An overhead water tank is supported at a depth of 3m by four isolated…

Question

An overhead water tank is supported at a depth of 3m by four isolated square footing of sides 2m each placed in a square pattern with ac/c spacing of 8m. Compute the vertical stress at the foundation level.

i) at the four footings and

ii) at the centre of one footing.

The load on the footing is $700\text{ kN}$. Adopt Boussinesq's point load approximation.