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1
Sharma, V. J., S. A. Vasanvala, and C. H. Solanki. "Behaviour of Load-Bearing Components of a Cushioned Composite Piled Raft Foundation Under Axial Loading." Slovak Journal of Civil Engineering 22, no. 4 (December 1, 2014): 25–34. http://dx.doi.org/10.2478/sjce-2014-0020.
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Abstract In the last decade piled raft foundations have been widely used around the world as intermediate foundation systems between piles and rafts to control the settlement of foundations. However, when those piles are structurally connected to rafts, relatively high axial stresses develop in relatively small numbers of piles, which are often designed to fully mobilize their geotechnical capacities. To avoid a concentration of stress at the head of piles in a traditional piled raft foundation, the raft is disconnected from the piles, and a cushion is introduced between them. Also, to tackle an unfavourable soil profile for a piled raft foundation, the conventional piled raft has been modified into a cushioned composite piled raft foundation, where piles of different materials are used. In the current study the behavior of cushioned foundation components, which transfer the load from the structure to the subsoil, are analyzed in detail, i.e., the thickness of the raft, the length of a long pile and the modulus of a flexible pile.
2
Ahmed, Huda Hussein, and Salah Rohaima Al-Zaidee. "Experimental Investigation for Effects of Mini-piles on the Structural Response of Raft Foundations." Civil Engineering Journal 5, no. 5 (May 21, 2019): 1084–98. http://dx.doi.org/10.28991/cej-2019-03091313.
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Mini-piles made their debut as a cost-effective way to stabilize the historical structures. Recently, mini-piles have increased in popularity all over the world and are being used for bridges, buildings, slope stability, antenna towers, and residential construction. This paper presents the preparing, executing, data acquisition, and result presentation for an experimental work concerns with five scale-down mini-piled raft foundation models. All models were prepared to study the effectiveness of the mini-piled raft foundation in reducing the settlement and the bending moments. Five tests have been achieved. The reference first test includes a raft foundation with 15mm thickness. Second, third, and fourth tests are mini-piled raft foundations with five mini-piles and with thicknesses of 15 mm, 10 mm, and 8mm respectively. Finally, the fifth test dealt with a single mini-pile 178mm in length and 6mm in diameter. It has been adopted to investigate the reference behavior of the single mini-pile. When they were used, the piles have 42 mm center to center distances. A scale-down factor of , a sandy soil with with of , and relative density of 60% have been considered in all tests. Test results indicated a 45% decrease in settlement for 15mm mini-piled raft foundation comparing with the reference 15mm raft foundation. Moreover, there is no significant difference in settlement between 15mm mini-piled raft foundation comparing with the 10mm and 8mm thick mini-piled raft foundations. Regarding to the bending moments, they decrease at the mid and edge of the 15mm mini-piled raft foundation comparing to those of the reference raft foundation. It has also been noted that the moments are inversely proportional to the thickness of the piled raft foundations. With respect to the mini-piles, it has been found that most of the pile axial loads are transferred to the underneath soil through friction and this friction increases as the raft thickness decreases.
3
Soares, Wilson Cartaxo, Roberto Quental Coutinho, and Renato Pinto da Cunha. "Piled raft with hollow auger piles founded in a Brazilian granular deposit." Canadian Geotechnical Journal 52, no. 8 (August 2015): 1005–22. http://dx.doi.org/10.1139/cgj-2014-0087.
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Geotechnical projects typically achieve load transfer to the ground using shallow or deep foundations. The conventional design approach does not provide for the combination of these two types of foundation. The piled raft philosophy allows the association of the soil elements, raft, and piles to obtain technical and economic advantages over conventional design. The city of João Pessoa, in northeastern Brazil, has developed foundation practices with hollow auger piles in piled raft design. The coastal area of the city has topsoil layers with favorable conditions for using such a technique. This paper addresses the results of a research project with instrumented load tests on foundation systems of hollow auger piles and a piled raft. The analysis is based on the load–settlement curve through extrapolation criteria. The Poulos–Davis–Randolph (PDR) method is applied according to a trilinear and hyperbolic approach to simulate the load–settlement curve of piled rafts. The results indicate that the raft absorbs most of the load, and the raft–soil contact significantly increases the load capacity of the foundation. The PDR hyperbolic method could apply to practical use in the foundations of the region, as it allows a more detailed assessment of the behavior of the foundation and can forecast the behavior of the (locally nontraditional) piled raft foundation system.
4
Zhu, Xiao-jun, Kang Fei, and Sheng-wei Wang. "Horizontal Loading Tests on Disconnected Piled Rafts and a Simplified Method to Evaluate the Horizontal Bearing Capacity." Advances in Civil Engineering 2018 (September 16, 2018): 1–12. http://dx.doi.org/10.1155/2018/3956509.
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Disconnected piled raft (DPR) foundations have been widely adopted as an effective foundation system where the piles are separated from the raft by a granular layer, which can limit the shear forces and moments transmitted between the raft and the piles. Thus, DPR foundations may avoid the problem of horizontal forces, such as those from an earthquake or dynamic loads, which damage the structural connection between the pile head and raft. A series of static horizontal loading tests were carried out on three types of foundation models, i.e., piled raft, disconnected piled raft, and raft alone models, on fine sand using a geotechnical model in a 1 g field. In this paper, the influences of vertical loading and interposed layer thickness were presented and discussed. The results showed that most of the horizontal force was carried by raft/interposed layer friction in the DPR foundation type, and the shear force and moment of the piles were greatly reduced due to the gap between the raft and the heads of the piles. The tested foundations were simulated using a simplified method with theoretical equations derived by making several approximations and assumptions. The simulated results agreed well with the test results.
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Kacprzak, Grzegorz, Katarzyna Mazurek, and Tomasz Daktera. "A simplified algorithm for the design of piled raft foundations applied for the case study of a building erected within Żoliborz-Szczęśliwice glacial tunnel valley." Annals of Warsaw University of Life Sciences, Land Reclamation 47, no. 2 (June 1, 2015): 113–26. http://dx.doi.org/10.1515/sggw-2015-0018.
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Abstract A common engineering solution for excessive settlement with raft foundation (s) is the use of piles in order to reduce the vertical displacements, in this method, the whole structural load is transferred to the piles. This is an overly cautious approach, and there remains a need to find an optimal design method for a building’s foundations. Such a solution may be the piled raft foundation, which allows a reduction of the number of piles due to the integration of the raft in the bearing capacity of the foundation. The aim of the article is to estimate the contribution of foundation elements such as the raft and the piles in the bearing capacity of a residential building located in Warsaw, where the geological conditions are characterized by organic soil layers, principally of gyttja.
6
Wang, Cheng Hua, and Jian Guo An. "A Nonlinear Numerical Analysis of Vertical Bearing Behavior of Bored Pile Foundations Including Defective Piles with Stem Shrinkage." Advanced Materials Research 374-377 (October 2011): 2071–77. http://dx.doi.org/10.4028/www.scientific.net/amr.374-377.2071.
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In order to investigate the influence of the defective piles with stem shrinkage on the working behavior of pile foundations under vertical loadings, a numerical model was set up for the analysis of pile foundations. A series of contrastive analyses were made to a group piled foundations including a pile with defect of stem shrinkage in a shallow or a deeper depth and a pile foundation with normal piles with a three dimensional nonlinear finite-infinite element method. The basic working behavior of the pile foundation with a defective pile of stem shrinkage was initially revealed by the results of the analyses; and the basic rules of the affects of pile stem shrinkage defect on the distribution of axial forces among piles and the bending moments in pile caps were obtained. The results of this research are not only helpful for the understanding and rational judgment of the working mechanism, but also of practical importance in the assessment of the bearing behavior of pile foundations including defective piles with stem shrinkage and in the structural designs of piles and pile caps.
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de Freitas Neto, Osvaldo, Renato P. Cunha, Olavo Francisco Santos, Paulo J. R. Albuquerque, and Jean R. Garcia. "Comparison of Numerical Methods for Piled Raft Foundations." Advanced Materials Research 838-841 (November 2013): 334–41. http://dx.doi.org/10.4028/www.scientific.net/amr.838-841.334.
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The methodologies used to calculate piled raft foundations are normally more complex than conventional foundations due to the large number of variables involved in the problem. In the conventional block, the interaction variables considered are only between the pile and the soil. In the piled raft, all the interaction effects must be considered, as follows: plate-soil, plate-piles and piles-soil, simultaneously. The Finite Element Method (FEM) has proven to be a useful tool in analyzing these types of problems. This study aims at assessing the behavior of piled rafts using the Cesar-LCPC numerical tool, version 4.0, which is based on the finite element method. Literature cases of rafts supported by 9, 15 and 16 piles were analyzed. The results obtained were compared with analysis methods presented in the bibliography. The following parameters were assessed: relative spacing (S/D), relative length (L/D), relative stiffness between piles and the soil (KPS), and settlement of piles and the raft. The spacing between piles has a significant influence on load distribution between piles and the raft. Very small spacing provides stiffness to the foundation, which then functions as a conventional pile foundation, in which only the piles absorb the load from the superstructure. The larger the L/D ratio, the lower the settlement and for a given modulus of elasticity of the pile, the increase in relative stiffness (KPS) causes an increase in settlement. In all analyses, the data obtained corroborated the results presented by other methods published in the literature.
8
Xie, Xin Yu, Ming Xin Shou, Jie Qing Huang, and Kai Fu Liu. "Application Study of Long-Short-Piled Raft Foundation." Applied Mechanics and Materials 170-173 (May 2012): 242–45. http://dx.doi.org/10.4028/www.scientific.net/amm.170-173.242.
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The long-short-piled raft foundation is an unusual type of building base. This kind of foundation is usually applied for pile foundation reinforcement of existing buildings when shortage of bearing capacity of piles occurs. The bearing capacity of pile foundation is improved and less settlement is expected. Since this method has so many obvious advantages, it is recommended in the reinforcement design of piled raft foundation of an existing building in Tianjin. Longer reinforced concrete bored piles are adopted as the supplementary ones. The bearing capacity of this kind of piled raft foundation was studied. The settlement was also analyzed with the National standard method together with the finite element numerical method. According to the study, the bearing capacity of piled raft foundation is enhanced effectively after adding piles. Also, the results show that the total settlement and differential settlement during the construction is in control respectively.
9
Yushchube, S. V., and I. I. Podshivalov. "Stress-strain state finite element modeling of concrete foundation along the concrete pile perimeter of a multistory brick building." Vestnik Tomskogo gosudarstvennogo arkhitekturno-stroitel'nogo universiteta. JOURNAL of Construction and Architecture 23, no. 3 (June 28, 2021): 155–66. http://dx.doi.org/10.31675/1607-1859-2021-23-3-155-166.
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The use of concrete foundations on a natural subgrade of brick buildings with a spatial cross-wall structural system can lead to its ultimate limit and elastoplastic states along the perimeter and, as a consequence, unallowable soil deformation and movement. The paper proposes to eliminate ultimate limit and elastoplastic states along the perimeter of concrete piles through the replacement of the foundation slab by the combined piled-raft foundation. The finite element modeling of the stress-strain state of the concrete foundation and the building superstructure of the base-foundation-building system is performed in the MicroFe software package allowing to appropriately estimate this state in real geotechnical conditions. According to calculations, 46 % of the vertical load of the building is taken by concrete piles along the perimeter, and 54 % of this load is taken by the concrete foundation. The use of the combined piled-raft foundation allows eliminating unallowable soil deformation of the foundation and provides meeting the standard requirements.
10
Alhassani, Athraa Mohammed Jawad, and Ala Nasir Aljorany. "Parametric Study on Unconnected Piled Raft Foundation Using Numerical Modelling." Journal of Engineering 26, no. 5 (May 1, 2020): 156–71. http://dx.doi.org/10.31026/j.eng.2020.05.11.
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Piled raft is commonly used as foundation for high rise buildings. The design concept of piled raft foundation is to minimize the number of piles, and to utilize the entire bearing capacity. High axial stresses are therefore, concentrated at the region of connection between the piles and raft. Recently, an alternative technique is proposed to disconnect the piles from the raft in a so called unconnected piled raft (UCPR) foundation, in which a compacted soil layer (cushion) beneath the raft, is usually introduced. The piles of the new system are considered as reinforcement members for the subsoil rather than as structural members. In the current study, the behavior of unconnected piled rafts systems has been studied numerically by means of 3D Finite Element analysis via ABAQUS software. The numerical analysis was carried out to investigate the effect of thickness and stiffness of the cushion, pile length, stiffness of foundation soil, and stiffness of bearing soil on the performance of the unconnected piled raft. The results indicate that when unconnected piles are used, the axial stress along the pile is significantly reduced e.g. the axial stress at head of unconnected pile is decreased by 37.8% compared with that related to connected pile. It is also found that the stiffness and thickness of the cushion, and stiffness of foundation soil have considerable role on reduction the settlement.
11
Han, Ai Hong, and Hui Jun Zheng. "Elasto-Plastic Design of Piled Raft Foundation." Advanced Materials Research 446-449 (January 2012): 588–91. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.588.
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When the loading sustained by the foundation is large, employing piled raft foundation is one of the best solutions. In the elasto-plastic design of piled raft, piles could improve the differential settlement and reduce raft thickness. As the raft sustains high earth and water pressures, by reducing the span length of raft and excavation depth, one can get economic design. Using elasto-plastic property of the pile is a better method to avoid increasing the pile length and pile diameter and making full capacity of the piled raft foundation in design compared to normal piled raft. With adoption of few small diameter piles, the raft thickness could be reduced significantly. This makes it much better than raft foundation.
12
M S, Padmanaban, and J. Sreerambabu. "Issues on Design of Piled Raft Foundation." JOURNAL OF ADVANCES IN CHEMISTRY 14, no. 1 (January 18, 2018): 6057–61. http://dx.doi.org/10.24297/jac.v14i1.5905.
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A piled raft foundation consists of a thick concrete slab reinforced with steel which covers the entire contact area of the structure, in which the raft is supported by a group of piles or a number of individual piles. Bending moment on raft, differential and average settlement, pile and raft geometries are the influencing parameters of the piled raft foundation system. In this paper, a detailed review has been carried out on the issues on the raft foundation design. Also, the existing design procedure was explained.
13
Huang, Yuan, Xin Jian Feng, Jian Lin Zhang, and Shu Zhi Lin. "Working Mechanism of Two-Phase Varying Stiffness Piled Raft Foundation." Applied Mechanics and Materials 590 (June 2014): 326–30. http://dx.doi.org/10.4028/www.scientific.net/amm.590.326.
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In this paper, the FEM software ABAQUS is used to analysis the pile-soil load share ratios, load share value of pile side friction and tip resistance for three bases, including natural raft foundation, conventional piled raft foundation and two-phase varying stiffness piled raft foundation. Furthermore, the deformation and settlement of deformation-coordinating device are studied as well. Based on the research of the working characteristic of piles and soil, it highlights the good working mechanism of two-phase varying stiffness piled raft foundation. The analysis results show that two-phase varying stiffness piled raft foundation, with obvious two phase stress characteristics, has a working principle between natural raft foundation and conventional piled raft foundation, fully making use of the bearing capacity of foundation soil, effectively improving the joint bearing capacity of piles and soil.
14
Chen, Taihao, Yiming Xu, and Jie Chen. "Experimental study on horizontal bearing capacity of enlarged cap-group pile composite foundation." E3S Web of Conferences 136 (2019): 04066. http://dx.doi.org/10.1051/e3sconf/201913604066.
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In order to provide reference for the engineering design in the area with large wind, water flow and other horizontal loads, the experimental study on the horizontal bearing capacity of composite foundation under three different working conditions was carried out in this paper, which includes cap-single pile, cap-9 piles and enlarged cap-9 piles. The results show that under the condition of cap-9 piles, the group pile effect coefficient is 1.17, and the load sharing ratio of the back piles is the largest, and the middle and front piless decrease sequentially. Also, with the increase of horizontal load, the load sharing ratio of the back pile increases while the middle and front piless is decremented. Under the condition of enlarged cap-9 piles, the group pile effect coefficient is 1.36, which is 16.24% higher than that of the cap-9 piles, which means the horizontal resistance is obviously enhanced. At the same time, compared with the cap-9 piles, the load sharing ratio of the back pile is reduced while the middle and front piless is increased, which means the stress of pile body tends to be more uniform.
15
Karkush, Mahdi O., and Ala N. Aljorany. "Numerical Evaluation of Foundation of Digester Tank of Sewage Treatment Plant." Civil Engineering Journal 5, no. 5 (May 22, 2019): 996–1006. http://dx.doi.org/10.28991/cej-2019-03091306.
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In the present study the foundation of digester tank, main part of sewage treatment plant, is reanalyzed analytically and numerically to check the adequacy of such foundation to support superstructure loading. The foundation of digester tank consists of raft foundation and bored piles. The diameter of raft is 33 m and thickness of 1 m, while the piles are bored type of diameter 0.6 m and length 15 m. After testing eleven working piles, it is found that three piles cannot support a load of 1.5 times the working load (1305 kN) safely or in other words the factor of safety of these failed piles is less than 1.5. The results of filed pile tests are reanalyzed using two well-known methods, Davisson’s method and Brinch-Hansen method to check the ultimate carrying capacity of tested piles. Also, this paper includes analysis of previous soil investigation report and conducting additional soil investigation by drilling three boreholes to secure the soil parameters used in the analytical and numerical analysis of digester tank foundation. SAFE 12 software is used to analysis the foundation of structure as piled-raft instead of pile group to interest from the interaction between soil and raft foundation. The results of analysis showed that the piles failed in the tests can support its share of the superstructure load by a factor of safety 1.8 and the piles success in the field tests can support its share of the superstructure load by a factor of safety not less than 2.86. Also, the settlement under structure will be less than 100 mm, where using piled-raft analysis reduces the settlement to be within allowable limits.
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Ahmed, Danish, Siti Noor Linda Bt Taib, Tahar Ayadat, and Alsidqi Hasan. "A Review on the Behaviour of Combined Stone Columns and Pile Foundations in Soft Soils when Placed under Rigid Raft Foundation." ASM Science Journal 16 (July 15, 2021): 1–8. http://dx.doi.org/10.32802/asmscj.2021.709.
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In the last few decades, it has been observed that raft foundations are very commonly used as a foundation solution for moderate to high rise structures either by resting on stone columns or on piles in soft soils. It is believed that, combining stone columns and piles in one foundation system is the more suitable foundation for medium rise structures. The combined foundation system provides a superior and more economical alternative to pile, and a more attractive alternative to stone columns in respect to ground improvement. This paper presents the review of existing studies reported in the literature in the last two decades about the behaviour of stone columns under raft foundations and piled raft foundation in soft soil, notably the failure mechanism and the bearing capacity. Also, a limited work from the literature concerning the performance of combined (pile/stone columns) foundation system in soft soil is comprised. Furthermore, very extensive ongoing research work regarding the investigation and study on the performance of combined (pile/stone columns) foundation system in soft soils is discussed. The main goals and methodology to study the performance of the combined (pile/stone columns) foundation systems in soft soil are also addressed.
17
Pidlutskyi, Vasyl, Igor Boyko, and Viktor Nosenko. "Research of the Interaction of Piles with Different Lengths and the Grillage in the Foundations of High-Rise Buildings." Civil and Environmental Engineering Reports 26, no. 3 (September 26, 2017): 59–68. http://dx.doi.org/10.1515/ceer-2017-0035.
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Abstract The interaction of piles with different lengths and the grillage in the foundations of high-rise buildings is considered. The numerical modeling of the «base - foundation - superstructure» system is performed. The redistribution of the efforts in piles depending on the sizes of a foundation slab and the parameters of piles (length and location) is investigated. Typical zones of a foundation such as central, lateral, and angular ones are separated. The redistribution of efforts between piles and a grillage is revealed.
18
Jaremski, Jan. "SOME ASPECTS OF JOINING PILES." Studia Geotechnica et Mechanica 35, no. 2 (June 1, 2013): 39–48. http://dx.doi.org/10.2478/sgem-2013-0022.
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Abstract Application of the pile joining is a new solution of the complex pile foundation including the base, made in the ground, and the piles joining the base with the girt. This kind of piles can be used for foundation under special geological conditions (proglacial stream valleys) for foundation reinforcement of the existing buildings and new foundations. The solution proposed may be used in the swelling soils. In this work, the possibilities of applying joining piles in different soils, like fine sands, silts, clays, clay shale, sandstones, which can be the foundation for the pales have been considered.
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Hoffmann, Marcin, Krzysztof Żarkiewicz, Adam Zieliński, Szymon Skibicki, and Łukasz Marchewka. "Foundation Piles—A New Feature for Concrete 3D Printers." Materials 14, no. 10 (May 13, 2021): 2545. http://dx.doi.org/10.3390/ma14102545.
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Foundation piles that are made by concrete 3D printers constitute a new alternative way of founding buildings constructed using incremental technology. We are currently observing very rapid development of incremental technology for the construction industry. The systems that are used for 3D printing with the application of construction materials make it possible to form permanent formwork for strip foundations, construct load-bearing walls and partition walls, and prefabricate elements, such as stairs, lintels, and ceilings. 3D printing systems do not offer soil reinforcement by making piles. The paper presents the possibility of making concrete foundation piles in laboratory conditions using a concrete 3D printer. The paper shows the tools and procedure for pile pumping. An experiment for measuring pile bearing capacity is described and an example of a pile deployment model under a foundation is described. The results of the tests and analytical calculations have shown that the displacement piles demonstrate less settlement when compared to the analysed shallow foundation. The authors indicate that it is possible to replace the shallow foundation with a series of piles combined with a printed wall without locally widening it. This type of foundation can be used for the foundation of low-rise buildings, such as detached houses. Estimated calculations have shown that the possibility of making foundation piles by a 3D printer will reduce the cost of making foundations by shortening the time of execution of works and reducing the consumption of construction materials.
20
Leung, C. F,, C. W. Ong, and K. Y. Yong. "Effect of Tunneling on Adjacent Piled Foundation in Clay." Journal of Civil Engineering and Construction 8, no. 1 (February 15, 2019): 19–24. http://dx.doi.org/10.32732/jcec.2019.8.1.19.
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Soil movements arising from tunnel excavation may induce severe stresses on adjacent piled foundations. This paper investigates the behavior of piles due to nearby tunneling in soft clay using centrifuge modeling technique. Centrifuge modeling has an advantage that the consolidation time of the clay under forced gravity field can be expedited significantly to study the long term performance of a pile due to tunneling. The types of piles investigated in the present study include floating pile, socketed pile and end bearing piles with different pile head conditions. The test results on the induced axial and lateral pile responses due to tunneling are presented in this paper and the implications of the findings to engineering practice are highlighted.
21
Burkovič, Kamil, Martina Smirakova, and Pavlina Matečková. "Testing and Modelling of Concrete Pile Foundations." Key Engineering Materials 738 (June 2017): 287–97. http://dx.doi.org/10.4028/www.scientific.net/kem.738.287.
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Foundation of building on concrete piles is often used when it is necessary to carry the load into larger depth as by common foundation. Bearing capacity of piles or piled raft foundation is wide area to research. This paper deals with experimental load test of concrete pile and with their numerical modelling. Several types of foundation construction were tested and two kinds will be presented and compared in this paper - reinforced concrete foundation slab and raft foundation (made of reinforced concrete foundation slab supported by drilled reinforced concrete pilot). These types of foundation constructions were constructed as models, in a reduced scale, approx. 1:10. The size had to be adjusted due to limited capacity of the testing equipment and financial reasons. Except measuring of the foundation behaviour, there was also carried out measurement of the adjacent terrain.The aim of this paper is to compare the behaviour of rigid slab and the piled raft. The measurement results will be then compared with the results of numerical modelling.
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Zhu, Bin, Kai Wen, Tao Li, Lujun Wang, and Deqiong Kong. "Experimental study on lateral pile–soil interaction of offshore tetrapod piled jacket foundations in sand." Canadian Geotechnical Journal 56, no. 11 (November 2019): 1680–89. http://dx.doi.org/10.1139/cgj-2018-0292.
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Recently, tetrapod piled jacket (TPJ) foundations have shown considerable promise in offshore developments, due to the increases in power capacity and water depth for offshore wind turbines. This paper presents a set of centrifuge tests to look into the lateral loading behaviour of TPJ foundations in sand, with the overall load–displacement responses of the foundation as well as the soil resistance and internal forces on or within individual piles being examined carefully. Test results show that the back-row piles are more likely to be pulled out when the TPJ foundation is loaded laterally along the diagonal direction compared to when loaded along the orthogonal direction. The lateral soil resistance per unit length on the back-row pile(s) is approximately 60% of that on the front-row one(s) in the orthogonal loading case, and only about 40% in the diagonal loading case. Moreover, although the TPJ foundation is in its form a special case of pile groups, it is highlighted in the present study that the former case exhibits distinct loading behaviour from the latter case due to the typically large overturning moment encountered by the foundations for offshore wind turbines. Finally, the p-multipliers of the piles are demonstrated to be dependent on pile deflections, but independent on soil depths, and as a result, a modified pm model is proposed to provide guidance for the design of TPJ foundations in sand.
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Merin Jose, K., Divya Krishnan, and P. T. Ravichandran. "Behaviour of Vertically Loaded Piled Raft System." Journal of Computational and Theoretical Nanoscience 17, no. 5 (May 1, 2020): 2383–87. http://dx.doi.org/10.1166/jctn.2020.8900.
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A foundation gives the overall strength to a building by providing a level surface for the building to stand and distributing the total load uniformly to the underlying soil. The type of foundation to be chosen varies with the foundation soil and site conditions. Piled raft system are a type of foundation preferred when the bearing strata has less soil bearing capacity and a huge load has to be transferred. Thus Piled raft foundation is a foundation system which uses the combined effects of both rafts and piles such that it is expected to transfer huge loads without large settlement. An ample evaluation of factors like number of piles, length of piles, and degree of compaction of soil that affects the performance of the foundation is required, to understand the concept of piled raft foundation. This study was based on the behaviour of vertically loaded piled raft system by varying the length of pile as 100 mm, 150 mm and 200 mm with 4 and 9 numbers of pile conducted on loose and dense state in cohesion less soil. A vertical load test was conducted on unpiled raft both in loose and dense state of soil also and the results obtained from both piled and unpiled rafts were compared together. The compared results indicated an improvement in ultimate load capacity and settlement reduction. A settlement reduction of 32.71% and increased bearing capacity of 63.67% were observed when compared to unpiled raft under dense condition. About 84% of increase in bearing capacity of the piled raft system was observed with varying the degree of compaction of soil from loose to dense state of soil. An optimum design of this piled raft foundation can provide an alternative foundation for high rise buildings, transmission towers, bridges etc. and it can provide an aid to the threat of differential settlement for heavy loaded buildings in poor bearing strata.
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Vynnykov, Yuriy, and Sergiy Manzhalii. "RESIDENTIAL BUILDING’S DEFORMATION ON PILE FOUNDATION." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 53 (October 31, 2019): 98–106. http://dx.doi.org/10.26906/znp.2019.53.1899.
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A considerably distinctive deformed five-storeyed three-section brick residential house erected over 40 years ago on drivenprismatic piles combined by a strip grid foundation by a standardized project is under investigation. The geotechnical monitoring results of the building's technical condition are presented. Methods and results of the instrumental control analysis ofthe piles' actual length and visual evaluation of their integrity are presented. The causes of the foundations base's excess deformation were determined: the inability of the piles' tips to reach the designed mark; the piles' destruction during their immersion in dense sands; rupture of the primary thermal network, which led to "negative friction" effect on the piles' lateralsurface, etc.
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Feng, Shi Lun, Jie Liu, Jun Li, Pu Lin Li, and Yong Han. "The Bad Effects of Foundation Pit Heave on Foundation Piles." Advanced Materials Research 261-263 (May 2011): 1225–28. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1225.
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Deep excavations release stresses in the earth and redistribute these stresses causing deformation. The pressure loss due to excavation may result in a base instability, where the soil flow beneath the sheeting into the excavation, producing a rise in the base elevation commonly termed as heave. The heave can lead the foundation piles casted before excavation to floating and being in tension, and even induce the tensile failure of pile in severe case. The characters of foundation piles in different excavation conditions, different location have been analyzed by a case study. The calculation results show that the deeper excavation, the larger vertical force acted on the foundation pile and the heave could induce the tensile failure of the foundation piles. So it is recommended that the tensile capacity of the foundation piles should be verified when the excavation is very deep.
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Kolesnikov, Aleksei O., Tatiana N. Kostiuk, and Vladimir N. Popov. "Calculation of foundation vertical stiffness with the piles mutual influence effect." Structural Mechanics of Engineering Constructions and Buildings 15, no. 3 (December 15, 2019): 229–36. http://dx.doi.org/10.22363/1815-5235-2019-15-3-229-236.
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Aims of research. Studies to determine the effect of the distance between the piles in group with vertical oscillations of pile foundations on the value of dynamic stiffness are carried out and the results obtained in full-scale tests, within the wave model and according to SP 26.13330.2012 are compared. Methods. The eigenfrequency changes of the foundation of nine piles with a diameter ( d ) with a high pile cap are calculated depending on the distances between the piles - 2 d , 3 d and 5 d . The obtained results are compared with the data obtained after a series of pulse dynamic loads performed under semi-natural conditions on foundation models. The values of the transverse wave velocities were determined directly at the test site. Results. It is found that the reduction of the distance between the piles in the bush leads to a decrease in the natural vibration frequencies of pile foundations. Reducing the distance between piles from 5 to 2 diameters of piles leads to reduce the frequency of vertical vibrations of pile foundations by 1. times. It is shown the advantage of the results of calculations in the frame-work of the wave model in comparison with the method of SP 26.13330.2012. Also shown their high coincidence with the values obtained in the course of experiments, which allows to accurately determine the amplitude-frequency characteristics of the foundations. The results determined according to SP 26.13330.2012 have significantly lower values of natural frequencies and do not fully reflect the change in the distance between the piles. The maximum discrepancy with the experimental data is 2.7 times for the vertical oscillations of the pile foundation.
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Liu, Ming-Quan, Da Huang, Yi-Xiang Song, and Duo-Feng Cen. "Numerical and Theoretical Study on the Settlement of Capped Piles Composite Foundation under Embankment." Advances in Civil Engineering 2020 (August 18, 2020): 1–11. http://dx.doi.org/10.1155/2020/3978780.
Full textAbstract:
Capped piles are efficient in settlement control and have been widely used in the reinforcement of soft soil foundations for high-speed railways and highways. In this study, scenarios involving both capped piles and ordinary piles without caps are numerically studied using the finite element software (ABAQUS). The settlement characteristics of capped piles composite foundation considering the effects of both the pile spacing and the ratio of pile cap to pile diameter are achieved. Based on the numerical results, assuming that the capped pile and the soil under the cap jointly bear load and settle together, a settlement calculation model for capped piles composite foundation is established. By both replacing the compression modulus with the deformation modulus obtained from the field static load test and calculating the area replacement ratio, the formula for calculating the total settlement of the capped piles composite foundation is derived using the layer-wise summation method. In addition, a real embankment engineering with capped piles composite foundation is adopted to validate the accuracy of this method; by comparing with other methods, the results show that this method is in better agreement with the field monitoring data. Therefore, the proposed method is recommended in the relevant engineering design.
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Liu, Kaifu, Yiguo Yang, Lei Wang, Jiapei Xu, and Xinyu Xie. "Experimental Investigation of Geosynthetic-Reinforced Pile-Supported Composite Foundations under Cyclic Loading." Advances in Civil Engineering 2020 (December 17, 2020): 1–11. http://dx.doi.org/10.1155/2020/8886131.
Full textAbstract:
A series of model tests were conducted in this study to investigate the deformation characteristics of geosynthetic-reinforced pile-supported (GRPS) composite foundations under cyclic loading. The effects of the applied load, the number of geogrid layers, and types of piles on the performance of the GRPS composite foundation were studied through 1g physical models of composite foundation with well-planned instrumentation. Furthermore, a numerical fitting method was used to assess the relationship between the foundation settlement and the number of load cycles. The results show that with the increase in the magnitude of cyclic load and the number of load cycles, the settlement of GRPS composite foundations and the strain of the pile and geogrid increased accordingly. Adding rigid piles and increasing the number of geogrid layers both could reduce the settlement of GRPS composite foundations, while adding rigid piles was more effective. The relationship between the foundation settlement and the number of load cycles can be expressed by an exponential regression function. The pile strain varied from place to place that the strain of the upper part of the pile was greater than that of the lower part. The geogrid showed a significant impact on the load transfer mechanism of the composite foundation as the geogrid closer to piles endured larger strain. It is critical to consider the variation of the pile strain and the geogrid strain under cyclic loading in the geotechnical practice of composite foundation. The model test results also suggest that the use of GRPS system can effectively reduce the composite foundation settlement. This paper can provide useful references for developing the theoretical framework and design guides for GRPS composite foundations under cyclic loading.
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Xie, Yunfei, and Shichun Chi. "Optimization Method for Irregular Piled Raft Foundation on Layered Soil Media." Advances in Civil Engineering 2019 (May 20, 2019): 1–15. http://dx.doi.org/10.1155/2019/5713492.
Full textAbstract:
Important buildings such as nuclear power plants always require stricter control of differential settlement than ordinary buildings. Therefore, it is necessary to provide an optimized design for the piled raft foundations of important buildings. In this paper, a new optimization method (using different pile diameters and different pile spacing) was proposed for the design of piled raft foundations. This method adjusts the pile diameters and pile spacing according to the stress distribution at the pile top of the initial design to achieve a more uniform settlement of the raft and stress distribution on top of piles, which can solve the differential settlement problems caused by uneven loads of the superstructure. After optimized design, the differential settlement and integral bending moment of the raft decreased more than 64% and 52%, respectively, and the differential stress on top of piles decreased by at least 63%. The new method proposed in this paper could be applied to large-scale piled raft foundations with complex superstructure loads.
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Yesakova, S. V. "TRANSVERSAL LOADED PILES DEFORMATION TASK DECISION METHOD." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 49 (January 27, 2018): 243–51. http://dx.doi.org/10.26906/znp.2017.49.851.
Full textAbstract:
The deformation method allows to describe the stress-strain state of foundation structures by means of dependency that binds settling of foundations to the parameters of stiffness in the system «base – piles foundation» at different stiffness coefficients of the basis, along length or depth of foundation. The proposed methodology allows improving the calculations of the stress-strain state of laterally loaded piles, which can significantly improve the performance of buildings and structures. Deformations of a foundation structure are described by approximate dependency that includes the sinking of ends of foundation and the stiffness parameter of the system "basis-foundation". The calculation embraces various (linear and nonlinear) distributions patterns of the of the stiffness coefficient of the basis along the length of the structure as well as distribution properties of the ground basis.
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Li, Yu Chen, Wei Qi Shi, Rui Long Shi, and Qiu Zhai. "Numerical Study on Deform Properties of Transverse Bent Frame under Berthing Loads." Applied Mechanics and Materials 638-640 (September 2014): 1266–69. http://dx.doi.org/10.4028/www.scientific.net/amm.638-640.1266.
Full textAbstract:
The finite element software ABAQUS is employed to study the force of transverse frame of piled wharves under the berthing loads. Several setups of the foundation of piles, single, double, triple piles and transverse bent, are modeled and the deformation and deflection under different setups are calculated. The deformation properties of transverse bent are analyzed under the berthing loads.
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Cui, Kai, Jun Feng, and Chengyong Zhu. "A Study on the Mechanisms of Interaction between Deep Foundation Pits and the Pile Foundations of Adjacent Skewed Arches as well as Methods for Deformation Control." Complexity 2018 (2018): 1–19. http://dx.doi.org/10.1155/2018/6535123.
Full textAbstract:
The construction of deep foundation pits is characterized by heavy loads on pile foundations, complex interactions between the foundation pit and pile foundations, and stringent requirements for deformation control. In this work, FLAC3D was used to perform computational analyses on the displacement responses of pile caps and the retaining walls of foundation pits in a variety of cases and reinforcement schemes. The computational results indicate that the piles of skewed arches interact with the retaining walls of the foundation pits through soil masses. We also revealed the mechanism by which deep foundation pits interacted with the pile foundations of adjacent skewed arches. Based on the mechanisms of interaction between foundation pit excavations and the piles of skewed arches, we proposed three reinforcement schemes for controlling the deformations associated with these interactions. The arched wall reinforcement scheme could provide a satisfactory result in terms of the control of horizontal displacements in the pile foundations and project costs.
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Zhou, Ke Feng, and Yu Zhi Li. "Computer Modeling for the CFG Pile in Highway Soft Foundation." Applied Mechanics and Materials 84-85 (August 2011): 421–25. http://dx.doi.org/10.4028/www.scientific.net/amm.84-85.421.
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In past 10 years, composite foundations, especially multipile composite foundations have been extensively used. Multi-pile composite foundation is a method of ground improvement that involves using different pile types with different lengths and diameters beneath the same raft. The CFG piles are generally much stiffer than lime piles and they are used in a manner similar to that used for conventional piles; that is, to mobilize bearing capacity from the deeper soil strata. This paper presents the results of a series of three dimensional (3D) finite element analyzes on CFG–lime composite pile foundations. The parameters investigated are the spacing of CFG pile and cushion thickness.
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Wang, Qing Jian, Shu Jie Zhang, Chao Guo, and Zheng Ran Lu. "Centrifuge Model Study of High Strength Piles Composite Foundation Settlement & Instability under Embankment in Different Kind Soils by Different Pile Spacing." Applied Mechanics and Materials 580-583 (July 2014): 38–47. http://dx.doi.org/10.4028/www.scientific.net/amm.580-583.38.
Full textAbstract:
A series of centrifuge model tests has been conduced to examine the behavior of high strength piles composite foundation stability under railway embankment in silt or clay or sand different kind of soils. The high strength composite foundation has a symmetrical plan layout consisting of 3×4, 4×6, and 5×8 piles with a center-to-center spacing of 6 or 4 or 3 times pile width. The piles are under the same height of railway embankment, with the same length, and on the same lying soil layer. The high strength composite foundation stability test results are expressed in terms of soils kinds-pile displacement response of the composite foundation, embankment load experienced by soil between piles and piles in the composite foundation, and bending moment profile along individual pile. It is established that the high strength composite foundation stability efficiency reduces significantly with decreasing of the strength of soil between piles in composite foundation. The tests reveal the shadowing effect phenomenon in which the marginal piles experienced larger laterally and bending moment than that of the central piles. The shadowing effect is most significant for the lead row piles and considerably less significant for subsequent rows of middle piles. The approach adopted by many researchers of taking the average performance of piles in the same row is found to be inappropriate for the middle rows, of piles for composite foundation as the outer piles in the row carrying significantly more laterally load and experience considerably higher bending moment than those of the inner piles.
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Ding, Zu De, Li Min Peng, and Cheng Hua Shi. "Numerical Analysis of Deformation Effect on Adjacent Piles Due to Excavation." Applied Mechanics and Materials 256-259 (December 2012): 1258–62. http://dx.doi.org/10.4028/www.scientific.net/amm.256-259.1258.
Full textAbstract:
Combined with the project of an open cut metro tunnel passing through a viaduct, three- dimensional finite element method is applied to study the lateral deformation law of viaduct pile foundations induced by adjacent excavation in the pile foundations reinforcement and un-reinforcement conditions. The results show that the lateral deformation of pile foundations increases with the increasing of excavation depth. The closer distance and the larger deformation, the influence of pile foundations on excavation will be more obvious. The pile foundations deformation is significantly reduced when taking protection measures such as adding new piles, expanding the pile cap and strengthening stratum. Compared with the maximum deformation of the un-reinforcement condition, the reinforcement condition is only 27% to 30%, and the reinforcement measure is remarkably effective. In addition, the length of the piles, the depth of foundation pit, as well as the relative positions of walls and piles have significant influences on piles deformation forms, and it should be taken into account in the design and construction of foundation pit.
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Feng, Zhen, Na Wang, and Yong Da. "Study on System Reliability Analysis Method for Composite Foundation Improved by Combined Piles." Applied Mechanics and Materials 777 (July 2015): 130–34. http://dx.doi.org/10.4028/www.scientific.net/amm.777.130.
Full textAbstract:
Based on bearing capacity and settlement control design methods for composite foundation improved by combined piles,as well as the system reliability analysis theory,the system of reliability analysis for composite foundation can be divided into three sub-systems;that are bearing capacity sub-system,settlement sub-system and differential settlement sub-system.The system probability of failure for composite foundation call be obtained by calculating that of three sub-systems respectively.It provides a method of system reliability analysis for composite foundations improved by combined piles.
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Omer, Joshua, and Hasan Haroglu. "Tests on Model Piled Rafts in Sand: Measured Settlements Compared with Finite Element Predictions." Geotechnical and Geological Engineering 39, no. 4 (February 2, 2021): 3271–83. http://dx.doi.org/10.1007/s10706-020-01664-0.
Full textAbstract:
AbstractLaboratory tests were carried out on non-piled rafts, single piles, surface contacting and non surface-contacting piled rafts which were made of aluminum and instrumented with strain gauges and deflection gauges. The foundations were installed in dry sand contained in a large metal tank to minimize boundary effects. Maintained loads were applied to each foundation until failure was closely approached. In parallel, analyses were performed using PLAXIS™ 3-D finite element program to compare the calculated and measured load-settlement trends hence assess the influence of soil stiffness on the foundation behaviour. The results confirmed that group efficiency of non-surface contacting piled increased with increasing pile–pile spacing and approached unity at a spacing equivalent to 8D (D = pile diameter). The data obtained from the strain gauges provided valuable insight into the load-transfer characteristics of different foundations and subsequently proved that the capacity of a surface contacting piled raft is significantly enhanced compared to that of either a non-piled raft or a non-surface contacting piled raft.
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Comodromos, Emilios M., Mello C. Papadopoulou, and Lyesse Laloui. "Contribution to the design methodologies of piled raft foundations under combined loadings." Canadian Geotechnical Journal 53, no. 4 (April 2016): 559–77. http://dx.doi.org/10.1139/cgj-2015-0251.
Full textAbstract:
Although simplified design methods for piled raft foundations have been proposed to allow for the group effect and soil–pile–raft interaction, most of them are concentrated on one type of loading, rendering the applicability of these methods limited to cases under such loads. In the case of a combined pile raft foundation (CPRF), the structural loads are carried partly by the piles and partly by the raft as a function of the foundation settlement, rendering the CPRF a complex soil–structure interaction issue. Despite the recent development of computational resources and advances in numerical expertise, a detailed three-dimensional (3-D) numerical analysis, accounting for soil nonlinearities, nonlinear behavior of the interfaces between the soil, piles, and raft under various combinations of loadings remains impractical. The objective of this paper is to provide a rather simplified and straightforward design methodology for pile foundations under combined loadings. To achieve this goal, previous research works on the group effect under axial and lateral loading have been evaluated and the piles–raft interaction effect has been considered. The proposed procedure is fully compatible with structural software codes and can be straightforwardly applied to the design of the structural members, as it is able to effectively solve a CPRF under the numerous combinations of loadings required by most design codes.
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Kang, Gichun, Seong-Kyu Yun, Tae-Hyung Kim, and Jiseong Kim. "Lateral and Overturning Resistance of Wind Turbine Foundations Reinforced with Piles on Bedrock by Modelling Experiments." Journal of Marine Science and Engineering 9, no. 9 (August 24, 2021): 919. http://dx.doi.org/10.3390/jmse9090919.
Full textAbstract:
This study evaluated the lateral and overturning resistance of wind turbine foundations reinforced with piles on bedrock through model experiments. In particular, changes in lateral and overturning resistance of wind turbine foundations were analyzed according to cross-sectional size and the presence of piles of wind turbine foundations. As a result, by reducing the cross-section, the lateral resistance of the pile-reinforced wind turbine foundation was compared to the existing wind turbine foundation with large cross-sections and was shown to be 1.68 times greater. In the case of vertical displacements affecting overturning, the safety of overturning was also greater, as the vertical displacement of the pile-reinforced wind turbine foundation was 36% smaller than the existing wind turbine foundation. As a result of the unidirectional cyclic load on a pile-reinforced wind turbine foundation, lateral resistance value was similar to that of the static load in target displacement value, and it showed that the elastic resilience was very large due to pile reinforcement. According to the bending moment measurement of piles embedded in wind turbine foundations and bedrock, bending moments were large in the order of the front row, the right-hand row, and the back row, while the maximum bending moment generation was found on the boundary surface of the wind turbine foundation and the rubble mound layer for the front row, as well as on the boundary surface of the rubble mound layer and bedrock for the right-hand row and back row.
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Talbot, J. P., and H. E. M. Hunt. "A computationally efficient piled-foundation model for studying the effects of ground-borne vibration on buildings." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 217, no. 9 (September 1, 2003): 975–89. http://dx.doi.org/10.1243/095440603322407227.
Full textAbstract:
Understanding the effects of ground-borne vibration on buildings is becoming increasingly important as pressure grows to construct high-quality buildings on existing urban sites, which are often close to busy roads or railways. The motivation behind the work presented here is the development of a computational model that enables engineers to evaluate the effectiveness of isolating buildings. This paper presents one component of such a model, namely a new three-dimensional model for modelling the propagation of ground-borne vibration through a piled foundation. A row of piles is considered, with the piles modelled using the solutions for an elastic bar and Euler beam, and the soil represented by an elastic half-space. The model is comprehensive in that it accounts for the longitudinal and transverse motion of the piles due to both external pile-head loads and interaction between neighbouring piles through wave propagation in the surrounding soil. Computational efficiency is achieved by assuming that the row comprises an infinite number of identical piles and using a combination of the boundary element method and periodic structure theory.
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Naghibi, Farzaneh, and Gordon A. Fenton. "Target geotechnical reliability for redundant foundation systems." Canadian Geotechnical Journal 54, no. 7 (July 2017): 945–52. http://dx.doi.org/10.1139/cgj-2016-0478.
Full textAbstract:
Geotechnical support systems (e.g., deep and shallow foundations) generally involve at least some redundancy. For example, if a building is supported by np separate foundations, then failure (e.g., excessive settlement) of a single foundation will generally not result in failure of the building if the building is able to shed the load from the failed foundation to adjacent foundations. This load-shedding ability lends the foundation system redundancy — system failure only occurs if multiple foundations fail. This paper investigates the relationship between the level of geotechnical redundancy, individual foundation reliability, and system reliability for deep foundations (piles). In the particular case where the pile resistance remains constant after achieving its ultimate capacity (at a certain displacement), the relationship between individual and system reliabilities is computed theoretically. The more general case, where the load carried by the pile reduces after exceeding its ultimate capacity, is investigated by Monte Carlo simulation. Charts relating system and individual reliability indices are presented, which can be used to aid in the design of individual piles as part of a pile support system.
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Sedin, Volodymyr, Vladyslav Kovba, Yurii Volnianskyi, and Kateryna Bikus. "Numerical simulation of the stress strain state of base of the multi-helix screw pile under static loading in clay soil." Bases and Foundations, no. 40 (June 4, 2020): 28–36. http://dx.doi.org/10.32347/0475-1132.40.2020.28-36.
Full textAbstract:
A full-scale experiment was conducted to study the operation of a multi-helix screw pile under static pressing and pulling load in dusty clay soil.
Based on the full-scale test of a multi-helix screw pile under static loading in dusty clay soil, numerical modeling of the stress-strain state of the base of the multi-helix screw pile was performed.
Multi-helix screw piles are actively used all over the world, and have also become widespread in Ukraine. Foundations made of multi-helix screw piles are often used for industrial construction as well as the foundations of low-rise buildings and structures.
Despite the growing demand for the use of multi-helix screw piles in modern construction, there is no official document calculating the features of their design and bearing capacity of a multi-helix screw pile. This poses a number of new tasks for engineers and geotechnical: a) development of new modern calculation methods; b) development and use of modern normative documents and recommendations for the calculation of foundations from multi-helix screw piles in various soil conditions; с) use of computer-aided design systems for calculation of complex geotechnical tasks; d) development of calculation models that will take into account nonlinear models of deformation of materials and soil base. Foundations made of multi-helix screw piles are a promising direction in the field of foundation construction due to the reduction of the duration of the foundation and its economic. This requires the development of regulations with recommendations for the calculation and use of multi-helix screw piles in the field of foundation construction, development of modern calculation models for the calculation of bearing capacity and settling of multi-helix screw piles in different geological conditions.
Based on the results of the field study of the work of multi-helix screw piles in clay soils, numerical modeling of the stress-strain state of the base of the multi-turn pile was performed, and their results were compared.
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Fioravante, Vincenzo, and Daniela Giretti. "Contact versus noncontact piled raft foundations." Canadian Geotechnical Journal 47, no. 11 (November 2010): 1271–87. http://dx.doi.org/10.1139/t10-021.
Full textAbstract:
In the last few decades there has been a rapid increase in the number of piled foundations where the piles have been employed as settlement reducers; in some recent projects, the piles have been separated from the raft by a granular layer, which creates a more uniform pressure distribution on the raft bottom and reduces constraint reactions in the soil, foundation, and superstructure. A series of centrifuge model tests has been performed to investigate the load transfer mechanisms between a square rigid raft and a group of instrumented piles jacked in dry dense sand, in direct contact with the raft or separated from the raft by an interposed granular layer. The test results have shown that contact piles act as settlement reducers by diffusing the load applied to their heads to greater and deeper volumes of soil. The insertion of a deformable layer between a raft and pile heads does not ensure displacement compatibility, and the pressure diffused by the granular fill acts partly on the pile heads and partly produces shallow soil settlements, which mobilize negative skin friction on the upper part of the pile shaft. Noncontact piles act mainly as soil reinforcement.
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Wymysłowski, Michał, and Zygmunt Kurałowicz. "Study of displacements of a bridge abutment using FEM." Studia Geotechnica et Mechanica 38, no. 2 (June 1, 2016): 61–70. http://dx.doi.org/10.1515/sgem-2016-0020.
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Abstract Steel sheet piles are often used to support excavations for bridge foundations. When they are left in place in the permanent works, they have the potential to increase foundation bearing capacity and reduce displacements; but their presence is not usually taken into account in foundation design. In this article, the results of finite element analysis of a typical abutment foundation, with and without cover of sheet piles, are presented to demonstrate these effects. The structure described is located over the Więceminka river in the town of Kołobrzeg, Poland. It is a single-span road bridge with reinforced concrete slab.
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Utkin, Vladimir. "Bearing strength calculation of end-bearing piles under recognition of cohesive friction on the pile surface." Stroitel stvo nauka i obrazovanie [Construction Science and Education], no. 2 (June 30, 2019): 1. http://dx.doi.org/10.22227/2305-5502.2019.2.1.
Full textAbstract:
Introduction. It is a drawback of the existing end-bearing pile design method for soil base bearing capacity that the latter is not taken into account in the assessment of the foundation soil action above the rock or a low-compression soil layer in all cases in accordance with the Building Code 24.13330.2011. However, taking into account the bearing capacity of this layer of the soil base in the load accommodation by the end-bearing pile (under recognition of the pile weight) could increase its calculated bearing capacity by the respective value of the soil base bearing capacity in combination with the soil support action under the pile’s lower end. The objective of the research is improving the trustworthiness of the calculation result of the bearing strength of end-bearing piles in the soil base, identifying the pile’s bearing strength reserve by taking in account the additional soil base bearing capacity due to the cohesive friction on the side surface of the pile. Materials and methods. The object of the research are piles of any applicable materials. The methods of calculation of the end-bearing piles are based on on cohesive friction values and their distribution along the pile length in a limit state calculation model in terms of the soil base bearing capacity. Results. The paper presents the equation of the ultimate compression load of the end-bearing pile in terms of the foundation base soil bearing capacity and the formula for the base soil bearing capacity reserve factor of the pile. The calculation of the pile bearing strength in terms of the material strength is referenced in the bibliography. Conclusions. A calculation method of end-bearing piles bearing strength was developed based both on the bearing capacity of soil base under the pile lower end and the additional soil bearing capacity along the flanks of the pile. The method could be applied also for calculations of the bearing strength of deep slot-type foundations. A quantitative assessment of the end-bearing pile on the design stage of a building with a pile foundation is given, prerequisite is made for further studies of the action of end-bearing piles and development of design codes for various piles in terms of material, type of support action, methods of immersion in the soil, etc.
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Yao, Rong, Meng Yun Mao, and Yun Que. "Pile Response Analysis with Unloading Abutment on Soft Ground and Pile Supported Reinforced Embankment Foundation." Advanced Materials Research 1065-1069 (December 2014): 840–43. http://dx.doi.org/10.4028/www.scientific.net/amr.1065-1069.840.
Full textAbstract:
There ware numeral analysis by ABAQUS finite element software to discover the pile’s status with unloading abutment in soft ground, three model were built, first model was unloading abutment and pile supported reinforced embankment, second model was only unloading abutment, third model was only pile supported reinforced embankment, the piles horizontal displacement, axial force and bending moment were discussed; the results show that the piles horizontal displacement with pile supported reinforced are smaller than the others models, pile axial force in three model are little difference.
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Sun, Qiang, Qiu Yi Lin, and Jing Wei Wu. "Determined Methods of Dynamic Stability Critical Length of the Foundation Pile." Advanced Materials Research 261-263 (May 2011): 1434–38. http://dx.doi.org/10.4028/www.scientific.net/amr.261-263.1434.
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Based on the principle of elastic stability, this paper deduces the calculating formulas for dynamic stability critical length of foundation piles when lateral syntony occurs under the axial dynamic loads, and analyzes the effects on dynamic stability critical length of foundation piles from the aspects of parameters such as section dimensions of piles, horizontal resistance forces of foundation soil and excitation frequency etc. Study shows that different soil stratum has the bigger effects on the critical length of piles, while damping coefficient smaller. It also puts forward some related measures for reducing vibration of foundation piles, and can provide reference values to the practical engineering.
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Feng, Shi Lun, Hai Feng Jin, Jun Li, and Pu Lin Li. "Numerical Analysis of the Pit Excavation Influence on Foundation Piles." Applied Mechanics and Materials 99-100 (September 2011): 1239–42. http://dx.doi.org/10.4028/www.scientific.net/amm.99-100.1239.
Full textAbstract:
Excavation of the soil is actually the unloading process. The unloading process of soil makes the soil uplift, and the soil uplift is restricted by the pit engineering piles. And then, engineering piles should bear the vertical upwards pulling force caused by soil uplift. When pulling force is huge and tensile bearing capacity of pile is low, engineering piles could be pulled apart, and it is harmful to bearing capacity and durability of engineering piles. This paper adopts the finite element method to simulate engineering piles during pit excavation, and studies the traits of engineering piles in various excavation working conditions and different position. The computational results show that the deeper pit, the bigger displacement and tensile forces of piles, and the farther away from edges of the pit, the bigger displacement and forces of piles. In addition, the paper also gives a formula about the relationship between depth of pit excavation and uplift force on piles.
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Allotey, Nii, and M. Hesham El Naggar. "A numerical study into lateral cyclic nonlinear soil–pile response." Canadian Geotechnical Journal 45, no. 9 (September 2008): 1268–81. http://dx.doi.org/10.1139/t08-050.
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Pile foundations are generally designed to resist both axial and lateral loads. Under lateral cyclic loading, the response of the pile foundation is affected by factors such as soil and pile yielding, gapping, and soil cave-in. These factors directly influence the effective lateral stiffness and strength of the foundation and can govern the design. In this paper, two case studies of single piles, one in clay and one in sand, are used to examine the influence of the aforementioned factors on nonlinear cyclic response of piles. The numerical study is conducted using a recently developed beam on a nonlinear Winkler foundation (BNWF) model. The results of the study point to the important role soil cave-in and recompression play in the cyclic soil–pile response, and elucidate how this could particularly be beneficial to piles that develop plastic hinges below ground level.
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Pidlutskyi, V. L. "FORMATION OF THE FOUNDATIONS STRESS-STRAIN STATE FROM THE LOCATION CHANGE AND PILES PARAMETERS." ACADEMIC JOURNAL Series: Industrial Machine Building, Civil Engineering 2, no. 49 (October 17, 2017): 135–43. http://dx.doi.org/10.26906/znp.2017.49.834.
Full textAbstract:
The work of high-rise buildings with different piles arrangement foundations is investigated rationally and on a regular grid. The comparative analysis of the results is presented. Typical zones of foundation such as central, lateral, and angular ones are separated. The redistribution of efforts between piles and a grillage is shown. The interaction of piles with different lengths and the grillage in the foundations of high-rise buildings is considered. The numerical modeling of the «base – foundation – superstructure» system is performed. A finite-element model of high-rise buildings comples and a multilayer soil mass is developed. The choice of soil parameters for the deformation model of soil environment on the basis of their identification is shown.
Comparative results of calculations with data of field observations on bearing structures behaviour. The features of buildings complex base deformation are revealed.