a detailed examination of the method is required before its safe application to cast-in-place Piles. Case history analyses of six load-tested driven Piles at two sites are presented. The analyzed cases indicate possible substantial savings when the ultimate Capacity well exceeds the maximum applied load. Moreover, the method already demonstrates its enormous importance from aspects of engineering and economics.
Mohamed Harfoush - One of the best experts on this subject based on the ideXlab platform.
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Effect of Soil Improvement Techniques on Increasing the Lateral Resistance of Single Piles in Soft Clay (Numerical Investigation)
Geotechnical and Geological Engineering, 2020Co-Authors: Saeid Eltaweila, Marawan M. Shahien, Ahmed M. Nasr, Ahmed Farouk, Mohamed HarfoushAbstract:Soft clay soil extends in many areas all over the world. The construction on soft clay is one of the most important problems in engineering practice. When the design engineers face this problem, they always use deep foundations. In many cases, the vertical loads are satisfied but the lateral Capacity of the Piles is not satisfied. In this paper, a series of 3D finite element analysis was performed to investigate the effect of soil improvement techniques on increasing the lateral Pile Capacity. The 3D finite element results indicate that the improvement in the lateral Pile Capacity is strongly dependent on the combined effect of the lateral extent and the thickness of the improved zone around the Pile head. The analysis indicates that the lateral Pile Capacity increased to about 240% greater than the Capacity in native soft clay when a portion of soft clay is excavated and replaced with dense sand. In addition, the lateral Pile Capacity increased to a value greater than 600% when the soft clay is mixed with cement.
L J Hart - One of the best experts on this subject based on the ideXlab platform.
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Comparison between model and full scale Pile Capacity gain in the boston area
Geo-Frontiers 2005, 2005Co-Authors: Samuel G Paikowsky, L J Hart, Engineers Geo-institute Of The American Society Of Civil, Int Geosynthetic Mater. Assoc. Of The Industrial Fabri, Edward L. Hajduk, Institute GeosyntheticAbstract:Piles driven into low permeability soils gain Capacity over time. This Capacity gain, often called "set-up" or "freeze", is believed to be controlled by the mechanisms of effective stress increase due to the dissipation of excess pore pressures built up during driving and stress independent phenomena such as strength increase due to thixotropic bonding. Practical efforts have been recently made to quantify time dependent Pile Capacity and develop a methodology of incorporating it into Pile design by utilizing insitu testing. The following paper examines the use of the Multiple Deployment Model Pile (MDMP) and a full-scale instrumented pre-stressed concrete Pile to examine time dependent Pile Capacity gain in Boston Blue Clay. Normalized relationships were used to examine the overall and segmental Pile Capacity gain for both the MDMP and the full scale Pile and correlations are made to normalized excess pore pressure dissipation. The results of the MDMP and full scale instrumented Pile compare favorably with previously comPiled Pile Capacity gain and excess pore pressure measurements.
Int Geosynthetic Mater. Assoc. Of The Industrial Fabri - One of the best experts on this subject based on the ideXlab platform.
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Comparison between model and full scale Pile Capacity gain in the boston area
Geo-Frontiers 2005, 2005Co-Authors: Samuel G Paikowsky, L J Hart, Engineers Geo-institute Of The American Society Of Civil, Int Geosynthetic Mater. Assoc. Of The Industrial Fabri, Edward L. Hajduk, Institute GeosyntheticAbstract:Piles driven into low permeability soils gain Capacity over time. This Capacity gain, often called "set-up" or "freeze", is believed to be controlled by the mechanisms of effective stress increase due to the dissipation of excess pore pressures built up during driving and stress independent phenomena such as strength increase due to thixotropic bonding. Practical efforts have been recently made to quantify time dependent Pile Capacity and develop a methodology of incorporating it into Pile design by utilizing insitu testing. The following paper examines the use of the Multiple Deployment Model Pile (MDMP) and a full-scale instrumented pre-stressed concrete Pile to examine time dependent Pile Capacity gain in Boston Blue Clay. Normalized relationships were used to examine the overall and segmental Pile Capacity gain for both the MDMP and the full scale Pile and correlations are made to normalized excess pore pressure dissipation. The results of the MDMP and full scale instrumented Pile compare favorably with previously comPiled Pile Capacity gain and excess pore pressure measurements.