A New Model for the Prediction of Load Sharing in Piled Raft System—An Experimental Investigation

TLDR: In this article, an experimental investigation on piled raft foundation under vertical load was conducted to establish a new method for estimating the loads shared by the piles and raft using the interaction factors and the stiffness values of unpiled raft and pile group.

Abstract: The complex load sharing mechanism between the raft and piles involving various interaction effects makes the piled raft system very popular and economic for the foundations of high-rise buildings around the world. This study highlights the outcomes of an experimental investigation on piled raft foundation under vertical load to establish a new method for estimating the loads shared by the piles and raft using the interaction factors and the stiffness values of unpiled raft and pile group. From the results, the pile-raft interaction factor $$\left( {\lambda_{{{\text{p}} - {\text{r}}}} } \right)$$ is found to decrease initially and then increase as the raft settles further. However, the raft-pile interaction factor $$\left( {\lambda_{{{\text{r}} - {\text{p}}}} } \right)$$ is observed to increase initially and then decrease indicating a positive influence of raft-pile interaction on the load response of piles. The piled raft coefficient (αPR) is found higher, i.e., 0.83 initially and then converges to 0.51 when the raft settlement reaches a value equals to 10% of the raft width. The developed model is validated with the centrifuge test data available in the literature. Simplified expressions to calculate various interaction factors and the piled raft coefficient are also proposed on the basis of the experimental results.