MODEL FOR CAPACITY OF SINGLE PILES IN SAND USING FUZZY SETS. DISCUSSION. CLOSURE

Prediction of load-carrying capacity of piles in cohesionless soils has been and is still one of the most challenging problems facing geotechnical engineers. The problem is complex and difficult due to the lack of understanding of the phenomena of soil-pile interaction, and the limited quantity and inexact quality of subsurface soil information that can be provided for analysis. Current methods of estimating pile capacity have uncertainties that are not accounted for, including uncertainties in the method and in the data used to execute the method. Many of these uncertainties defy conventional quantification. The application of fuzzy-set theory, which can assist in accounting for these uncertainties, is offered as a solution. A model based on the theory of fuzzy sets that estimates ultimate capacity of single piles in sand is presented. Uncertainties associated with both input data and predicting methods are accounted for. In particular, qualitative information and subjective judgment are incorporated in the computations. A computer program that adopts the proposed model yields improved prediction of ultimate capacity for the cases studied.