Safety Assessment of a Shallow Foundation Using the Random Finite Element Method

In this paper, the reliability assessment of the bearing capacity of a shallow strip footing was conducted using a reliability index beta. In applicable standards (Eurocode 7) there is not presented any explicit method of an evaluation of characteristic values of soil parameters. Therefore some approaches of an estimation of characteristic values of soil properties were compared by evaluating values of reliability index beta. Method of Orr and Breysse, Duncan's method, two Schneider's methods and suggestion included in Eurocode 7 were examined. Design values of the bearing capacity based on these approaches were referred to the stochastic bearing capacity estimated by the random finite element method (RFEM). A probability distribution of the bearing capacity was estimated basing on 3000 simulations. Assessed probability distribution was applied to compute design values of the bearing capacity and related reliability indices beta. Conducted analysis were carried out for a cohesive soil. Hence a friction angle and a cohesion were defined as a random parameters and characterized by two dimensional random fields. Design values of the bearing capacity were evaluated for various widths and depths of a foundation in conjunction with design approaches DA defined in Eurocode 7.