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The design of shallow foundations typically proceeds by using the load and resistance factor design (LRFD) methodology to avoid various limit states with some probability. This paper looks at the sliding limit state of shallow foundations, and the sliding resistance factors required for the LRFD approach are estimated using reliability analyses of surface strip foundations. Cohesive and frictional soils are separately studied under wind loading conditions. Monte Carlo simulations are used to estimate the sliding failure probability of foundation designs on cohesive soils, and an analytical method is developed for frictional soils. The results indicate the existence of a "worst case" correlation length for cohesive soils, and the sliding resistance factor required to achieve target maximum lifetime failure probabilities is around 0.4–0.65 for moderate soil variability. For frictional soils, the required sliding resistance factor is about 0.5–0.85 for νϕ′ = 0.15. Overall, the sliding resistance factors recommended here agree well with the resistance factors of ϕgu = 0.6 for cohesive soils and ϕgu = 0.8 for frictional soils stipulated by geotechnical LRFD code provisions in Canada. The analyses can be used to estimate the reliability of current designs and can also aid the calibration of geotechnical design codes. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Geotechnical Journal is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The in situ behaviour of pile foundations is considerably influenced by variability in soil properties. Cone penetration (CPT) data are often used to determine the pile ultimate capacity. A wider range of values of the ultimate capacity are predicted when different CPT-based methods are used, as compared to using pile load test results. The present study considers inherent soil variability, measurement, and transformation variability. The undrained shear strength obtained from CPT data is considered to be a random variable. An approach to obtain load–settlement curves and the associated statistics from CPT data is suggested. Component reliability indices, based on ultimate limit state (ULS) and serviceability limit state (SLS) criteria, and system reliability indices combining ULS and SLS are evaluated. The variability in the pile–soil interface parameters and pile ultimate capacity is quantified in a Monte Carlo framework using the measured data. The effects of variability, scale of fluctuation, and limiting serviceability settlement on the reliability of pile foundations are also examined. A geotechnical database from the Konaseema site in India is utilized as an example. It is shown that the reliability based design of pile foundations considering spatial variability of soil, along with the variables associated with pile–soil interface properties, enables a rational choice of design loads. Le comportement in situ des fondations sur pieux est considérablement influencé par la variabilité des propriétés des sols. On utilise souvent les données de pénétration du cône (« CPT ) pour déterminer la capacité ultime des pieux. Une large plage de valeurs de capacité ultime sont prédites par différentes méthodes basées sur le « CPT comparées aux résultats d’essai de chargement sur les pieux. La présente étude examine la variabilité inhérente du sol, la variabilité de la mesure et de la transformation. La résistance au cisaillement non drainé obtenue par les données de « CPT est considérée comme une variable aléatoire. On suggère une approche pour obtenir les courbes charge-tassement et les statistiques associées des données de « CPT . On évalue les indices de la composante de fiabilité, basée sur l’état limite ultime (« ULS ») et les critères de l’état limite de commodité (« SLS ), et les indices de fiabilité du système combinant « ULS »et « SLS . La variabilité dans les paramètres de l’interface pieu-sol et de la capacité ultime du pieu est quantifiée dans un cadre de travail de Monte-Carlo basé sur les données mesurées. On examine aussi les effets de la variabilité, l’échelle de fluctuation, et la commodité limite de tassement sur la fiabilité de la fondation sur pieux. On utilise comme exemple une base de données provenant du site de Konaseema en Inde. On montre que la fiabilité basée sur la conception des fondations sur pieux prenant en considération la variabilité spatiale du sol, de même que les variables associées aux propriétés de l’interface pieu-sol, permet un choix rationnel de charges de conception. [ABSTRACT FROM AUTHOR]