Q$3.$ A column foundation shown below is $4m2\mathrm{.}5m$ in plan. Given: $D_f=2\mathrm{.}5m,{}^{\text{'}}=28,c^{\text{'}}=30k\frac{N}{m^2}($FS$=2\mathrm{.}0).$ Determine the net allowable load the foundation could carry.

a$.$ Use Terzaghi's equation $($Note: Assume general shear failure in soil.$)$

b$.$ Using Meyerhof's bearing capacity general equation $($Use bearing capacity, shape and depth factors.$)$