scholarly journals Behaviour of Load-Bearing Components of a Cushioned Composite Piled Raft Foundation Under Axial Loading

2014 ◽  
Vol 22 (4) ◽  
pp. 25-34 ◽  
Author(s):  
V. J. Sharma ◽  
S. A. Vasanvala ◽  
C. H. Solanki
Keyword(s):  
Soil Profile ◽  
Axial Loading ◽  
Load Bearing ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
The World ◽  
Raft Foundations ◽  
Flexible Pile

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.

scholarly journals 3D Numerical Modeling of Large Piled-Raft Foundation on Clayey Soils for Different Loadings and Pile-Raft Configurations

2020 ◽  
Vol 42 (1) ◽  
pp. 1-17
Author(s):  
Shivanand Mali ◽  
Baleshwar Singh
Keyword(s):  
Numerical Modeling ◽  
Soil Profile ◽  
Bending Moment ◽  
Load Sharing ◽  
3D Numerical Modeling ◽  
Interface Elements ◽  
Pile Spacing ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation

AbstractIn a piled-raft foundation, the interaction between structural elements and soil continuum can be simulated very precisely by numerical modeling. In the present study, 3D finite element model has been used to examine the settlement, load-sharing, bending moment, and shear force behavior of piled-raft foundation on different soil profiles for different load configurations and pile-raft configurations (PRCs). The model incorporates the pile-to-soil and raft-to-soil interactions by means of interface elements. The effect of parameters such as pile spacing and raft thickness are also studied. For any soil profile, larger pile spacing is observed to be more efficient in reducing the average settlement and enhancing the load-sharing coefficient. The smaller pile spacing is observed to be efficient in reducing the differential settlement. For any soil profile, the behavior of piled-raft foundation is significantly affected by the PRCs and load configurations. Furthermore, the raft thickness has significant effect on settlement, bending moment, and shears force. Thus, the results of the present study can be used as guidelines for analyzing and designing large piled-raft foundation.

AN ESTIMATING METHOD FOR LATERAL BEHAVIOR OF PILED-RAFT FOUNDATION

2017 ◽  
Vol 4 (1) ◽  
Author(s):  
Haruyuki Yamamoto ◽  
He Huang
Keyword(s):  
Ground Surface ◽  
Surface Displacement ◽  
Lateral Loading ◽  
Location Factors ◽  
Location Factor ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Cone Model ◽  
Raft Foundations

Some simplified design methods were proposed to predict behavior of lateral loaded piled-raft foundations on homogenous soil. One of them is the cone model method. However, only one average solution of pile behavior can be given by this method. It can’t evaluate the location factors of piles. Therefore, this paper describes a new simplified method to predict behavior of lateral loaded piled raft foundations covering the location factor of piles. At first, ground surface displacement is derived theoretically by Cerutti’s solution, then assuming that the raft foundation has rigid stiffness, these displacements are the same to calculation lateral loading distribution. Second, the ground displacement where pile placed could be estimated under calculated lateral loading. Third, the piles behavior are evaluated based on these lateral ground displacements. In addition, 3-D FEM numerical analysis were performed to compared with these solutions.

scholarly journals Experimental Investigation for Effects of Mini-piles on the Structural Response of Raft Foundations

2019 ◽  
Vol 5 (5) ◽  
pp. 1084-1098
Author(s):  
Huda Hussein Ahmed ◽  
Salah Rohaima Al-Zaidee
Keyword(s):  
Structural Response ◽  
Cost Effective ◽  
Bending Moments ◽  
Historical Structures ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Significant Difference ◽  
Scale Down ◽  
Raft Foundations

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.

scholarly journals ESTIMATING THE INTERNAL FORCES OF RAFT IN PILED RAFT FOUNDATION FOR NORMAL AND GROUNDWATER PUMPING CONDITIONS: A CASE STUDY SOC TRANG PROVINCE, VIETNAM

2021 ◽  
Vol 1 (42) ◽  
pp. 86-93
Author(s):  
Hiep Van Huynh ◽  
Tri Huu Huynh ◽  
Truyen Gia Ngo ◽  
Tuan Van Tran
Keyword(s):  
Shear Force ◽  
Soft Soil ◽  
Groundwater Pumping ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Length Width ◽  
Internal Forces ◽  
Raft Foundations

Piled raft foundations are widely used in infrastructure built on soft soil to reduce the settlement and enhance bearing capacity. The raft can be used for basements and to share the load. In this paper, Poulos method, in which the raft was cut into many piled strips, was used as an analytical method. The study also used Plaxis2D and SAP 2000 to calculate internal forces for the raft in a piled raft foundation. A case of Vietcombank building with 10 floors and 1 basement, constructed on a soil profile in Soc Trang province, was studied. The piled raft with a 35m×19m×1m (length×width×thickness) raft and 28 piles were used for the analysis. Normaland groundwater pumping conditions were applied for the soil. The results showed that the maximum moment and shear force that occurred in the raft were affected when the groundwater pumping condition was applied to the model. The internal forces of the raft in the piled raft foundation for different conditions were captured,discussed, and presented in this paper.

ANALYTICAL STUDY OF PILED-RAFT FOUNDATIONS CONSIDERING PLAN GEOMETRY AND NONLINEAR BEHAVIOR OF GROUND

2015 ◽  
Vol 2 (1) ◽  
Author(s):  
Haruyuki Yamamoto ◽  
He Huang
Keyword(s):  
Pile Foundation ◽  
Analytical Study ◽  
Nonlinear Behavior ◽  
Theory Of Elasticity ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Raft Foundations

The piled-raft foundation transfers loading to the ground by the raft and the piles together. It was proposed in the 1970s and is widely used for controlling settlement. Simplified estimate equations are used for the primary design. Equations by Randolph can presume the settlement stiffness of the piled-raft foundation and the loading share ratio from the settlement stiffness of raft and pile foundation. Raft foundations not only have regular shapes as squares, they also have some particular shape like triangular or L-plan. Therefore, different shape plans are discussed in this paper to verify the applicability of these equations. Also, these equations are proposed based on a theory of elasticity. However, the ground has nonlinear behavior even under small loading levels, so estimating the applicability of these equations when the ground behaves nonlinearly is necessary.

Issues on Design of Piled Raft Foundation

2018 ◽  
Vol 14 (1) ◽  
pp. 6057-6061 ◽  
Author(s):  
Padmanaban M S ◽  
J Sreerambabu
Keyword(s):  
Contact Area ◽  
Concrete Slab ◽  
Design Procedure ◽  
Bending Moment ◽  
Foundation Design ◽  
Detailed Review ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Influencing Parameters

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.

scholarly journals Comparative Analysis of Kazakhstani and European Design Specifications: Raft Foundation, Pile Foundation, and Piled Raft Foundation

2021 ◽  
Vol 11 (7) ◽  
pp. 3099
Author(s):  
Assel Zhanabayeva ◽  
Nazerke Sagidullina ◽  
Jong Kim ◽  
Alfrendo Satyanaga ◽  
Deuckhang Lee ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
International Standards ◽  
Piled Raft ◽  
Codes Of Practice ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Eurocode 7 ◽  
Elastic Settlement ◽  
Geotechnical Design ◽  
The Difference

The introduction of Eurocode in Kazakhstan allows for the application of modern technological innovations and the elimination of technical barriers for the realization of international projects. It is significant to study the international standards and design requirements provided in Eurocode. This study presents a comparative analysis of Kazakhstani and European approaches for the geotechnical design of foundations and provides the design methods in the considered codes of practice. Three different types of foundations (i.e., raft, pile, and piled raft foundations) were designed following SP RK 5.01-102-2013—Foundations of buildings and structures, SP RK 5.01-103-2013—Pile foundations, and Eurocode 7: Geotechnical design for the Nur-Sultan soil profile. For all three types of foundations, the calculated results of bearing resistance and elastic settlement showed the conservativeness of Eurocode over SNiP-based Kazakhstani building regulations, as the values of bearing resistance and elastic settlement adhering to Kazakhstani code exceeded the Eurocode values. The difference between the obtained results can be explained by the application of higher values of partial safety factors by Eurocode 7. Sensitivity analysis of the bearing resistance on foundation parameters (i.e., raft foundation width and pile length) for the Kazakhstani and European approaches was performed to support the conclusions of the study.

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