ANALYTICAL STUDY ON PILED-RAFT FOUNDATION CONSIDERING NONLINEAR BEHAVIOR OF GIBSON SOIL

2016 ◽  
Vol 3 (2) ◽  
Author(s):  
He Huang ◽  
Haruyuki Yamamoto
Keyword(s):  
Analytical Study ◽  
Soil Layer ◽  
Nonlinear Behavior ◽  
Elastic Theory ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation

Randolph (1994) was proposed simplified estimated equations to carried out the proportion of load between the components of piled-raft foundation. These equations are based on elastic theory. Therefore, Authors focus on the point of applicability for nonlinear behavior of soil. This paper is a part of study on behavior of piled-raft foundation under considering the nonlinear behavior of ground. Authors already discussed the effect of nonlinear behavior of soil on the equations by Randolph. In addition, as the extension of research, authors also discussed the applicability of these equations for irregular raft shape. However, foundations were rarely set in an ideal homogeneous single soil layer in our previous studies. Therefore, the applicability of these equations are discussed in case of inhomogeneous soil (Gibson soil) 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.

scholarly journals Parametric Study on Unconnected Piled Raft Foundation Using Numerical Modelling

2020 ◽  
Vol 26 (5) ◽  
pp. 156-171
Author(s):  
Athraa Mohammed Jawad Alhassani ◽  
Ala Nasir Aljorany
Keyword(s):  
Axial Stress ◽  
Soil Layer ◽  
Structural Members ◽  
Element Analysis ◽  
Foundation Soil ◽  
High Rise ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Pile Length

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.

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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