Testing and Modelling of Concrete Pile Foundations

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.

Download Full-text

Behaviour of Vertically Loaded Piled Raft System

Journal of Computational and Theoretical Nanoscience ◽

10.1166/jctn.2020.8900 ◽

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.

Download Full-text

Using ground penetrating radars to detect internal defects in concrete foundation slabs

Vestnik MGSU ◽

10.22227/1997-0935.2020.7.980-987 ◽

2020 ◽

pp. 980-987

Author(s):

Evgeny O. Zerkal ◽

Alexey Yu. Kalashnikov ◽

Andrey E. Lapshinov ◽

Aleksey I. Tyutyunkov

Keyword(s):

Reinforced Concrete ◽

Internal Structure ◽

Ground Penetrating Radar ◽

Core Material ◽

Internal Defects ◽

Foundation Slab ◽

Reinforced Concrete Slabs ◽

Piled Raft Foundation ◽

Raft Foundation ◽

Ground Penetrating

Introduction. The co-authors have analyzed a monolithic reinforced concrete piled raft foundation of a multi-storied residential building under construction. The mission of this research effort is to obtain trustworthy information about the internal structure of a foundation slab, to detect and survey internal defects, if any. This research project is to capture potential problems that may accompany the inspection of a foundation, to generate awareness about ground penetrating radar surveys and their methods that can help to optimize operating processes in the process of inspection. Materials and methods. The co-authors have employed a method of ground penetrating radar surveying, performed using a regular mesh of orthogonal projections over an easily accessible surface area of a raft foundation and several antennas producing sounding signals with centre frequencies varying within the range of 1,500 and 2,000 MHz. Results. A number of internal defects has been detected in the structure of a foundation slab, including several horizontal cold joints, cavity pockets and honeycombs. Their presence was later confirmed by control drilling and core material sampling. The information thus obtained was later generalized and entered into surface maps of cold joints, that depicted both the relief and the layout of detected defects in space. The analysis of core material chips has proven that reflecting boundaries are the same as those of the core material destruction; it has also demonstrated the presence of air pockets and the proofs of poor quality concrete mix compaction. Conclusions. The resolution of the ground penetrating radar method is sufficient to identify features of reinforced concrete slabs significant for their structure; it enables researchers to obtain trustworthy information about the internal structure of a foundation slab and make conclusions about the presence or absence of internal defects inside it, including cold joints, cavity pockets or honeycombs.

Download Full-text

Issues on Design of Piled Raft Foundation

JOURNAL OF ADVANCES IN CHEMISTRY ◽

10.24297/jac.v14i1.5905 ◽

2018 ◽

Vol 14 (1) ◽

pp. 6057-6061 ◽

Cited By ~ 1

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.

Download Full-text

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

Applied Sciences ◽

10.3390/app11073099 ◽

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.

Download Full-text