Study on Piled Raft Foundation for Buildings

Abstract

In recent years there has been a significant rise in usage of high rise structures in India. Hence there arises a need for the foundations to carry heavy loads. The use of piled raft foundation is an effective way of minimizing both total and differential settlements and of improving the bearing capacity of shallow foundations. The be- haviour of piled raft is determined by the complex interaction between raft, pile and soil. Thus the understanding of these effects is indispensable for the reliable design of the foundation. Hence there is a need of appropriate procedure for the analysis and design of piled raft for achieving economic construction of foundation while maintain- ing satisfactory performance. The present work is an attempt in doing the analysis and design of piled raft foun- dation taking in to account all the interaction factors. An appropriate procedure for the analysis of piled raft is presented, two examples have been solved and results are verified with that of literature. A study on the analysis and design of piled raft foundation is done for a 20 storey building model on the layered soil in Ahmedabad city. Comparison has been made with piled raft having piles at normal location i.e. with uniform spacing and piled raft having optimum pile location. Parametric study is done by changing various parameters such as pile length and pile diameter to study its effect on Piled raft. Finally analysis and design of piled Foundation is carried out for same building and soil data and comparison has been made with that of piled raft to find the most economical type of foundation.