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1
Salem, Tarek, Atef Eraky i Abdalla Elmesallamy. "Locating and Quantifying Necking in Piles Through Numerical Simulation of PIT". Frattura ed Integrità Strutturale 16, nr 61 (19.06.2022): 461–72. http://dx.doi.org/10.3221/igf-esis.61.30.
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Defects of concrete piles can occur at any point during the construction of piles. Most common types of pile integrity issues are; presence of voids, inconsistency in concrete mix, entrapped groundwater or slurry, and geometric dislocation. These defects can be categorized based on the place in the construction sequence at which the defect occurs. This research introduces several numerical models of defected piles with various scenarios in order to identify, locate, and quantify the necking occurring in these piles. The finite element software (ADINA) is used to simulate the studied models. The soil domain is modeled as an axisymmetric space around the concrete pile. Five diameters of piles (40, 60, 80, 100 and 120 cm) are studied. Necking is modeled at three different locations along the pile namely; upper, middle, and bottom third. Four ratios between the necking diameter and pile diameter are also studied. The dynamic force used in this research is that simulating the pile integrity test (PIT) case, with 2.5 N impact load applied at the pile head, half wave of sinusoidal pattern, and 0.5 kilo hertz frequency. The time domain of the dynamic force analysis is equal to 0.0175 sec, and applied in 450 steps.
2
Fellenius, Bengt H. "Observations and analysis of wide piled foundations". Canadian Geotechnical Journal 56, nr 3 (marzec 2019): 378–97. http://dx.doi.org/10.1139/cgj-2018-0031.
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Available case histories on observations on full-scale piled rafts show that the settlement response to applied load can be modeled as that for an Equivalent Pier due to compression of the piles and the soil matrix plus that of an Equivalent Raft for compression of soil layers below the pile toe level. Interior piles engage the soil from the pile toe level upward in contrast to a single pile, which engages it from the ground downward. Piles and soil, combined as a pier, have strain compatibility, which determines the distribution of load between the piles, the contact stress, and the load-transfer movement of the piles. The responses between the interior and perimeter piles differ. Particularly so in non-subsiding and subsiding environment, because perimeter piles can be subjected to downdrag and drag forces, while neither downdrag nor drag force will affect the interior piles. In non-subsiding environment, it is advantageous to make perimeter piles shorter, while in subsiding environment perimeter piles best be longer. The load distribution across the raft is also governed by the degree of rigidity of the raft and by the difference in dishing at the pile toe level and in the dishing of the actual raft.
3
Manandhar, Suman, Noriyuki Yasufuku, Kiyoshi Omine i Taizo Kobayashi. "Response of tapered piles in cohesionless soil based on model tests". Journal of Nepal Geological Society 40 (1.12.2010): 85–92. http://dx.doi.org/10.3126/jngs.v40i0.23613.
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This paper describes model tests of different types of tapered piles in cohesionless soils. Chromium plated three steel piles, one straight and two taper-shaped piles of same length and pile tip diameters have been executed for pile loading test in a downward frictional mode. Two different types of model grounds have been prepared for the test. Relative densities of 80 % and 60 % have been modeled to penetrate piles in two different types of sands to observe the effectiveness of skin frictions of different types of piles. The response of tapered piles has shown that the skin friction has increased with increasing the tapering angle at normalized settlement ratio of 0.4. High density ground yields higher skin friction when the maximum tapered pile was penetrated. Slightly increased tapering angle of the pile affects remarkably on the skin friction with compared to conventional straight cylindrical pile even at small 0.1 settlement ratios.
4
Huang, Jie, Jie Han i James G. Collin. "Geogrid-Reinforced Pile-Supported Railway Embankments". Transportation Research Record: Journal of the Transportation Research Board 1936, nr 1 (styczeń 2005): 221–29. http://dx.doi.org/10.1177/0361198105193600125.
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Piles or columns have been used successfully in combination with geosynthetics to support embankments over soft soil. The inclusion of geosynthetic reinforcement over piles enhances load transfer from soil to piles, reduces total and differential settlements, and increases slope stability. It creates a more economical alternative than that without the geosynthetic. An existing geosynthetic-reinforced pile-supported embankment in Berlin was selected for numerical modeling and analysis. This embankment was constructed to support railways over deep deposits of peat and soft organic soils. Precast piles and caps were installed with a load transfer platform formed by three layers of geogrid and granular materials installed between the piles and the embankment fill. Instrumentation was installed to monitor the settlements of the embankment and the strains in the geogrid layers over time. A finite difference method, incorporated in the fast Lagrangian analysis of continua three-dimensional software, was used to model this embankment. In the numerical analysis, piles were modeled with pile elements, and caps were modeled as an elastic material. Geogrid elements built in the software were used to represent the geogrid reinforcement. Embankment fill, soft soil, firm soil, and platform fill material were modeled as linearly elastic perfectly plastic materials with Mohr–Coulomb failure criteria. The embankment was built by a number of lifts to simulate its construction. Numerical results and comparisons with field measurements on the vertical and lateral displacements, the tension along the reinforcement, and the axial forces and moments on piles are presented.
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Shawky, Omar, Ayman I. Altahrany i Mahmoud Elmeligy. "Study of Lateral Load Influence on Behaviour of Negative Skin Friction on Circular and Square Piles". Civil Engineering Journal 8, nr 10 (1.10.2022): 2125–53. http://dx.doi.org/10.28991/cej-2022-08-10-08.
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Negative skin friction developed on the pile surface causes many problems when piles are built in fully saturated clay. In this work, a study of NSF on a square cross-section pile corresponding to the circular pile circumference was developed. The pile was modeled as a concrete element, embedded and fully contacted with fully saturated soft clay. The clay layer is supported on a sand layer as a sub-base using ABAQUS software, and the NSF was developed on piles due to the consolidation of the clay over a 5-year period. A square pile has been found to provide lower NSF values than a round pile. Then, for the first investigation, both piles were loaded with lateral loads at the top to investigate the effect of the horizontal load on the NSF values, as there is no literature or study done on this point. The results emphasized that lateral loads reduce the NSF developed on piles. A parametric study was performed to investigate the parameters affecting the NSF values induced on piles, such as soil permeability, ballast, and lateral load values. It was concluded that square piles provide better NSF values than round piles for both single piles and pile groups. Doi: 10.28991/CEJ-2022-08-10-08 Full Text: PDF
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Freitas, Alessandra C., Bernadete R. Danziger i Marcus P. Pacheco. "A Case of 3-D Small Pile Group Modeling in Stiff Clay Under Vertical Loading". Soils and Rocks 38, nr 1 (1.01.2015): 67–79. http://dx.doi.org/10.28927/sr.381067.
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The behavior of experimental pile groups is simulated by 3-D finite element modeling in this paper. The modeled results are compared to small-scale tests in a row of three closely spaced piles in the London clay. The tests aimed at investigating soil-pile-cap interaction and pile-group effect. It is shown that 3-D FE modeling can be regarded as an appropriate tool to predict settlements and load-transfer mechanisms in pile groups under working conditions, with a satisfactory match between simulated and measured results.
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YESILCE, YUSUF, i HIKMET H. CATAL. "FREE VIBRATION OF SEMI-RIGIDLY CONNECTED PILES EMBEDDED IN SOILS WITH DIFFERENT SUBGRADES". International Journal of Structural Stability and Dynamics 08, nr 02 (czerwiec 2008): 299–320. http://dx.doi.org/10.1142/s0219455408002661.
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This paper is concerned with the free vibration analysis of Timoshenko piles partially embedded in elastic soil, semi-rigidly connected at the upper end, and subjected to an axial force. The pile is divided into three regions: the pile portion above the soil constitutes the first region, while the second and third regions are the pile portion that is embedded in two different layers of the soil type. The pile material is assumed to be linearly elastic and the axial force is constant along the pile length. The soil is idealized by the Winkler model and the semi-rigid connection of the pile is modeled by a rotational spring. The natural frequencies of the piles are calculated from the transfer matrix for different axial forces, rotational spring constants, subgrade reaction moduli and embedded lengths of the pile. The results indicate that the natural frequency of the pile decreases as the axial force increases. Further, the increase in the stiffness of the rotational spring at the upper end of the pile causes only a small increase in the natural frequency. Finally, both the pile length and the subgrade reaction of the soil influence significantly the natural frequency of the pile.
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Xiong, Hui, Shou Ping Shang i Liang Huang. "Simplified Dynamic Finite-Element Analysis for Three-Dimensional Pile-Grouped-Raft-High-Rise Buildings". Key Engineering Materials 400-402 (październik 2008): 613–19. http://dx.doi.org/10.4028/www.scientific.net/kem.400-402.613.
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Combined with the respective advantages in S-R(Sway-Rocking) impedance concept and finite-element method, a simplified 3D structural dynamic FEM considering composite pile-group-soil effects is presented. The structural members including piles are modeled by spacial beam or shell elements, and raft-base is divided into thick-shell elements with its spring-dashpot boundary coefficient obtained by impedance backcalculated. The mass-spring elements for soil between piles are set to simulate vertical, horizontal pile-group effects by strata-equivalent approach. The soil beside composite body is separated into near-field and far-field parts. The former is modeled by nonlinear spring-dashpot elements based on Winkler’s hypothesis, while the latter is modeled by a series of linear mass-spring-dashpots. With the effects of boundary track forces and energy radiation, the presented model enables researchers to conduct the time-domain nonlinear analysis in a relatively simple manner which avoids sophisticated boundary method and solid-element mesh bringing with tremendous computational cost. The seismic effect on dynamic interaction of pile-soil-complicated structures would be efficiently annotated from two structural engineering and geotechnical engineering aspects and the numerical calculation effort would be drastically decreased too. The complete procedure is mainly performed using the parametric design language assembled in the Finite Element Code Ansys. With the dynamic analysis of foundation and superstructure for a pile-supported 15-storey building, the influence of the participant effect on structural dynamic response will be depicted by various dynamic parameters of pile-soil-raft foundation in detail. Not only do the results have an agreement with some conclusions drawn by the general interaction theory, but also certain of phenomena which would be disagree with that by general analysis is involved. Even with the finite-element meshes for 68 piles, the time-history analysis procedure for PGSS (Pile-Group-Soil-Superstructure) system and the qualitative evaluation with various SSI parameters can be also fulfilled efficiently and rapidly by presented means. These results may be of help to the designers to quickly assess the significance of interaction effect for the high-rise buildings resting on any type or layout of pile-group foundation.
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Tran, Khiem T., Scott J. Wasman, Michael McVay i Rodrigo Herrera. "Capacity evaluation of voided driven piles using embedded data collectors". Canadian Geotechnical Journal 54, nr 10 (październik 2017): 1397–407. http://dx.doi.org/10.1139/cgj-2017-0008.
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This paper presents an application of a method that will be implemented in the embedded data collector (EDC) system in the near future, to estimate the capacity of driven piles with a combined solid and voided cross section. Data from accelerometers and strain gauges located in the solid sections at both the top and the bottom of a pile are used to independently estimate the pile’s skin friction and tip resistance. Wave propagation along the pile is modeled as a one-dimensional wave equation, with a nonuniform cross section and with nonlinear static skin friction and viscous-damping soil resistances acting along multiple segments of the pile. The static skin friction is extracted by least-squares fitting of computed particle velocities with measured data at both the top and the bottom of the pile. The pile tip is modeled as a nonlinear single degree of freedom with viscous damping. Static tip resistance (nonlinear stiffness–displacement relationship) is extracted by least-squares fitting of the predicted total force and energy with the measured tip data. The new EDC method was applied to four combined solid–voided cross section driven piles with capacities varying from 2800 to 6700 kN. The results of the data evaluated with the new EDC method are consistent with those from the static load tests to within 15%.
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Jogiadinata, Evelyn, Paulus Pramono Rahardjo i Aswin Lim. "Three Dimensional Analysis of Pile-raft Foundations on Clay, Menteng-Jakarta". MEDIA KOMUNIKASI TEKNIK SIPIL 27, nr 1 (20.08.2021): 107–17. http://dx.doi.org/10.14710/mkts.v27i1.27923.
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Piled-raft foundation is a combination of pile foundation and raft foundation. Bearing capacity of piled-raft foundation yielded from contribution of both pile capacity and raft capacity. Most of the time, design of pile foundation is assumed that all load is solely carried by pile and the capacity of raft is ignored. In this study, three-dimensional finite element analysis was applied to analyze the load percentage that can be carried by raft. A case study, which is located in Central Jakarta, Indonesia, was modeled to investigate this issue. This project was instrumented with two pressure cells where the data were used to verified the model and the load distribution. The analysis results showed good agreement with the measurement data, where the load carried by the raft is around 33-42%.
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Pashayan, Mojtaba, i Gholam Moradi. "Experimental Investigation on Efficiency Factor of Pile Groups Regarding Distance of Piles". Civil Engineering Journal 5, nr 8 (25.08.2019): 1812–19. http://dx.doi.org/10.28991/cej-2019-03091373.
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There are a lot of the parameters which affect pile group behavior in soil. One of these factors is the distance of piles from each other. The impact of distance on pile groups in sand has been investigated through some researches, whereas most of them have not represented an exact estimation according to the continuous change of the distance in sand. Moreover, most of previous investigations have considered two piles as a perfect group. Since two-pile group has the least interaction effect among piles, it cannot suitably demonstrate the influence of spacing. In this lecture, several 4-pile groups modeled with different spacing were subjected to axial loading in laboratory. The pile groups were free-head with length to diameter ratio of 13.5. The piles are designed in a way which the shaft resistance of piles can be completely mobilized through the test. Then, the bearing capacities of pile groups are measured and compared with the single pile's resistance in order to calculate the efficiency coefficient of the groups. It is revealed that the distance is noticeably effective in efficiency factor and this effectiveness, non-linearly decreases by increase of spacing. The results show that the efficiency coefficient is changing between almost 1 and 1.4.
12
Wang, Wanqi. "Correspondence analysis method of anti-slide pile information monitoring and slice model". MATEC Web of Conferences 353 (2021): 01007. http://dx.doi.org/10.1051/matecconf/202135301007.
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In order to effectively grasp the real-time working status of anti-slip piles and the reinforcement effect of slopes, timely information monitoring of anti-slip piles is carried out, and the reinforcement range is modeled, and the analysis and evaluation method of slicing model numerical calculation and information monitoring data is proposed, and the information monitoring data is compared with numerical simulation to achieve effective grasp of By comparing the information monitoring data with the numerical simulation, we can effectively grasp the timely working condition of the anti-slip pile and the reinforcement effect of the soil around the pile. This is a very important engineering practice for the evaluation of anti-slip pile reinforced slope areas.
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Nadilla, Saskia, i Widjojo Adi Prakoso. "Pile lateral subgrade reaction modulus for Jakarta". MATEC Web of Conferences 270 (2019): 02002. http://dx.doi.org/10.1051/matecconf/201927002002.
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The behavior of laterally loaded piles could be simulated by the subgrade reaction model. The primary soil parameter for this model is the subgrade reaction modulus, and in this paper, the correlation between the subgrade reaction modulus and the soil N-SPT value is examined by conducting numerical analyses of 34 pile cyclic lateral load tests in Jakarta. In each analysis, the pile is modeled as a series of beam elements, while the surrounding soil is modeled as a series of linear elastic springs. The moduli are varied according to the N-SPT values recorded in the associated deep boring data. In each load cycle, a trial and error process is conducted to match the resulting pile head lateral deflection to the measured value. The resulting correlation between the subgrade reaction modulus and the pile lateral deflection is presented for the 34 case studies and compared to a correlation in the literature. Furthermore, the analyses reveal that subgrade reaction modulus is affected by the magnitude of measured deflection, by the applied lateral loads, as well as by the construction methods.
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Abu-Farsakh, Murad, Firouz Rosti i Ahmad Souri. "Evaluating pile installation and subsequent thixotropic and consolidation effects on setup by numerical simulation for full-scale pile load tests". Canadian Geotechnical Journal 52, nr 11 (listopad 2015): 1734–46. http://dx.doi.org/10.1139/cgj-2014-0470.
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During pile installation, stresses and void ratios in the surrounding soils change significantly, creating large displacements, large strains, soil disturbance, and development of excess pore-water pressures. The surrounding disturbed soil tends to regain its strength with time due to both consolidation and thixotropic effects. In this paper, the pile installation process and subsequent consolidation, thixotropy, and load tests conducted at different times after end of driving (EOD) were modeled for test piles at the Bayou Laccassine Bridge site, Louisiana. In the finite element (FE) model, the pile was considered as an elastic material and the anisotropic modified Cam-clay model (AMCCM) was used to describe the behavior of the surrounding clayey soils. Pile installation was modeled by applying prescribed radial and vertical displacements on the nodes at the soil–pile interface (volumetric cavity expansion), followed by vertical deformation to activate the soil–pile interface friction and simulate static load tests. The thixotropic effect was incorporated by applying a time-dependent reduction parameter, β, which affects both interface friction and material properties. Results from the FE numerical simulation include the development of excess pore-water pressure during pile installation and its dissipation with time, the increase in effective lateral stress at the pile–soil interface, changes in stress state of the surrounding soil, and setup attributed to both the soil consolidation and thixotropy at different times. FE results are compared with measured values obtained from full-scale instrumented pile load tests, which show good agreement between measured and FE-predicted results.
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Sun, Ling, Jun Jie Zheng, Jun Zhang i Qiang Ma. "Mechanical Performance of Geosynthetic-Reinforced Pile-Supported Embankments". Advanced Materials Research 156-157 (październik 2010): 1696–701. http://dx.doi.org/10.4028/www.scientific.net/amr.156-157.1696.
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According to the characteristics of the soft soil subgrade reinforced by geosynthetic and piles, the deformation of geosynthetic was modeled as circular arc and the arching effect in embankments and the interaction of piles and soil are both considered in the calculation. The interaction mechanism of geosynthetic, pile and soil under the embankment load was analyzed. The method presented in this paper was validated by comparing with the testing results and three current design methods in the literature. The results show that the analytical solutions have agreement with the measured data and can be applied in engineering practice. Finally, four important parameter (the differential settlement, the diameter of pile, the width of pile cap, the height of equal settlement plane) were investigated.
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Nawel, Bousbia, Messast Salah i Houssou Noura. "A simplified 3D model for existing tunnel response to piles construction". Selected Scientific Papers - Journal of Civil Engineering 16, nr 2 (1.12.2021): 87–103. http://dx.doi.org/10.2478/sspjce-2021-0018.
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Abstract The construction and loading of deep foundations (piles) of high-rise buildings causes a considerable effect in terms of stresses and deformation and requires assessing their impact on the response of adjacent tunnels to deformations, particularly for pile foundations, which are often constructed in locations very close to existing tunnels. The execution process for piles structures generates displacements, stresses, and forces, which are transferred through the piles’ soil surrounding a nearby existing tunnel. The research presented in this paper has led to a significantly improved understanding of pile-tunnel interaction problem. It is crucial for the analysis of the impact of the pile construction on an existing tunnel. The treated topic appears in a setting of an urban environment, where we construct numerous profound foundations, sometimes in contact or adjacent to a. In this paper, the response of the existing tunnel under constructed pile process is studied. Numerical modeling was carried out using Plaxis3D software in which the Mohr-Coulomb Model (MC) has been used for modeling, while the piles/ tunnels are modeled as a linear elastic material. Furthermore, a parametric study is conducted, and its cases are investigated. The displacements and the stresses generated on the tunnel lining decreases with the increase in relative distance between pile and tunnel (spacing), the location/length of the pile from the tunnel, the pile diameter, the number of piles. We have also identified two geometrical parameters of the tunnel: shape section and thickness lining which play a prominent role in the interaction between an existing tunnel and a new pile to excavate.
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Y. Fattah, Mohammed, Nahla M. Salim i Asaad M. B. Al-Gharrawi. "FINITE ELEMENT SIMULATION OF PLUGGED OPEN ENDED PILE BEHAVIOR". Kufa Journal of Engineering 8, nr 2 (17.07.2017): 1–17. http://dx.doi.org/10.30572/2018/kje/821166.
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Open-ended steel pipe piles are widely used for foundations both on land and offshore because of low cost compare with other types of piles and it does not need a high effort for driving. During driving process of these piles into the soil, a soil column known as the soil plug is formed inside the pile. As the penetration continues, the frictional resistance between the inner pile shaft and the soil plug may be developed and in turn may prevent further soil intrusion. Depending on the relative movement between the pile and the soil plug, the pile is considered to be perfectly plugged, imperfectly plugged or unplugged. A numerical modeling of experiments was carried out using PLAXIS-2015 software, in which the Hardening Soil Model (HS small) has been used for soil modeling. During the verification problem used to simulate the experimental results of the pile group G2(2x2), the piles simulated as volume piles and steel cap were modeled using linear elastic model. The simulation showed that the maximum percentage of deviation between experimental and theoretical results is not more than 13.0%. This ratio is considered good when compared to the actual results and the theoretical results with the same values in some of the results.
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Mohamad Ali, Anis Abdul Khuder, Jaffar Ahemd Kadim i Ali Hashim Mohamad. "Design Charts for Axially Loaded Single Pile Action". Civil Engineering Journal 5, nr 4 (27.04.2019): 922–39. http://dx.doi.org/10.28991/cej-2019-03091300.
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The objective of this article is to generating the design charts deals with the axially ultimate capacity of single pile action by relating the soil and pile engineering properties with the pile capacity components. The soil and are connected together by the interface finite element along pile side an on its remote end. The analysis was carried out using ABAQUS software to find the nonlinear solution of the problem. Both pile and soil were modeled with three-dimensional brick elements. The software program is verified against field load-test measurements to verify its efficiency accuracy. The concrete bored piles are used with different lengths and pile diameter is taken equals to 0.6 m. The piles were installed into a single layer of sand soil with angles of internal friction (20° t0 40°) and into a single layer of clay soil with Cohesion (24 to 96) kPa. The getting results showed that for all cases study the total compression resistance is increased as pile length increased for the same property of soil, also illustrious that the total resistance of same pile length and diameter increased as the soil strength increasing. In addition, the same results were obtained for the end bearing resistance, skin resistance and tension capacity. Design charts were constructed between different types of soil resistance ratio and the pile length/diameter ratio (L/D) for all cases of study. One of improvement found from these curves that it is cheaply using piles of larger diameter than increasing their lengths for dense sand and to increasing piles lengths for loose sand. Moreover, it is inexpensively using piles of larger length in soft clay soil than increasing their diameter and piles of larger diameter in firm and stiff clay soils than increasing their length.
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Amaral, Jennifer L., James H. Miller, Gopu R. Potty, Kathleen J. Vigness-Raposa, Ying-Tsong Lin, Adam S. Frankel, Arthur E. Newhall, Daniel R. Wilkes i Alexander N. Gavrilov. "Analysis of underwater sounds from impact pile driving at the Block Island Wind Farm". Journal of the Acoustical Society of America 151, nr 4 (kwiecień 2022): A239—A240. http://dx.doi.org/10.1121/10.0011188.
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Impact pile driving creates intense, impulsive sound that radiates into the surrounding environment. Piles driven vertically into the seabed generate an azimuthally symmetric underwater sound field whereas piles driven on an angle will generate an azimuthally dependent sound field. Measurements were made during impact pile driving of raked piles to secure jacket foundation structures to the seabed at the Block Island Wind Farm at ranges between 500 m and 15 km. These measurements were analyzed to investigate variations in rise time, decay time, pulse duration, kurtosis, and sound received levels as a function of range and azimuth. Variations in the radiated sound field along opposing azimuths resulted in differences in measured sound exposure levels of up to 10 dB and greater due to the pile rake as the sound propagated in range. The raked pile configuration was modeled using an equivalent axisymmetric FEM model to describe the azimuthally dependent measured sound fields and compared to the measured data. These measurements made during wind farm construction will be presented and discussed. [Work supported by the Bureau of Ocean Energy Management.]
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Fayyazi, M. Sajjad, Mahdi Taiebat i W. D. Liam Finn. "Group reduction factors for analysis of laterally loaded pile groups". Canadian Geotechnical Journal 51, nr 7 (lipiec 2014): 758–69. http://dx.doi.org/10.1139/cgj-2013-0202.
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The lateral response of piles embedded in soil is typically analyzed using the beam on nonlinear Winkler springs approach, in which soil–pile interaction is modeled by nonlinear p–y curves (where p is soil resistance and y is horizontal displacement). In this approach, one of the most common methods of accounting for interaction effects in pile groups is to modify the single pile p–y curves using a p-multiplier for each row of piles in the group, with higher values for leading row and lower values for trailing rows. The leading and trailing rows interchange during seismic loading; therefore, sometimes an average p-multiplier is used for all piles in the group. This average p-multiplier is called the group reduction factor. Group reduction factors have been established from experimental data from static loading tests on small pile groups, mostly 3 × 3 groups with free pile head conditions and center-to-center pile spacings of about 3 pile diameters. In this paper, continuum simulations are used to study the group reduction factors in 3 × 3 to 6 × 6 square pile groups subjected to static loading. The study includes the effects of various parameters, including pile spacing, pile head condition, and the friction angle of soil, on the group reduction factors. Calculated group reduction factors from this study compare well with available group test data, that is, typically small pile groups. However, the study shows that design guidelines such as the American Association of State Highway and Transportation Officials (AASHTO) and Federal Emergency Management Agency (FEMA) P-751 overestimate the group reduction factors, hence the lateral resistance, in larger pile groups and larger spacings, especially for fixed pile head conditions.
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Nosenko, Viktor, i Ostap Kashoida. "Influence of the choice of the base model on the stress-strain state of the vertical load-bearing elements of a monolithic-frame house". Bases and Foundations, nr 41 (17.12.2020): 45–54. http://dx.doi.org/10.32347/0475-1132.41.2020.45-54.
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Comparison of the stress-strain state of vertical elements of the frame of a monolithic house (basement, first and fourth floors), depending on the method of modeling the soil environment and piles, is carried out.
The use of pile foundations is due to the fact that they provide the transfer of loads to deeper soil layers and, as a rule, a greater bearing capacity compared to shallow foundations. In the design of foundations, engineers face the question of how to model the soil environment and piles?
This paper presents the influence of the decision taken (the selected soil model and the method of modeling piles) on the stress-strain state of the vertical load-bearing elements of the house frame.
Comparison of the stress-strain state of vertical elements of the frame (basement, first and fourth floors), which were obtained using the following models of the system «base - pile foundation - overhead supporting structures»:
1) the piles are modeled by single-node finite elements, have only vertical stiffness according to the results of testing the piles for vertical static pressing loads, the mutual influence of piles and soil characteristics are not taken into account (FE-56 hereinafter, this is the number of the finite element in the library of elements of the PС «Lira -SAPR»)
2) the piles are modeled by single-node finite elements, are located with a given step along the length of the pile and have rigidity in different directions and approximately take into account the surrounding soil around the pile and under its tip (FE-57);
3) the soil environment is modeled by volumetric elastic finite elements; piles - rod finite elements.
It is shown that the choice of the foundation model carries stress-strain state not only for the foundation structures, but also for the vertical bearing elements of the house. When using various options for modeling the base: using a single-node finite element that simulates a smoke like elastic ligature (FE-56), using a chain of single-node skinned elements (FE-57), or a volumetric soil massif, it is possible to obtain quantitative differences in stresses from 2 to 20%, and a qualitative change, which is observed in a change in the sign of bending moments.
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Vakili, Amir, Seyed Mohammad Ali Zomorodian i Arash Totonchi. "Small scale model test on lateral behaviors of pile group in loose silica sand". Acta Geotechnica Slovenica 18, nr 1 (2021): 41–54. http://dx.doi.org/10.18690/actageotechslov.18.1.41-54.2021.
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The accurate predictions of load- deflection response of the pile group are necessary for a safe and economical design. The behavior of piles under the lateral load embedded in soil, is typically analyzed using the Winkler nonlinear springs method. In this method, the soil-pile interaction is modeled by nonlinear p-y curves in a way that the single pile p-y curve is modified using a p-multiplier (Pm) for each row of piles in the group. The average Pm is called the group reduction factor. The Pm factor depends upon the configuration of pile group and the pile spacing (S). The present study was conducted to investigate the effects of various parameters, such as the pile spacing in the group, different layouts and the lateral load angle (Ѳ) change as a new parameter on the Pm factor and group efficiency based on the 1-g model test. The Pm factor is well comparable with the results of the full-scale test on pile group. However, based on the results, the calculated values of the Pm factor for 3×3 pile groups under 2.5-diameter spacing was estimated about 0.38 and under 3.5-diameter spacing was estimated about 0.52, so the calculated values at S/D=3, obtained from interpolation the values of group reduction factor at S/D=2.5 and S/D=3.5, are close to the AASHTO recommendation.
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Chen, Chien Yuan, i Chi Xun Tsai. "Batter Pile Behavior Modeling Using Finite Difference Analysis". Applied Mechanics and Materials 566 (czerwiec 2014): 199–204. http://dx.doi.org/10.4028/www.scientific.net/amm.566.199.
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Pile foundation has been widely used in supporting various structures, for example, bridges and tall buildings in Taiwan. With the development of mountainous area, pile foundation has been used as mitigation slope movement. Batter piles used in a group pile subjected to lateral forces are common. In this study, we used 3D finite difference program to analyze the mechanical response of a batter pile subjected to lateral soil movement. In order to verify the correction of the numerical simulation, its validation was compared with a published case study. The analysis of a single pile in different incline angles subjected to lateral soil movement was modeled. Results of the analysis show that batter pile under the conditions of lateral soil movement will cause pile larger lateral displacement and increasing bending moment on the pile shaft. The pile displacement reduced with the increasing pile incline angle. Vertical pile shaft subjected to negative and positive moment during soil movement, while, only positive moment distributed in the batter pile shaft. The moment is higher in batter pile shaft in weak layer than in non-weak layer. The pile shaft maximum moment occurred nearby the interface of weak layer and stable layer. The moment increased with the incline angle of batter pile. While, the moment increasing ratio reduced with the increased incline angle.
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BANERJEE, SUBHADEEP, SIANG HUAT GOH i FOOK HOU LEE. "RESPONSE OF SOFT CLAY STRATA AND CLAY-PILE-RAFT SYSTEMS TO SEISMIC SHAKING". Journal of Earthquake and Tsunami 01, nr 03 (wrzesień 2007): 233–55. http://dx.doi.org/10.1142/s1793431107000146.
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The behavior of pile foundations under earthquake loading is an important factor affecting the performance of structures. Observations from past earthquakes have shown that piles in firm soils generally perform well, while the performance of piles in soft or liquefied ground can raise some questions. Centrifuge model tests were carried out at the National University of Singapore to investigate the response of pile-soil system under three different earthquake excitations. Some initial tests were done on kaolin clay beds to understand the pure clay behavior under repetitive earthquake shaking. Pile foundations comprising of solid steel, hollow steel and hollow steel pile filled with cement in-fill were then embedded in the kaolin clay beds to study the response of clay-pile system. Superstructural inertial loading on the foundation was modeled by fastening steel weight on top of the model raft. The model test results show that strain softening and stiffness degradation feature strongly in the behaviour of the clay. In uniform clay beds without piles, this is manifested as an increase in resonance periods of the surface response with level of shaking and with successive earthquakes. For the pile systems tested, the effect of the surrounding soft clay was primarily to impose an inertial loading onto the piles, thereby increasing the natural period of the piles over and above that of the pile foundation alone. There is also some evidence that the relative motion between piles and soil leads to aggravated softening of the soil around the pile, thereby lengthening its resonance period of the soil further. The centrifuge model tests were back-analyzed using the finite element code ABAQUS. The analysis shows that the simple non-linear hypoelastic soil model gave reasonably good agreement with the experimental observations. The engineering implication arising from this study so far is that, for the case of relatively short piles in soft clays, the ground surface motions may not be representative of the raft motion. Other than the very small earthquakes, the raft motion has a shorter resonance period than the surrounding soil.
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Hafudiansyah, Edward, i An An Anisarida. "ANALISIS STRUKTUR MOORING DOLPHIN KAPASITAS KAPAL 2000 GT (STUDI KASUS PELABUHAN MUNSE SULAWESI TENGGARA)". JURNAL TEKNIK SIPIL CENDEKIA (JTSC) 2, nr 1 (8.02.2021): 69–83. http://dx.doi.org/10.51988/vol1no1bulanjulitahun2020.v2i1.31.
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Sea transportation is the main transportation used by residents in the islands. The development of marine transportation facilities is expensive to support these activities. Therefore, several alternatives are needed to streamline construction costs, one of which is the construction of a pier using a mooring dolphin. The purpose of this study is to calculate the structural strength of the mooring dolphin with a ship capacity of 2000 GT at Munse Port, Southeast Sulawesi Province. Structural analysis is carried out by analyzing pile capacity and joint displacement analysis. The calculation of the strength of the pile elements at the pier was analyzed using the SAP 2000 program. For soil which is modeled as an elastic support, the ability to support the load depends on the magnitude of the modulus of subgrade reaction from the soil. Embedded pile modeling is modeled with a nonlinear spring force. The results of the analysis by analyzing the capacity of piles with dimensions of 508 mm with a thickness of 12 mm resulted in a capacity ratio of 0.72. The results of the analysis of joint displacement in service or operational conditions are 37.09 mm and in earthquake conditions, they are 13.01 mm.
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Liu, Jing-Liang, Si-Fan Wang, Jin-Yang Zheng, Chia-Ming Chang, Xiao-Jun Wei i Wei-Xin Ren. "Time–Frequency Signal Processing for Integrity Assessment and Damage Localization of Concrete Piles". International Journal of Structural Stability and Dynamics 20, nr 02 (23.12.2019): 2050020. http://dx.doi.org/10.1142/s0219455420500200.
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This paper presents a new integrity assessment and damage localization method for piles based on one-dimensional wave propagation theory by integrating the analytical mode decomposition (AMD), recursive Hilbert transform (RHT) and complex continuous wavelet transform (CCWT) into a single assessment tool. The AMD is first used as a band pass filter to extract the mono-component over a frequency band of interest from the response of a pile head, aimed at attenuating the interference from various noisy signals. Then, the mono-component signal is demodulated into a purely frequency-modulated signal by means of RHT, which greatly reduces the interferences from the amplitude-modulated function. Finally, the CCWT is utilized to process the frequency-modulated signal and to calculate phase angles; the latter are subsequently mapped into the time–frequency domain to localize pile damage. The methodology is verified by a numerical example, in which a concrete pile is modeled by the finite element method considering the soil-pile interaction, and by an experimental case study on an actual pile. The results from the numerical and experimental examples demonstrate that the proposed method improves the efficiency of damage identification when compared with other three methods ([Formula: see text], [Formula: see text] and CCWT). In addition, the proposed method enables the localization of damage in full-scale piles situated in soil with an acceptable engineering accuracy by mutual validation with other pile integrity assessment methods, e.g. the ultrasonic emission method.
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Al-Obaidi, Ahmed, i Pinar Mahmood. "Ultimate capacity of piles penetrating in weak soil layers". MATEC Web of Conferences 162 (2018): 01025. http://dx.doi.org/10.1051/matecconf/201816201025.
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A pile foundation is one of the most popular forms of deep foundations. They are routinely employed to transfer axial structure loads through the soft soil to stronger bearing strata. Piles generally used to increase the load carrying capacity of the foundation and reduce the settlement of the foundation. On the other hand, many cases in practice where piles pass through different layers of soil that contain weak layers located at different depths and extension, also some time cavities with a different shape, size, and depth are found. In this study, a total of 96 cases is considered and simulated in PLAXIS 2D program aiming to understand the influence of weak soil on the ultimate pile capacity. The piles embedded in the dense sand with a layer of weak soil at different extension and location. The cross section of the geometry used in this study was designed as an axisymmetric model with the 15-node element; the boundary condition recommended at least 5D in the horizontal direction, and (L+5D) in the vertical direction where D and L are the diameter and length of pile, respectively. The soil is modeled as Mohr-Coulomb, with five input parameters and the behavior of pile material represented by the linear elastic model. The results of the above cases are compared with the results found in a pile embedded in dense soil without weak layers or cavities. The results indicated that the existence of weak soil layer within the surrounding soil around the pile decreases the ultimate capacity. Furthermore, it has been found that increase in the weak soil width (extension) leads to reduction in the ultimate capacity of the pile. This phenomenon is applicable to all depth of weak soil. The influence of weak layer extension on the ultimate capacity is less when it is presentin the upper soil layers.
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McVay, Michael C., Limin Zhang, Sangjoon Han i Peter Lai. "Experimental and Numerical Study of Laterally Loaded Pile Groups with Pile Caps at Variable Elevations". Transportation Research Record: Journal of the Transportation Research Board 1736, nr 1 (styczeń 2000): 12–18. http://dx.doi.org/10.3141/1736-02.
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A series of lateral load tests were performed on 3×3 and 4×4 pile groups in loose and medium-dense sands in the centrifuge with their caps located at variable heights to the ground surface. Four cases were considered: Case 1, pile caps located above the ground surface; Case 2, bottom of pile cap in contact with the ground surface; Case 3, top of pile cap at the ground surface elevation; and Case 4, top of pile cap buried one cap thickness below ground surface. All tests with the exception of Case 1 of the 4×4 group had their pile tips located at the same elevation. A special device, which was capable of both driving the piles and raining sand on the group in flight, had to be constructed to perform the tests without stopping the centrifuge (spinning at 45 g). The tests revealed that lowering the pile cap elevation increased the lateral resistance of the pile group anywhere from 50 to 250 percent. The experimental results were subsequently modeled with the bridge foundation-superstructure finite element program FLPIER, which did a good job of predicting all the cases for different load levels without the need for soil–pile cap interaction springs (i.e., p-y springs attached to the cap). The analyses suggest that the increase in lateral resistance with lower cap elevations may be due to the lower center of rotation of the pile group. However, it should be noted that this study was for pile caps embedded in loose sand and not dense sands or at significant depths. The experiments also revealed a slight effect for the case of the pile cap embedded in sand with a footprint wider than the pile row. In that case the size of the passive soil wedge in front of the pile group, and consequently the group’s lateral resistance, increased.
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Nuzhdin, M. L. "EXPERIMENTAL STUDIES OF PILE FOUNDATION GROUND BASE REINFORCED WITH HARD INCLUSIONS". Construction and Geotechnics 10, nr 3 (15.12.2019): 5–15. http://dx.doi.org/10.15593/2224-9826/2019.3.01.
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Often in construction practice there is a need to strengthen the pile foundation of buildings and structures. The traditional methods include the implementation of additional, as a rule, bored piles with the subsequent erection of a grillage incorporating them into operation. Often, this work has to be done in the conditions of dense urban development, in cramped rooms of the basement, etc., which leads to significant technological difficulties. One of the alternative ways to strengthen pile foundations is the method of high-pressure group injection, which consists in injecting a movable cement-sand mortar into the soil under pressure that exceeds its structural strength. As a result, after its hardening, solid injection bodies are formed at the base, reinforcing the soil base. The article describes the results of experiments to assess the impact of the layout of hard inclusions on the deformability of the soil foundation of the pile foundation model. The experiments were carried out in a small soil tray, which was filled with medium-grained loose sand. The piles were modeled with metal rods, the pile grillage with a metal square stamp. The pile foundation model included 9 piles arranged in a square grid. As injection bodies, gravel grains of various sizes and shapes were used. The studies included 10 series of experiments (each experiment was repeated at least 3 times): the volume of the inclusions used, their sizes, the positioning step in the plan and in depth varied. As a result of the analysis of the performed experiments, conclusions were formulated regarding the purpose of the optimal layout of hard inclusions when strengthening the soil foundation of pile foundations by high-pressure injection of mobile cement-sand mixtures.
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Deng, Hao-Yun, Xin-Yang Jin i Ming Gu. "A Simplified Method for Evaluating the Dynamic Properties of Structures Considering Soil–Pile–Structure Interaction". International Journal of Structural Stability and Dynamics 18, nr 06 (czerwiec 2018): 1871005. http://dx.doi.org/10.1142/s0219455418710050.
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A simplified method is presented for evaluating the dynamic properties of structures considering the effects of soil–pile–structure interaction (SPSI). A substructure method is used to establish the model of the soil–pile–structure system which is characterized by several dimensionless parameters. The shear-type structure is modeled as a generalized single-degree-of-freedom system using the virtual displacement principle, and the impedance functions of the floating pile-foundation are formulated by the thin-layer method. A number of coupled systems are analyzed and the results are used as the statistical base to obtain the mathematical relations between the dimensionless parameters and the dynamic properties. The dynamic properties solved by the equations are compared with those of the field experiment, shaking-table test and other analytical methods. The results indicated that the proposed equations are of high accuracy and can be used to obtain the dynamic properties of piles directly without performing complex analysis.
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Mitrović, Stefan, i Snežana Mašović. "Comparative analysis of concrete integral overpass with variable soil characteristic". Tehnika 77, nr 1 (2022): 27–34. http://dx.doi.org/10.5937/tehnika2201027m.
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In this paper concrete integral overpass with span of 30 meters on magistral road which based on piles is considered. It is analysed influence of soil stiffness on value of design forces and pile stress. Three types of soil is considered in this analysis, where stiffness of soil was determined with characteristic of soil layers. For this analysis was made numerical model of this overpass in software CSiBridge v20 where is soil modeled with "springs" (flexible supports) placed along the piles whose stiffness match with stiffness of soil layer.
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Al-Jeznawi, Duaa, Ismacahyadi Bagus Mohamed Jais, Bushra S. Albusoda i Norazlan Khalid. "The slenderness ratio effect on the response of closed-end pipe piles in liquefied and non-liquefied soil layers under coupled static-seismic loading". Journal of the Mechanical Behavior of Materials 31, nr 1 (1.01.2022): 83–89. http://dx.doi.org/10.1515/jmbm-2022-0009.
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Abstract This study presents the findings of a 3D finite element modeling on the performance of a single pile under various slenderness ratios (25, 50, 75, 100). These percentages were assigned to cover the most commonly configuration used in such kind of piles. The effect of the soil condition (dry and saturated) on the pile response was also investigated. The pile was modeled as a linear elastic, the surrounded dry soil layers were simulated by adopting a modified Mohr-Coulomb model, and the saturated soil layers were simulated by the modified UBCSAND model. The soil-pile interaction was represented by interface elements with a reduction factor (R) of 0.6 in the loose sand layer and 0.7 in the dense sand layer. The study was compared with the findings of 1g shaking table tests which were performed with a slenderness ratio of 25. In the validation case, there was a clear correlation between the laboratory findings and the numerical analyses. It was observed that the failure mechanism is influenced by the soil condition and the slenderness ratio to some extent. Under the dry soil condition, no base pile deformation was observed; However, tip pile movement was observed under the saturated soil condition with pile slenderness ratios of 25 and 50. The findings of this study are also aimed to include an approximation of the long-term deformations at the ground surface which has experienced shaking.
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Ali, Ahmed S., Nahla M. Salim i Husam H. Baqir. "The Performance of Taper Helical Pile Embedded in Loose Sand Under Uplift Static and Cyclic Load Using 3D-Finite Element Analysis". IOP Conference Series: Earth and Environmental Science 961, nr 1 (1.01.2022): 012033. http://dx.doi.org/10.1088/1755-1315/961/1/012033.
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Abstract Piles with helices are a kind of foundation that is capable of withstanding compression, tension, and lateral loads. However, for almost 25 years, this kind of Pile was widely used across the world. Its behaviour is unpredictable and terrifying, especially in Iraq. The present study analysed this kind of Pile using the finite element method. It was recommended that the helical pile geometry be modeled by numerical model technique and the computer program Plaxis 3D. The plaxis 3D software is a well-known geotechnical engineering tool that numerically analyses soil and simulates experimental work in terms of curve matching and outcomes. Furthermore, an analysis of variables was conducted. The primary variable research investigates the influence of the number of helices and the tapered helix distance under static and cyclic load. The final finding is that the more helices in a pile, the smaller the displacement (or amplitude) in comparison to one helix under the effect of uplift static and cyclic load. As a result that the effect of helix number on soil behaviour is more than the effect of changing the distances between helix.
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Wang, Shaomin, Bruce L. Kutter, M. Jacob Chacko, Daniel W. Wilson, Ross W. Boulanger i Abbas Abghari. "Nonlinear Seismic Soil-Pile Structure Interaction". Earthquake Spectra 14, nr 2 (maj 1998): 377–96. http://dx.doi.org/10.1193/1.1586006.
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Analytical design tools for evaluation of soil-pile-structure interaction during seismic events are evaluated and modified. Several implementations of the “Beam on Nonlinear Winkler Foundation” (BNWF) method were used to predict results of centrifuge model tests of single piles in a soft clay soil profile. This paper shows that calculations from these computer codes can be sensitive to the details of the arrangement of nonlinear springs and linear viscous dashpots. Placing the linear viscous dashpots (representing radiation damping in the far field) in series with the hysteretic component of the p-y elements (representing the nonlinear soil-pile response in the near field) is shown to be technically preferable to a parallel arrangement of the viscous and hysteretic damping components. Preliminary centrifuge data is reasonably modeled by the numerical calculations using this implementation of damping, but additional field or physical model data are needed to fully evaluate the reliability of BNWF procedures.
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Alyavdin, Dmitriy, Vladimir Belyakov, Artemiy Levin, Andrey Alekseev, Erika Grechishcheva, Olga Kozlova i Roman Makhota. "Reline Jacket: Efficient Reduction of Frost-Heave Uplift of Piles in Warming Permafrost". Geosciences 12, nr 9 (23.08.2022): 313. http://dx.doi.org/10.3390/geosciences12090313.
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Air temperature in the Northern Hemisphere has been progressively warming in the recent decades, and the ground temperatures have increased correspondingly. The air temperature increasing due to the climate change induces degradation of permafrost and frost heaving activation. The frost heaving forces cause unevenly distributed damaging displacement of foundations and thus poses problems to the development of Arctic regions. Frost-heave uplift forces can be reduced by protecting piles with an OSPTReline (or Reline) polymer heat-shrinkable jacket. The interaction of heaving soil with a pile covered with the Reline jacket is modeled in laboratory to estimate the uplift force and the related shear strength of frozen soil along the soil-pile adfreeze surface at temperatures from −6 to −1 °C. The data are obtained for silty sand and silty clay soils and mortar (1:5 cement-sand mixture). The experiments show that frost-heave uplift forces on Reline-protected piles are 52% to 85% lower than on uncovered steel piles (steel grade 09G2S—analog to European steel grade S355JR), depending on soil type and temperature.
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Putraloka, Bagas, Gregorius Sandjaja i Amelia Yuwono. "ANALISIS SENDI PLASTIS LOKAL PADA PUSHOVER KELOMPOK TIANG PANCANG". JMTS: Jurnal Mitra Teknik Sipil 3, nr 2 (17.05.2020): 337. http://dx.doi.org/10.24912/jmts.v3i2.6981.
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Foundation is part of an engineering system which forwards the load supported by the foundation and its own weight into underneath the rock and the soil.Based on technical aspects and implementation it can be classified into pile and bore pile.Based on number piles divided into single pile and group piles.Group pile is a group of piles structured relatively close and connected with the pile cap at the top. Because of enhancement of earthquake acceleration on certain area on SNI 1726:2012, Analysis of group pile is needed on area with enhancement of earthquake acceleration. The collection data method is obtained by collecting data from the project by form bore log and laboratory test meanwhile for data analysis method using basic theory used as a reference for learning pushover analysis which refers fom ATC-40. By doing pushover analysis on a group pile, Performence of group pile can be known as Performence Point which will be compared to each of the pile configurations. And the result from this research is more the number of piles on the configuration being modeled, the result is the value of performence point getting higher, because of the lateral force will be tested be more higher. AbstrakFondasi ialah bagian dari suatu sistem rekayasa yang meneruskan beban yang ditopang oleh fondasi dan beratnya sendiri ke dalam tanah dan batuan yang terletak di bawahnya. berdasarkan segi teknis pelaksanaan dapat diklasifikasikan menjadi tiang pancang dan tiang bor. Berdasarkan jumlah tiang ada dua macam yaitu tiang tunggal dan tiang kelompok, tiang kelompok adalah sekumpulan tiang yang dipasang secara relatif berdekatan yang dihubungkan bagian atasnya dengan pile cap. Karena adanya peningkatan percepatan gempa di daerah tertentu pada SNI 1726:2012, perlu dilakukan analisis terhadap kelompok tiang di daerah yang terkena peningkatan percepatan gempa. Metode pengumpulan data dilakukan dengan mengumpulkan data-data yang berasal dari proyek berupa hasil boring log dan hasil tes laboratorium sedangkan untuk Metode analisis data digunakan teori dasar yang digunakan sebagai acuan pembelajaran dalam melakukan analisis Pushover yang mengacu pada ATC-40. Dengan melakukan analisis pushover pada suatu kelompok tiang, tingkat kinerja suatu kelompok tiang dapat diketahui berupa nilai Performance Point yang akan dibandingkan setiap konfigurasi tiang. Dan hasil yang didapat dalam penelitian ini adalah semakin banyak jumlah tiang dalam konfigurasi yang dimodelkan maka nilai performence point pun semakin tinggi, karena gaya lateral yang diuji akan semakin tinggi.
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Souri, Ahmad, Murad Abu-Farsakh i George Voyiadjis. "Study of static lateral behavior of battered pile group foundation at I-10 Twin Span Bridge using three-dimensional finite element modeling". Canadian Geotechnical Journal 53, nr 6 (czerwiec 2016): 962–73. http://dx.doi.org/10.1139/cgj-2015-0345.
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In this study, the static lateral behavior of a battered pile group foundation was investigated using three-dimensional finite element (FE) analysis. The FE model was used to simulate the static lateral load test that was performed during the construction of the I-10 Twin Span Bridge over Lake Pontchartrain, La., in which two adjacent bridge piers were pulled against each other. The pier of interest was supported by 24, 1:6 batter, 34 m long piles in a 6 × 4 row configuration. The FE model of the battered pile group was developed in Abaqus and verified using the results from the field test. The model utilized an advanced constitutive model for concrete, which allowed distinct behavior in tension and compression, and introduced damage to the concrete stiffness. The soil domain comprised of several layers in which the constitutive behavior of clay layers was modeled using the anisotropic modified Cam-clay (AMCC) model, and for sands using the elastic perfectly plastic Drucker–Prager (DP) model. FE results showed good agreement with the results of the lateral load test in terms of lateral deformations and bending moments. The results showed that the middle rows carried a larger share of lateral load than the first and the last rows. The pile group resisted a maximum lateral load of 2494 t at which the piles were damaged within a 6 m zone from the bottom of the pile cap. The edge piles carried larger internal forces and exhibited more damage compared to the inner piles. The soil resistance profiles showed that soil layering influenced the distribution of resistance between the soil layers. A series of p–y curves were extracted from the FE model, and then used to study the influence of the group effect on the soil resistance. The p–y curves showed that the group effect reduced the soil resistance in all rows, with the lowest resistance in the third row. Finally, the p-multipliers were calculated using the extracted p–y curves, and compared to the reported p-multipliers for vertical pile groups.
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Kuzhakhmetova, Elvira R. "Modeling of a piled foundation in a Femap with NX Nastran". Structural Mechanics of Engineering Constructions and Buildings 16, nr 4 (15.12.2020): 250–60. http://dx.doi.org/10.22363/1815-5235-2020-16-4-250-260.
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Relevance. The underground part of the building (foundation and soil) has a significant impact on its stress-strain state and behavior under the influence of operational loads. Therefore, the existing regulatory and technical documentation regulates the design of buildings (structures), taking into account the joint work of their aboveground and underground parts. In practice, such accounting becomes possible on the basis of a comprehensive engineering analysis of the building as a large mechanical system building - foundation - soil, which today can be carried out using the finite element method. In the case of pile foundations, the correctness of the result depends largely on the reasonable choice of the design model of the pile-soil subsystem. The article analyzes three design models of piles operating in an array of soil foundation. The first model is discrete. In it, the pile is modeled by bars and is based on elastic supports (Spring) with generalized stiffnesses. Second model - spatial, in which the pile and soil are typed in by volumetric elements (Solid). Third model - spatial-bar or combined, in which the bar pile is embedded in the mesh of the soil mass using a rigid substructure formed by bars of high rigidity. The aim of the work - to determine a rational calculation model of the pile - soil subsystem, which allows, on the one hand, to reduce the general order of the system of resolving equations, and, on the other hand, to maintain the accuracy of the assessment of the stress-strain state of the calculation model of pile - soil and the building as a whole. Materials and methods. The numerical results of the analysis of the pile foundation statics using the three pile - soil calculation models were performed in the CAE software package - the Femap with NX Nastran class, which implements the finite element method. Results. Comparative-numerical analysis of the stress-strain state of the pile foundation - soil subsystem made it possible to determine the advantages, disadvantages, and also the areas of rational use of bar, spatial combined calculation models. In the next articles, it is planned to consider the calculation of piles for vertical loads, as well as a comparative analysis of numerical results with experimental data (in the labo-ratory or in field conditions) for horizontal and vertical effects.
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Sun, Jiu Min, Lin Chao Liu i Qi Fang Yan. "Vertical Vibration of Pile Groups in Soil Described by Fractional Derivative Viscoelastic Model". Advanced Materials Research 189-193 (luty 2011): 3492–97. http://dx.doi.org/10.4028/www.scientific.net/amr.189-193.3492.
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The stress-strain relationship of soil is described by fractional derivative viscoelastic model, and established the vertical governing equations of viscoelastic soil. The stiffness and damping of the soil layer described by fractional viscoelastic model are obtained based on the method of layer. The pile-soil dynamic interaction is modeled by Winkler dynamic elastic-damping model, the pile to pile dynamic interaction and vertical vibration of the pile groups in the soil described by fractional derivative viscoelastic model is solved. The influence of the pile spacing, order of fractional derivative and model parameter of soil on the vertical dynamic impedance of pile groups is also investigated. The result indicated that the curves of the dynamic impedance varying with frequency were more complex with the increase of pile spacing, the influence of the order of fractional derivative on vertical dynamic impedance of pile groups is different at lower frequency and high frequency, and the selection of the constitutive model of viscoelastic soil had great effect on the vertical dynamic impedance of pile groups.
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Yunus, Muhammad O. "Model Test Ultimate Bearing Capacity of Bakau Piles Foundation on Soft Soil Deposit". EPI International Journal of Engineering 1, nr 2 (20.11.2018): 94–99. http://dx.doi.org/10.25042/epi-ije.082018.15.
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The pile foundation is one of the deep foundation types commonly used to support building loads when hard soil layers are deeply located. To determine the ultimate bearing capacity of a pile foundation of the load test results, there are several methods commonly used to interpretation test results such as Davisson method, Mazurkiewich method, Chin method, Buttler Hoy method and De Beer method. The aim of this study was to determine the characteristics of soft soil and bakau piles used in the study and to analyze the size of the bearing capacity ultimate of pile foundation that is modeled on a small scale in the laboratory. From the test results of material characteristics of the soil used is organic clay type with medium plasticity with specific gravity 2.75, liquid limit, LL = 50.36% and plasticity index, PI = 13.2%. While the results of testing the characteristics of bakau piles obtained average water content of 21.58%, tensile strength of 18.51 MPa, compressive strength of parallel fiber 23.75 MPa and perpendicular fiber 14.10 MPa, bending strength 106, 22 MPa, and strong split 29.91 MPa. From the result of loading test of the foundation model in the laboratory, it is found that the ultimate bearing capacity of the model without foundation is 41.00 kN with the ultimate settlement of 14.00 mm, the model of the 20 cm long bakau piles foundation is 52.00 kN with the ultimate settlement of 13.00 mm, the foundation model a 30 cm long bakau piles foundation of 54.00 kN with a 10.00 mm ultimate settlement, a 40 cm long bakau piles foundation model of 56.00 kN with an ultimate settlement of 8.50 mm.
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Benbouras, Mohammed Amin, Alexandru-Ionuţ Petrişor, Hamma Zedira, Laala Ghelani i Lina Lefilef. "Forecasting the Bearing Capacity of the Driven Piles Using Advanced Machine-Learning Techniques". Applied Sciences 11, nr 22 (18.11.2021): 10908. http://dx.doi.org/10.3390/app112210908.
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Estimating the bearing capacity of piles is an essential point when seeking for safe and economic geotechnical structures. However, the traditional methods employed in this estimation are time-consuming and costly. The current study aims at elaborating a new alternative model for predicting the pile-bearing capacity based on eleven new advanced machine-learning methods in order to overcome these limitations. The modeling phase used a database of 100 samples collected from different countries. Additionally, eight relevant factors were selected in the input layer based on the literature recommendations. The optimal inputs were modeled using the machine-learning methods and their performance was assessed through six performance measures using a K-fold cross-validation approach. The comparative study proved the effectiveness of the DNN model, which displayed a higher performance in predicting the pile-bearing capacity. This elaborated model provided the optimal prediction, i.e., the closest to the experimental values, compared to the other models and formulae proposed by previous studies. Finally, a reliable and easy-to-use graphical interface was generated, namely “BeaCa2021”. This will be very helpful for researchers and civil engineers when estimating the pile-bearing capacity, with the advantage of saving time and money.
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Qinglai, Fan, i Gao Yufeng. "Effect of Reinforcement Ratio and Vertical Load Level on Lateral Capacity of Bridge Pile Foundations". Polish Maritime Research 25, s3 (1.12.2018): 120–26. http://dx.doi.org/10.2478/pomr-2018-0120.
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Abstract The bearing response of pile foundations for cross-sea bridge subjected to lateral loading is investigated through threedimensional finite element numerical analyses. In the analyses, non-linear behavior of concrete is simulated using smeared cracking model, and the strain-stress relationship of rebar is modeled through perfectly elasto-plastic model obeying Mises yield criterion. The finite element model is validated against published lateral static loading test in situ. The effect of reinforcement ratio of reinforced concrete and vertical load level is explored on the displacement of pile head and lateral capacity of pile. The results show that for the pile with low reinforcement ratio, the allowable lateral capacity is controlled by concrete cracking, however the allowable lateral capacity is controlled by the displacement of pile head with high reinforcement ratio. The vertical load applied on the pile head may reduce its displacement but increase simultaneously the maximum moment in the pile body. Therefore, the optimum vertical load level is 0.4~0.6 times of the vertical ultimate load of a single pile.
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Панасюк, Леонид, Leonid Panasyuk, Галина Кравченко, Galina Kravchenko, Елена Труфанова, Elena Trufanova, Инал Тарба, Inal Tarba, Лаша Цвейба i Lasha Cveyba. "FINITE ELEMENT MODELLING OF INTERACTION BUILDING FRAME AND SLAB-PILE FOUNDATION". Construction and Architecture 7, nr 1 (19.04.2019): 34–38. http://dx.doi.org/10.29039/article_5c646f16bffb38.56532696.
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The article deals with the simulation of joint work of slab grillage and monolithic frame of the building by finite element method. The finite-element model is developed in the spatial formulation according to the complex scheme "upper structure-base plate-pile Foundation". The pile field was modeled by pliable rods with stiffness corresponding to the average draft of the pile field. Static and dynamic calculations are performed in the ING+software package. The results of the stress-strain state of the building frame elements demonstrate the correctness of this approach to take into account the compliance of the base.
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Shen, Ji Ping. "Torsional Vibration of a Single Pile in Transversely Isotropic Soil Based on Fractional Derivative Viscoelastic Model". Advanced Materials Research 1065-1069 (grudzień 2014): 260–63. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.260.
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A single pile in soil is modeled as a vertical circular elastic prismatic bar, and the soil around the pile is regarded as transversely isotropic medium. The relationship between stress and displacement of the soil is described by fractional derivative viscoelastic model. Ignoring the radial and vertical displacement, the torsional vibration equation of the soil is built. It is solved by using the method of separation of variables and the boundary conditions of the soil. The torsional vibration of the single pile is also obtained. The torsional complex stiffness at pile head is investigated in particular. The results indicate that anisotropic parameters and model parameters of the soil have effects on the torsional complex stiffness, and the influence rules are different with the homogeneous soil.
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Al-Murshidi, Kareem R., Kadhim Naief AL-Ta'ee i Marwa Abdullah AL-Janabi. "FINITE ELEMENT ANALYSIS OF CELLULAR CIRCLE COFFERDAM FOR WET SOIL". Kufa Journal of Engineering 6, nr 1 (21.09.2021): 25–44. http://dx.doi.org/10.30572/2018/kje/611310.
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This paper presented nonlinear finite element analysis to predict the load deflection behavior of circular cell cofferdam under lateral load by using ANSYS (Analysis System) (version 12.1) computer program. Eight-node solid element (SOLID 45) has been used to model filling soil, and the same element by using overlap and glue technique to model steel sheet pile of cofferdam. The bond between steel sheet pile and filling soil has been modeled by using nodes merge.
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Huang, Weiming, Chao Ren, Jinchang Wang i Qinyun Yu. "A simplified planar model for geosynthetics reinforced composite foundation subjected to vertical load". E3S Web of Conferences 198 (2020): 01039. http://dx.doi.org/10.1051/e3sconf/202019801039.
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A simplified planar model for geosynthetics reinforced composite foundation under large-scale loading was established with a new consolidation analysis. The cushion was modeled by modified Pasternak model and the reaction of pile and subsoil was modeled by Winkler model. The effect of geosynthetics layer was directly considered as an elastic cable and the subsoil was divided into numerous columns with only vertical drainage. The solution was obtained by a finite difference based iterative scheme. The feasibility of the model was demonstrated by a case study. Then a parameter study was executed to analyze the effect of several influential factors. The results showed that there is a critical pile –to-pitch ratio that makes the increase of the stiffness of the geosynthetic material the most conducive to deformation control.
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Zhang, Zhiqing, Jian Zhou, Kuihua Wang, Qiang Li i Kaifu Liu. "Dynamic Response of an Inhomogeneous Viscoelastic Pile in a Multilayered Soil to Transient Axial Loading". Mathematical Problems in Engineering 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/495253.
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A quasi-analytical solution is developed in this paper to investigate the mechanism of one-dimensional longitudinal wave propagating in inhomogeneous viscoelastic pile embedded in layered soil and subjected to a transient axial loading. At first, the pile-soil system is subdivided into several layers along the depth direction in consideration of the variation of cross-sectional acoustic impedance of the pile or differences in soil properties. Then, the dynamic governing equation of arbitrary soil layer is established in cylindrical coordinates and arbitrary viscoelastic pile segment is modeled using a single Voigt model. By using the Laplace transform and boundary conditions of the pile-soil system, the vertical impedance at the top of arbitrary pile segment is defined in a closed form in the frequency domain. Then by utilizing the method of recursion typically used in the Transfer Function technique, the vertical impedance at the pile top can be derived in the frequency domain and the velocity response of an inhomogeneous viscoelastic pile subjected to a semi-sine wave exciting force is obtained in a semi-analytical form in the time domain. Selected numerical results are obtained to study the mechanism of longitudinal wave propagating in a pile with a single defect or double defects.
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Li, Lin, Jingpei Li, De’an Sun i Weibing Gong. "Semi-analytical approach for time-dependent load–settlement response of a jacked pile in clay strata". Canadian Geotechnical Journal 54, nr 12 (grudzień 2017): 1682–92. http://dx.doi.org/10.1139/cgj-2016-0561.
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Mechanical behaviour of the soil around a jacked pile changes significantly during pile installation and subsequent consolidation. Hence, an axially loaded jacked pile exhibits apparent time-dependent bearing performance after pile installation. This paper presents a semi-analytical approach to predict the time-dependent bearing performance of an axially loaded jacked pile in saturated clay strata. The effects of pile installation and subsequent consolidation on the changes in mechanical properties of the surrounding soil are modeled by the cavity expansion theory and the radial consolidation theory, respectively. An exponential function–based load-transfer (t–z) curve is employed to describe the nonlinear behaviour of the pile–soil interface during pile loading. The evolutions of the three-dimensional strength and shear modulus of the surrounding soil are subsequently incorporated into the two model parameters of the proposed t–z curve to capture the time-dependent pile–soil interaction behaviour. The time-dependent elastic response of the soil outside the pile–soil interface is also considered in the proposed approach. With the proposed load-transfer curve, an incremental algorithm and a corresponding computational code are developed for assessing the time-dependent load–settlement response of a jacked pile. To verify the proposed semi-analytical approach, predictions of the time-dependent load–settlement curves are compared with the measured values from pile tests at two sites. The good agreement shows that the time-dependent bearing performance can be reasonably predicted by the proposed approach.
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Yousif Aziz, Hussein, i Jianlin Ma. "Deep Foundation Numerical Analysis Using Modified Compression Modulus". Open Civil Engineering Journal 6, nr 1 (14.09.2012): 65–86. http://dx.doi.org/10.2174/1874149501206010065.
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This paper is a study on the behavior and prediction of settlement values of bridge pile foundations due to con-struction loads. Field test results show new field technique using the single point of account settlement meter to estimate the thickness of compressed layer in the deep soft soils which is considered as a difficult task in the field. The settlement is predicted using hyperbolic model and statistical regression. The statistical models indicate that the structure would re-main safe for a long period of time, and the field measurements are compared with the hyperbolic model results and those predicted by the statistical regression. The finite element Plaxis 3D Foundation program is used in the analysis with a new empirical equation to modify the input parameters represented by the soil compression modulus. The foundation soils are modeled with the Mohr-Coulomb plasticity material model. The piles are represented with pile elements, between the pile and the surrounding soil, interface elements are automatically generated by the program. In the analysis, the effects due to soil stiffness, pile length and pile spacing are considered. The calculated results for the simulation of the pile installation sequence are compared with the measured results obtained from the field monitoring. The results of the numerical analy-sis using the proposed empirical equation provide insight to the settlement analysis of pile groups in soft clayey soils and the finite element Plaxis 3D program can be a useful tool for numerical analysis. In this paper, the numerical analysis cal-culations are modified using a new empirical equation to calculate the compression modulus from those obtained from the test which modify the results of the settlement and thus become close to the reality. Finally, the numerical finite element analysis produced logical and conservative results as compared to the statistically derived equations and those calculated by hyperbolic model analysis. This scenario can be applied to the similar problems in the theoretical applications of bridge foundations.
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Moon, Jiho, Dawn E. Lehman, Charles W. Roeder, Hak-Eun Lee i Tae-Hyung Lee. "Analytical Evaluation of Reinforced Concrete Pier and Cast-in-Steel-Shell Pile Connection Behavior considering Steel-Concrete Interface". Advances in Materials Science and Engineering 2016 (2016): 1–14. http://dx.doi.org/10.1155/2016/4159619.
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The seismic design of bridges may require a large-diameter deep pile foundation such as a cast-in-steel-shell (CISS) pile where a reinforced concrete (RC) member is cast in a steel casing. In practice, the steel casing is not considered in the structural design and the pile is assumed to be an RC member. It is partially attributed to the difficulties in evaluation of composite action of a CISS pile. However, by considering benefits provided by composite action of the infilled concrete and the steel casing, both the cost and size of CISS pile can be reduced. In this study, the structural behavior of the RC pier and the CISS pile connection is simulated by using an advanced 3D finite element (FE) method, where the interface between the steel and concrete is also modeled. Firstly, the FE model is verified. Then, the parametric study is conducted. The analysis results suggest that the embedment length and the friction coefficient between the steel casing and the infilled concrete affect the structural behavior of the RC pier. Finally, the minimum embedment length with reference to the AASHTO design guideline is suggested considering the composite action of the CISS pile.