Analysis of Piled Raft Foundation- A Geo-Structural Approach

Abstract

Tall buildings are constructed on pile foundation provide global stability of build- ing under the e ect of lateral loads. To reduce the overall and di erential set- tlements there has been an increase in number of structure using piled raft as foundation. The piles are mainly designed to take up the foundation loads and the raft only carries a small proportion the raft foundation performance alone does not satisfy the design requirements. Under these situations, the addition of a limited number of piles may improve the ultimate load capacity, the settlement, and di erential settlement performance, and the required thickness of the raft. An nite element method of analysis using ETABS and SAFE has been performed to estimate the settlement and load distribution of a large piled raft foundation. In this method, the raft is modeled as a thin plate and the pile and soil together are treated as interactive springs. Both the resistance of the piles as well as the base of the raft are incorporated into the model and it was found that there was more than 20% of settlements and di erential settlements and more than 10% of bending moment comapred to pile foundations. The analysis also highlights that the settlement of raft and bending moment decreases with increase in pile diameter and length.