Reliability-based analysis of strip footings subjected to an inclined or an eccentric loading

This paper presents a reliability-based approach at the ultimate limit state for the analysis of a shallow strip footing resting on a frictional and cohesive soil and subjected to an inclined or an eccentric loading. Only the soil shear strength parameters are modeled as random variables. The Hasofer-Lind reliability index is used for the computation of the footing reliability. The response surface methodology is employed for the assessment of the reliability index. The performance function adopted in the analysis makes use of the safety factor defined with respect to the soil shear strength parameters c and tanφ. For both cases of an inclined and an eccentric loading, it was shown that there is a load inclination and a load eccentricity for which the two failure modes involved by the loading case are not predominant. It was also shown that the hypothesis of negative correlation between random variables increases the reliability of the footing and that the failure probability is very sensitive to the variation of the angle of internal friction compared to that of the cohesion.