Target geotechnical reliability for redundant foundation systems

Naghibi, Farzaneh; Fenton, Gordon A.

doi:10.1139/cgj-2016-0478

Cited by 16 publications

(4 citation statements)

References 8 publications

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“…Note that the coefficient of variation of the total load, F v , is assumed constant at 0.1. This assumption is based on coefficients of variation for live load of 0.27 and for dead load of 0.1 with a dead to live load ratio of 3, as shown by Naghibi and Fenton (2017). Note that…”

Section: Regression Approximation To Simulation Resultsmentioning

confidence: 99%

Design of foundations against differential settlement

Naghibi

Fenton

2022

Can. Geotech. J.

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The serviceability limit state (SLS) design of foundations typically proceeds by limiting the total settlement of individual foundations and thereby attempting to restrict the differential settlement between pairs of foundations. Due to the uncertain nature of the supporting ground, the magnitude of settlement and differential settlement are random. As it is often the differential settlement which governs serviceability, it is desirable to provide design requirements which suitably restrict differential settlements. This paper investigates, by Monte Carlo simulation, the distribution of the maximum differential settlement between pairs of foundations as a function of the spacing between foundations and the number of foundations – groups of 4, 9, or 16 foundations, arranged on a grid, are considered. The effects of the correlations between the equivalent stiffness of the ground under each foundation, as well as between the loads applied to the foundations, on the distribution of the maximum differential settlements and angular distortions are investigated. Ratios of resistance factor to resistance bias factor are presented that can be used to calibrate design requirements on the total settlement of individual foundations which also simultaneously achieve acceptable performance with respect to angular distortion.

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Section: Regression Approximation To Simulation Resultsmentioning

confidence: 99%

Design of foundations against differential settlement

Naghibi

Fenton

2022

Can. Geotech. J.

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“…The design of liners for low-reliability index may result in an unsafe design, though it could be less expensive. A reliability index of 3.0 corresponds to a probability of failure of approximately 0.00135 (or 0.135%) is commonly prescribed in geotechnical and geoenvironmental design practices 49 . This level of risk is deemed acceptable for many geotechnical engineering applications where the consequences of failure are significant but not catastrophic.…”

Section: Materials and Methodologymentioning

confidence: 99%

Target reliability-based design optimization studies on cohesive soil amended with chitosan and casein for liner applications

Rasheed,

Moghal,

Basha

et al. 2024

Sci Rep

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The current study investigated the primary and secondary compressibility characteristics of organic clay with two biopolymers, Chitosan (Dch) and Casein (Dca) at dosages of 0.5%, 1%, 2%, and 4%. The primary compression index (Cc) values were reduced by 18% and 59% at dosage (Dch and Dca) of 4% at a consolidation pressure of 800 kPa. The secondary compression indices of chitosan and casein-treated soils fell below the normal range specified for organic soils and lay in the range of 0.01–0.017. The biopolymers also accelerated the consolidation process at all dosages (Dch) and 2% Dca. The hydraulic conductivity increased for all dosages of chitosan whereas it declined for all dosages of casein compared to untreated soil. The reliability analysis was conducted for biopolymer-treated soils and presented a rational approach toward the selection of a suitable liner. Chitosan failed to achieve a target reliability index of 3 whereas casein-amended samples attained values equal to and greater than 3 at all dosages and consolidation pressures at COV of Kmax = 20%. At all dosages, the casein-treated soils exhibited reliability index values greater than 3 up to COV of Kmax = 40% indicating the higher stability of casein mixes as a liner material.

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“…Some studies highlight the importance of reliability analyses applied to Geotechnical Engineering, which can be mentioned: Duncan (2000), Aoki (2002), Phoon et al (2003), Silva (2003), Silva (2006), Teixeira (2012), Li et al (2015), Souza and Albuquerque (2016), Neves and Reis (2017), Beloni et al (2017), Naghibi and Fenton (2017), Phoon (2018), Silva Neto andOliveira (2018), Haldar (2019), Romanini (2019), Romanini et al (2019), Velloso (2019) and Tang and Phoon (2019). Duncan (2000) presents that simple reliability analyses, involving neither complex theory nor unfamiliar terms, can be used in routine geotechnical engineering practice.…”

Section: Introductionmentioning

confidence: 99%

“…The authors also point to the importance of the reliability study for the correct assessment of the safety of any engineering design. Naghibi and Fenton (2017) investigate, based on Monte Carlo simulations, the relationship between the level of reliability of the isolated foundation element and the reliability of the set for deep pile foundations. Phoon and Tang (2018) state that the codes of geotechnical design are migrating to the concepts of design based on reliability (Reliability-Based Design -RBD).…”

Section: Introductionmentioning

confidence: 99%

Reliability and geotechnical safety applied to deep foundations in precast concrete piles - case study

2021

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The Brazilian standard pertinent to the design and execution of foundations, NBR 6122/2019, establishes that the safety inspection of foundations of a given project must be conducted based on compliance with specified safety factors. Safety factor verification is imperative to meet regulatory requirements; however, it is not enough to guarantee the safety of a foundation. As there is variability in the resistance and solicitation of the piles that make up a foundation, each safety factor value reflects a failure probability. Therefore, it is fictitious that the use of an adequate safety factor value implies the absence of failure risk. Thus, a reliability analysis, applied to a real building with an access ramp whose foundations are composed of precast concrete piles, based on the probabilistic moments, mean, and coefficient of variation, associated with the variability of pile resistance and solicitation, is presented in this article. The values obtained for the safety factors (2.14 and 1.98 for the building and the ramp foundations, respectively) and failure probabilities (1:2,244 and 1:3,131 for the building and the ramp foundations, respectively) implies that the project in question has an acceptable safety level. This article allows us to conclude that a small variation in the reliability index results in a large variation in failure probability; that a greater global safety factor does not necessarily lead to a lower failure probability and it becomes evident that this reliability analysis is a practical way, to manage the uncertainties inherent in foundation design, allowing rational decision making regarding performance.

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Target geotechnical reliability for redundant foundation systems

Cited by 16 publications

References 8 publications

Design of foundations against differential settlement

Design of foundations against differential settlement

Target reliability-based design optimization studies on cohesive soil amended with chitosan and casein for liner applications

Reliability and geotechnical safety applied to deep foundations in precast concrete piles - case study

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