Performance of micropiled raft in clay subjected to vertical concentrated load: centrifuge modeling

The overall behavior of a micropiled raft foundation (MPR) system is similar to a piled raft foundation where the load is transferred by both the raft and micropiles. However, there is no guidance available regarding the design of MPRs or indication of their performance. In this study, geotechnical centrifuge testing was conducted to investigate the behavior of MPR foundations in clay and evaluate their performance characteristics. The study evaluated the performance of MPRs compared to the isolated raft in terms of raft total and differential settlements; raft contact pressure; raft bending moment; and load sharing between the raft and the micropiles. The results showed that for the MPR configuration considered in the study, the raft carried 48% of the applied load. It was found that the Poulos-Davis-Randolph (PDR) method can be used to evaluate the performance of MPR for preliminarily design purposes with approximately 17% error.