Possibilistic Reliability Assessment of Geotechnical Foundations using Databases: Application to Wind Turbine Foundations

Reliability analysis based on probabilistic methods is widely applied in geotechnical engineering. Several analytical and numerical methods have been developed to assess reliability based on the concept of occurrence of failure. Nevertheless, the critical aspect involves the input data used for performing these analyses. Common geotechnical engineering real-world problems deal with scarce and sparse information due to the lack of experimental data, which are not available to a sufficient extent and quality to be used to infer a reliable probability distribution. Therefore, non-probability and hybrid methods based on fuzzy logic and possibility theory as well as imprecise probabilities, have been developed. In this paper, a methodology based on the possibility approach has been proposed to account for an external local database to support the reliability assessment of wind turbine foundations. A Target Reliability Index is proposed to assess the fuzzy reliability. This cardinality is calibrated to be consistent with the probabilistic concept of failure probability, if data were of an ideal random nature. Moreover, fuzzy clusterization is carried out to determine fuzzy partitions to be used for the computation of the fuzzy limit state. The number of subclasses is related to a specific degree of understanding; therefore, the proposed method integrates the practitioner’s local experience for finalizing the decision-making process and assessing the reliability of the geotechnical problem. The reliability assessment of the bearing capacity for a wind turbine foundation is provided to highlight the potential of the proposed methodology.