Comparative analyses of large diameter bored piles using international codes

Gendy, M El; El-Arabi, Ibrahim A.; Kamal, Mumtaz Ahmed

doi:10.1179/1937525514y.0000000001

Cited by 7 publications

(8 citation statements)

References 2 publications

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“…However, Meyerhof's method underestimated the soil unit skin friction, with differences ranging from 10% to 21%. (6) The ultimate bearing stress below the large diameter pile base is affected by pile diameter, pile length, soil effective cohesion, soil lateral earth pressure coefficient, and soil effective friction angle increases. However, several settlement-based methods proposed by different codes and design standards suggest constant bearing stress at a particular settlement value (i.e., 5% D) irrespective of pile geometry and without any discrimination for any class of the cohesive soils.…”

Section: Discussionmentioning

confidence: 99%

A Parametric Numerical Study for Diagnosing the Failure of Large Diameter Bored Piles Using Supervised Machine Learning Approach

2021

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The full-scale static pile loading test is without question the most reliable methodology for estimating the ultimate capacity of large diameter bored piles (LDBP). However, in most cases, the obtained load-settlement curves from LDBP loading tests tend to increase without reaching the failure point or an asymptote. Loading an LDBP until reaching apparent failure is seldom practical because of the significant amount of settlement usually required for the full shaft and base mobilizations. With that in mind, the supervised learning algorithm requires a huge labeled data set to train the machine properly, which makes it ideal for sensitivity analysis, forecasting, and predictions, among other unsupervised algorithms. However, providing such a huge dataset of LDBP loaded to failure tests might be very complicated. In this paper, a novel practice has been proposed to establish a labeled dataset needed to train supervised machine learning algorithms on accurately predicting the ultimate capacity of an LDBP. A comprehensive numerical parametric study was carried out to investigate the effect of both pile geometrical and soil geotechnical parameters on both the ultimate capacity and settlement of an LDBP. This study was based on field measurements of loaded to failure LDBP tests. Results of the 29 applied models were compared with the calibrated model results, and the variation in LDBP behavior due to change in any of the hyperparameters was discussed. Accordingly, three primary characteristics were identified to diagnose the failure of LDBPs. Those characteristics were utilized to establish a decision tree of a supervised machine learning algorithm that can be used to predict the ultimate capacity of an LDBP.

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Section: Discussionmentioning

confidence: 99%

A Parametric Numerical Study for Diagnosing the Failure of Large Diameter Bored Piles Using Supervised Machine Learning Approach

2021

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“…El Gendy et al 2014 [17] calculated the ultimate capacities of 38 LDBPs with different geometries in multi-layered soils, using ECP202/4 2005 [3], German standard (DIN 4014 1990 [4]), AASHTO 2005 [6], and modified Chin 1970 [10] methods. A summary of the results is shown in Figure 2.…”

Section: Figurementioning

confidence: 99%

“…Compared to DIN 4014 1990 [4] and AASHTO 2005 [6] codes calculations, It was perceived that the determined ultimate capacities using the ECP202/4 2005 [2] are mostly more conservative. [3], DIN 4014 1990 [4], AASHTO 2005 [6], and modified Chin 1970 [10] approaches for 8 of 38 case studies (After El Gendy et al 2014 [17]).…”

Section: Figurementioning

confidence: 99%

Estimation of the Large Diameter Bored Pile Ultimate Capacity Using Different Design Methods: Assessment Study

Al‐Atroush

Aloufi

2022

IOP Conf. Ser.: Earth Environ. Sci.

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In this paper, in situ measurements of two well-instrumented loading tests performed on large diameter bored piles (LDBP) have been utilized to assess the reliability of the predicted ultimate pile capacity using three settlement-based and capacity-based methods. The first test was conducted on a short LDBP with a 1.3m and 9.50 length. This LDBP was constructed in stiff clay soil and loaded till the achievement of the failure. While the second in-situ loading test was performed on a long LDBP with a 1.00 m diameter and 34.00 m length. This LDBP was constructed in multi-layered soil and examined under three axially loading and unloading cycles to obtain the ultimate load settlement relationship. Although this LDBP was loaded with an applied load of three times its working capacity, but no apparent failure was reached at the end of the loading test. Thus, two different methods are adopted to interpret the test data and determine the ultimate pile capacity. The obtained ultimate capacities of the two tests were utilized in an assessment study. The comparative analysis results showed a significant difference between the ultimate capacity obtained using three different methods and field measurements. Out of the three utilized methods in this study, the two settlement-based methods underestimated the LDBP ultimate capacity of the two LDBP cases; conversely, the third capacity-based method overestimated the ultimate capacity of the two LDBP cases.

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“…On the other hand, as mentioned before, Meyerhof’s capacity-based method 31 overestimates the ultimate capacity of the LDBP; in contrast, different codes’ settlement-based criteria underestimate the LDBP's ultimate capacity. This conviction was built on the results of several comparative analyses performed to assess the associated uncertainties with different capacity-based methods and settlement-based approaches recommended by various international standards 28 , 29 , 34 for different pile loading tests with various large diameters and in different subsurfaces. That’s why Meyerhof 31 method has been chosen for the capacity-based part of this investigation.…”

Section: Hypothesismentioning

confidence: 99%

Modified Meyerhof approach for forecasting reliable ultimate capacity of the large diameter bored piles

Al‐Atroush

Hefny

Sorour

2022

Sci Rep

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The static loading test is undoubtedly the most reliable method for forecasting the ultimate capacity of the large diameter bored piles (LDBP). However, in-situ loading of this class of piles until reaching failure is practically seldom due to the large amount of settlement required for shaft and base mobilization. Therefore, many international design standards recommend either capacity-based or settlement-based methods to estimate the LDBP ultimate capacity in case of the impossibility of performing loading tests during the design phase. However, those methods are invariably associated with various degrees of uncertainty resulting from several factors, as evidenced in several comparative analyses available in the literature. For instance, the settlement-based method of the Egyptian code of practice (ECP 202/4) usually underestimates the ultimate capacity of LDBP. In contrast, Meyerhof's capacity-based method often overestimates the LDBP’s ultimate capacity. In this paper, a modified approach has been proposed to forecast the ultimate capacity of the LDBP. This approach was modified from Meyerhof’s classical formula (1976) through three fundamental stages. First, an assessment study was performed to evaluate the reliability of the estimated LDBP ultimate capacity using Meyerhof’s classical method. For this purpose, results of full scale loaded to failure loading LDBP test and related twenty-eight parametric numerical models with various pile geometrical and soil geotechnical parameters have been used. Based on the assessment study findings, the essential modifications were suggested in the second stage to adapt Meyerhof’s classic method. In the third stage, the results of several numerical models and in-situ loading tests were employed to assess the accuracy of the developed modified method. This study showed that Meyerhof's classical method overestimated the ultimate capacity of LDBP with an error percentage ranging from 14 to 46%. On the other side, the proposed modified approach has succeeded in estimating the ultimate capacity of loaded to failure in-situ LDBP test and twenty numerical LDBP models with error percentages ranging from 0.267 to 7.75%.

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Comparative analyses of large diameter bored piles using international codes

Cited by 7 publications

References 2 publications

A Parametric Numerical Study for Diagnosing the Failure of Large Diameter Bored Piles Using Supervised Machine Learning Approach

A Parametric Numerical Study for Diagnosing the Failure of Large Diameter Bored Piles Using Supervised Machine Learning Approach

Estimation of the Large Diameter Bored Pile Ultimate Capacity Using Different Design Methods: Assessment Study

Modified Meyerhof approach for forecasting reliable ultimate capacity of the large diameter bored piles

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