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## Saturday, May 19, 2018

Few months ago, I made a publication on the design of pile foundation founded on sandy soils by using Lekki Pennisula Lagos, as case study. Engr. Maxwell Azu (Nigeria) has submitted modifications to the post, and his inputs will be published soonest. We are grateful for his contributions.

You can read the original post by clicking HERE

In this post, I want to repeat the same calculation by using Prokon software. The design parameters are repeated below;

Depth of pile = 20 m
Diameter of pile = 600 mm

First layer (3m thick) - Loose to Medium Silty Sand, Cu = 0, Ï• = 32°, Î³ = 18.5 kN/m2
Second layer (1.5m thick) - Soft silty clay, Cu = 24 kN/m2 , Ï• = 28°, Î³ = 15 kN/m2
Third layer (4.5m thick) - Very loose sand,  Cu = 0, Ï• = 30°, Î³ = 18.5 kN/m2
Fourth layer (11m thick) - Medium dense sand,  Cu = 0, Ï• = 33°, Î³ = 19.5 kN/m2

Analysis Using Prokon
(1) Input Pile Dimensions as given below

(2) Input soil parameters

Note that the angle of internal friction has been modified by 0.75Ï• in the table above.

(3) Input factor of safety

(4) Input other design parameters and design load

(5) On analysis, the output below can be seen;

The total allowable load on the pile = 1258.01 kN
This can be compared to the load from manual analysis which is obtained as 1048 kN using DA1 and 1248 kN using DA2 of Eurocode 7.

However, once the appropriate soil parameters have been entered, Prokon can be trusted to give reliable result for pile foundations.

Other useful results;

However, study the previous example on this topic, and notice the differences in assumptions made. Your comments and reactions are highly welcome.