A square footing $$2m \times 2m$$ is built in a homogenous bed of sand of density $$\frac{1.9t}{m^{3}}$$ and having an angle of shearing resistance of $$38^\circ$$ The depth of base of footing is 0.8m below the ground surface. What is the safe load according to Terzaghi analysis which can be carried by the footing with a factor of safety of 3 against complete shear
failure? Assume $$\psi=38^\circ$$; $$N_{q}=65$$,$$N_{r}=80$$