Q$4.$ Figure $4$ shows a schematic cross$-$section through an offshore platform supported by $4$ legs. Each leg is attached to the centre of a square pad foundation on the seabed. In plan view, the pad foundations are located with their centres at the corners of a square with a side length of $56m.$ The horizontal load is a result of wave and wind load in the platform and it is applied to the centroid of the platform the seabed soil has a friction angle of $36$ and a saturated unit weight of $20k\frac{N}{m^3}.$ Determine the size of the foundation if a factor of safety on soil strength of $1\mathrm{.}25$ is applied to $tan{}^{\text{'}}.$