scholarly journals Study on Parametric Analysis of Piled Raft Foundation System Using Finite Element Approach

2021 ◽  
Vol 6 ◽  
pp. 143-157
Author(s):  
Santosh Niraula ◽  
Indra Prasad Acharya
Keyword(s):  
Static Loading ◽  
Strain Analysis ◽  
High Rise ◽  
Piled Raft ◽  
Variation Of Parameters ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Element Approach ◽  
Displacement Behavior ◽  
Plain Strain

To accommodate the shear requirement and settlement requirement of high rise construction, the concept of piled-raft foundation has been developed. This research deals with successive analysis of parameters of piled-raft foundation system using PLAXIS-2D as a FEM tool. Plain strain analysis of piled raft foundation system has been conducted out by successive fixing up of parameters. For the analysis two cases has been studied for piled-raft lying on silty soil deposit and on clayey deposit with respect to uniform static loading from superstructure. The result of successive variation of parameters showed that variation has limiting effect on stress and displacement behavior. The analysis is also performed for raft of different relative stiffness and pile of different relative compressibility and load sharing between plain strain pile and raft has been analyzed.

scholarly journals INVESTIGATING THE BEHAVIOR OF PILED RAFT FOUNDATION IN CORE WALL FOUNDATION OF HIGH-RISE BUILDINGS

2021 ◽  
pp. 1-9
Author(s):  
Tuan Nguyen Anh
Keyword(s):  
Core Structure ◽  
High Rise ◽  
Geometry Model ◽  
The Core ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Wall Foundation ◽  
The Moment ◽  
Plaxis 3D

Core structure is an indispensable part of high buildings. Normally, the foundation of the core structure has a raft of larger size than the other foundations in the same project; therefore, the foundation of the core structure can be viewed as a small piled raft foundation. Currently, when calculating the piled foundation of the core, it is mostly assumed that the piles system will bear all the project loads. But this calculation method is not suitable for the actual constructions as well as does not make full use of the bearing capacity of the structure and the ground, leading to using more materials and causing more waste. Core structure aims to increase both stiffness and horizontal load capacity in high-rise buildings, so the moment inside the core transmitted to the foundation is very large. One of the shortcomings of the Plaxis 3D Foundation software is its inability to declare the moment affecting on the foundation due to the loads in this program just includes distributed loads, line loads and point loads in the geometry model. Consequently, when using Plaxis 3D Foundation software to calculate the core wall foundation of high-rise buildings, this moment is converted into an equivalent pair of moments. The research shows that when the core foundation of a high-rise building is placed on soft soil, the pile carries 96%, most of the load transmitted to the foundation. However, when the foundation is placed on hard soil, the soil surrounding the raft will bear about 10% of the load transmitted to the foundation. If this matter is skipped, there will be a large error in calculation and design

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.

The Analysis of Long Pile for Piled Raft Foundation Reinforcement

2014 ◽  
Vol 1065-1069 ◽  
pp. 223-226
Author(s):  
Yan Sun ◽  
Man Yang
Keyword(s):  
Reference Value ◽  
High Rise ◽  
Piled Raft ◽  
Pile Diameter ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Practical Engineering ◽  
Vertical Bearing ◽  
Reinforcement Model ◽  
Foundation Parameters

For high-rise buildings piled raft foundation reinforcement, use ANSYS to establish the piled raft foundation complement pile reinforcement model which is called long-short-piled raft foundation. Parameters of complement pile respectively from the aspects of pile length and pile diameter for change, study its effect on piled raft foundation vertical bearing performance. Provide certain reference value for practical engineering.

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