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1
Xu, Hong-Fa, Ji-Xiang Zhang, Xin Liu, Han-Sheng Geng, Ke-Liang Li, and Yin-Hao Yang. "Analytical Model and Back-Analysis for Pile-Soil System Behavior under Axial Loading." Mathematical Problems in Engineering 2020 (March 19, 2020): 1–15. http://dx.doi.org/10.1155/2020/1369348.
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The interaction mechanism between piles and soils is very complicated. The load transfer function is generally nonlinear and is affected by factors such as pile side roughness, soil characteristics, section depth, and displacement. Therefore, it is difficult to solve the pile-soil system based on load transfer function. This paper presents a new method to study the soil-pile interaction problem with respect to axial loads. First, the shapes of the axial force-displacement curves at different depths and the displacement distribution curves along pile axis at different pile-top displacements were analyzed. A simple exponential function was taken as relationship model to express the relationship curves between two distribution functions of axial force and displacement along pile shaft obtained by using the geometric drawing method. Second, a new analytical model of the pile-soil system was established based on the basic differential equations for pile-soil load transfer theory and the relationship model and was used to derive the mathematical expressions on the distribution functions of the axial force, the lateral friction, and the displacement along pile shaft and the load transfer function of pile-side. We wrote the MATLAB program for the analytical model to analyze the influence laws of the parameters u and m on the pile-soil system characteristics. Third, the back-analysis method and steps of the pile-soil system characteristics were proposed according to the analytical model. The back-analysis results were in good agreement with the experimental results for the examples. The analysis model provides an effective way for the accurate design of piles under axial loading.
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Richwien, W., and Z. Wang. "Displacement of a pile under axial load." Géotechnique 49, no. 4 (August 1999): 537–41. http://dx.doi.org/10.1680/geot.1999.49.4.537.
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Meyerhof, G. G., and V. V. R. N. Sastry. "Bearing capacity of rigid piles under eccentric and inclined loads." Canadian Geotechnical Journal 22, no. 3 (August 1, 1985): 267–76. http://dx.doi.org/10.1139/t85-040.
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The ultimate bearing capacity of instrumented vertical single rigid model piles in homogeneous loose sand and soft clay under vertical eccentric and central inclined loads has been investigated. The results of these load tests provide a more realistic lateral soil pressure distribution on the pile shaft and better theoretical estimates of pile capacity under pure moment and under horizontal load. For intermediate eccentricities and inclinations of the load, the bearing capacity can be obtained from simple interaction relationships between the axial load and moment capacities and between the axial and horizontal load capacities, respectively. The influence of lateral soil pressures due to installation of displacement piles in clay is examined in relation to the ultimate load of the pile. The analyses are compared with the results of model tests and some field case records. Key words: bearing capacity, clay, eccentric loading, horizontal load, instrumentation, model test, pile, sand.
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Cai, Yan-yan, Bing-xiong Tu, Jin Yu, Yao-liang Zhu, and Jian-feng Zhou. "Numerical Simulation Study on Lateral Displacement of Pile Foundation and Construction Process under Stacking Loads." Complexity 2018 (2018): 1–17. http://dx.doi.org/10.1155/2018/2128383.
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Lateral displacement of pile foundation is crucial to the safety of an overall structure. In this study, a numerical simulation on the lateral displacement of pile foundation under stacking loads was conducted to determine its relation with different influencing factors. Simulation results demonstrated that stacking loads at the pile side mostly influence the lateral displacement of pile foundation. The lateral displacement of pile foundation increases by one order of magnitude when the stacking loads increase from 100 kPa to 300 kPa. Other influencing factors are less important than stacking loads. Lateral displacements of the pile body and at the pile top can be reduced effectively by increasing the deformation modulus of surface soil mass, reducing the thickness of soft soil, and expanding pile diameter. Our analysis indicates that a nonlinear relationship exists between the lateral displacement at the pile top and the pile diameter. The lateral resistance of the pile body can be enhanced by coupling the stacking load along piles and the axial force at the pile top. An actual large-scale engineering project was chosen to simulate the effects of postconstructed embankment on lateral displacement and axial force of bridge pile foundation under different construction conditions and to obtain the lateral displacement of the pile body and the negative frictional resistance caused by soft soil compression under stacking loads. On the basis of the calculated results, engineering safety and stability were evaluated, and a guide for the design and construction was proposed.
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Ma, Tianzhong, Yanpeng Zhu, Xiaohui Yang, and Yongqiang Ling. "Bearing Characteristics of Composite Pile Group Foundations with Long and Short Piles under Lateral Loading in Loess Areas." Mathematical Problems in Engineering 2018 (November 12, 2018): 1–17. http://dx.doi.org/10.1155/2018/8145356.
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It is very necessary to research the bearing characteristics of composite pile group foundations with long and short piles under lateral load in loess areas, because these foundations are used widely. But few people researched this problem in loess areas up to now worldwide. In this paper, firstly, an indoor test model of a composite pile foundation with long and short piles is designed and then employed to explore the vertical load bearing characteristics and load transfer mechanisms of a single pile, a four-pile group, and a nine-pile group under different lateral loads. Secondly, ANSYS software is employed to analyze the load-bearing characteristics of the test model, and for comparison with the experimental results. The results demonstrate the following. (1) The lateral force versus pile head displacement curves of the pile foundation exhibit an obvious steep drop in section, which is a typical feature of piercing damage. A horizontal displacement limit of the pile foundation is 10 mm and 6mm for the ones sensitive to horizontal displacement. (2) The axial force along a pile and frictional resistance do not coincide, due to significant variations and discontinuities in the collapsibility of loess; a pile body exhibits multiple neutral points. Therefore, composite pile groups including both long and short piles could potentially maximize the bearing capacity and reduce pile settlement. (3) The distribution of stress and strain along the pile length is mainly concentrated from the pile head to a depth of about 1/3 of the pile length. If the lateral load is too large, short piles undergo rotation about their longitudinal axis and long piles undergo flexural deformation. Therefore, the lateral bearing capacity mainly relies on the strength of the soil at the interface with the pile or the horizontal displacement of the pile head.
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Qiu, Hong Zhi, Ji Ming Kong, and Yin Zhang. "Analysis on Dynamic Response of the Foundation Pit Supporting Structure under Vehicle Loads." Advanced Materials Research 790 (September 2013): 638–42. http://dx.doi.org/10.4028/www.scientific.net/amr.790.638.
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Using ABAQUS software analyzed the dynamic response of foundation pit supporting structure under vehicle loads. The vehicle load was simplified as a half-wave sinusoidal load, in order to analyze the influence of internal force and displacement of pile-anchor supporting structure under the vehicle loads, the position of half-wave sinusoidal load and the size of radian frequency were considered. Loading location away from the supporting structure is more nearly and the displacement value of support piles is greater, the greater the axial force of the bolt; with the increasing of radian frequency, the horizontal displacement value of supporting piles increased, on the contrary, the axial force of bolt reduced. A practical engineering was studied here. analysis of the monitoring data and compared with the numerical results, the analysis showed that the experimental results and numerical results are in good agreement, and the numerical method can be used as an effective means of research. The conclusion of the study has significance on engineering practice.
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Chen, Chi, Long Zou, and Hong Bo Shen. "Axial Force Analysis of the Single Pile Based on FLAC3D." Advanced Materials Research 790 (September 2013): 418–21. http://dx.doi.org/10.4028/www.scientific.net/amr.790.418.
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Complex interaction mechanism of pile and soil, pile load transfer analysis is difficult. On the basis of analyzing the load transfer mechanism of the friction pile, using the FLAC3D analysis on the initial ground stress state of equilibrium , axial load under the action of pile axial force and displacement, got the ultimate load bearing capacity of single pile and the stress of the contact surface. Analysis results show that the load and displacement in a certain stage into a proportional relationship. Also shows that simulation is feasible and provide a reliable method for the analysis of pile groups.
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El Naggar, M. Hesham, and Jin Qi Wei. "Axial capacity of tapered piles established from model tests." Canadian Geotechnical Journal 36, no. 6 (December 1, 1999): 1185–94. http://dx.doi.org/10.1139/t99-076.
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Tapered piles represent a more efficient distribution of pile material than uniform cross section piles in several respects. An extensive experimental research program was conducted to study the efficiency of tapered piles compared with piles of uniform cross section with the same material input. Three instrumented model steel piles with different degrees of taper were used in this program. The piles were tested in a large-scale laboratory setup under compressive and tensile loads. The pile head load and displacement and the strain along the piles were measured simultaneously. The objectives of the present paper were twofold: to examine the validity of the experimental results, and to use the unit load transfer curves established from the experimental results to predict the bearing capacity of prototype tapered piles. The shaft resistance for straight-sided wall piles established from the experimental results compared well with the theoretical predictions using the standard design procedure. The beneficial effect of pile taper was significant up to a depth of 20 pile diameters. The negative effect of the pile taper on the uplift capacity diminished quickly with depth and hence the performance of actual tapered piles (with greater length) would be comparable to that of straight-sided wall piles.
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Karkush, M. O. "Impacts of Soil Contamination on the Response of Piles Foundation under a Combination of Loading." Engineering, Technology & Applied Science Research 6, no. 1 (February 5, 2016): 917–22. http://dx.doi.org/10.48084/etasr.616.
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The behavior of single piles driven into contaminated clayey soil samples subjected to a combination of static axial and cyclic lateral loadings have been studied in this research. A laboratory model was manufactured especially for studying such behavior. A solid circular cross sectional area pile of diameter 19 mm and made from aluminum, the pile was embedded into the soil with an eccentricity to embedded length (e/L) ratio of 0.334. The intact soil samples and industrial wastewater were obtained from the center of Iraq. The industrial wastewater is a byproduct disposed from Musayib thermal electric power plant. The intact clayey soil samples were synthetically contaminated with four percentages of 10, 20, 40 and 100% from the weight of water used in the soaking process which continued for a period of 30 days. The different percentages of contaminant concentrations have significant effects on the lateral load-displacement relation of the piles subjected to a combination of axial and lateral loadings. The vertical displacement under the same vertical load increased by 5–95%, the axial strength of piles decreased by 10–34% and the lateral-bearing capacity of the piles decreased by 10–34% with increasing the percentage of contamination from 10 to 100%. The ratio of permanent lateral displacement to the total lateral displacement was increased by 23–27% when the concentration of contaminant increased by 10-100%. Generally, the application of axial loading increases the lateral-bearing capacity of piles, and reduces the total lateral displacement.
10
Chen, Xing Chong, Xue Lin Yue, and Yong Liang Zhang. "Research on Method of Non-Linear Static Pushover Analysis and Influential Mechanism of Displacement Ductility of Single Pile." Applied Mechanics and Materials 204-208 (October 2012): 990–94. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.990.
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In this article, the distribution of plastic hinge model is adopted to simulate the elastic and plastic of pile body, p-y curve is used to simulate resistance of pile foundation soil. We do static non-linear pushover analysis of the single pile of pile foundations, and research the influence of the axial compressive ratio η of pile shaft, longitudinal reinforcement rate ρ of section, stirrup ratio µof section and shear strength C of foundation soil to the system-interaction of pile and soil. The result shows that axial compressive ratio of pile shaft has a significant influence on horizontal limit bearing capacity and the displacement ductility of the system. With the increase of the axial compressive ratio, system of the displacement ductility reduces gradually, but the limit bearing capacity increases gradually. Under a horizontal load, the order and the mechanism of plastic hinge are obviously different because of different axial compressive ratio of pile shaft，This analysis method may further provide a reference for nonlinear seismic analysis of pile bents.
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El Sharnouby, M. M., and M. H. El Naggar. "Field investigation of axial monotonic and cyclic performance of reinforced helical pulldown micropiles." Canadian Geotechnical Journal 49, no. 5 (May 2012): 560–73. http://dx.doi.org/10.1139/t2012-017.
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Helical piles are used increasingly to support new and existing foundations. This paper presents a field study on the axial monotonic and cyclic behaviour of steel fibre–reinforced helical pulldown micropiles. Test piles consisted of a round corner square helical pile with three helices attached to it, and a steel fibre–reinforced grout shaft. To assess the grout shaft contribution, one helical pile without a grout shaft was tested. Piles were instrumented with strain gauges to evaluate the load-transfer mechanism. This paper discusses the load–displacement response of this pile system, and load-sharing mechanism between the grout shaft and lead section. The study shows that the grout shaft significantly improves the helical pile axial performance. It was found that the load-transfer mechanism within the lead section is through individual bearing of each helix. Also, the findings demonstrate that the behaviour of this pile system is satisfactory under one-way cyclic loading conditions. The results suggest that the reinforced helical pulldown micropile is a viable deep foundation option for axial monotonic and one-way cyclic loading applications.
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Shao, Hailong, and Jongsoo Lee. "Optimal pile design of dolphin structure considering axial compressive pressure-bending moment ratio under offshore load conditions." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 233, no. 4 (November 22, 2018): 1141–53. http://dx.doi.org/10.1177/1475090218813598.
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This study proposes an optimal design of a dolphin structure under offshore load conditions such as berthing, mooring, wind, wave, and current loads. The design objective is to reduce the total weight of the pile structure by determining its diameter, thickness, and arraying direction with constraints of axial compressive pressure-bending moment ratio and total displacement. As design requirements, the stress has to be satisfied under the allowable compressive pressure-bending moment, and the total displacement of the steel piles should be less than 0.1 m on the upper deck. The structural analysis data are generated using Box–Behnken design based on the design of experiments. In the meta-model-based approximate optimization process, the pressure-bending moment ratio and total displacement are expressed using a backpropagation neural network, and the structural weight of the pile is approximated via a second-order polynomial-based response surface model. Compared with the initial design, the optimal solution of the total weight of the steel piles reduces by 27.37% under the satisfied constraint conditions. For the post-optimization study, the optimal sensitivity analysis with respect to the seabed level is conducted.
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Cao, Zhi Xiang, and Xiu Li Cao. "Seismic Performance Analysis of Transmission Tower System Based on MATLAB Numerical Calculation." Advanced Materials Research 446-449 (January 2012): 43–48. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.43.
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Transmission tower line system dynamic response and failure mechanism are very complex under seismic load, the dynamic response and cooperation mechanism of the upper structure, pile and soil of transmission tower line system under seismic load based on the MATLAB numerical calculation method in this paper, and the displacement, acceleration velocity and displacement of axial force distribution of different positions of transmission tower line system are calculated by building transmission tower line of the stiffness matrix, equivalent load node, system quality matrix, motion equation and the upper structure of whole pile of model and with the help of the solution of the MATLAB function. The numerical calculation results show that the soil-consider the upper structure of pile-coordination effects for displacement and acceleration amplification effect are obvious, but the truss of axial force amplification effect is relatively small. Meanwhile, the earthquake action soil pile-between the upper structure are strong dynamic interaction, which provides certain theoretical guidance for recognizing transmission tower line system dynamic response mechanism under earthquake and adopting efficient anti-seismic measures.
14
Jia, Jin Lu, Zhong Fu Wang, and Jian Hua Zheng. "Experimental Study on Bearing Behavior of Large-Diameter Overlength Squeezed Branch Pile." Advanced Materials Research 243-249 (May 2011): 3244–50. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.3244.
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Squeezed branch pile is based on the traditional uniform pile in development of a new type of pile, with a high bearing capacity, settlement of small features widely used in the engineering. Based on the actual project site static test, analyzed the vertical bearing capacity characteristics of two adjacent squeezed branch piles; By means of testing of the pile stress gauge steel embedded in different parts of piles, the axial force transfer characteristics of the body, support plate side resistance drag and play characteristics of the squeezed branch pile were analyzed. The results showed that: the branch pile Q-S curve is slowly varying type, the three branch share of the load ratio increases with the pile top load increases and then decreases, load sharing ratio of 12% or so. The side resistance increased with the pile top displacement, the curve showed significant enhancement traits. Measured friction value of two test piles is too conservative under the existing norms, the actual measured value of 1.2～1.6 times of the standardized value.
15
Lin, Hai, Muhannad T. Suleiman, Hanna M. Jabbour, and Derick G. Brown. "Bio-grouting to enhance axial pull-out response of pervious concrete ground improvement piles." Canadian Geotechnical Journal 55, no. 1 (January 2018): 119–30. http://dx.doi.org/10.1139/cgj-2016-0438.
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Bio-grouting is an environmentallly friendly, sustainable, and low-cost ground improvement technique, which mainly utilizes microbial-induced carbonate precipitation. Previous large-scale applications of MICP have encountered practical difficulties including bio-clogging, which resulted in a limited zone of cemented soil around injection points. The research presented in this paper focuses on evaluating the feasibility of cementing a limited soil zone surrounding permeable piles using MICP bio-grouting to improve the mechanical response of permeable piles under axial pull-out loading. Two instrumented pervious concrete piles (test units), one with and one without MICP bio-grouting, were subjected to pull-out loading at the Soil-Structure Interaction Facility at Lehigh University. The pervious concrete pile served as an injection point during the MICP bio-grouting. The mechanical responses of the test units and surrounding soil were analyzed, along with shear wave (S-wave) velocities, moisture, and CaCO3 contents of the surrounding soil. The results presented in this paper demonstrate that the limited MICP-improved zone, extending a radial distance of approximately 102 mm around pervious concrete piles, improved the load–displacement response, load transfer, and pile capacity under pull-out loading. The ratios between ultimate loads of the test units with and without MICP bio-grouting were 4.2. The average shaft resistance along the pile with MICP bio-grouting was up to 2.8 times higher than that of the pile without bio-grouting.
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Xu, Zhijun, and Zhaoxiang Guo. "Experimental Study on Bearing Characteristics and Soil Deformation of Necking Pile with Cap Using Transparent Soils Technology." Advances in Civil Engineering 2021 (March 23, 2021): 1–11. http://dx.doi.org/10.1155/2021/6625556.
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This paper will employ the transparent soil experiment technology to explore the influences of shallow necking on the vertical bearing capacity of single pile with cap. Model experiment is carried out on one intact pile and nine shallow necking piles. The load-settlement curves of all piles are obtained, which are used to study bearing characteristics of piles. The displacement fields of soil around piles are employed to investigate the reasons for the loss of vertical bearing capacity of piles with shallow necking. The vertical bearing capacity is greatly reduced which is caused by shallow necking. When the axial dimension of necking is the same, the larger the radial size is, the greater the loss of vertical bearing capacity is. When the radial dimension of necking is the same, the greater the axial size is, the greater the loss of vertical bearing capacity is. The soil near the pile shaft and under the pile cap produces a large area of vertical downward deformation, which causes the relative displacement between the pile shaft and the soil to greatly reduce. Therefore, it is easy that the necking piles with caps develop negative friction, which causes the vertical bearing capacity of piles to reduce. When the radial dimension of the shallow necking is 80% of pile diameter, the pile is easy to be damaged.
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Zhang, Shi Min, and Gang Wei. "A Destructive Field Study on the Behavior of Pile under Ten." Advanced Materials Research 163-167 (December 2010): 4524–28. http://dx.doi.org/10.4028/www.scientific.net/amr.163-167.4524.
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This paper involves a destructive full-scale load test on long bored pile instrumented with strain gauges along the shaft. The load-displacement response, the distribution of axial force, and the thresholds of displacement for fully mobilizing the skin resistances in different soils in tension case were discussed in this paper. The field test results show that the measured tip resistance in the pile under tension is near zero during the whole loading, and the softening is accompanied with a reduction in skin friction when the skin friction is fully developed. It also can be investigated that the threshold of displacement for fully mobilizing skin friction is different even if in the same soil type due to different soil stress states. Generally speaking, the thresholds of relative pile-soil displacement for fully mobilizing skin frictions in the sandy silt, silty sand mixed silt, silty clay, silty clay mixed sand and gravel are about 4 mm, 11 mm, 7 mm, 6 mm, and 5.5 mm, respectively.
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Elsiragy, M. N. "Filed Comparative Investigation of Loading Test on Micro-Piles Installed with Different Technique – (Case Study)." European Journal of Engineering and Technology Research 6, no. 4 (June 17, 2021): 88–93. http://dx.doi.org/10.24018/ejers.2021.6.4.2454.
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Foundation can be subjected to additional load and constructed in soft soils; therefore, the settlement or foundation tilting is achieved. The most beneficial method to control the settlement and foundation tilting are to be used Micro-piles which have been considered is an effective and easy to reinforce the existing foundation, it also successfully adopted in many ground improvement techniques to safeguard structure from collapse. The paper aims to study the behavior of full-scale micro piles under compression in the filed with length of 20 m as end bearing with diameter of 88.9 mm. This study is focused on the observing the behavior of three micro-piles installed with different technique. The first is normal one without injection as pipe piles MP1, the second is pipe pile with grouted bulb MP2 only under the toe of micro-piles and inside grouting. The last one or third micro-pile MP3 is pipe pile with fully injection for both toe and around the pile length. Three loading tests in the field are carried out to show the load settlement response under axial compression and horizontal load to get the ultimate micro-pile capacity. The results showed that the fully injected micro-piles with grouting have a higher ultimate load capacity and minor settlement compared with other two cases. The ultimate load capacities for fully grouted micro-piles and only with grouted bulb are found to be 13 and 8 times of ultimate capacity of pipe micro-piles without grouted bulb at the toe respectively. Also, it is found that the ultimate horizontal load capacity of Mp3 is found to be 27 ton while it is recorded as 3 and 4 ton for MP1 and MP3 respectively at horizontal displacement of 0.2 micro-pile diameter.
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Chen, Jia Xing, Yuan Cheng Guo, Jing Wei Zhang, and Tong He Zhou. "Experimental Research on Lateral-Load Behavior of Large Diameter Drilled Shaft under Axial-Load." Applied Mechanics and Materials 584-586 (July 2014): 2028–36. http://dx.doi.org/10.4028/www.scientific.net/amm.584-586.2028.
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Using the Two-way composite loading experimental device, the bearing performance of post-grouting drilled shaft under lateral and axial load is studied by full-scale field test. The result of this research reveals that the lateral critical load Hcr and lateral ultimate load Hu are improved when the axial load is applied to post-grouting drilled shaft, the settlement of post-grouting drilled shaft and not grouting drilled shaft increase while the axial load is close to ultimate load, because the settlement of a foundation pile has a relationship with the size of axial load on the top of pile in the damage process of drilled shaft under lateral load, as well as the variation of vertical settlement of normal drilled shaft is more than that of post-grouting drilled shaft, since the non-grouting drilled shaft is more sensitive to the lateral load than the post-grouting drilled shaft.
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Chen, Hong Kai, Hong Mei Tang, Xian Tao Zhao, Yi Hu, and Xiao Ying He. "Study on Damage Mechanism for Foundation Pile of Girder Bridge under Seismic Influence." Advanced Materials Research 530 (June 2012): 115–21. http://dx.doi.org/10.4028/www.scientific.net/amr.530.115.
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Based on the analysis for seismic load and failure modes of pile foundation, this article adopts dynamic Winkler foundation beam model, and employs continuous distributional and independent spring and damper, instead of the dynamic resistance of the soil around the pile, and to explore interaction between pile and soil dynamic at horizontal load. In consideration of six kinds of boundary conditions combination, this paper proposes the solution method for displacement and internal force on pile. From analysis of cases, it finds that the effect of pile’s length on dynamic response can be negligible when pile slenderness ratio l/d>20, and the pile can be simplified into infinite long pile. Dynamic response of pile increases with the increase of stiffness ratio. When establish the control equations, influence of axial force can not be ignore. Otherwise, results will be small than the actual value.
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Fu, Gui Hai, Li Min Wei, and Hui Zhou. "Analysis of Single Pile Settlement in Layered Soils Based on Shear Displacement Method." Advanced Materials Research 368-373 (October 2011): 2688–91. http://dx.doi.org/10.4028/www.scientific.net/amr.368-373.2688.
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Based on the theory of shear displacement method, the transfer matrix of pile in layered soils was deduced, so the analytical theory of settlement of single pile in layered soils is established, which can take into account the nonlinear influence of soils, and with which settlement, distribution of axial force, displacement and skin resistance of single pile along the depth in layered soils can be easily attained. By contrast with the practically measure data, it can be seen that the method proposed in this paper is simply and comparatively accurate in calculating the pile settlement under working load.
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Zhang, Jian Wei, Zhi Long Wang, and Dong Qin Qiao. "Model Test on Negative Skin Friction for Super-Long Pile under Surcharge Load Considering Time Effect." Applied Mechanics and Materials 470 (December 2013): 1105–8. http://dx.doi.org/10.4028/www.scientific.net/amm.470.1105.
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Super-long pile bridges and high-rise buildings are commonly used in the form of pile foundation. In the flood area, due mainly silt stratum, as well as the decline in groundwater mound pile under the conditions set out in the consolidation, there will be a negative pile skin friction and negative friction obvious time effect, which bearing capacity of the pile has a great influence. Current research on negative friction for super-long pile considering time effect is relatively little. In the model box, on the base of the super-long pile silt model test, set out in a pile mound under consolidation, soil testing flour gradually over time preloading consolidation settlement, pile-soil relative displacement, so as to arrive negative friction pile variation with time, tip resistance variation with time from the pile-axial force curve deduce the location of the neutral point and changes in circumstances, the pile foundation engineering practice has a certain significance.
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Aghayarzadeh, Mehdi, and Hadi Khabbaz. "Numerical simulation of concrete pile groups' response bored in cemented sand deposit under axial static load testing." E3S Web of Conferences 92 (2019): 16011. http://dx.doi.org/10.1051/e3sconf/20199216011.
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For a safe foundation to perform as desired, the ultimate strength of each pile must fulfil both structural and geotechnical requirements. Pile load testing is considered as a direct method of determining the ultimate bearing capacity of a pile. Pile groups are commonly used in foundation engineering and due to the difficulties and cost of full-scale load tests, most pile group tests are scaled down regardless of whether performed in the field or laboratory. In this paper, it is aimed to simulate the behaviour of concrete bored pile groups under axial static load testing using PLAXIS 3D software and to compare the obtained results with measured curves in an experimental study introduced in the literature. In numerical simulation, to account for the stiffness variation existing inside the pile group and to achieve a reasonable correlation between measured and predicted load-settlement curves three different analyses, including linear elastic, completely non-linear, and a combination of non-linear and linear analyses were performed. The results indicate that the combined non-linear and linear analysis seems a suitable analysis for pile group behaviour prediction.
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Tang, Chong, and Kok-Kwang Phoon. "Statistical evaluation of model factors in reliability calibration of high-displacement helical piles under axial loading." Canadian Geotechnical Journal 57, no. 2 (February 2020): 246–62. http://dx.doi.org/10.1139/cgj-2018-0754.
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An industry survey suggests an increasing application of high-displacement helical piles with greater shaft and helix diameters to support various structures. In this paper, a database of 84 static load tests is compiled and analyzed to evaluate the disturbance effect and characterize the model factors that can be used for reliability-based limit state design. The measured capacity is defined as the load at a pile head settlement equal to 5% of helix diameter. For similar helix configurations tested at the same site, the ratio of uplift to compression capacity indicates a low degree of disturbance for very stiff clay (0.8–1) and a medium degree of disturbance for dense sand (0.6–0.8). At the ultimate limit state, the model factor is defined as the ratio between measured and calculated capacity, where three design guidelines are considered. A hyperbolic model with two parameters is used to fit the load–displacement curves. At the serviceability limit state, the model factor can be defined with the hyperbolic parameters. Based on the database, probabilistic distributions of the capacity model factor and hyperbolic parameters are established. Finally, the capacity model statistics are applied to calculate the resistance factor in the load and resistance factor design.
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Yang, Tong, Yuming Men, Cassandra J. Rutherford, and Zhen Zhang. "Static and Dynamic Response of Micropiles Used for Reinforcing Slopes." Applied Sciences 11, no. 14 (July 8, 2021): 6341. http://dx.doi.org/10.3390/app11146341.
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To study the static and dynamic response of micropile-reinforced slopes, static model tests and shaking table tests were performed. The failure modes, the pile-slope interaction, the displacement, and the static/dynamic earth pressure distributions were analyzed based on static and dynamic model tests with a prescribed sliding surface. The test results indicated: (1) The micropile failure mode is mainly bending failure under both loading conditions. As far as the damage to the pile body is concerned, under static loading, the rear row piles showed more damage than the middle row piles followed by the front row piles. Under dynamic loading, the damage of the rear row piles was approximately the same as the middle row piles, which was greater than the front row piles; (2) The earth pressures in front of and behind each row of micropiles and the axial force of the pile body distributed triangularly for both loading conditions, with the bending moment of the pile body distributed in an “S” shape; (3) The landslide thrust experienced by the micropiles has a relatively large group effect. The group effect or shear ratio parameters are recommended for each loading case; (4) The interaction between the micropiles and the soil landslide presents evident progressive failure and load transfer between the rows.
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Kahribt, Muqdad Abdallah, and Jasim M. Abbas. "Lateral Response of a Single Pile under Combined Axial and Lateral Cyclic Loading in Sandy Soil." Civil Engineering Journal 4, no. 9 (September 24, 2018): 1996. http://dx.doi.org/10.28991/cej-03091133.
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According to practical situation, there have been limited investigations on the response of piles subjected to combined loadings especially when subjected to cyclic lateral loads. Those few studies led to contradictory results with regard to the effects of vertical loads on the lateral response of piles. Therefore, a series of experimental investigation into piles in dense sand subjected to combination of static vertical and cyclic lateral loading were conducted with instrumented model piles. The effect of the slenderness ratio (L/D) was also considered in this study (i.e. L/D= 25 and 40). In addition, a variety of two-way cyclic lateral loading conditions were applied to model piles using a mechanical loading system. One hundred cycles were used in each test to represent environmental loading such as offshore structures. It was found that under combined vertical and cyclic lateral loads the lateral displacement of piles decreased with an increase in vertical load whereas it causes large vertical displacements at all slenderness ratios. In addition, for all loading conditions the lateral, vertical (settlement and upward) displacements and bending moments increased as either the magnitude of cyclic load or the number of cycles increases.
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Subair, Aysar Hassan, and Ala Nasir Aljorany. "Shaft Resistance of Long (Flexible) Piles Considering Strength Degradation." Journal of Engineering 27, no. 3 (February 27, 2021): 54–66. http://dx.doi.org/10.31026/j.eng.2021.03.04.
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Soil-structure frictional resistance is an important parameter in the design of many foundation systems. The soil-structure interface area is responsible for load transferring from the structure to the surrounding soil. The mobilized shaft resistance of axially loaded, long slender pile embedded in dense, dry sand is experimentally and numerically analyzed when subjected to pullout force. Experimental setup including an instrumented model pile while the finite element method is used as a numerical analysis tool. The hypoplasticity model is used to model the soil adjacent to and surrounding the pile by using ABAQUS FEA (6.17.1). The soil-structure interface behavior depends on many factors, but mainly on the interface soil's tendency to contract or dilate under shearing conditions. To investigate this tendency, three piles with different surface roughness and under different confining pressures are used. A dilation behavior is observed in the relation of the average shaft resistance with the axial displacement for piles with rough and medium roughness surfaces, while contraction behavior is noticed when shearing piles with smooth surfaces. A large shear strength degradation of about (10%) reduction in the shaft resistance is observed under low confining pressure compared to a lesser reduction value of about (2%) under high confining pressure. Good agreement is obtained between the experimental and the numerical results.
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Xiao, Wen Sheng, Xiu Juan Lin, and Hong Yan Wang. "Mechanical Stability Analysis of Subsea Wellhead for Deepwater Production to Earthquake Load." Applied Mechanics and Materials 44-47 (December 2010): 1061–65. http://dx.doi.org/10.4028/www.scientific.net/amm.44-47.1061.
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Subsea wellhead for deepwater production subjects to axial force, lateral force and bending moment under the seismic loading, the effect of subsea christmas tree and casing string’s gravity. Joint action of these forces makes it is possible that horizontal displacement exceeds the limitation and thus loses the stability. A mechanical analytical model of subsea wellhead for deepwater production is established on the basis of the pile foundation theories and material mechanics, the seismic load and behavior between casing string and formation are considered. The analyses on lateral displacement, angular distortion, bending moment and shear force show that the affection of lateral load is focus on the upper section of casing string, and the lateral displacement of subsea wellhead for deepwater production increases along with earthquake load and thus decreases stability. The stability improves notably with the increase of coefficient of soil reaction. Therefore it is necessary to obtain the on-the-spot geological data in shallow formation. The wellhead stability may be improved to different degrees by taking measures such as minimizing axial load, enhancing the conductor bending strenth, increasing the depth of the casing string in soil, reducing the outcropping length of the casing string.
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Rakh, Avinash A. "Behavior of Pervious Concrete Pile based on Vertical Loading." International Journal for Research in Applied Science and Engineering Technology 9, no. VII (July 31, 2021): 3884–91. http://dx.doi.org/10.22214/ijraset.2021.37231.
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Permeable granular piles are used to increase the time rate of consolidation, reduce liquefaction potential, improve bearing capacity, and reduce settlement. However, the behaviour of granular piles depends on the confinement provided by surrounding soil, which limits their use in very soft clays and silts, and organic and peat soils. This research effort aims to develop a new ground-improvement method using pervious concrete piles. Pervious concrete piles provide higher stiffness and strength, which are independent of surrounding soil confinement, while offering permeability comparable to granular piles. This proposed ground-improvement method can improve the performance of different structures supported on poor soils. To achieve the goal of the research project, a series of pervious concrete sample mixing has been conducted to investigate the pervious concrete material properties. Laboratory tests are carried out on a pervious concrete pile of 100 mm diameter and variation at different lengths (500mm,400mm,300mm) surrounded by sand of different density. The tests are carried out either with an entire equivalent area loaded to estimate the stiffness of improved ground or only a column loaded to estimate the limiting axial capacity. Pervious concrete is a special concrete product made primarily of a single-sized aggregate. Pervious concrete has been used in pavements to reduce storm-water-runoff quantities and perform initial water-quality treatment by allowing water to penetrate through the surface. In the United States, pervious concrete is mainly used in pavement applications, including sidewalks, parking lots, tennis courts, pervious base layers under heavy-duty pavements, and low traffic-density areas. The vertical load responses of pervious concrete are the variation of soil stresses and displacement are discussed. Nine tests are conducted on pervious concrete pile further investigate the behaviour of the pervious concrete pile and surrounding soil under vertical load condition. Therefore, Pervious Concrete Piles is particularly suitable for reinforcing subsoil that has low strength and poor permeability.
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Wu, Zuo-ju, Zhi-jia Wang, Jun-wei Bi, Xiao Fu, and Yong Yao. "Shaking Table Test on the Seismic Responses of a Slope Reinforced by Prestressed Anchor Cables and Double-Row Antisliding Piles." Shock and Vibration 2021 (May 11, 2021): 1–13. http://dx.doi.org/10.1155/2021/9952380.
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The combined retaining structure has gradually received considerable attention in the slope engineering, due to its good reinforcement effects. However, most of the published research studies were focused on the seismic responses of the single-formal supporting structure only. The investigations of dynamic responses of the combined retaining structures are scarce, and the current seismic design is conducted mainly based on experiences. In this work, a series of large-scale shaking table tests were conducted to investigate the seismic responses of the combined retaining structures (i.e., prestressed anchor cables and double-row antisliding piles) and the reinforced slope under seismic excitations, including amplification effect of internal and surface acceleration of the reinforced slope, distribution and change of prestress of the anchor cable, dynamic response of soil pressure behind the antislide pile, and horizontal displacement of the reinforced slope surface. Test results show that, supported by the reinforcement of composite support system, the slope with the multilayer weak sliding surface can experience strong ground motion of 0.9 g. The load of the antisliding pile has reached 80% of its bearing capacity, and the load of the anchor cable has reached 75.0% of its bearing capacity. When the seismic intensity reaches 0.5 g, the slope surface has an obvious downward trend, which will make the corresponding soil pressure suddenly increase after the antislide pile. At the potential sliding zone, the axial force of the anchor cable will increase suddenly under the action of earthquake; after the earthquake, the initial prestress of the anchor cable will be lost, with the loss range of 17.0%∼23.0%. These test results would provide an important reference for the further study of the seismic performance of such composite support structure.
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Zhang, Xizhi, Sixin Niu, Jia-Bao Yan, and Shaohua Zhang. "Seismic behaviour of prestressed high-strength concrete piles under combined axial compression and cyclic horizontal loads." Advances in Structural Engineering 22, no. 5 (October 12, 2018): 1089–105. http://dx.doi.org/10.1177/1369433218806191.
Full textAbstract:
In order to simulate the seismic behaviour of the prestressed high-strength concrete piles under working state, six full-scale prestressed high-strength concrete piles were tested under combined axial compression and cyclic horizontal loads. Different axial compression levels and prestressing levels of prestressed tendons were studied in this test programme. The failure mode, bending resistance, displacement ductility, stiffness degradation and energy dissipation of the prestressed high-strength concrete piles under different loading scenarios were measured and analysed. Test results indicated that the axial compression ratio and prestressing level of prestressed tendon significantly influenced the seismic performance of prestressed high-strength concrete piles. Theoretical models were developed to predict cracking, yielding and ultimate bending resistances of the prestressed high-strength concrete pile under combined compression and bending. Finite element model was also developed to simulate the ultimate strength behaviour of the prestressed high-strength concrete pile under combined compression and flexural bending. The accuracies of the theoretical and finite element model were checked through validations of their predictions against the reported test results.
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Xu, Jingjing, Xu Xu, and Wenjuan Yao. "New Method for Calculating the Settlement of Single Pile and Pile Group in Soft Soil Area." Advances in Civil Engineering 2020 (November 10, 2020): 1–9. http://dx.doi.org/10.1155/2020/8816704.
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This paper fits the τ-z curve of a single pile by mathematical methods. Based on the one-dimensional similarity of the τ-z curves, the τ-z curves of single pile under different loads are derived. It studies the distribution of the axial force of a single pile by taking the self-weight of the pile and the pile-end resistance ratio into account and establishes the calculated equation of settlement for single pile. The mutual reinforcing effect between the piles is fully considered, and the settlement of each foundation pile in the pile group is deduced in use of shear displacement method. The example analysis shows that the axial force distribution of single pile considering the self-weight and the pile-end resistance ratio is in good agreement with the experimental data. The settlement error of a single pile calculated by the traditional method is 18.52% compared with measured value. When the self-weight and end resistance ratio are not considered, the error reaches 2.26%. However, the error could reduce to 1.64% when they are taken into consideration. It has a good applicability to calculate the settlement of pile group through the τ-z curves of single pile. Also, it can better forecast the settlement behavior of the pile group under similar conditions.
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Gao, Xiao Juan, and Yan Sun. "Load Bearing Capacity Analysis of Squeezed Branch and Plate Pile under Vertical and Lateral Loads." Advanced Materials Research 255-260 (May 2011): 3110–13. http://dx.doi.org/10.4028/www.scientific.net/amr.255-260.3110.
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Considering the initial stress field and concrete damage, no-linearity caused by crack of concrete, non-linear of reinforcement, elastic-plastic of soil around pile, couple interaction between concrete and steel, non-linearity contact of interface between pile and soil, the lateral load bearing capacity of squeezed branch and plate pile under vertical and lateral load is studied with infinite element and finite element couple method. The results indicate that the vertical load decreases the lateral displacement of pile top and increase the pile lateral load bearing capacity at the same time.
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Zhou, Min, Zhong Fu Wang, and Si Wei Wang. "Non-Linear Finite Element Analysis of Squeezed Branch Pile." Advanced Materials Research 243-249 (May 2011): 2409–14. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.2409.
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In this paper, in order to analyze the capability of squeezed branch pile under different work condition and the cooperation mechanism between the pile and soil, non-liner numerical simulation was carried out using ANSYS. In the finite element model, the elastic-perfectly plastic Drucker-Prager material was assumed for soil. Contact interface elements were placed between the pile and soil. It showed that the squeezed branches took lots of the load, and the ratio it took was related to the load and the elastic modulus of soil; the plastic section of the soil was run-through from bottom to the top; the horizontal displacement of the top soil was moved to the pile, but the horizontal displacement of the soil of the bottom was moved away from the pile; the squeezed branch will break away from the soil above the squeezed branch when the load was at a certain value.
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Han, Xue Feng, Yan Dong Wang, Tao Wang, Tong Chao Ding, and Hong Guang Jia. "Study on Dynamic Response of Cylindrical Shells under Combined Load." Applied Mechanics and Materials 333-335 (July 2013): 2151–55. http://dx.doi.org/10.4028/www.scientific.net/amm.333-335.2151.
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In order to study the dynamic response of the cylindrical shell structure which is similar to the missile cabin under the combined effects of axial compressive load and radial aerodynamic load, the equilibrium equation of dynamic response of cylindrical shell is derived based on the Hamiltons principle. The displacement response of cylindrical shell is calculated through employing the numerical method. The calculation results show that the axial displacement response and the radial displacement response of cylindrical shell are much greater than the circumferential displacement response; the radial displacement will be maximum when the excitation frequencies are 285Hz, 594Hz, 1039Hz, 1062Hz, 1093Hz, 1962Hz and 1987Hz; the axial displacement will be maximum when the corresponding excitation frequencies are 81Hz and 294Hz; the peak values of displacement response in non-load plane are not all obtained at the resonance frequency and a certain effect is generated due to the modal coupling.
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Han, Jie, and Shu-Lin Ye. "A field study on the behavior of micropiles in clay under compression or tension." Canadian Geotechnical Journal 43, no. 1 (January 1, 2006): 19–29. http://dx.doi.org/10.1139/t05-089.
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Micropiles have been used for underpinning existing foundations founded on problematic soil, disturbed by the intrusion of underground activities (such as tunneling), or subjected to additional loads (such as stories added to existing buildings). This paper presents a field study on the behavior of single micropiles in soft clay subjected to compression or tension. Two compression and two tension loading tests were conducted on four single micropiles. All the micropiles were instrumented with rebar strain gauges, and they were monitored during the progress of loading. To set up a baseline for underpinned loading tests presented in a companion paper, a full-scale loading test was performed on natural soil. The results from all these full-scale loading tests are presented and analyzed in this paper. The paper discusses loaddisplacement responses, elastic moduli, axial forces, tip resistance, and skin friction relating to micropiles and their interactions with soft clay. Theoretical solutions for bearing capacity of soil, load capacity of piles, and percentage of tip resistance to the total load were adopted for examination of the test results.Key words: micropile, loaddisplacement, load capacity, skin friction, tip resistance.
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Yi, Lu Ping, and Jing Ji. "Finite Element Analysis on an Independent Variable Diameter Pile under Marine Environment." Advanced Materials Research 549 (July 2012): 861–65. http://dx.doi.org/10.4028/www.scientific.net/amr.549.861.
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Research on the mechanical properties of variable diameter Independent pile under the combined action of wind, wave and flow is carried out. Taking a variable diameter Independent pile in CB11F platform of Chengdao oilfield for example, simulative analysis is performed using the finite element software ANSYS , considering the influence for some factors to structure response, that is environmental load, soil conditions and variable diameter position. The variable diameter part of the smooth gradient cone is simplified reasonably, getting the top of the displacement and the whole body stress of variable diameter pile under wave and flow actions, comparing with the result of non-variable diameter pile, the results show that the displacement and stress of variable diameter pile decrease more than 20%, the measure adopted in this paper about decreasing the displacement of independent pile and the stress of whole body is validated.
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Xu, Jin, and Lin Ma. "Study on Bearing Capacity of Prestressed Pipe Pile Foundation Under Horizontal Load." Open Construction and Building Technology Journal 11, no. 1 (November 24, 2017): 301–12. http://dx.doi.org/10.2174/1874836801711010301.
Full textAbstract:
Background and Objective: Prestressed high strength concrete pipe pile (PHC) shows brittle fracture when subjected to more than its own bearing capacity. Therefore, the non-prestressed steel bar is added to the PHC pipe pile, that is, the mixed reinforced pipe pile (PRC). The mechanical behavior of PRC group piles and PHC group piles under horizontal force is studied, and the bending moment diagram and displacement diagram of the pile body are compared so as to find the weak parts. Material and Method: In this paper, Φ600 pipe piles are chosen, and the PRC pipe piles are made of non prestressed steel bars of the same number as the prestressing steel bars, and the two steel bars are spaced apart. Referring to a specific project of Binhai New Area, the geological parameters are used, and the force analysis of group piles under horizontal force is carried out by using the ANSYS software. Results: ANSYS simulation results show that, under the horizontal loading, when the number of piles in group piles is different, the locations of maximum bending moments are different. Increasing the number of the PRC pipe pile with non prestressed reinforcement can effectively reduce the maximum bending moment of the pile body. Conclusion: Under horizontal load, with the increase of pile number and the pile cap aggrandizement, the position of maximum moment of pile body is shifted from 5-8 times diameter of pile to the top of pile. When the pile number reaches a certain amount, the maximum bending moment will appear at the joint between the pile cap and the pile body. At the same time, increasing the non prestressed steel bar does not influence the bending moment, and the reinforcement of the pile cap and the pile top should be strengthened.
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Soomro, M. A., A. S. Brohi, M. A. Soomro, D. K. Bangwar, and S. A. Bhatti. "3D Numerical Modeling of Pile Group Responses to Excavation-Induced Stress Release in Silty Clay." Engineering, Technology & Applied Science Research 8, no. 1 (February 20, 2018): 2577–84. http://dx.doi.org/10.48084/etasr.1748.
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Development of underground transportation systems consists of tunnels, basement construction excavations and cut and cover tunnels which may encounter existing pile groups during their construction. Since many previous studies mainly focus on the effects of excavations on single piles, settlement and load transfer mechanism of a pile group subjected to excavation-induced stress release are not well investigated and understood. To address these two issues, three-dimensional coupled-consolidation numerical analysis is conducted by using a hypoplastic model which takes small-strain stiffness into account. A non-linear pile group settlement was induced. This may be attributed to reduction of shaft resistance due to excavation induced stress release, the pile had to settle substantially to further mobilise end-bearing. Compared to the Sp of the pile group, induced settlement of the single pile is larger with similar settlement characteristics. Due to the additional settlement of the pile group, factor of safety for the pile group can be regarded as decreasing from 3.0 to 1.4, based on a displacement-based failure load criterion. Owing to non-uniform stress release, pile group tilted towards the excavation with value of 0.14%. Due to excavation-induced stress release and dragload, head load of rear piles was reduced and transferred to rear piles. This load transfer can increase the axial force in front piles by 94%.
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Zhang, Qian Qing, and Zhong Miao Zhang. "A Modified Shear Displacement Method for Calculating Settlement of Single Pile." Advanced Materials Research 261-263 (May 2011): 1804–8. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1804.
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A modified shear displacement method is presented to analyze the load-settlement response of a single pile in homogenous soil using two models. One model adopts a hyperbolic model to simulate the stress-strain relationship of soil under shear stress before failure occurs, and the other model uses a non-linear stress-strain relationship to evaluate the load-displacement behavior of the soil beneath the pile base. Comparisons of the load-settlement responses between the present modified model and the model suggested by Randolph and Wroth are given to demonstrate the effectiveness and accuracy of the proposed modified method.
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Zhou, Kun, Linhua Chen, and Shanshan Yu. "Vision-based Deformation Measurement for Pile-soil Testing." MATEC Web of Conferences 275 (2019): 03009. http://dx.doi.org/10.1051/matecconf/201927503009.
Full textAbstract:
Image measurement technology has been widely used in monitoring the deformation of the soil field around the pile with its advantages of no damage, no contact, full-field measurement, no added quality and high sensitivity. But there are few researches on image-based bearing deformation measurement of the pile. Through an indoor pile-soil semi-model test, the rigid body displacement and load-bearing deformation of a new type of prefabricated steel tube pile foundation under horizontal load was measured based on image features. In this study, the concept of optical extensometer is first applied to the measurement of local average strain of a non-uniform deformed structure. Based on an improved feature point tracking algorithm SURF-BRISK, non-contact measurement of tiny strain of pile body is realized. In addition, based on DIC technology, this study also obtained the progressive development of displacement field of soil around pile. The above work fully reflects the non-contact convenience and full-field richness of the optical measurement method compared with the traditional measurement method.
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Zhu, Feng Bin. "Numerical Analysis of the Influence of Shield Tunneling to Adjacent Loaded Piles." Advanced Materials Research 538-541 (June 2012): 548–51. http://dx.doi.org/10.4028/www.scientific.net/amr.538-541.548.
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Suzhou Light Railway Line 1 is used as a case history to investigate the effects of the non-homogeneity of soil, distance to the tunnel and cushion cap on the pile foundation performance including horizontal displacements, settlements, axial forces and bending moments. According to behaviors of the single pile and pile group under different concentrated loads, it is concluded that with tunneling, the loaded pile foundation will rotate toward to the tunnel and their bearing capacity is influenced significantly.
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Li, Lin, Xiao Xin Hu, Guang Hui Dong, and Ju Liu. "Three-Dimensional Numerical Analyses of Pile Response due to Braceded Excavation-Induced Lateral Soil Movement." Applied Mechanics and Materials 580-583 (July 2014): 524–31. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.524.
Full textAbstract:
Using the explicit finite difference code FLAC3D, the behavior of pile adjacent to braced excavation is investigated. The Modified-cam clay constitutive model was employed to model the non-linear stress-strain soil behavior, and the pile was assumed to have linear elastic behavior. The interface model incorporated in FLAC3D code was used to simulate the soil/pile contact, The built-in 'fish' language was used to calculate the data demanded. The pile response such as pile deflection, bending moment and lateral soil pressure were studied, and it is shown that the pile response is different from that caused by the excavations which are unstructted. In "standard" problem, the effect of different pile head constraints on the pile response was investigated, the effect of lateral displacement of the wall, distance from the excavation face, pile stiffness, pile length and axial load on the pile response are also investigated when the pile head is constrained from deflection. The research finding was compared with other published case history and reasonably good agreement was found between them.
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Yan, Qiushi, Chen Liu, Jun Wu, Jun Wu, and Tieshuan Zhuang. "Experimental and Numerical Investigation of Reinforced Concrete Pile Subjected to Near-Field Non-Contact Underwater Explosion." International Journal of Structural Stability and Dynamics 20, no. 06 (May 30, 2020): 2040003. http://dx.doi.org/10.1142/s0219455420400039.
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High-pile wharf is an important port structure and may suffer from accidental explosions or terrorist bombing attack during the service life. The reinforced concrete (RC) pile is one of the popular vertical load-bearing piles of high-pile wharf structure. As a main load-bearing member of the high-pile wharf structure, the damage of RC pile due to underwater explosive may cause subsequently progressive collapse of the whole structure. In this paper, the dynamic response and failure mode of RC pile in high-pile wharf structure under the near-field non-contact underwater explosion are investigated using a combined experimental and numerical study. First, a typical RC pile was designed and tested for the near-field non-contact underwater explosion. The failure mode and damage of the RC pile specimen were obtained and analyzed. Second, the numerical model of the RC pile under near-field non-contact underwater explosion was established by adopting the commercial software AUTODYN, and then validated based on experimental results. It was shown that the results from numerical model and experimental test compared very well in terms of the damage pattern and lateral displacement. Furthermore, the full-scale numerical model of the RC pile for the near-field non-contact underwater explosion was developed based on the validated numerical model to investigate the damage pattern and failure mode of RC pile under varied underwater explosives. Lastly, the safety distance for the RC pile for the underwater explosion loading with consideration of different explosive mass, the explosive depth and the concrete strength was suggested. The outcome of this study presented reference for analysis, assessment and design of the type of RC pile for high-pile wharf structure subjected to near-field non-contact underwater explosion.
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Ikbir, Munir Faraj M. A., S. M. Sapuan, A. A. Nuraini, and Mohamad Ridzwan Ishak. "Experimental Quasi-Static Axial Crushing of Non-Woven Kenaf Fibre/Epoxy Hexagonal Composite Tubes." Applied Mechanics and Materials 564 (June 2014): 361–65. http://dx.doi.org/10.4028/www.scientific.net/amm.564.361.
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An experimental study was carried out to study the crashworthiness parameters of non-woven kenaffibre/epoxy composite hexagonal tubes. The static crushing behavior of composite hexagonal tubes under constant axial load was investigated experimentally. Three lengths of hexagonal composite tubes were tested 50, 100, and 150 mm with the same hexagonal angle 45°. Load-Displacement curves and deformation histories of typical specimens are presented and discussed. Results exhibited that tube with length 150 mm exhibits high specific energy absorption.
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Krasiński, Adam. "Proposal for calculating the bearing capacity of screw displacement piles in non-cohesive soils based on CPT results." Studia Geotechnica et Mechanica 34, no. 4 (October 1, 2012): 41–51. http://dx.doi.org/10.2478/sgm041204.
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Abstract Screw displacement pile technology is relatively new and is still being developed. A specific characteristic of those piles is their very considerable influence on soil properties during the installation, which renders classical bearing capacity calculation methods insufficient. Some methods for calculating the bearing capacity of screw displacement piles have already been presented in literature, for example, by Bustmante and Gianesselli [2], [3], Van Impe [17], [18], Maertens and Huybrechts [15], Ne Smith [16] as well as Basu and Prezzi [1]. This paper proposes a new method of calculating the bearing capacity of screw displacement piles in non-cohesive soil which is based on CPT results. It has been devised as a result of research project No. N N506 432936 [11], carried out in 2009-2011. At 6 experimental sites screw displacement pile static loading tests were carried out together with CPTU tests of the subsoil. The results allowed us to establish soil resistances along the shaft ts as well as under the pile base qb and their correlations to the CPT soil cone resistances qc. Two approaches, both adapted to the general guidelines of Eurocode 7 (EC7) [20], were proposed: a classical approach and the second approach with load transfer functions application.
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N., Parthasarathi, Satyanarayanan K.S., Prakash M., and Thamilarasu V. "Linear and non-linear analysis on two-dimensional steel frame under different temperatures." Journal of Structural Fire Engineering 10, no. 1 (February 28, 2019): 48–55. http://dx.doi.org/10.1108/jsfe-12-2017-0047.
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Purpose Progressive collapse because of high temperatures arising from an explosion, vehicle impact or fire is an important issue for structural failure in high-rise buildings. Design/methodology/approach The present study, using ABAQUS software for the analysis, investigated the progressive collapse of a two-dimensional, three-bay, four-storey steel frame structure from high-temperature stresses. Findings After structure reaches the temperature results like displacement, stress axial load and shear force are discussed. Research limitations/implications Different temperatures were applied to the columns at different heights of a structure framed with various materials. Progressive collapse load combinations were also applied as per general service administration guidelines. Originality/value This study covered both steady-state and transient-state conditions of a multistorey-frame building subjected to a rise in temperature in the corner columns and intermediate columns. The columns in the framed structure were subjected to high temperatures at different heights, and the resulting displacements, stresses and axial loads were obtained, analysed and discussed.
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bin Pokaad, Alif Zulfakar, Md Radzai bin Said, Fauzi bin Ahmad, and Mohd Nazeri bin Kamaruddin. "An Experimental on Honeycomb Core in the Axial Direction under the Quasi-Static Loading." Applied Mechanics and Materials 699 (November 2014): 405–10. http://dx.doi.org/10.4028/www.scientific.net/amm.699.405.
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This paper focuses on the quasi-static response of the aluminum honeycomb core based on an experimental work. The load-compression and energy absorb characteristics of the out-of-plane aluminium honeycomb core are studied for three varieties of the core cell sizes which are 0.01905, 0.0127 and 0.00635 m. The crushing tests were conducted on the Instron machine with a displacement control of 5 mm/min. The initial part in the load-displacement graph shows linear elastic characteristic, followed by a non-linear elastic-plastic regime before it collapses. Based on the observation, the cell sized 0.01905 m shows the global buckling collapse, but the cell sized 0.0127 and 0.00635 m collapse as progressive buckling mode. The cell size 0.00635 m shows highest energy absorption due to it has the highest density and it collapses like the progressive buckling mode compared with the others specimen.
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Saaly, Maryam, Pooneh Maghoul, and Hartmut Holländer. "Investigation of the effects of heat loss through below-grade envelope of buildings in urban areas on thermo-mechanical behaviour of geothermal piles." E3S Web of Conferences 205 (2020): 05010. http://dx.doi.org/10.1051/e3sconf/202020505010.
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Harvesting geothermal energy through the use of thermo-active pile systems is an eco-friendly technique to provide HVAC energy demand of buildings. Mechanical behaviour of thermo-active piles is impacted by thermal cycles. Moreover, in urban areas, the temperature of the ground is higher than non-constructed areas due to the heat loss through the below-grade enclosure of buildings. This heat dissipation increases the thermal capacity of the soil and affects the mechanical response of the geothermal pile foundation subjected to thermo-mechanical loading. To investigate the effect of buildings heat loss on thermo-active piles, a numerical thermo-mechanical (TM) analysis was carried out on a proposed energy foundation system for an institutional building, the Stanley Pauley Engineering Building (SPEB) in the campus of the University of Manitoba, Winnipeg, Canada. The mechanical response of the geothermal piles to the thermal cycles with and without considering heat leakage through the basement of the SPEB is compared. Results showed that the cooling loads induced a maximum vertical pile head displacement of -1.18 mm. After 5 years operation of the system, the maximum vertical pile head displacement decreased to -1.05 mm for the case in which heat loss through the basement in considered in the models. In addition, the maximum axial load effective along the pile axis was 6% higher for the case that considers heat loss through the basement compared to the case without considering heat leakage through the building’s below-grade envelope.
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Akbaş, Şeref Doğuşcan. "Post-Buckling Analysis of Edge Cracked Columns Under Axial Compression Loads." International Journal of Applied Mechanics 08, no. 08 (December 2016): 1650086. http://dx.doi.org/10.1142/s1758825116500861.
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In this paper, post-buckling analysis of an edge cracked cantilever column subjected to non-follower axial compression loads are studied by using the total Lagrangian Timoshenko column element approximation. The cross-section of the column is circular. The cracked column is modeled as an assembly of two sub-column connected through a massless elastic rotational spring. In the case of columns subjected to compression loads, load rise causes compressible forces end therefore buckling and post-buckling phenomena occurs. It is known that post-buckling problems are geometrically nonlinear problems. The considered highly non-linear problem is solved considering full geometric nonlinearity by using incremental displacement-based finite element method in conjunction with Newton–Raphson iteration method. There is no restriction on the magnitudes of deflections and rotations in contradistinction to von-Karman strain–displacement relations of the column. The columns considered in numerical examples are made of lower-carbon steel. In the study, the effect of the cracks on the deflections, rotational angles, post-buckling configuration and Cauchy stresses of the columns are illustrated in detail in post-buckling case. The difference between cracked case and intact case is investigated in detail.