Finite element simulation of piled raft capacity under different loading conditions

Document Type : Original Article

Authors

1 Department of Soil Mechanics and Foundations at faculty of engineering at Nub ,bani suief ,egypt

2 Professor, Civil Engineering Department, Faculty of Engineering - Minya University, Egypt.

3 Lecturer, Civil Engineering Department, Higher Institute of Engineering and Technology, El-Minia, Egypt

4 Associate Professor in Civil Engineering Dept., Faculty of Engineering, Minia University,

Abstract

In the general design of piled raft foundations, total loads are assumed to be taken by the pile. The contact pressure between raft and the soil is neglected. This may lead to loading piles with larger loads than they should be which could be reduced by sharing it with soil on which the raft is based. In this study, a trial was made to separate the amount of load carried by piles and that carried by soil. This was achieved by elevating raft one meter above ground surface. 3D finite element program PLAXIS 3D was used to simulate this case. In this paper, the effect of different parameters on carrying capacity of the piled raft were taken into consideration, such as pile spacing, pile diameter and raft thickness. Finally, to introduce an economical design for piled raft foundation, the settlement reduction ratio (SRR) and load sharing ratio of piles (αpr) were determined. The numerical results showed that the load carry by soil increases with the increases of pile spacing. In case of elevated piled raft, the load carried by piles was constant, although the pile spacing was increased under the raft thickness and pile diameter are constant. The discussion of results shows that the load carried by soil ranges from 7-14% of the total load, and maximum settlement at the elevated piled raft was higher than the maximum settlement at piled raft rested on soil with different pile spacing.

Keywords

Main Subjects

Files

Share

How to cite

Statistics