Evaluation of Nonlinear Load Sharing Ratio of Pile and Raft in Piled Raft Foundation in Cohesionless Soil

Load sharing ratio between pile and raft is an important parameter in designing the piled raft foundation. Load sharing ratio between pile and raft in piled raft foundation depends on many factors such as raft, pile and soil properties, spacing between piles, raft–pile area ratio, stiffness ratio of the pile, raft, and soil. In the present study, limited number of experimental study and extensive numerical analysis has been carried out to understand the behavior of piled raft foundation. Based on the experimental studies, the load sharing mechanism of pile and raft in a piled raft has been presented. Load sharing between pile and raft has been evaluated through experimental investigations on the model piled raft and three-dimensional finite element-based numerical analysis. The nonlinear variation of load sharing between pile and raft with foundation settlement has been discussed by determining the pile–pile and pile–raft interactions. The influence of soil stiffness, soil–raft stiffness, pile group area and length to pile diameter ratio on load sharing of pile and raft in piled raft foundation has been presented. The parameters of numerical analysis have been considered similar to the experimental studies for the purpose of comparison of results. The study will be useful in developing the load sharing model for estimating the nonlinear load sharing between pile and raft in a piled raft foundation. The paper describes the modeling procedure, material properties, parameters adopted in the analysis, and the results.