Application Study of Long-Short-Piled Raft Foundation

2012 ◽  
Vol 170-173 ◽  
pp. 242-245
Author(s):  
Xin Yu Xie ◽  
Ming Xin Shou ◽  
Jie Qing Huang ◽  
Kai Fu Liu
Keyword(s):  
Bearing Capacity ◽  
Pile Foundation ◽  
National Standard ◽  
Application Study ◽  
Existing Building ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Total Settlement ◽  
Reinforcement Design

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.

Behaviour of Vertically Loaded Piled Raft System

2020 ◽  
Vol 17 (5) ◽  
pp. 2383-2387
Author(s):  
K. Merin Jose ◽  
Divya Krishnan ◽  
P. T. Ravichandran
Keyword(s):  
Bearing Capacity ◽  
Load Capacity ◽  
Load Test ◽  
Ultimate Load Capacity ◽  
Foundation Soil ◽  
Total Load ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Dense State

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.

scholarly journals 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

2015 ◽  
Vol 47 (2) ◽  
pp. 113-126
Author(s):  
Grzegorz Kacprzak ◽  
Katarzyna Mazurek ◽  
Tomasz Daktera
Keyword(s):  
Bearing Capacity ◽  
Design Method ◽  
Residential Building ◽  
Organic Soil ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Geological Conditions ◽  
Vertical Displacements ◽  
Simplified Algorithm

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.

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 Three Dimensional Analysis of Pile-raft Foundations on Clay, Menteng-Jakarta

2021 ◽  
Vol 27 (1) ◽  
pp. 107-117
Author(s):  
Evelyn Jogiadinata ◽  
Paulus Pramono Rahardjo ◽  
Aswin Lim
Keyword(s):  
Pile Foundation ◽  
Three Dimensional ◽  
Measurement Data ◽  
Element Analysis ◽  
Pile Capacity ◽  
Piled Raft ◽  
Piled Raft Foundation ◽  
Raft Foundation ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Piled-raft foundation is a combination of pile foundation and raft foundation. Bearing capacity of piled-raft foundation yielded from contribution of both pile capacity and raft capacity. Most of the time, design of pile foundation is assumed that all load is solely carried by pile and the capacity of raft is ignored. In this study, three-dimensional finite element analysis was applied to analyze the load percentage that can be carried by raft. A case study, which is located in Central Jakarta, Indonesia, was modeled to investigate this issue. This project was instrumented with two pressure cells where the data were used to verified the model and the load distribution. The analysis results showed good agreement with the measurement data, where the load carried by the raft is around 33-42%.

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