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Foundation analysis and design

01 Jan 1968-
TL;DR: In this paper, Fondation de soutenagement et al. presented a reference record for Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Keywords: Fondation ; Mur de soutenement ; Pieux ; Capacite portante ; Ancrage ; Dimensionnement Reference Record created on 2004-09-07, modified on 2016-08-08
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Journal Article
TL;DR: In this article, a load transfer mechanism of a driven pile in sandy soil using finite element code, Plaxis, was predicted using stress analysis and the results showed that numerical prediction on the percentage of the ultimate load which is carried by skin or shaft of the pile is in close agreement with that of empirical method.
Abstract: Proper estimation of axial bearing capacity of driven piles plays an important role in pile design. The amount of ultimate load which can be carried by skin of the pile determines the type of the piles as they are classified according to their load-transfer mechanism. Although there are numerous methods for skin resistance prediction of piles such as analytical methods, empirical methods, and High Strain Dynamic Pile Test (HSDPT) but often in semi-empirical methods, there is an amount of uncertainty more specifically in case of sandy soils for which collecting undisturbed sample is difficult. On the other hand, performing insitu tests such as instrumented pile load test or HSDPT for estimation on distribution of skin resistance with depth is time consuming and expensive. Hence use of numerical method is often of interest. This paper gives an insight into the load-transfer mechanism of a driven pile in sandy soil using finite element code, Plaxis. The end-bearing and skin resistance capacity of the pile were predicted using stress analysis. The outputs of numerical modelling were compared with a well-established empirical method for estimation of ultimate axial bearing capacity of the pile. The results show that numerical prediction on the percentage of the ultimate load which is carried by skin or shaft of the pile is in close agreement with that of empirical method.

5 citations

Book ChapterDOI
01 Jan 2005
TL;DR: In this paper, a large portion of the Yelgun to Chinderah Freeway is located in area underlain by soft and acidic soils and the road embankments in these areas presented significant constraints and risks to the project, involving short-term stability, long-term settlement and durability of structures.
Abstract: A large portion of the Yelgun to Chinderah Freeway is located in area underlain by soft and acidic soils. Construction of the road embankments in these areas presented significant constraints and risks to the project, involving short-term stability, long-term settlement and durability of structures. Safe and economical soft ground treatment measures were developed to overcome the difficulties and problems related to soft soils. Modern numerical techniques were utilised to model the complex soft ground problems leading to optimised soft ground designs. Extensive geotechnical investigations field trials and instrumentation were implemented to better characterise the soft ground behaviours and hence control and manage risks. The project was successfully completed before the dead-line and within the budget.

5 citations

Journal ArticleDOI
TL;DR: In this article, the performance of piled rafts connected to short piles and resting on soft cohesive soil was investigated. But the authors did not consider the effect of the number of piled piles on the bearing pressure.
Abstract: Piled rafts have been used successfully in a wide variety of geotechnical applications. However, behaviour of piled raft placed in cohesive soil is not extensively studied. The present research paper describes the performance of eccentrically loaded square rafts connected to short piles and resting on soft cohesive soil. The load was applied with varying eccentricity (e) to raft width (B) ratios of 0.05, 0.1 and 0.2. Experiments were conducted with two different raft sizes of 180 mm × 180 mm and 220 mm × 220 mm connected to 0, 2, 3, 4 and 5 numbers of piles in different cases. The results showed that in general as compared to unpiled rafts, the average bearing pressure increased almost two times for piled rafts having 5 piles corresponding to e/B = 0.2. For rafts with 5 numbers of piles the average settlement reduced to almost one-third in most cases as compared to rafts without pile corresponding to identical e/B ratio. The foundations were also proved to be greatly effective in reducing the tilt. For e/B = 0.05, on increasing the number of connected piles from 0 to 5, the tilt reduced from 2.00° to 0.19° in case of 180 mm × 180 mm raft, and from 2.15° to 0.10° corresponding to 220 mm × 220 mm raft respectively.

5 citations

Journal Article
TL;DR: In this paper, different theoretical methods have been used for the evaluation of pile capacities and then their comparison with the pile load test evaluations have been made for the project of Rathoa Haryam Bridge being constructed in Mirpur Azad Jammu & Kashmir at Mangla reservoir.
Abstract: The estimation of axial load carrying capacity of bored piles is a complicated problem because it depends upon number of factors which may include boring method, concrete quality, concreting method, experience of the staff and the ground conditions. Validation of pile design through testing of piles either test piles or working piles is considered an essential part of deep foundation design. This is recognized as being the most reliable means of dealing with the uncertainties that may rise during design and construction phase of pile foundations. In this paper, different theoretical methods have been used for the evaluation of pile capacities and then their comparison with the pile load test evaluations have been made for the project of Rathoa Haryam Bridge being constructed in Mirpur Azad Jammu & Kashmir at Mangla reservoir. The subsoil at the bridge site consists mostly of lean clay with ground water table at a shallowest depth of 0.3 m below NSL during the period of field investigations. Six pile load tests have been conducted on test piles with length in the range of 35 m and 45 m and with diameter of 1000 mm. Based on pile capacity analysis, it has been revealed that the theoretical method for pile capacity estimation by NAVFAC DM 7.02 gives 20% to 40% lesser pile capacity relative to the pile capacity evaluated from pile load test data. The SPT method proposed by Decourt gives higher pile capacity relative to the pile capacity derived from pile load test data and therefore, it is not recommended to be used for cohesive soils. The CPT based methods suggested by Schmertmann and Philipponnat give close results to each other but with a difference of 10% to 20% relative to the pile load test interpretation and may be considered reliable methods for cohesive soils. Pile capacities from the pile load test interpretation by Limit Value method and 90% Hansen method match closely whereas the 6 mm net settlement method gives slightly lower estimate of pile capacity as compared to the other load test methods. The best approach for pile capacity evaluation from pile load test data is to use the average value of pile capacity of all the load test interpretation methods.

5 citations


Cites background from "Foundation analysis and design"

  • ...[7] Bowles, J. E. (1996), “Foundation Analysis and Design”, Fifth edition, McGraw-Hill, New York....

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  • ...02 [15] Bowles [7] Gunaratne [14] EM 1110-22906 (1991) [18] EM 1110-11905 [19] 1 115 0....

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  • ...The value of α is 19% and 23% lower than that recommended by [7] and [14]....

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BookDOI
01 Jan 2018
TL;DR: In this paper, the authors used load-settlement data of 23 nos. static pile load tests performed on driven piles and drilled shafts to evaluate the ultimate load capacity of a pile.
Abstract: The in-situ static pile load testing is often carried out on the test pile by applying 1.5 times to 2.5 times the design pile capacity. Due to practical and time constraints, it is not possible to always load and test the pile up to the failure. The load-settlement behavior of the pile during pile load testing under this loading often does not reach the ultimate pile capacity. Hence, in order to utilize the maximum available pile capacity in the design of pile foundations, an extrapolation of load-settlement data are required to evaluate the ultimate pile capacity. Various methods were proposed in the past by researchers such as Chin, Decourt, Davisson, De Beer, Brinch Hansen etc. to evaluate extrapolated ultimate pile capacity. These methods have been adopted in this paper to estimate ultimate pile capacity using load-settlement data of 23 nos. static pile load tests performed on driven piles and drilled shafts. The ultimate capacities evaluated from different methods have been discussed and compared with each other and with ultimate pile capacities for piles tested up to the failure. Based on this comparison, it has been observed that when the test load is high and close to the ultimate load limit, the accuracy in estimated ultimate load can be achieved by all the methods. However, study on piles tested under very less or partial load revealed the overestimation of ultimate pile load except for the Davisson method. Each method estimated different values of ultimate load under different test loads and no specific method can be recommended based on accuracy to evaluate the ultimate pile capacity.

5 citations