The ultimate load capacity is based on the formula:

$q,f_s=\frac{c_u}{FS}$ Where $f_s=$ allowable skin friction $(kPa)$

where: $Q_{\text{a}\text{l}\text{l}}=f_s$ Ashaft

$Q_{\text{a}\text{l}\text{l}}=$ allowable load $on$ pile $(kN)$

$FS=$ factor $of$ safety

Tomlinson charts are used to obtain $$ factors.

Use a Factor of Safety of $3$ to calculate the allowable skin friction.

The skin friction on the upper $2m$ of the pile shaft is ignored.

Find the capacity of a $600mm$ diameter concrete pile.