Civil Insight: A Technical Magazine Volume 3 | Page 62

Gautam A. et al.
Civil Insight (2019) 57-63
Table 7. Distribution of axial load on piles using the Finite Element Method (FEM)
Pile Number
Axial Load (kN)
Pile Number
Axial Load (kN)
1
-586
9
880
2
-116
10
1370
3
285
11
1827
4
633
12
2083
5
173
13
1585
6
678
14
2043
7
1134
15
2460
8
1448
16
2820
3.3) Comparison of Axial Load Distribution
The comparison of the axial load distribution using the Classical Method and the FEM method is shown in
Fig 3. It can be seen from Fig 3 that the distribution of loads on piles are significantly different while using
the Classical and the FEM Methods. The Classical Method has the higest load at pile 16, which is 1910kN,
whereas for the same pile the FEM model predicted a load of 2820kN. Moreover, the FEM model predicted
negative axial loads at piles 1 and 2, which signifies that the piles are in tension. This might be because the
Longitudinal and Transverse moments are high enough to produce an uplift at one corner of the pile group.
It needs to be noted that the total loads carried by the piles for both the methods are same, only the
distribution of the load is different.
This result is supported by Ukritchon et al. (2015) in which he states that the axial load distribution for pile
group using the present Classical Method as expressed in Eqn (1) may not be sufficient for finding the
design forces on the piles, since this method can predict the pile loads smaller than those of more realistic
analysis, such as the finite element methods.
Fig. 3. Axial load distribution (kN) comparison between the Classical and FEM Methods
4) Conclusions
The major conclusions of the study are as follows:
x Although the total loads carried by the piles for Classical Method and FEM are same, the
distribution of loads on piles are different. The Classical Method has the highest load at pile 16,
which is 1910kN, whereas for the same pile the FEM model predicted a load of 2820kN.
x The FEM model predicted negative axial loads at piles 1 and 2, which signifies that the piles are in
tension, but the Classical Method did not predict tension in any piles.
62