Application of Model Pile Tests to Axial Pile Design

Bogard, J.D.; Matlock, Hudson

doi:10.4043/6376-ms

Cited by 21 publications

(17 citation statements)

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“…Therefore, a studies were performed to define the behavior of the axial capacity in clay soil with time. Clarke (1993) and Bogard and Matlock (1990) ) conducted field measurements studies in which it was shown that the time required for driven piles to reach ultimate capacity in a cohesive soil can be relatively long, as much as 2À3 years. It is worth mentioning that the rate of strength gain is highest immediately after driving, and the rate decreases during the dissipation process.…”

Section: Changes In Axial Capacity In Clay With Timementioning

confidence: 98%

Geotechnical data and piles design

El-Reedy¹

2015

Marine Structural Design Calculations

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Section: Changes In Axial Capacity In Clay With Timementioning

confidence: 98%

Geotechnical data and piles design

El-Reedy¹

2015

Marine Structural Design Calculations

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“…Based on a series of load tests following EOD, Bogard and Matlock (1990) and Tan et al (2004) showed that the increase in pile capacity due to setup could be approximated using a hyperbolic curve; applying this approach to Eq 1. yielded:…”

Section: Recalibration Of the Skov And Denver (1988) Setup Predictionmentioning

confidence: 99%

“…Based on the limited number of examples presented, the proposed model provided a more accurate estimation of setup compared to Skov and Denver (1988). Other setup prediction methods have been proposed by Svinkin (1996) (power law), Bogard and Matlock (1990) (hyperbolic function), and Wang et al (2010) which used a variable growth rate approach.…”

Section: Estimation Of Setupmentioning

confidence: 99%

Time-Dependent Capacity Increase of Piles Driven in the Puget Sound Lowlands

Reddy

Stuedlein

2014

From Soil Behavior Fundamentals to Innovations in Geotechnical Engineering

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Piles driven in the Puget Sound Lowlands frequently exhibit a high magnitude of soil setup or gain in capacity over time. In fact, the energy associated with production pile driving hammers is often insufficient to fully mobilize pile toe bearing resistance during dynamic restrike testing. Due to the potential for significant increases in capacity, practitioners often must consider the uncertain trade-off between the potential for setup and time-to-restrike. This study presents the results of 76 pile case histories from the Puget Sound Lowlands that were dynamically monitored during end-of-drive (EOD) and begin-of-restrike (BOR). The setup time (i.e. time between EOD and BOR) ranged from 5.5 to 312.5 hours. Signal matching using CAse Pile Wave Analysis Program (CAPWAP) indicated that the majority of the piles experienced significant increases in shaft resistance. In order to assess setup, piles were grouped into three categories: closed-end steel pipe piles, open-end steel pipe piles, and solid concrete piles. The accuracy and uncertainty of the well-known Skov and Denver (1988) setup prediction model was evaluated using the mean bias, defined as the ratio of measured and predicted shaft resistance, and the coefficient of variation (COV), defined as the ratio of the standard deviation of the point biases to the mean bias. The Skov and Denver model exhibited considerable uncertainty (COV = 45 to 59 percent) when evaluated using the local database. Recalibration efforts made using a hyperbolic function and least squares regression resulted in a reduction of the COV to 29 to 32 percent. Based on considerable scatter in the setup ratio (i.e. ratio of BOR to EOD shaft resistance), it was determined that the behavior of setup over time could not be adequately captured by considering total shaft resistance. Therefore, setup due to the overall increase in shaft resistance between EOD and BOR was characterized in an initial effort to provide guidance for incorporating setup into pile design. Closed-end concrete piles exhibited the largest average setup ratio (3.92), followed by closed-end steel piles (2.37) and open-ended steel piles (2.26).

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“…Brief summaries of those empirical methods could be found in Svinkin et al (1994), Tan et al (2004), Yang and Liang (2007), and Wang et al (2011), etc. Tan et al (2004 recommended and elaborated the empirical hyperbolic equation proposed by Bogard and Matlock (1990) based on the collected data from different field tests. They thought that the method was more reliable to predict pile set-up in sand than the logarithm of time method.…”

mentioning

confidence: 99%

Estimating Pile Set-up Using 24-h Restrike Resistance and Computed Static Capacity for PPC Piles Driven in Soft Lousiana Coastal Deposits

2015

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In this paper, the CPT-based predicted ultimate pile resistances (R p ) were compared with the measured pile resistances (R m ) at different elapsed time for the piles driven into saturated soft clays where piles displayed significant set-up effect. The measured pile resistances were based on 115 restrike records collected from 95 production piles, and 74 records of 9 tested piles. The predicted ultimate pile resistances were calculated from the LCPC, the Schmertmann, and the de Ruiter-Beringen methods, respectively. With the significant pile set-up effect taken into account, the relationship between measured resistances and predicted capacities at different times after pile installation were investigated. The ratios of the measured pile resistances to the predicted capacities scattered in a large spectrum. The ratios fluctuated and stayed within a range of 0.6-1.6 for different CPT methods since end of initial driving until more than 2 months after pile installation. Plots of the ratios versus the predicted pile capacities using different CPT methods have revealed that the ratio (R m /R p ) presented a strong dependence on the predicted capacities. Great research efforts have been devoted to the analyses of the ratios of the 24-h measured resistance to the predicted capacity based on different CPT methods, in an attempt to find a feasible empirical correlation. It is found that a simple linear relationship exists between the quad root of the ratio and the predicted capacity. The developed empirical equations will give pile foundation engineers an insight into the ultimate resistances of driven piles demonstrating significant pile set-up effects. Pile set-up makes pile resistances grow with time, and it might be one of the reasons that cause the frequently reported large discrepancy between calculated static capacity and measured resistance at a certain time after pile installation.

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Application of Model Pile Tests to Axial Pile Design

Cited by 21 publications

References 0 publications

Geotechnical data and piles design

Geotechnical data and piles design

Time-Dependent Capacity Increase of Piles Driven in the Puget Sound Lowlands

Estimating Pile Set-up Using 24-h Restrike Resistance and Computed Static Capacity for PPC Piles Driven in Soft Lousiana Coastal Deposits

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