Reliability-based assessment of foundations under HM combined loading using random finite element method

Abstract

Indirectly dealing with uncertainties using safety factors is a common process in geotechnical engineering. Recently, the increasing computational ability of computers and advancement of numerical techniques have led to the development of numerical investigations attempting to account for uncertainties in a direct systematic way and to integrate them into geotechnical designs and assessments. The Random Finite Element Method (RFEM) combines random field theory with finite element method. RFEM is used in this paper to investigate the stochastic response of offshore strip foundations resting on a spatially variable soil considering horizontal and rotational (HM) combined loadings. Spatial variability of undrained soil shear strength is assumed in this study using homogeneous random fields. A reliability analysis, based on approximate expression of failure envelopes in H-M loading plane, is derived to calculate estimates of foundations probability of failure. Sensitivities of foundations reliability to the statistical characterisation of soil random property are as well assessed. Performed analyses highlighted the significant effect the soil spatial variability could have on reliability of strip foundations subjected to HM combined loadings.