FOOTINGS AT DIFFERENT LEVELS: STEPPED FOOTINGS.

When the existing ground is sloping and a wall is to be founded over it, it becomes highly uneconomical to provide the base of the footing at the same level all along the length of the wall. In such a circumstance, stepped foundation, such as the one shown in Fig. 3.34 may be provided. The foundation trench is excavated in steps.

The heighta of steps should preferably be not more than the depth of the concrete block and each step should be a multiple of the thickness of brick or stone course. The ovelap between tow layers of foundation concrete should be less than the vertical thickness of concrete.

Another problem of footing at two different levels is illustrated in Fig. 3.35 where a wal footing at the ground
floot adjoint a basement wall. It is common practice to lower the ground floor footings in gradual steps, down to the basement footing as shown.

By doing so, the naturai state of the subsoil is considered unaltered.

FIG. 3.34 STEPPED FOOTING ON SLOPPING GROUND.

FIG. 3.35 WALL FOOTINGS AT DIFFERENT LEVELS.