Example $1$

A footing $3$ x $3$m is to be located at a depth of $1\mathrm{.}5$ m in a sand deposit, the water table being $3\mathrm{.}5$ m below the surface. Values of standard penetration resistance were determined as detailed in Table $1.$ Determine the allowable bearing capacity?

$($use y $=17$kN$/$m above the water table and Ysat $=19\mathrm{.}8$ kN$/$m$)$