On a unified theory for reliability-based geotechnical design

Fenton, Gordon A.; Naghibi, Farzaneh; Griffiths, D. V.

doi:10.1016/j.compgeo.2016.04.013

Cited by 41 publications

(9 citation statements)

References 12 publications

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“…The allowable stress design (ASD) philosophy has combined all these uncertainties into a global factor of safety (FOS), but a global FOS can be selected subjectively from previous experiences and judgements and correspond to varying levels of risk (Becker, 1996;Duncan, 2000;Phoon et al, 2003). On the contrary, a RBD considers the likelihood of failure with probabilistic methods and reliability theories and has been gradually replacing ASD over the last few decades in geotechnical engineering (Fenton et al, 2016;Paikowsky, 2004;Phoon & Kulhawy, 2008).…”

Section: Reliability-based Designsmentioning

confidence: 99%

Reliability-based Design for Axially Loaded Driven Piles in Glacial Deposits

Jesswein

2024

Preprint

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Many factors and uncertainties, especially from the soil conditions, challenge the accuracy of a pile design for the geotechnical ultimate limit state (ULS) and serviceability limit state (SLS). The uncertainties can be contributed by the inconsistent material properties of glacial deposits or a lack of provisions by many design methods for the pile set-up, which is an increase in the pile capacity with time. Thus, for driven steel piles subjected to static and maintained axial loads, the goal of this research was to improve the predictability of these limit states by modifying reliability-based design (RBD) methods. A database was collected first in this thesis with a total of 120 piles subjected to static and/or Pile Driving Analyzer (PDA) tests. These tests were used to evaluate the accuracy of several existing design methods that predict the pile capacity with in-situ measurements, particularly by the standard penetration test (SPT) or piezocone penetration test (CPTu). Since existing methods commonly overestimated the capacity or exhibited significant variations in their predictions, correlations were conducted between results from the in-situ and pile tests to develop new design methods to better consider the soil content and set-up time. Many existing set-up prediction methods rely on time-consuming laboratory tests, but this study offers a practical CPTu-based approach. Afterwards, reliability analyses were performed to help designers account for the uncertainties in designs and estimate the factored resistance for the ULS and SLS. Although a few studies have previously incorporated set-up into RBDs for the ULS, very few, if any, have incorporated set-up for the SLS; thus, this thesis presents a series of resistance factors that were calibrated by Monte Carlos simulation for a range of set-up to end-of-driving resistance ratios and allowable settlements. The findings demonstrate the benefits of versatile methods that consider a range of conditions, such as set-up time, soil classification, and pile geometry. In addition, economic benefits may be received for designs by using a greater factored resistance at a set-up time compared to the end-of-pile-driving condition. Overall, the findings can assist practitioners to mitigate geotechnical risks and deliver more economic and reliable pile designs.

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Section: Reliability-based Designsmentioning

confidence: 99%

Reliability-based Design for Axially Loaded Driven Piles in Glacial Deposits

Jesswein

2024

Preprint

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“…Probabilistic considerations in deep foundation have emerged in applications towards excessive differential settlement; analysis of excavation-induced retaining wall deflection, ground movements, and damage potential to an adjacent building with focus on component reliability assessment of serviceability criterion [27] Fenton [123], Fenton et al [114], Fenton and Naghibi [124] have made comparison among existing codes regarding periodic updates and revisions for professional practice harmonization. They indicated that countries have already been shifting the national geotechnical design codes of standards towards reliability-based design concepts where separate "partial" factor of safety is employed unlike that of comprehensive one in the traditional method.…”

Section: Dealing With Uncertainties and Reliabilitymentioning

confidence: 99%

Deep Foundation Pit Excavations Adjacent to Disconnected Piled Rafts: A Review on Risk Control Practice

Uge¹,

Guo²

2020

OJCE

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Foundation pit excavation engineering is an old subject full of decision making. Yet, it still deserves further research due to the associated high failure cost and the complexity of the geological conditions and/or the surrounding existing infrastructure around it. This article overviews the risk control practice of foundation pit excavation projects in close proximity to existing disconnected piled raft. More focus is given to geotechnical aspects. The review begins with achievements to ensure excavation performance requirements, and follows to discuss the complex soil structure interaction involved among the fundamental components: the retaining wall, mat, piles, cushion, and the soil. After bringing consensus points to practicing engineers and decision makers, it then suggests possible future research directions.

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“…where F L is the characteristic live load; F D is the characteristic dead load; and ␣ L and ␣ D are the live and dead load factors, respectively. The characteristic loads F L and F D are obtained by applying bias factors to the means of the load distribution: (Fenton et al 2016), where L and D are the means of the maximum lifetime dead and live loads, respectively. The bearing capacity of a strip footing subjected to static loading was given by Meyerhof (1963) Budhu and Al-karni (1993) introduce seismic factors into eq.…”

Section: Footing Designmentioning

confidence: 99%

Calibration of resistance factors for geotechnical seismic design

Naghibi

Fenton

2019

Can. Geotech. J.

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The next edition of the Canadian Highway Bridge Design Code will contain a table of geotechnical resistance factors to be used for seismic design. This paper will estimate the geotechnical resistance factors for shallow foundations required to achieve various target maximum acceptable failure probabilities, which in turn may depend on the assumed design earthquake return period. The investigation will include consideration of design lifetime, uncertainty in the magnitude of the maximum lifetime earthquake event, and the uncertainty in ground properties. The results suggest resistance factors that are lower than commonly used at the moment in Canada and that the failure probability is not greatly dependent on the return period of the design earthquake. The paper will present recommendations on geotechnical resistance factors for seismic design that can be used to guide and calibrate future editions of civil design codes in Canada.

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On a unified theory for reliability-based geotechnical design

Cited by 41 publications

References 12 publications

Reliability-based Design for Axially Loaded Driven Piles in Glacial Deposits

Reliability-based Design for Axially Loaded Driven Piles in Glacial Deposits

Deep Foundation Pit Excavations Adjacent to Disconnected Piled Rafts: A Review on Risk Control Practice

Calibration of resistance factors for geotechnical seismic design

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