Problem $4(30$ points$)$

A tall cylindrical silo carrying flour is to be supported by a ring foundation that can be designed as a continuous foundation. The inner and outer diameters of the ring foundation are $10m$ and $13m$ respectively. The soil at the site is entirely sand $)$ and the ring foundation is placed on the ground with $D_t=0.$ Determine the maximum net allowable silo load that can be carried by the ring foundation. Allow a factor of safety of $3\mathrm{.}0.$