Foundation On Sloping Site:
When structure is to be constructed on sloping ground, it becomes uneconomical to provide foundation of the whole of the structure at the same level.
The work can be economized by providing stepped foundation. In stepped foundation excavation of the foundation trench is done in steps. The depth of each step in excavation should not be more than the thickness of the concrete bed block to be provided under the foundation. The depth of each step should be multiple of even number of masonry courses.
The concrete beds meeting at the step should lap for length equal to the thickness of the concrete bed or twice the depth of the step, whichever is greater. At no point, the depth of the foundation should be less than 80 cm. This is essential from point of view of protecting the foundation from weathering effects.
If the bottom of different walls of the same structure happens to be at different levels following I.S.I recommendations should be adhered to:
1. Depth at no point should be less than 1 m, in case foundation is located in soils and 0.6 m if it is located in rocks.
2. Imaginary line joining upper surfaces of adjacent steps at step points should not have slope steeper than 2:1 (i.e two horizontal: one vertical).